fa "81ARJO-DEDESSA IRRIGATION PROJECT FEASIBILITY STUDY REPORT CONTENTS OF THE REPORT SERIAu NO VOLUME NO PARTICULARS EXECUTIVE SUMMARY MAIN REPORT 2 3 Parr i - Report Pan ll - Maps & Drawings ANNEXURES VOLUME -1 SURVEY AND INVETIGATION (ANNEXURES - 1 to 3) 4 Volume -1 (a) Topograpnic Survey Geomorpnoiogical Studies & Geoiogicai & Geotecnmcai investigation Pan i - Repon 5 Volume -1 (b) Pan II - Append'ces 6 VOLUME -II NATURAL RESOURCES (ANNEXURES - 4 to 6) Forestry Energy & Catchment Development Plan VOLUME - III WATER RESOURCES (ANNEXURES - 7 to 11) 7 Volume - III (a) Meteorological & Hydrological & Hydrogeological Studies Dam & Appunenant Works 8 Volume - III (b) 9 10 Volume-III (c) 11 12 13 Volume - III (d) Pan I - Repon Pan II - Drawings Irrigation & Drainage Part I - Repon Pan II - Drawings Hydraulic Structures Pan I - Repon Pan II - Drawings VOLUME IV AGRICUTLRUE (ANNEXURES - 12 to 18) 14 15 16 Volume - IV (a) Soil Survey & Lana Evaluation Volume - IV (b) Agncultural Planning Volume - IV (c) Livestock Fisnenes Agricultural Mechanization & Agnculturai Marketing VOLUME - V ENVIRONMENTAL AND SOCIO - ECONOMIC ASPECTS (ANNEXURES - 19 to 25) 17 18 Volume - v (a) Environment Health & Socio-economic Aspects Volume - v (b) Organization & Management Physical Infrastructure Resettlement Financial & Economic AnalysisExecutive Summary Arjo Dedeui Irrigation Project May 2007 TABLE OF CONTENT I. INTRODUCTION 2. topographic survey 3. GEOMORPHOLOGICaL study 4. GEOLOGICAL and geotechnical investigations_ 5. FORESTRY .. 6. ENERGY STUDY.. 7. CATCHMENT DEVELOPMENT PLAN 8 9. METEOROLOGICAL and hydrological studies hy drogeological investigations 10. Dam and appurtemant xyorks. II. irrigation and drainage 12. SOIL SURVEY 13. LAND SUITABILITY 14. AGRICULTURAL PLANNING i 10 13 16 18 ...21 26 31 33 ...36 45 53 58 15. LIVESTOCK............................................................................................................ ............................................................ 62 16. FISHERY DEVELOPMENT_________________________________________________________ ________ _ ___ M 17. AGRICULTURAL MECHANIZATION.................................................................................... 68 18. AGRICULTURAL MARKETING............................................................................................... ...... ...... ~...................... 72 19. ENVIRONMENTAL ASPECTS_______________________________________________________ _________ ___ 76 20. PUBLIC AND ENVIRONMENTAL HEALTH___________________________________________________ ____ 81 21. SOCIO ECONOMIC STUDY___________________________________________________________ _________ _ u 22. ORGANIZATION aND MANAGEMENT................................................................ ............................._.................._9o 23. SETTLEMENT PLANNING____________________________________________ _______ ______ ____________ 95 24. PHYSICAL INFRASTRUCTURES______________________________________________________ 102 25. FINANCIAL AND ECONOMIC ANALYSES LIST OF TABLES 1 04 Table 6 1 Table 6 2 Energy demand in the arjo-Dedessa irrigation area, Tera joules Strategies for Development of Energy for Different Sectors 19 20 Table 11 1 hydraulic Particulars for Primary Secondary and Tertiary canals 40 Table 11 2 (jst of Structures on Primary Canals 41 Table 12 1 Area distribution of Major Soil Groups and Soil Units of arjo -Dedessa 40 Table 12 2 Physical ano Chemical Properties of the Mapping units 50 Table 131 Crops Suitability of Arjo-Dedessa Command Area 55 Table 13.2 Crops Suitability of Arjo-Dedessa Command area 57 Water Works Design L Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 1Executive Summary Ar jo Dedessa Irrigation Project May 2007 1. INTRODUCTION The E xecutive Summary or the Feasibility Study for Arjo Deaessa Irrigation Project has been presented in this report. The Feasibility Study has been undertaken by a multidisciplinary team consisting of experts from Water Works Design & Supervision Enterprise (WWDSE) Ethiopia as Lead Consultant and intercontinental Consultants and Technocrats (ICT) Pvt India as an Associate Consultant Several local consultancy agencies have also been associated with the study team the Feasibility study has been completed in accordance with Terms of Reference (TOR) which forms a pan of contract agreement for tne study executed between the client, Ministry of Water Resources (MOWRj, Federal Democratic Republic of Ethiopia (FDRE) and WWDSE, the Lead Consultant The Abbay Basin : Arjo-Dedessa irrigation Project is proposed on the River Dedessa, which is the largest tributary of Abbay (Blue Nile) nver The Abbay basin is by several criteria the most important river basin of Ethiopia It accounts for almost 20 percent of Ethiopia s land area, 50 percent of its totai average rainfall. 25 percent of its population, 39 percent of national cattle herd; and over 40 percent of cultivated land and crop production The Abbay River itself has an average annual run-off of about 49 BCM. The rivers of Abbay basin contribute about 62 percent of Nile total at Aswan. The basin is a Key surplus food producing area of Ethiopia. It is, therefore, critically important in terms of national agricultural economy and for national food security Arjo-Dedessa Imgation Project assumes importance in this background Dedessa River Sub-Basin : The Dedessa River is the largest tributary of the Blue Nile River in terms of volume of water contributing roughly a quarter of the total flow as measured at the Sudan border Draining an area of nearly 34.000 square kilometers, the Dedessa River originates in the Mt. Vennio and Mt. Wache ranges, flowing in an easterly direction for about 75 kilometers, then turning rather sharply to the north until it reaches the Blue Nile River The major tributaries of the Dedessa River are the Wama entering from the east, the Debana from the west, and the Angar from the east. Project Location : The project area is located in East Wollega, lllubabor and Jima Administrative Zones of Oromiya National Regional State. It falls between latitude 8o-30' 00 "and 8o-40’-00" N and longitude 36o.22'-00" and 36o 43' 00"E Fig 1 1 shows the zones and Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pn. Ltd.Executive Summary Ar Jo Dedessa Irrigation Project May 2007 woredas in which the different components of the project are located and Fig 1.2 shows the location and features of the project area The Components of Project: The Arjo Dessa Irrigation Project envisages the following i) An earth and rock fill dam of height 40 6 m in Jima Zone on main stream of Dedessa River before its confluence with Wama River The geographical location of the proposed aam site is logituae 36° - 40'-04"E ana latitude 8°-3T-12'"N (UTM 241836 E and 0940873 N) ii) Two canal systems offtaking on both banks from the dam to irrigate 13,665 ha iii) Watershed management plans for development of the catchmetn area. The Project area consists of the following three components i) Catchment Area The total catchment area of River Dedessa is 34000 sq km However, the catchment area at proposed dam site is 5280 Sq Km The catchment area extends over the following eight woreaas of Jima Zone. Limu Seka, Limu Kossa, Mana, Goma, Setema, Sigmo, Gera & Seka Chekorsa ana under three woreaas Gechi, Boracha & Dedessa of lllubabor zone ii) Dam site : The nght bank of the Oam srte is located in Wama Maribo Kebeie of Limu Seka Woreda under Jima Zone and the left bank is located in Chitu Bosona Kebeie of Gechi Woreda of lllubabor Zone. iii) Reservoir Area: The area of submergence at FRL is 8785 ha. It extends partly over fifteen kebeles. Out of these eleven kebeles are located in Borecha woreda under lllubabor zone and four kebeles in Limu Seka Woreda under Jima zone iv) Command area: The command area is located on both banks of river Deaessa. On the right bank it is located in three kebeles of Jima Arjo Woreaa under East Wollega Zone. On the left bank it extends over eight kebeles of Beaele woreda and four kebeles of Gechi woreda under lllubabor Zone. Thus the command area extends over fifteen kebeles of three woredas under two zones of Oromiya National Regional State The gross command area is 17,825 ha. and the culturable command area is 13665 ha. Out of this 7450 ha. is located on the left bank and 6215 ha on the right bank The average elevation of the command area is 1340 m as) and the mean annual precipitation in the command area is oehreen 1600 to 1800 mm Water Works Design & Supervision Enterprise 2 la Association with IntareontinenUl Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 The Consultancy Team : It consists of Water Works Design and Supervisions Enterprise (WWDSE) Ethiopia as Lead Consultant ano Intercontinental Consultants and Technocrats (ICT) Pvt. Ltd (India; as Associate Consultant. Several local consultancy agencies have also Deen associated their names and responsibilities are as given beiow • Desta Horecha Water Supply Engineering Service PLc - Economist - Watershed Specialist - Fisheries Specialist ■ Zena Engineering PLc - Hydraulic Engineer - Hydrogeologist • Generation Integrated Rurai Development PLc - Hydrologist /Meteorologist - Engineering Geologist - Infrastructural (civil) Engineer - Agricultural Marketing Expert - Energy Expert - Agnculturai Mechanization Expert - Settlement Planner • B & M Development Consultants PLc - Forestry Specialist - Organization and Management expert - Health Specialist • Yerer Engineenng PLc - Geotechnical Engineer Besides these, several local consultants, having vaiuaDle experience and knowledge of their discipline, have also been associated in their individual capacity Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt. Ltd. 3Executive Summary Arjo Dedessa Irrigation Project May 2007 Mobilization : The mobilization was startea even oefore signing of the agreement between the WWDSE (Ethiopia), the Lead Consultant and ICT Pvt. Ltd. (India) the Associate Consultant The Project Office was opened during December 2005 with the Project Manager The Office furniture and equipments were procured requisite staff members were engaged and office started functioning during December 2005 With a view to expedite the work, the local consultants for several disciplines such as soil and land evaluations, agriculture, socio-economic aspects, environment etc. were also mobilized. The Team Leader along with the Dam Engineer (Foreign; arrived from India on the 3rd February 2006. immediately after their arnval they along with local consultants for Dam Design Group undertook a visit to the Project sites during February 7-14, 2006 Other foreign ana local consultants were mobilized subsequently The Report: Studies have been undertaken for each sector/discipline in accordance with the provisions made in the Terms of Reference (TOR; ana a detailed report has been prepared for eacn sector The entire Feasibility Study has been organized in the following five broad sections and all the sectoral studies have been grouped under these broad sections i) Survey and Investigations ii) Natural Resources iii) Water Resources iv) Agnculture v) Environmental & Socio-economic Aspects Detailed studies have been conducted for all the sectors/disciplines as given in TOR and separate Detailed Report has been prepared for each sector/discipline. Based on these Detailed Reports, a Main Report has been prepared which contains the abndgea reports of all the Sectoral Reports and the important maps and drawings have been presented in an album accompanying the Main Report. A brief Executive Summary for the Feasibility Study has also been prepared which contains a very brief account of all the Sectoral Reports ana has been presented in separate volume for sake of convenience. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 4Executive Summary Arjo Dedessa Irrigation Project May 2007 However the detailed Sectoral Repons have been presented in different Volumes as Annexures to the Main Report Efforts have been made to present the Annexures of Sectoral Reports related to one broad section, as indicated above, in one volume However, depending on the size and for the sake of convenience of handling the Annexures related to Survey and Investigations have been presentea in two volumes; water resources in four volumes, agriculture in three volumes ana environmental and socio-economic aspects in two volumes Drawings relating to Dam & Appurtenant works, Imgation & Drainage and Hydraulic Structures nave been presented in separate volumes as Part II of the relevant Annexures Thus the Feasibility Study Report compnses the following: Executive Summary Main Report Part I - Report Part II - Maps & Drawings - Sectoral Reports - Available in twenty five Annexures in twelve separate volumes of repons and three albums of Drawings Water Works Design & Supervision Enterprise 5 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project The broad lay out of the Sectoral Reports is as follows May 2007 VOLUMES/CHAPTERS Chapter -1 VOLUME-I VOLUME-l(a) Chapter - 2 Chapter - 3 Chapter - 4 VOLUME l(b VOLUME - II Chapter - 5 Chapter - 6 Chapter - 7 VOLUME - III VOLUME-lll(a) SECTIONS I SUBJECTS Introduction SURVEY AND INVESTIGATION Topographic Survey Geomorpnologicai Studies Geological & Geotechnical Investigations Part I - Report Pan II - Appendices_____________ NATURAL RESOURCES Forestry Energy Catchment Development Plan WATER RESOURCES ANNEXURES Annexure - 1 Annexure - 2 Annexure - 3 Annexure - 4 Annexure - 5 Annexure - 6 Chapter - 8 Chapter - 9 VOLUME - III (b) Meteorological & Hyaroiogical Studies Hydrogeological Studies ' Chapter -10 Dam & Appurtenant Works Part I Report Part II Drawings VOLUME-III (c) Chapter -11 VOLUME - III (d) irrigation & Drainage Part I Report Part II Drawings Hydraulic Design of Canai Structures Part I Report Part II Drawings Annexure - 7 Annexure - 8 Annexure - 9 Annexure -10 Annexure -11 VOLUME-IV AGRICULTURE VOLUME - IV (a) Chapter-12 Chapter - 13 VOLUME - IV (b) Chapter - 14 VOLUME-IV (c) Chapter -15 Chapter - 16 Chapter - 17 Chapter - 18 Soil Survey Land Evaluation Agricultural Planning Livestock Fisheries Development Agncultural Mechanizations Agricultural Marketing Annexure -12 Annexure - 13 Annexure - 14 Annexure -15 Annexure -16 Annexure -17 Annexure - 18 VOLUME-V ENVIRONMENTAL AND SOCIO-ECONOMIC ASPECTS Volume V (a) Chapter - 19 Chapter - 20 Chapter - 21 VOLUME-V(b) Chapter - 22 Chapter - 23 Chapter-24 Chapter - 25 Environmental Impact Assessment Public Health Socio-economic aspect Organization & Management Resettlement Planning Infrastructure Development Financial & Economic Analysis Annexure -19 Annexure - 20 Annexure - 21 Annexure - 22 Annexure - 23 Annexure - 24 Annexure - 25 Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 6Executive Summary Arjo Dedeasa Irrigation Project May 2007 SURVEY AND INVESTIGATION Chapter 2 Chapter 3 Chapter 4 Topographic Survey Geomorphologic Studies Geological and Geotechnical Investigations Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 7Executive Summary Ar jo Dedessa Irrigation Project 2. TOPOGRAPHIC SURVEY May 2007 The planning, aesign and construction of water resources development projects require very detailed knowledge of the topographic features of the area Accordingly detailed topographic surveys have been earned out for the dam & appurtenant works, reservoir area and the command area, and based on the details of the survey topographic maps on different scales and contours at required interval have been prepared to be used for planning and design of various components of the project These are discussed below Reconnaissance Prior to the start of the detailed surveys a rapid reconnaissance survey was made of the area from the previous Master Plan Study document and 1.50 000 EMA base map to define the scope of work ano identify the irrigable area and dam site After that a hand GPS Garmin 1 2xl instrument was used for navigation and fixing the command area and dam site features to be surveyed Dy total station at later date Dam Site : After detailed topographic survey for the dam site the following topographic maps have been prepared i) Topographic map of dam site with one meter contour interval on following scales 1:500, 1:1000 and 1:2000 ii) Longitudinal profile at 15m interval along dam axis and also along lines parallel to dam axis at 25 m interval up to 500 m width on the both upstream and downstream of dam axis iii) Longitudinal profile along the center line of spillway, intake structures and proposed scheme of diversion. Reservoir Area The contour map with 1.0 meter contour interval and scale 1 10,000 for the reservoir area was prepared by generating contours with Global Mapper since the area was very inaccessible. The Digital Elevation Model (DEM) used for generation of one meter contour was based on 90 x 90 meter resolution image. National benchmarks were used to calibrate the contours Subsequently detailed ground topographies survey were undertaken to take cross-sections across the reservoir at five representative locations spread over entire reservoir Cross sections were prepared based on the actual topography survey and contours developed with Water Works Design & Supervision Enterprise 8 la Association with Intercontinental Consultants and Technocrats Pn. Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 DEM The comparison of the two sits of the cross sections of the reservoirs area shows that they are quite in agreement with each other This snows that process adopted is quite reliaole Command Area : The detailed topographic surveys for the proposed command area indicating all features & natural drainage lines have been carried out and the topographic maps on scale 1 10.000 with contour interval of one meter have been prepared Against a tentative command area of 16,800 ha as given in the TOR, the topograpnic surveys nave been carried out for 27,000 ha Altogether, seven topographic maps (Topographic map for Arjo Dedessa Irrigation Sheet No 1 to 7) have been prepared for the command area Sample Area : Detailed topographic surveys for sample area measuring about 500 ha have been cameo out and topographic maps on scale 1:2000 with contour interval of 0.5 meter have been prepared. These maps nave oeen utilized for detailed planning of the distribution system at micro level. Control Points / Benchmarks : A total of 72 control points were estaDlished, and concrete pillars were constructed at all these control points Permanent benchmark has also been established at all these points. Use of Software : The topographic surveys have been carried out with the help of Totalstations. The details of the topographic surveys oDtained from the field have been fed directly into the computer for processing ano preparation of maps on desired scale and required contour interval. The encoding of the surveying data to computer programme and processing to produce topograpnic maps, profiles, layouts and boundary mark have been done by using LIS CAD, Land CAD, surfer and civil designer software Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 9Executive Summary Arjo Dedessa Irrigation Project 3. GEOMORPHOLOGICAL STUDY May 2007 Various forms of channel changes such as widening, bank erosion, meander movement, and degradation are bound to occur in the downstream of a River where a dam is located Generally, these changes occur because of impoundment of stream flow and sediment by reservoir The objective of the Geomorphoiogiacl Investigations is to determine the landscape types around the proposed project area and to understand the fluvial geomorphology of the Didesa River. Understanding sediment types in the Didesa River and its channel-geometry would help in interpretations of these parameters Studying of discharge cnannei-geometry. stage-time, and channel-sediment could indicate whether the channel would be modified or resistant to changes resulting from trapping of sediment and regulation of stream flow by upstream reservoir Moreover it would help to explore feasible methods of reducing the economic losses and enhancing the environmental charactenstics resulting from the channel changes. Land-sat imagery and aenai photographs interpretation combined with brief on-site inspection were used to determine the geomorphology of Didesa irrigation Project area near the proposed dam site Previous geomorhoiogical investigations around the present project area nave to date barely scratched the surface. The Didesa Irrigation Project area and its environs are divided in to three physiograpmc regions. These are : The Didesa plane (1270- 1400m); uplands or chain of ndges (1400- 2500m); and plateau (greater than 2500m) and pediments The uplands, the plateau and the pediment are covered by Tertiary volcanic rocks and colluvial deposits has been transected by NE and NW running sets of lineaments. The Didesa plane is covered by alluvial soils They are mainly silty to sandy reddish brown and black cotton soils and are products of the break down of granitoids and basalts. The flood plain along the Didesa River consists of alluvial sands, silty clays and lacustrine deposit that cover the river valley and the terraces. The Didesa River around the proposed dam site is chracterised by an anastomismg narrow and deep valley with expansive well vegetated flood plain and associated wetlands The nver Water Works Design & Supervision Enterprise 10 ta Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessi Irrigation Project May 2007 represents a mature river, wnich has cut down to an approximately graded profile (Gentle gradient types) in such nvers, there is a little change in the elevation of the riverbed along the nver channel, and the bed forms are relatively stable. The Didesa River channel is moderately entrenched and is a free-formed alluvial reacn type (pool-riffle reach). Unregulated mature River fluvial systems like Didesa always tend towards a balance among charactenstics of water ano sediment discnarge and channel properties (size, shape, gradient, and bed ano bank matenal) It can be argued that the proposed reservoir in the Didesa River sub-basin would trap and store large amounts of sediment that would have been otherwise transported by the River. Water released from the reservoirs will be nearly sediment-free and would nave a tendency to acquire a sediment load consistent with discharge and channel conditions. The downstream reaches of the Didesa River have relatively cohesive banks and channel shapes and gradients appropriate for transporting only small amounts of coarse sediment (sand and gravel) Regulation of stream flow in the Didesa River system will reduce the occurrences of very large flow rates that normally are channel widening and erosive The availability and particle sizes of sediment down-stream from a reservoir will largely determine whether the reduced stream- flow will have a narrowing or a widening effect on a cnannel in the Didesa River, the narrowing effect of stable discharge will be counteracted by the suspended-sediment deficiency of the water and erosion can occur locally at discharge rates that otherwise would have been non-erosive. The reduction of sediment supply to the Didesa River will favor a long- term trend (decades to centuries) of reduction of channel gradient. If the Didesa River remains sediment deficient in the silt and clay sizes, the gradient reduction is likely to occur principally by channel degradation. If supplies of fine sediment approximating those of preregulated conditions become available to the river, gradient reduction can be expected to occur principally by increased meandenng (channel lengthening) Human activities that further shorten the channel length of the Didesa River, reduce its sediment load, or artificially narrow or degrade the present channel are expected to intensify the tendency for further channel changes. An imposed lengthening of the channel or an increase in the supply of sediment is expected to reduce the tendency for channel changes Water Works Design & Supervision Enterprise II tn Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Ar jo Dedessa Irrigation Project May 2007 Settlement, road construction, sand and gravel operations and similar human activities on the Didesa River flood plain would probably aggravate the tendency toward local, short-term channel cnanges associated with the proposea dam. Any flood-plain activity that disturbs the Didesa River alluvium and removes vegetation will iessen the resistance to erosion and releases both fine and coarse sediment to the river The fine fraction will be transported through the Didesa River system, whereas the coarse fraction will be added to the bed load Gravel oars formed from the bed load under certain conditions may in turn promote further channel cnanges, particularly local widening. A deficiency of sediment inflow tc the Didesa River due to the proposed dam is likely to cause continuing change in the channel Reduced inflow of coarse sediment probably will result into a decrease of cnannel gradient by bed degradation or increased meandering, and the supply of fine-grained sediment apparently insufficient to maintain alluvial banks that are resistant to erosion. Pnor to proposed reservoir construction and other intensive flood-piain activity in the Didesa River system, channel conditions of the River are unindicative of frequent cnanges. Significant rates of channel degradation of the Didesa River presently are not occurring, but may occur in response to long-term (decades to centuries) regulation by the proposed dam project. Channel degradation might be intensified more with extraction of sand and gravel. Natural or imposed changes that will shorten the channel or further reduce the sediment inflow to the Didesa River are expected to cause additional channel changes Water Works Design & Supervision Enterprise 12 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 4. GEOLOGICAL AND GEOTECHNICAL INVESTIGATIONS The geology and geotechnical investigation conducted included the following main activities • Geological mapping of reservoir and dam site area • Borenole drilling at dam site ana at quarry areas • Permeability testing within the boreholes for the dam site and installation of piezometers • Geopnysicai investigation along dam axis, spillway and saddle dam sites • Construction material prospecting and test pitting at selected locations • Laboratory testing The objective of the geotechnical and geological investigation conducted was to study sub surface conditions at major structure sites including the dam site. Identify suitable construction materials for use in the proposed dam, study the property of the construction materials, assess foundation permeability properties, identify the geology of the project site at feasibility level and preparing preliminary design to enable to conduct the feasibility of the project Rotary core drilling was used for investigation at the cam site, saddle dam sites and quarry sites and tne investigation was earned out by by the Construction Design Share Company (CDSCOj A total of 10 vertical electrical sounding (VES) were also conducted at the above locations. Geological mapping of reservoir area has been done making use of aenai pnotograph, topography maps and field work. Outcrops of rocxs were mapped along with joint onentations, spnng areas etc 12 borenoles were drilled with a total depth of 405m. Out of the 12 boreholes, 7 were drilled along the dam axis (Named AD1 to AD7), 1 at spillway (ADSp1), 2 at rock quarry sites (ADQ1 and ADQ2) and two along the saddle dam (ADS1 and ADS2j. Except two noles drilled along the dam axis at 60° to the horizontal, the remaining boreholes were vertical. In situ permeability of the vanous rock formations has been determined by the use of Packer tests and falling head method in the section of the boreholes. The total number of permeability tests conducted in boreholes was in the order of 61 Piezometers were installed in AD4 ana AD7 two of the boreholes for observation of ground water fluctuations Test pits were excavated at borrow areas to determine depth of suitable matenal available and to evaluate their engineering property by conducting laboratory tests from samples collected. The total number of tests pits manually excavated in 5 designated clay borrow areas was 53. Besides the test pits excavated in clay borrow areas 5 tests pits were excavated in sand quarry areas to determine extent of sand availability and to assist in collection of samples Water Works Design & Supervision Enterprise tn Association with intercontinental Consultants ano Technocrats Pn. Ltn. 13Executive Summary Arjo Dedessa Irrigation Project May 2007 Soil testing has been earned out at CDSCo laboratory to determine engineering property of various materials on samples collected from • Foundation areas • Impervious Clay material • Sand Filter material • Rock samples • Aggregate samples The geology of the project area is charactenzea by presence of crystalline rocks (igneous and metamorphic), which are covered by alluvial and colluvial deposits, residual soils and flood plain aeposits. Upstream side of the command area ana the reservoir area are covered by both volcanic at the top and metamorphic rock at the bottom under the soil cover Volcanic rocks cover the abutment of the Deaessa valley wnile going close to the valley bottom downstream of the Dedessa-Wama Junction the metamorphic rock is outcropping. Air pnoto and imagery interpretation at the desk level show that major faulting direction in the project area is NE-SW which is the direction of the aam axis. This major faulting direction is in concordance with the Adosa Hot springs of artesian well field in the reservoir area at about 4 Km upstream of the dam axis along the main Dedessa River Assessment of availability of vanous construction matenals suitable for the purpose of constructing a dam at close proximity to the proposed site was initially conducted visually Based on the initial assessment, the construction materials further studied included the following. • Clay material • Sand • Rocks for concrete aggregate • Rocks for shell material • Rocks for riprap etc Grain size distribution curve of the clay core material has been analysed and u/s ana d/s filter zones have been designed based on filter design criteria developed after extensive laboratory study carried out by Dunnigan, Talbot and Sherard The field investigations and results of laboratory test indicate that the material suitable for the construction of earth and rock fill dam is available in adequate quantities in the near vicinity of the proposed dam site. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 14M n ■ ■ a ■ ■ a a a a a a a ii ifl a a a a Executive Summary ArjoDedessa Irrigation Project May 2007 NATURAL RESOURCE Chapter 5 Forestry Chapter 6 Energy Chapter 7 Catchment Development Plan Water Works Design & Supervision Enterprise 15 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Ar Jo Dedessa Irrigation Project 5. FORESTRY May 2007 The total iana area of Ethiopia is aoout 1 14 million square kilometres The Ethiopian highlands represent about 36% of the total lano area while the remaining is in the lowlands (beiow 1,500 m a s I) Ethiopia is endowed with extensive land area, varied topography, soil, climate, plant and ammai biodiversity and ample surface and ground water resources About 53.3% of land area is covered with different types of vegetations which include high forest, plantation, woodland and shrub land and bamooo These forest resources have significant role in the production of different wood products for construction, energy supply, ecological conservation, climate protection, biodiversity conservation and improvement and maintenance of agricultural productivity However deforestation nas been a concern in Ethiopia - at least in certain localities - for a long time Information on the extent of forest cover and deforestation rates varies depending upon the source of data and type of analysis Sustainable management of forest resources is essential for continuous flow of different goods and service including water supplies maintaining species Biodiversity and protecting watersheds to ensure that forest resources can contribute to rural livelihoods, food security and income generation. Rampant deforestation nas resulted in degradation of fertile land and decline of land productivity loss of biodiversity shortage of forest products, expansion of desertification and frequent drought and famine. Thus, the issue of sustainability assumes crucial proportion when confronted by the twin challenges of environmental degradation ano rural impovenshment This study has Deen conducted to assess the existing natural recourses and their management in the watershed of Dedessa River which will oe used as source of water for proposed irrigation scheme to improve the productivity of the local communities to ensure food security and livelihood improvement. The study area falls under three Zones, namely East Wellega. Jimma ano lllubabor out of which the catchment area is located in Jimma and lllubabor Zones and the command areas is located under the three woredas Bedele, Gechi & Jima Arjo. The catchment area consists of undulating topograpmes with different ridges, valleys and steep slopes. The main objective of the study is to assess the past and current vegetation of the watershed areas and then to recommend the appropriate management system, conservation and development measures of the vegetation/forest resources to ensure sustainability and for the conservation of soil and water of the catchment. The scope of the study was to compile and Water Works Design & Supervision Enterprise 16 In Association with litereontinentaJ Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 analyse information pertinent to the potential contribution of forestry and forest resources in the protection of watersned with empnasis on their roies in the conservation of soil and water, and minimize deposition of silt in proposed reservoir Different metnods were used in the study, which include review of different literature, documents field assessments and visit to different institutions have been made to assess the existing forests resources in catchment and command areas, to identify current management situation of these resources ano identify potentials and constraints All Forest Priority Areas and patches of natural forests in the catchments are getting fragmented ano expansions of settlements in these forestlands have increased at alarming rates, which is the threat to the reservoir of the irrigation project Therefore the practical actions needed to further enhance the contribution of forestry in sustainaDie watersned management have Deen examined in the study Policy and programmatic issues that need further attention have also Deen hign lightened. Therefore, conservation of the existing natural forests, reforestation of the deforested lands and promotion of agroforestry has been found very essential for the protection of watershed areas conservation of biodiversity and provision of different goods and services for local communities Four working circles have been recommenced for the conservation ano development of forest resources, which include (i) conservation forestry, (ii) agroforestry/production forestry, (iii) forestry for recreation and tounsm, and (iv) multiple use forestry Objectives, components of activities and activities have been identified and elaborated for each working circle Thus, over four year period 18 state and 10 farmers’ nursenes will oe establisned to produce 56 million seedlings to plant about 16,800 ha. Boundary demarcation, management plan preparation and implementation of different activities shave been proposed for the conservation and development of the high forests in the catchment area. The total estimated budget for the conservation and development of forests in the catchment and command area is about Birr 41 62 million (USD$4.84million) over four years Water Works Design & Supervision Enterprise 17 In Association with Intercontinental Consultants and Technocrats Prt Ltd.Executive Summary Ar jo Dedessa Irrigation Project 6. ENERGY STUDY May 2007 The Arjo-Dedessa irrigation project is expected to surve a command area of 17,825ha. and there is potential for incidental hydropower generation of 3MW The irrigation scneme will increase food production and ensure food security for upto ten thousand households Cash and export crops may De cultivated in the area thus diversifying and enhancing local incomes and exports Surplus production from the irrigation development will support other value adding production such as agro-processing, transport and trade. Imgation development requires inputs from other sectors and its impacts will affect other sectors significantly As a result of a highly productive agriculture sector, the industrial, transport and service sectors will benefit in value added activities. The population engaged in the irngation scheme and others directly ano indirectly deriving benefits from it will require enhanced social services. Adequate energy must be delivered to the agriculture industrial commercial and social services to achieve the full benefits of the imgation development scheme Energy must be provided for agnculturai activities, agro-processing macnmery social service facilities, and for household uses As part of the integrated development plan for the imgation project the energy service study has been made to recommend actions for sustainable energy service delivery for economic and social services in the project area The study has thus evaluated energy needs and resources in the project area, indicated development strategies, and proposed specific project proposals. The main findings of the study are that housenold energy demand will be the single most important energy demand in the project area accounting for 95 percent of total energy demand Household energy demand will De mostly for cooking fuels, which will be met from wood and other Diomass resources Energy demand for the agriculture sector ^mainly diesel fuel) will be significant in the case where some agnculturai activities such as land preparation and harvesting are earned out by mechanized means (instead of the traditional human and animal based production). The agro industry sector will require petroleum products for processing equipment such as grain mills etc. Social services including water supply, health posts and clinics and schools will require electricity to deliver adequate services to the population. Water Works Design & Supervision Enterprise tn AuoeiitlOB with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 Total energy demand in the project area is estimated to be 995 Tera Joules for the first year or operation of the irrigation scheme. Total energy demand is expected to decline to 733 Tera Joules in year 10 The details are available in Table 6.1 This decline in demand can be expected if one of the proposed interventions (dissemination of efficient stoves) is carried out aggressively (100 percent of households using the efficient stove by year 10) Energy demand for the agriculture sector grows for the first three years and then stays constant. This is with the assumption that in the first ano second years only 25% and 60% of irrigation development respectively will take place and thereafter 100% development will take place in the third year Energy demand for social services will increase due to improvement in living standard as well as increase in population. Table 6.1 Energy demand in the Arjo-Dedessa irrigation area, Tera Joules Sector Fuel Year 1 Year 2 Year 3 Year 4 Year 5 Year 10 Household 980 997 1,007 1,002 973 681 Cooking Wood 961 977 987 981 951 655 Lighting Kerosene 19 19 20 21 22 25 Agriculture 12 29 48 48 48 48 Lana preparation Diesei 10 25 41 41 41 41 Harvesting Diesel 2 4 7 7 7 7 Agro-industry 2.5 2.6 2.7 2.8 2.9 3.4 Grain mill Electricity 1.8 1.9 2.0 2.1 2.1 2.5 Oil mill Electricity 0.6 0.7 0.7 0.7 0.7 0.9 Public service 0.29 0.30 0.31 0.32 0.34 0.39 Water Electncity 0.26 0.27 028 0.30 031 0 36 Health Electncity 0014 0.014 0.015 0.016 0 016 0.019 Education Electricity 0.010 0.011 0.011 0.011 0.012 0.014 Total 995 1,029 1,058 1,053 1,025 733 Findings from the demand analysis and review of energy resources have indicated the critical issues to be biomass energy supply to households and electncity for the social service sector The strategies listed in Table 6.2 are proposed to create a sustainable balance between supply and demand and also to enhance service quality for social services in the project area For the three highlighted interventions three project profiles have been prepared. Water Works Design & Supervision Enterprise 19 bi Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Ar jo Dedessa Irrigation Project May 2007 Table 6.2 Strategies for Development of Energy for Different Sectors Households 1 Increase sustainable production ana management of trees 2 Improve access for cooking fuels • Improve end use efficiency (efficient stoves; • Provide substitute fuels 3. Provide affordable modem energy for lighting and audio-visuals 4 Develop the hydropower potential of the dam and supply electricity for domestic uses Agriculture 1 Disseminate appropriate intermediate technologies for agriculture in the project area These would include cultivation planting, soil/water conservation, harvesting and post-harvest technologies 2. Improve access to petroleum fuels to the project area (for mechanized land cultivation, farm processing). Mechanized inputs may be made available to small holders on a hire basis.____________________________ Industry 1 Provision of electncity from hydropower from the dam 2. Development of petroleum storage facilities in the center of settlements to _ be established in the command area____ ____ ___ ________ ____ ____ Social services 1. Provision of electncity from hydropower from the dam 2. Provision of eiectncity from solar energy for water health ana education Water Works Design & Supervision Enterprise 20 In Association with Intercontinental Consultants and Technocrats Prt Ltd.Executive Summary Arjo Dedessa Irrigation Project 7. CATCHMENT DEVELOPMENT PLAN May 2007 Watershed management is the process of formulations and carrying out a course of action involving the manipulation of resources in a watershed to provide goods and services without adversely affecting the soil, vegetation and water case Watershed management helps to plan for optimum use of resources within it. The activities employed in the watersned as part of watersneo management programme help to ensure protection, improvement and rehabilitation of certain resources Prevention ano control of erosion, consequently reduction of sedimentation of reservoirs and other important assets is one of the advantages of watersned management Above all the improvement of land productivity and water availability at a certain location, thereoy improving the livelihood of the community is one of important aspects of watershed management In irngation development projects, the upstream ano downstream benefits of the community couid only be ensured through watershed management programmes considering the holistic approach in addition to the oenefits obtained from irrigation projects. The life span of irrigation projects depends on the management and development interventions cameo out in the watershed of the project, in this regard, treatment of the watershed with vanous soil and water conservation measures help to reduce sedimentation of reservoirs and field structures, moderate flooding of downstream side of the projects and ensure equity of benefits from development interventions. In this background, a study of Arjo-Dedesa watershed has been conducted as part of Arjo- Dedesa Irngation Project. The watersned onginates mainly from dense forest hills of Sigmo, Gera, Mana, Goma and hills of other Woredas and drains to Dedesa River, which is one of the tributary rivers to Abbay basin. Geographically, it is located Detween 36°02 and 36°46 East Longitude, ano between 7°4355 and 8°13 53 North Latitude The annual rainfall in the project area ranges between 1535 to 2214mm, average being 1835mm. The area is characterized by a humid tropical climate of heavy rainfall in its upper highlands. Almost 70% of the total annual rainfall is received during Kiremt. The maximum and minimum monthly temperature varies between 22.4 - 30.9° C and 8.4 - 14.4°C, respectively. The average wind speed is 56 km/day Monthly evapo-transpiration varies between 3.32 and 4.7mm/day The altitude ranges between 2006 and 3467m above sea level. The dominant agro-ecology is Wet Weyna Dega The watershed covers about 556,436 ha, including the reservoir area. Out of the total watershed area 33.5 per cent is cultivated, 15 per cent is grazing and 24.5 per cent is under forest or bush land cover. Of the total watershed area of 556,436 ha considered for watershed management program, excluding the reservoir area, 186571ha (33 5%) is cultivated, 82811 ha Water Works Design & Supervision Enterprise 2) In Association with Intercontinental Consultants and Technocrats Pn. Ltd.Executive Summary Ar jo Dedessa Irrigation Project May 2007 (15%) grazing, 136560ha (24 5%) is forest or bush land. 24829ha (4 5%) is open wood land 479ina (0 86%) as wet or swamp, 52314ha (9 4%) unused area, and the rest 68560na (12 3%) is under different uses such as settlement, cemetery gully, roads, etc Cultivated land is devoted to annual crops and perennial crops such as fruits and coffee Some cultivated lands exist in the form of cultivated land with scattered trees, cultivated land with trees and shrubs and seasonally cultivated lands Annual and perennial crops cover an area of about 80 2% and 19 8% of the total cultivated land, respectively The dominant slope is flat to almost flat (0 - 3%) and gently sloping (8 - 15%) in the order of 72.2 and 20 3 percent respectively This indicates that cultivation takes place on almost flat slopes Forest/bush area includes both naturally and artificially developed ones It accounts for aoout 24.5% of the watershed indicating the presence of Detter forest cover, about 8 times more than the percent forest cover for the whole country, which is 3% only The dominant slope of the forest or bush land is gently stoping (8 - 15%) and sloping (15 - 30%) in the order of 45.6 and 17.23 percent of the total forest/bush land, respectively Grazing land covers 82811 ha which is 15 percent of the total watershed area Grazing area is often found mixed with open wood tree stands The dominant stope of watershed is in the range of 0 to 3 percent, average being 2.1 percent, which is adequate slope to initiate erosion. Cultivation takes place in most of this slope range Soil and water losses from field are influenced by the steepness, length and snape of slopes. The shape of siope of the watershed is more of concave. Soils have particular importance in watershed management. The significances of soils characteristics, which influence the process in a watershed, are soil permeability, soil erodibility and compositions of nutrients that help vegetative growth These characteristics are influenced mainly by soil properties sucn as soil texture, structure, depth, organic matter content, soil fertility, soil reaction, soil colour and stoniness These properties of soils are highly important parameters in watershed development planning. The decisions taken dunng the planning process ought, therefore, to reflect at least a basic level of knowledge about the soil conditions According to FAO/UNESCO soils classification, six major soils have Deen identified for Arjo- Dedesa watershed; namely Vertisols, Fluvisols, Gleysols, Nitosols, Lithosols and Acnsols The characteristics of these soils are given in detail in catchment development plan report The land capability classes for Arjo-Dedessa watershed nave been identified based on the assessment of the major limiting factors (directly or indirectly) to use the land in a sustainable manner and the obtained class units are primarily categorized as SOIL CONSERVATION Water Works Design & Supervision Enterprise Ii Association with Intercontinental Consultants and Technocrats Pvt Ltd. 22Executive Summary Arjo Dedessa Irrigation Project May 2007 REQUIREMENT CLASSES. The major limiting factors considered for this purpose are one or two of land features including Slope Soil depth. Past erosion, Soil infiltration, Water-logging Top soil texture and Stoniness or Rockiness The assessment of each feature was made for each type of present iand uses in ranges of slopes Determination of the soil conservation requirement ciass is made following the procedures adopted for Ethiopian conditions by Escobedo (1988). The results of the land capability or soil conservation requirement classification show that the major limiting factor of the land use in the watershed is siope From categorization of the watershed according to land capability class aDout 197154 2ha (35.4%) is classified as class I Class I land is characterized by very good land in all aspects and very favorable for agncultural purposes if other minor factors such as acidity are not the limiting factors. Such type of land can be cultivated without any interventions. However preventive measures are of tantamount importance for protection from misuse and further cause of degradation through adjustment of management practices. An 18.5 percent of the watershed area is grouped under capability ciass II. About 118 percent of the watershed is classified as capability class III and the other major class is class IV which accounts for about 17 6 percent. Class VI accounts for 2.9 percent, followed by ciass VII that covers 0.6 percent The part of the watershed that is affected by water-logging or permanent or temporary swamps accounts for only 0.9 percent Class II land can be used for agricultural purposes with some adjustment in agronomic aspects such as crop rotation, strip cropping and manuring that helps to increase the yield of crops. The remaining capability classes except class I that requires simple agronomic and soil management measures, need some interventions, particularly vegetative measures and water disposing structures to get no of excess water in the form of run-off About 59.2 per cent of the watershed has slope less than or equal to 3 per cent. A study conducted on the biophysical and socio-economic conditions of the watershed shows that land degradation in the form of soil erosion, snortage of livestock feed as compared to the number of livestock, lack of community awareness in natural resources conservation and other socio-economic problems are enormous. Poor farming systems, lack of interventions to nalt soil erosion, deforestation are also prevalent predominantly In spite of the existing backlogs, efforts made in implementation of soil and water conservation activities in particular and watershed management in general are very poor, both at Woreda level and community level. However, some Woredas have tried to implement some measures in steep cultivated lands and where vegetation cover is adverse. Some of implemented measures include physical measures such as terraces, soil bunds, check dams, waterways, Water Works Design & Supervision Enterprise 23 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 cut-off drains and biological measures like plantation of vetiver grasses across the slope to halt run-off and inter cropping Pertinent to tnese problems, development interventions have oeen proposed. To mention few, the proposed interventions include soil and water conservation measures such as soil bunds, terraces, cut-off drains, SS dams, grass stnps, alley cropping and etc livestock management, rehabilitation of the old and establishment of new nurseries and others in this regard 82139 6 ha of land will be treated with soil bunds. 24867 ha with Tanya juu terraces. 32km of gully will oe treated with SS dams, and stone ano live cneck dams. Further development and improvement of 10 springs, treatment of 41232.2 ha with grass strips development of 954 Km new access roaos. renabilitation of 19 and establishment of 10 nursery sites from wnich 100 million planting materials are to be produced and preparation of 10,000 compost heaps, which are expected to benefit 10, 000 households have been proposed. These interventions are proposed to be implemented over 6 year’s period. Along with these interventions, strategies for implementation and institutions responsible for carrying out the implementation of proposed interventions have been indicated After implementing the proposed interventions as indicated in the development plan, it is expected that erosion in the watershed and sedimentation ano flooding in the downstream will be minimal and tolerable The existing traditional systems of resource management and awareness of the community would cenainiy be better Moreover througn implementation of agro-forestry practices at nousehold level. the encroachment of people to forest areas and destruction of trees in natural forests would be controlled, provided that the land use and administration by-laws and guidelines are in place A total cost of project has been estimated to be 301.3 million Ethiopian Birr over six years period of the project. These costs include costs for civil worxs, inputs required, salary, per diem and, transportation. If 10 per cent of this cost is covered oy the labour contribution of the community, the project investment would be about 271 17 million Ethiopian Birr Water Works Design & Supervision Enterprise 24 In Association with Intercontinental Consultants and Technocrats Prt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 WATER RESOURCES Chapter 8 Meteorological and Hydrological Studies Chapter 9 Hydro geological Stories Chapter 10 Dam and Appurtenant Works Part -1 Report Part - II Drawings Chapter 11 Irrigation and Drainage Part -1 Report Part - II Drawings Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd 25Executive Summary Arjo Dedessa Irrigation Project 8. METEOROLOGICAL AND HYDROLOGICAL STUDIES May 2007 The Dedessa sub basin is very important one, hydroiogically for the Aboay River being major flow contributing sub basin Nearly, 25 to 26% of the Aboay flows at the oorder is due to Deoessa sub Dasin Draining an area of nearly 34.000km2 it encompasses its tributaries like Wama Daoana and Angar, all of which have been investigated for ambitious irrigation ano power projects by vanous study groups in the past This is because of the hydrological virtues associated with this sub basin The Rainfall: With a vanaDility of rainfall from 2013 mm in DemDi station to 1417 mm at Agaro stations, the rainfall results in 1453mm over the proposed Arjo dam and its catchment These rainfall estimates in the study have been made by regionalization, followed by rigorous statistical anaiysis The data of the stations at Jimma, Dedessa. Bedelle Dembi and Agaro were included appropriately and after consistency checks and such checks on the adequacy in quality and length. The above mean annual rainfall, in the context of certain salient exceedance probability level years like 75%. 80% and 90% are respectively 1148mm, 1090mm and 951mm. Being unimodal type of temporal distribution, bulk of the rainfall (63%) occurs in the block of 5 months (May to September), ano as such, the proposed dam is to have season- to-season carry over The Agro climatic situation: The parameters like monthly mean temperature, relative humidity, wind speed and sunshine hours form the relevant inputs in the estimation of crop water requirements for the four different options of irngation development. The data of the stations Bedelle, Dedessa and Jimma were found to be appropriate, in representation and in quality for analysis by statistical techniques and hydrological methods On ascertaining these parameters, they were used in the estimation of the major input for crop water estimation, namely “Reference Evapotranspiration - ETo* The estimates of these parameters stand at the figures shown below, at annual mean level - Mean Temperature = 22.51°c - Relative Humidity = 75 51% - Wind Speed = - Sunshine Hours = - Reference Evapotranspiration (ETo) = 0.71m/sec 6.89hrs/day 1397mm/year Water Works Design & Supervision Enterprise 26 In Association with Intercontinental Consultants and Technocrats Pvl Ltd.Executive Summery Arjo Dedem Irrigation Project May 2007 The Water Resources; These could be establishea as a monthly time series of 45 years from 1960 to 2005 because of good data base availability in Dedessa and the neighborhood sub basins The data of the stations like Dedessa at Arjo, upper Dedessa at Dembi, DaDana near ADasma, Gilgel Ghibe near Ascendabo ano Gojeb near Shebe. all formed a good aata base for statistical analysis in estimating the aDove time series of flows at the proposed Arjo Dedessa dam site. The detailed monthly time series though available in the sectoral report, for ready appreciation, the annual flow estimates are given below - Mean year = 2328 Mm3 - 75% Exceedance probability year = 1729 Mm3 - 80% exceedance probability year = 1625 Mm3 - 90% exceedance probability year = 1384 Mm3 The historical time series, since may not form a spectrum of hydrological inputs for the simulation study, as recognized by the hydroiogical literature, a synthetic senes of length of 1000 years was generated, by the robust ano time tested, single site, multi season. AR1 type "Thomas-Fierring model” The simulations: These were carried out for four different irrigation development scenarios for about 14,000ha. The simulation modei was a tailor made type, developed in MS. Excel The MDDl was Kept at 1350 m, as dictated by irngation requirements The FRL was vaned between 1350.89m to 1351 87m. The synthetically generated flow time senes of 1000 years formed the hydrological inputs to the simulation runs. In all the runs, the irngation was successful at the appropriate norm, viz, 80% exceedance probability level; not only so, the irrigation is successful even in stringent years of 90% ano 95% exceedance probability levels. Hence, no ambiguity arises about the definite success of contemplated irngation development The dam, though being planned to be high and possessing good water resources, is constrained to have a small live storage to cater to the need of irrigation imposed situations Though not in the purview of the TOR, the Consultants carried out further simulations for exploring possible power generation over and above the irrigation For this, the Consultants developed another tailor made model, Fortran source coded, termed “Arjosim” Initially a couple of simulation runs were earned out with MDDL at 1350m and FRL at 1953m and at 1956m. At MDDL, two separate outlets were contemplated, one for irngation and another for power. Water Works Design & Supervision Enterprise 27 In Association with Intercontinental Consultants and Technocrats Prt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 A set of 8 simulation runs, with 4 different pattern of monthly releases indicated, so to say, a discouraging scenario The power generation could reach only up to 3MW at 97% exceedance level This stooa at 5MW and 7 MW in 65% and 50% exceedance level The exploratory simulations were to be earned out further with different FRLs, MDDLS and pattern of releases The model “Arjosim" was slightly recoded for the further runs. Three domains were set for these simulations, and a number of exploratory power generation runs were earned out The summary of the salient and optimal results of the domains, along with the nomenclature of these domains is as beiow Domain No. Domain Nomenclature FRL Power at 97% exceedance level 1 MDDL at a lower level of 1346m and assumed pattern of monthly releases 1370m 1372m 1374m 11.22MW 13.30MW 13.62MW 2 MDDL at lower level of 1346m, but releases based on decision support 1372m 1374m 1376m 1378m 16.49MW 17.20MW 17.90MW 19.50MW 3 MDDL for power at same levei as that of irrigation at 1350m. Power outlet separate. Decision support based releases 1370m 1372m 1374m 1376m 17 00MW 18.10MW 18.95MW 20.00MW The above simulation runs can be earned out for any set of combinations of MDDLs and higher FRLs for exploring higher power generation provided there is no constraint due to geology, geothechnical aspects, environmental and social aspects. Hydrologically, there is no constraint for such exploration. At present, from the above simulations, the optimal power will be 20MW in the domain 3 cases with MDDL at 1350 and FRL at 1376 which with a plant factor of 0.6 will lead to an installed capacity of 33.3 MW. In all the simulation runs, there is no indication of a major reduction in the sub basin flow of Dedessa. The present sub basin flows going to Abbay is about 14 053Mm3 and this will get reduced to 13,838Mm3. As such this reduction of 1.39% is a meager one, because of the proposed Arjo Dedessa dam. Floods: The approach was to estimate the various return period flood peaks by flood frequency analysis and to estimate such flood peak level corresponding to Probable Maximum Water Works Design & Supervision Enterprise 28 In Association with Intercontinental Consultants and Technocrats Pn. Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 Flood level by Hershfield tecnnique coupled with synthetic unit hydrograph, developed by Snyder's method In the flood frequency analysis the Generalized Extreme Value distribution (GEV) as well as Log Logistic distribution were explored The results of the later were selected Decause of closer suitability to Dedessa sub-basin. The flood peaks corresponding to salient return periods are as notified below Return period (years) Flood peat (m3/sec) 2 394 5 10 20 50 100 1000 500 575 654 771 10 000 871 1303 1948 3 The ProbaDle Maximum Flood nad a peax of 3690m /sec For the return period peaks, the respective flood hydrographs were developed cased on the JS Soil Conservation Services (SCS) dimensionless hydrograph development technique Design Flood; Out of the aDOve, for the design of the dam spillway, the 10,000-year return period hydrograph was recommended, instead of the Probable Maximum Flood hydrograph This is because of aiming at economy, in a situation, where the dam over topping and consequent failure will be confined to the irrigation command and the dam itself without loss of human lives at a large scale. The smaller return penod floods like 2 to 100 years return periods have been recommended for design of coffer dam, ano cross drainage works in the command area The appropriate one needs to be adopted for design of each component on its merit Flood routing: The 10,000 year return period hydrograph when routed through the reservoir becomes attenuated. Such attenuations for a coupie of spillway lengths were explored in the reservoir routing exercise The outflow peak for the given inflow peak of 1950m3/sec gets attenuated to 1165m’/sec for a spillway length of 125m. Sufficient fixation of MWL and free board has been taken care of, in the designs. Sedimentation: Suspended sediment concentrations had wide variations between 45mg/lit to 1670 mg/lit in the sediment observation in the Dedessa sub basin Relationships connecting discharge (flows) and sediment load were developed in the region for the stations in Guder Little Angar, Dabana and Abbay Rivers At site and regional approaches were developed to estimate the sediment load at the dam site using the flow data established With sediment Water Works Design & Supervision Enterprise 29 In Association with Intercontinental Consultant! and Technocrats Pvt Ltd.Executive Summary Ar Jo Dedessa Irrigation Project May 2007 3 3 density of 1 2gm/cc and with the assumption of oed load at 15% of the suspended load, the annual mean total sediment load at the dam site works out to be 0 775 Mm fyear The exercise Dy "Area Incremental Method" of USBR was carried out for distributing the sediment in the reservoir storage Tne results indicated that the volume of the reservoir gets reduced by 38 78Mm3 and 77 56Mm3 after 50 and 100 years of operation respectively The new zero elevation is far below the proposed MDDL of 1350m, provided at higher level due to command area constraints At this level, the dead storage provided is 874.67 Mm3, wnich is much more than the sediment accumulation of 77.56Mm , obtained after 100 years of operation of the dam As such, sediment interference with the operation of the dam is ruled out Water Quality: The quality of Dedessa waters seems to have no adverse impact on the irngation and crops proposed. Training Needs: The phase of development of various nver basins is very encouraging At this planning stage, there may not De encounters due to hydrological aspects. When tne basins become fully developed with vanous types of projects and with different objectives with trade off among them, the real time operation of these components of the basin system become very relevant A Judicial operation of a multi system will even offset expenditures on further projects. Such appropriate judicial operations on real time dunng flood or drought syndromes have immense benefits for combating floods or tide over of droughts The various basin authorities will have to possess a team of hydrologists involved in the real time operations of future multi systems in an integrated fashion The real time operations will have to be aided by modem soft ware, decision support system, flood forecasting network and telemetry tor data collection and transmission. The personnel (hydrologists) to De involved in such future real time operations are to be identified and provided training in these aspects in advance, perhaps in U.S or India. Conclusions: As sucn, Arjo Dedessa is a promising one with respect to irrigation development. The inbuilt power potential has to be studied in simulation models with the positive indications for higher levels from geological, geotechnical, design, environmental and social angles. Water Works Design & Supervision Enterprise 30 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project 9. HYDROGEOLOGICAL INVESTIGATIONS May 2007 Hydrogeological investigations have been undertaken in light of irrigation project for Arjo- Deaessa In fulfillment of this various methods and approaches have been used necessary aata pertinent to the hydrogeology sucn as geology, hydrometeorology, geomorphology Dorenole data, ana water point inventory water samples, etc have been collected, analyzed and interpreted The various approacnes and methodologies that have been applied include reviewing and analysis of secondary data including geological, hydrogeological and hydrometeorological data, field investigations to collect primary aata sucn as geological traverses, water supply schemes inventory, water sample collection for pnysico-cnemical and microbiological analysis, application of remote sensing and GlS techniques for data manipulation analysis and production of hydrogeological maps with different thematic layers. After applying all these techniques and methods, various maps of groundwater revealing nyarogeological units, water quality, and future prospects of grounawater have oeen produced Furthermore, fourteen piezometers/ooservation wells that will be used for groundwater monitonng Doth before and after implementation of the intended project have been located and recommenaed for drilling and construction Depth to groundwater especially in the proposed command area ranges from 2 meters to 5 meters below ground surface. After applying various methods for groundwater recnarge estimation, the annuai ground water recharge from precipitation in the area is found to be 246.99mm which works out to 17% of the annual precipitation Three major hydrogeoiogic units have been identified in the area, fractured and/or weathered volcanic rocks, alluvial deposits and delluvial deposits There are aiso some aquifers in Dedessa river valley that are attributed to weathered and/or fractured crystalline basement rocks. Water quality analysis has been conducted in light of domestic water supply and irrigation water quality According to Todd (1980), water is said to have poor irrigation quality if its SAR value is greater than 26; and fair imgation quality if its SAR value is between 18 and 26 Thermal groundwater emanating from deep volcanic aquifer sources and some water from weathered basement aquifers has high sodicity (maximum SAR value of 38 4). Hence, they have fair to poor quality for irrigation. However, they are limited to few areas only. The major part of the Water Works Design & Supervision Enterprise 3I In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Afjo Dedessa Irrigation Project May 2007 cold groundwater has excellent quality for irrigation as well as for domestic water supply if properly developed The apprehension of water logging ana the necessity of drainage during the execution of the irrigation practices after the implementation of the project have been assessed under different scenarios: stagnant groundwater condition, dynamic groundwater condition, and standard practices of some countries (e g USBR). Accordingly, it has been concluded that groundwater recharge due to the irrigation water is only 26 33% of the applied water Therefore, this amount will raise groundwater by 0 219m every year under dynamic groundwater condition. However the presence of natural drainages such as creeks ana streams in the command area will restrain the continual nse of groundwater by facilitating the flow of groundwater There are a number of such creeks and streams transversal to the command area in addition to the major natural drainage of Deaessa River itself Therefore, the apprehension of water logging in the area can be managed Dy ennancing natural drainages through the provision of well planned, constructed and managed surface drainages The possibility of salinity has also Deen assessed. However, the prevalence of high precipitation (average annual precipitation of 1452.9 mm), natural drainages (creeks and streams; ana some gentle slope in the command area counteracts salt accumulation by facilitating the fast leaching of the salt concentration 23% of the command area nas very gentle (2- 4% slope) to gentle (4- 6% slope) slope. The current and future prospect of groundwater in the area for various water supplies has also been evaluated. Potential groundwater areas have been delineated as a map at which test wells snail be drilled for future groundwater development. Water Works Design & Supervision Enterprise 32 In Associition with Intercontinental Consultants and Technocrats Pvt. Ltd.Executive Summary Arjo Dedessa Irrigation Project 10. DAM AND APPURTEMANT WORKS May 2007 A number of studies have been conducted since 1964 for the identification of potential dam sites on river Dedessa in Dedessa valley for development of irrigation and power in the country In this regard number of potential dam sites have been identified on river Dedessa during these studies However these studies were at reconnaissance level only and no detailed investigations were carried out. Amongst the various potential dams sites identified, the one located on Dedessa river about 1 5 km upstream of confluence of Deaessa river and Wama river near Arjo for impounding river inflows during monsoon and utilization of the same througn a networx of canal system for imgation in the command area is the first project that has been considered for development of the irngatea agriculture in the area. In the background ot previous studies the present dam site was identified earlier in year 2005 by a team WWDSE and MOWR experts after inspection of the site Subsequently a visit to the project site was made by the team of experts from ICT (India). The team inspected the dam site on nver Dedessa and the general topograpny of the area, the ndges forming the abutments and the saddle lines and after considenng various aspects recommended this site for taking up topographical surveys geological and geotechnical investigation, and other related studies at this site. Accordingly the Feasibility Studies Report of the Dam and Appurtenant Structures have been prepared in conformity with the terms of reference of the agreement. The entire Feasibility study has been organized in several chapters dealing with vanous aspects related to planning & design of dam such as topography, geological and geotechnical investigations, construction matenals ano their the availability and suitability along with the analysis of results of laboratory tests on samples. The dam nas been planned and designed as large dam on consideration of its height and storage capacity and therefore appropriate instrumentation has been proposed Spillway facilities, river diversion during construction, seismicity and hydropower generation have also been considered. The background and review of various studies earned out previously by USBR (1964), WAPCOS (1990) and BCEOM (1999) have been adequately discussed in the study The relevant findings contained in their studies are presented with respect to their planning and conceptualization of the project. The site selection, onentation of the dam axis with respect to Water Works Design & Supervision Enterprise 33 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Ar jo Dedessa Irrigation Project May 2007 the right ana left ridges of the abutment, ground topography and type of dam selected have also be discussed Geology and the geological structure of the project area in general and of the aam site area in specific including that of the saddle lines for iocation of spillway facilities and irrigation outlets for the primary canais have Deen discussed in detail. The rock on both abutments and foundation of the aam are reported to be highly jointed and fractured and calls for grouting treatment Two E-W Lineaments cross the dam axis at the foot of both right and left abutments Besides one lineament with E-W direction is also identified at the middle of right abutment oeyona the point of aam axis. These require to be investigated furtner regarding their areal extent and seepage potential and treatment. The foundation treatment for dam, stnpping under the dam, shell, curtain grouting and grouting requirements for seepage control have been dealt with in the report. The considerations for adopting dam height have been discussed appropriately The free board requirement under normal reservoir level and under maximum water level situations have been considered along with the computations The free board has been computed by T Savilles' method, which is commonly used for free board computation for earth and rock fill dams The feature of the dam design, parameters, and zoning of aam section including foundation treatment of the dam section, safety requirements, slope protection works and slope stability analysis for the dam section under different loading conditions considering the seismic effect as per codal requirements have been discussed in detail at appropnate places. The construction material required for the dam and appurtenant structure, identification of prospective borrow areas in close proximity to the dam, laboratory testing of samples from borrow areas for their properties to establish their suitability for use in core, shell, aggregates and filter have been dealt with in the Feasibility Report. From height as well as storage consideration the dam can be designated as large dam ana hence instrumentation of dam to monitor its behavior during construction, initial filling and during its functional life time has been proposed. Surface settlement and. parapet settlement points, pore water pressure, seepage measurement, horizontai and vertical movement measurements, earthquake measurement instruments have been also proposed Water Works Design & Supervision Enterprise 34 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 Spillway facilities, its location, layout and design inflow flood discharge have been described in the report For the sake of economy and considering remote location of the dam structure the loss of human life would probaoly be minimal as such routed flood discharge of 1156 cumec corresponding to 1 in 10,000 year return period which is greater than half of PMF has been considered for its design computation for different spillway width and flood lifts and finally spillway width of 125 0m with a flood lift of 2 62 m nas been adopted Hydraulic design of spillway structure with ungated Ogee type weir and stilling basin for energy dissipation arrangement has oeen considered. Hydraulic model studies for the performance behavior of the spillway structure has been proposed before taking up actual construction. The nyaraulic design computation of irrigation outlets for both the right bank and left bank pnmary canals has been done. The arrangement for nver diversion during the construction period has also been discussed The abutment rock being highly fractured and jointed, diversion of flood waters in the river through a diversion tunnel in one of the abutments has not been considered favourably. As such RCC twin barrel of size in the river channel near the nght abutment to pass the monsoon floods during the construction period have been provided. For the diversion of monsoon nver flows dunng the construction period routed inflow design flood of 1 in 100 year return penod nas been considered with upstream cofferdam at EL 1340.6m and a free board of 1.5 m has been provided A construction program spread over period of 4 years for completion of different components including completion of right and left bank imgation outlets has been proposed. As the dam site is located in seismically less dangerous area and also there are no earthquake records available, a reference was made to the Geophysical Observatory, University of Addis Ababa Ethiopia for seismic coefficients to be adopted for the design of dam. In their report they have enclosed "Seismic hazard map of Ethiopia and its Northern and Eastern Neighboring countries" for a return period of 1 in 300 years The contours in the seismic nazard map indicate peak horizontal acceleration as a fraction of g‘. The nearest contour to Arjo-Dedessa Dam of 0.05 of peak horizontal acceleration («H) has been considered The vertical acceleration (qcV) is considered half of horizontal acceleration i.e 0.025g and the same have been considered in the stability analysis of the dam Water Works Design & Supervision Enterprise 35 bi Association with Intercontinental Consultants and Technocrats Pn. Ltd.Executive Summary Arjo Dedessa Irrigation Project 11. IRRIGATION AND DRAINAGE May 2007 Arjo-Dedessa Irrigation Project, comprising two Primary Canals offtaking on either side of a 40.6 m high earth and rockfill dam on River Dedessa proposed to be located 1 5 km upstream of the confluence with river Wama, has been planned and designed basically as an irrigation project The lay out of the canal system has been planned sucn that it fits appropriately into the prevailing topograpmcal features The system has been designed to make available irrigation water in adequate quantity to cater for the needs of the various crops which have been proposed to be adoptea in the command in tne light of prevailing climatic factors, soil charactenstics, and other socio and agro-economic conditions Location: Geographically the project area is situated between 8°-30 -39" to 8°-39'-32" North latitude (941399 & 957395 Northing) and between 36°-22'-53" to 36°-38'-15" East longitude (211867 & 240240 Easting) The command area is located in Bedele & Getchi woredas of lllubabor zone and Jima Arjo woreda of Eastern Weiega zone under Onmiya Regional State Command Area: The gross commana area is 17,825 ha out of whicn 10,998 ha is on left bank and 6827 ha on the right bank of the river Dedessa The culturable command area is 7450 ha on the left bank and 6215 ha on the right bank, total Deing 13,665 ha, which is 76.6% of the gross commana Topography: The elevation in the command area varies between 1348 to 1330 a.m.s.l. The detailed soil survey has been earned for a gross area of 36,765 ha against the identified gross command area of 17825 ha. The results of detailed soil survey show that about 45% of the command area is level (0-1% slope;, 7%area nearly level (1-2% slope), 28% of the area is having very gentle (2-4% slope) and 20 % of the area gentle (4-6% slope). In general the command area is having a rolling topography On Doth sides of the river there are some isolated hills rising above the average level of the plain. Soil and Land Suitability: The results of the detailed soil survey of the proposed command area indicate that the most extensive soils of the project are vertisols largely occurring in the bottom of the valley. The well drained reddish brown soils, which include Luvisols, Cambisols and Nitisols are mostly located on upland of isolated hills ana gentle undulating to rolling land The soil in the command area is very deep. The fertility status of the soils of the project area is medium to very high. The major constraints of the area are steepness, poor drainage of the bottom land of the valley, uneven surface, compaction and vegetation cover The results of Water Works Design & Supervision Enterprise li Association with Intercontinental Consnituu and Technocrats Pvt Ltd. 36Executive Summary Arjo Dedessa Irrigation Project May 2007 land suitability evaluation reveai that sufficient suitable land is available for different cops proposed in the command area according to the proposed cropping pattern Canal Outlets: Two outlets (intake structures for canal) - one on either side - have been provided to cater for the needs of the primary (mam) canals proposed on either bank of the river. Right Primary Canal: Taking off from the outlet provided at saddle No 2 with a head discnarge of 7.52 m/sec, the total length of Right Primary canal is 44 km and it is a contour canal in its entire length. In upper reach the command area lies on both banks of River Wama, which is a major tributary of Dedessa River joining it downstream of the proposed dam After taking off from the rignt outleft (Intake structure; provided in the saddle no 2. the alignment of Right Primary Canal runs parallel to the course of River Wama in upstream direction on its left bank and then it crosses the Wama River at 8.5 km through an aqueduct There after the alignment runs on the right bank parallel to the course of River Wama and River Dedessa in downstream direction. Left Primary Canal : The Left Primary Canal takesoff from the left outlet located near the left abutment of the dam. The head discharge is 9.015 m /sec and the total length is 60 km. In its initial reach, it is aligned on steep slope covering only a very narrow command between the hills and the river Dedessa Gradually the command area widens ano again in the end it narrows down. Full Supply Level : The full supply level (FSL) of both Primary Canals - Right and Left - has been fixed at EL 1348 amsl. This has been fixed with the consideration of providing gravity irrigation in the proposed command area This FSL nas been fixed such that no area which is suitable for cultivation, is left out of command ano at the same time, the canai does not have unnecessary idle length and either excessive cutting or filling Macro-Irrigation System: The lay out of macro-irrigation system, compnsing the primary and the secondary canals, has been planned on the basis of the contour map available at a scale 1:10,000. The Primary canals are contour canals, where as the secondary canals have been aligned on ridges between two natural drainage channels The alignments of the secondary canals have been marked on the map along with the Primary canals However, the layout for 3 Water Works Design & Supervision Enterprise 37 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 secondary canals (except in the sample area) is only tentative to indicate the broad planning of the irrigation system. Normally the Primary canals (equivalent to main canal) and Secondary canals (equivalent to distributary) form the part of macro-irrigation system Micro-Irrigation System for Sample Area: The planning for micro-irrigation system comprising secondary, tertiary, and quaternary canals has been done for the sample area only The sample area is located under the command area of secondary canal no RS-16 (340 ha) ana RS-17 (416 ha). In the selected sample area, complete planning for tertiary and quaternary canals nas been done on a topographic map at scale 1 5000 Secondary Canals: As dictated by the topographic features, one secondary canal has been provided between the two natural streams The secondary canals offtake from the Primary canals on only one side. A nead regulator has been provided in the Primary canal at its offtake The secondary canals have been aligned on the rioges and tertiary canals are offtakmg secondary canals on either side There are 45 secondary canals having a total length of 47 19 km under Left Primary Canals and 40 secondary canais having a total length of 49.37 km under Right Pnmary Canals Tertiary and Quaternary canais: The layout of the sample area, available in the album of drawings, snows the layout of tertiary and quaternary canals along with the irrigation blocks While tertiary canais are taking off on both sides of secondary canal, which is aligned on the ridge, the quaternary canals are taking off from the tertiary canals only on one side because of constraint of topography as the land is slopping only on one side of tertiary The average size of the irrigation blocks is about 20 ha. though there are some exceptionally big block having an area of 37 ha and exceptionally small block of 6 to 10 ha There are 37 number of Tertiary canals having a total length of 24.228 km in the entire sample area Out of this 15 number of tertiary canals having a total length of 10.845 km are under secondary canal RS-16 ano 22 number with 13.383 km length are under secondary canal RS-17 Crop water requirement: The crop water requirement has been calculated on the basis of observed climatic data as estimated for the command area by Penman-Montieth Approach with the help of computer programme available in FAO Irrigation & Drainage Para No 46. The crop Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 38Executive Summary Arjo Dedessa Irrigation Project May 2007 water requirement nas been calculated for a cropping intensity 173% which has been assumed to prevail in final pnase of development The losses in different components of the canal system and their efficiencies have also been studied An earthen (unlined) canai system has been adopted in view of water availability and overall economics of the project The canal capacity has oeen fixed for the requirement of water dunng peax period on the basis of 24 hours running of the canal system A field application efficiency of 0 8 has been adopted for paddy in which irrigation water is added in field wnere water is already ponded In case of other crops a field application efficiency of 0 65 nas been adopted As regards conveyance efficiency, based on experiences in this country and other countries of the world it has been assumed that the total losses from head of primary canal to the end of quaternary canal will be 37.5%, which means the conveyance efficiency will be 62.5%. Accordingly the overall irrigation efficiency nas been adopted as 50% for ponded crop (paddy) and 40% for other non-ponded crops Over ano above the peak requirement of irrigation water the design capacity of the different components of the canal system has been increased by a flexibility factor - varying from 10% for pnmary canal to 25% for the quaternary canals Hydraulic Design: The different components of the canai system have been designed as unlined channel considenng the channels flowing for 24 hours The hydraulic design of canai system has been done for the capacities as worked out on the oasis of the crop water requirement in accordance with the proposed cropping pattern and peak crop-water requirement. While carrying out the hydraulic design the following parameters have been taken into consideration in accordance with the critena for Planning and Design of Irrigations system as already submitted in Final Interim Report. - Manning's formula for calculation of velocity - Rugosity co-efficient - Permissible Velocity - Longitudinal Slope - Bed width - depth ratio - Critical velocity & CVR The hydraulic parameters, as calculated, are given in Table 111 for the following components of the canal system: Water Works Design & Supervision Enterprise In Association with Intereonttnental Consultants and Technocrats Pvt Ltd. 39Executive Summary Arjo Dedessa Irrigation Project May 2007 - Primary Canais at neaa & tail reaches - Secondary Canals (RS-16 & RS-17) at head reach - Tertiary Canais for average condition. Table 11.1 Hydraulic Particulars for Primary Secondary and Tertiary canals Structures on Primary Canals: Different types of structures have been provided on the different components of the canal system. The types of structures provided on Primary Canal include controlling/regulating structures, cross-drainage works and bridges. Since the Pnmary Canals are contour canals, a large number of different types of cross-drainage works nave been provided which include aqueduct, canal syphon, supper passage etc The total number of structures on Pnmary canals are 158, out of wmcn 68 are on Right Pnmary Canal and 90 on Left Pnmary Canal. Details are available in Table 11.2. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 40Executive Summary Arjo Dedessa Irrigation Project May 2007 Table 11.2 List of Structures on Primary Canals Number of Structures Total s No Structure details 1 Right Pnmary Canal Left Primary Canal 10 Control structures 11 head regulators for secondary canal 37 39 76 12 Head regulators and cross regulators with foot bridge 3 7 10 1.3 Escape regulator 1 1 2 Sub Total ♦1 47 88 2.0 Cross Drainage works 2.1 Aqueducts 2 4 6 2.2 Siphon Aqueaucts 17 16 33 2.3 Canal sypnons 4 2 6 2.4 C D works with canal in earthen embankment 5 15 20 Sub Total 28 37 65 3 Bridges 3.1 Road Bridge 4 6 10 3.2 Foot Dridge 3 0 3 Sub Total 7 6 13 Grand total 76 90 166 Structures in Sample Area: Planning and design of micro-irrigation system nas been done in the sample area, wnicn comprised the command areas of secondary canal Rs-16 ano Rs-17 under the Right pnmary canal. As discussed in the previous section the micro-irrigation system i.e. canal system in sample area consists of the following: i) Secondary canals - Rs - 16 & Rs-17 ii) Tertiary canals - off taking from the secondary canals RS-16 & RS-17 ili) Quaternary canal - off taking from Tertiary canals Besides the nead regulators for the secondary canals whicn have been provided on Primary canals, the following structures have been provided for micro-irngation in the sample area i) Adjustable Proportionate Modular (APM) type Outlet for Tertiary canals on secondary canal. ii) Drops in Secondary & Tertiary canals. iii) Parshal Flume in secondary canals for measuring discnarge iv) Duckbill weir in secondary and tertiary canals for maintaining FSL and functioning as escape v) Road/Foot bridges on secondary canals. vi) Tum-out on tertiary canal to facilitate diversion of flow in the quaternary canals. Water Works Design & Supervision Enterprise in Association with Intercontinental Consultants and Technocrats Pvt Ltd. 41Executive Summary Arjo Dedessa Irrigation Project May 2007 Drainage System: Drainage is considered an integral part of the irrigation system Therefore, it is proposed to provide detailed surface drainage system both at macro and micro levels Hydrogeological study indicates that there is no apprenension of rise of ground water necessitating sub-surface drainage However it suggests the need and necessity for providing elaborate surface drainage system Therefore, the surface drainage system for the project should oe planned, designed constructed and maintained properly so that it functions efficiently and effectively If proper surface drainage system is implemented and its proper functioning is ensured, there will be no appreciable nse in ground water necessitating implementation of sub surface drainage system. With this end in view detailed planning and design of surface drainage system has been done Macro-Drainage System: River Dedessa divides the command into two pans and acts as master drainage channel. There are a large number natural streams passing through command area on both banks and joining the river Dedessa There are 25 number of natural streams on right bank and 31 number on the left bank. Dictated Dy the topographical features 40 secondary canals have been provided on the right bank in general one secondary canal has been provided for the area Detween two adjoining natural drainage streams. However there are several situations wnere two secondary canals nave been provided between two natural drainage channels as there are two distinct ridges with a marked valley without any existing natural drainage channel. In such situation a secondary drain has been provided between the two secondary canais. Thus there are 39 secondary drains on the right bank out of which 25 secondary drains are natural existing ones and remaining 14 will be constructed. Similarly there are 45 secondary canals and 35 secondary drains on the left bank. Out of these secondary drains 32 number of natural and balance - 3 number of drains are proposed for construction. The secondary drains - Doth naturally existing ano proposed to be constructed - have been numbered serially as RSD-1,2,,.. 49 for ngnt bank command and as LDS-1.2,............ 35 for the left bank. Locations of these drains have been shown on map available in the album of maps. Altogether 14 secondary drains with length varying between 637 m to 2.589 km (with total length of 20,205 km) have been proposed to be constructed on right bank. On the left bank only three secondary canals with length varying between 645 m to 1240 m (with total length of 2.693 km) has been proposed to be constructed. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 42Executive Summary Arjo Dedessa Irrigation Project May 2007 Micro-drainage System in Sample Area: The sample area whicn has been selected for the planning and design ot micro-irrigation & micro-drainage system consists of command area of two secondary canals RS-16 & RS-17 and it is bounded by two naturally existing arainage stream numbered RSD-14 and RSD-16 Since there are two distinct ridges in the sample area, so two secondary canals v/z RS-16 and RS-17 have been planned and in between the two seconaary canals one secondary drain numbered RSD-15 have been provided, which has been aligned along a existing distinct valley The layout of micro-drainage system has been shown along with the layout of micro irrigation system in the map available m the album of maps One tertiary dram for each tertiary canal and one quaternary drain for eacn quaternary canal have been provided Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 43Executive Summary Arjo Dedessa Irrigation Project May 2007 Agriculture Chapter 12 Soil Survey Chapter 13 Land Suitability Chapter 14 Agricultural Planning Chapter 15 Livestock Chapter 16 Fisheries Development Chapter 17 Agricultural Mechanization Chapter 18 Agricultural Marketing Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 44Executive Summary Arjo Dedessa Irrigation Project 12. SOIL SURVEY May 2007 Detailed soil survey covering gross area of some 36.787ha nas been cameo out at feasibility level The purposes this stuoy was to provide detail information on land and soils of the study area, which may form a basis for conforming/rejecting the irrigation potential, crop selection, irngation aesign and agricultural input requirements such as fertilizer application. Arjo-Dedessa command area is located in the Western part of the country, in Oromia Regional State and situated between 154880 ano 158040 UTM North and 250600 ana 260300 UTM East within altitudinal range of 1260 ana 1400 masl The project area is categorized into kolo agrodimatic zone ana situated in the hignest rainfall region of the country The annual rainfall is about 1452 mm. of wnich 80-85% falls in five months from May to September The hottest season is from February to May and the temperature ranges between 23 l5°c and 25 4°c, wnere as the coldest season occurs from November to January ana temperature vanes from 16.92°c ana 19 5°c The geology of the area belongs to the part of the Ethiopian highland which is composed ot Precambrain basement complex covered by Mesozoic sediment on top of which lie tertiary trapean lava that is formed of basalts ana basaltic tuffs In general the land form of the command area is plain that is slopping gently towards the Dedessa river. On both sides of the nver there are some isolated hills rising above average level of the plain The vegetation cover for the valley is mainly maae up of wooded savannah grass land The vegetation is composed of very sparcely distributed bushes and snrubs The uplands and sloppy land is covered by moderately dense trees and bushes with savannah grass Along the Didessa river and its tributaries the vegetation cover is more dense than the surrounding areas The land use of the area consists of moderately cultivated land and settlement which is mostly confined to well drained reddish brown soils, occurring on the upland and the hills The major crops grown in the area are maize, sorghum teff, mger seed, sesame and chick pea. The head water of Dedessa drainage systems originats from a high volcanic mountain called Sosana Mountain and eventually drains to Abbay river basin. The river flows from southeast to north west through the middle of the command area. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 45Executive Summary ArjoDedessaIrrigation Project May 2007 The project area is accessible by an asphalt ana gravelled road after travelling some 400km from Aadis Abaoa via Nekemte and Arjo town or about 500km from Addis Ababa through Jimma ana Beaele The command area is connected by temporary rough dry weathered road The present study followed rigid grid survey technique with a total of 267 auger boring and 179 profile pits and acnieved an observation density of one per ten na Beside that it has carried 17 physical test including hydraulic conductivity & infiltration measurements, deep boring and collection of core sampling. Soil sample were collected for analysis of standard parameteres The auger soil description has Deen made at every 200 x 500m along transect up to the depth of 1 20m and pits nave Deen excavated up to 2m depths on representative sites. Deep boring nas been carried out beiow the bottom of the profile pit up to 3-5m depth from surface for identification of drainage problems and samples were collected for determination of salinity ana sodicity characteristics The infiltration test has Deen performed to determine infiltration rate by double nng mfiltrometer in tnplicate The hydraulic conductivity test has been conducted insitu by using inverse auger nole method Undisturbed core samples ^pF- ring) have been collected from representative pits for determination of bulk density and water retention capacity Some 454 soil samples were collected from 113 profile pits All observations were recorded on soil description sheets and at observation site all necessary parameters have been recorded All the data collected dunng the field survey and laboratory analysis results have been entered into database in Microsoft Access and MS Excel for storage ana data processing. The soil database has been consisting of the following four different database recording different aspects • Location and site description • Horizon description • Physico-chemical analysis • Hydraulic conductivity and infiltration test Most of the soils of the project area have developed from alluvial and colluvial deposits from the surrounding rock formations of the hills and ridges. The soil classification has been made according to the World Reference Base for Soil (ISSS- ISRIOFAO. 1998) Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 46Executive Summary Ar jo Dedessa Irrigation Project May 2007 Four major soil UNITS have been loentified namely Vertisols, Luvisols, Nitisols and Camabisols. The most extensive soils are Vertisols which occupy 17 692 06 ha., which is 48 82% of the total area The Vertisols of the Arjo-Dedessa area are dominated Dy monlmrillonite clay with clay content ranging from 24 to 75% The nature of clay of these soils are extremely hard when dry and very plastic and very sticky when wet The surface cracks are quite wide with 7-15cm widths dunng dry season These soils occur on the lower lying areas of the valley Vertisols of the area is prone to water logging due to its vertic nature and the occurrence of the heavy rainfall in the region The other the most commonly found soils in the surveyed area are CamDiois. They occupy a large area measuring about 5602.63 ha whicn accounts for 15.23 % out of the total area and occur mostly on sloping land LjvisoIs are the third unit of soils present in the area that are that are characterized Dy deep to very deep in depth, reddish brown colour, moderate to well drainage, fine ano medium porse with faint cutamc features on the “B" nonzon They are distributed on gentle undulating to sloppy land ano cover 3192 6ha ( or about 8 68 %) The fourth soils, whicn occur in small extent in the study area is Nitisois, occupying omy 231 ha. The distribution of major soil Groups and soil units under Arjo Dedessa command area are given in Table 12.1 Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 47Executive Summary Arjo Dedessa Irrigation Project May 2007 Table 12.1 Area distribution of Major Soil Groups and Soil Units of Arjo -Dedessa Command Area Major Soil Groups FAO Identified Soil Units FAO.1998 Area Ha % Cambisols Verne Cambisols 5131.00 13.95 Chromic Cambisols 471 63 1.28 Vertisols Pelli - Eutric Vertisols 9299.00 25.28 - Pelli - Calcic Vertisols 305O.00 8 31 Chromi - Eutric Vertisols 3278.00 8.91 Chromi - Calcic Vertisol 2058.80 4.66 Luvisol Chromi - Vemc Luvisois 3192.6 8 68 Nitisois 231.0 0.63 Suo-totai 26,718.41 72.63 Miscellaneous Land RB River bank 2471.6 6.71 Hl Hill 3396.5 9.23 V Village 200 00 0.54 R Ridge 4006.00 10.89 Sub- total 1073.6 27.37 Grand Total 366,787 100.0 Generally the major texture of the investgated soils vanes from sandy loam to clay for reddish brown soils and for Vertisols clay to heavy clay The soils reaction in most cases is slightly acidic on top soils ano slightly to moderately alkaline in the sub soils. The average value of the CEC is 47 99 mg/100g of soil, indicating that the soil is fertile. The percentage base saturation is also high The organic content is high with an average value of 3.10%. The total nitrogen is low to medium, the available phosphorus value in average is 25.17 ppm wmch indicates that p content is in high level. The soils of the area have low content of potassium indicating that the soils require supplementary application of potassium. The soils of the project area are categorized into ten soil senes depending on soil honzon thickness, colour, and content of carbonate. The respective name of the soil series are taken from streams and villages located in the area. For further division, the soil phases and such characteristics, which are important for use and management of soils including, surface texture, slope, soil depth, and flooding have been taken into considerations. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 48Executive Summary Arjo Dedessa Irrigation Project May 2007 Finally the soils of project area nave Deen delineated into 41 soil phases and 4 miscellaneous lands Physical and cnemicai properties of soil mapping units are available in Table 12 2 The major constraints of the area are steepness poor drainage of the Dottomland of the valley uneven surface compaction ano vegetation cover Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 49Executive Summary Arjo Dedessa Irrigation Project May 2007 Table 12.2: Physical and Chemical Properties of the Mapping Units s. No Mapping unit Eft. Soil depth (cm) Texture class of top soil AWC mm/m BD g/cm3 IR cm/br HC m/day PH CEC meg/IOOg of soli top 25cm BS % OC % Top 25 cm EC ds/m top 100 cm TN % top 25m PjOj top 25cm CaCoj % Drainage class Slope % ESP top 100 cm% Represents tive Profile No 1 H, >150 Silty loam 104 92 1 64 0.8 041 65 54 65 4 4 95 0 03 0 29 49 70 Trace E 8 15 0 86 ADP084 2 H, >150 clay 190 76 1 76 005 041 55 33 5 73 3 33 0 04 0 28 23 20 Trace W 46 096 3 H, >150 Heavy clay 242.7 1 56 004 0 08 74 42 1 59 1 86 005 012 8 20 Trace S 041 ADP075 ADP125 4 H« >150 clay loam 196 23 1 84 08 051 ell 60 2 36 0 05 0 22 109 80 24 1 w 6-8 2-4 0 69 ADP091 5 Ki >150 Silty loam 19623 4.6 08 0 51 5 74 56 39 241 0 03 04 5 00 Trace 68 0 38 ADP129 6 H. 100 150 Clay 190 76 1 84 05 041 6 02 33 48 41 6 65 5 0 46 20 10 Trace 68 03 ADP124 7 H, 100-150 Clay loam 143 6 1 71 08 01 65 100 2 5 58 33 0 05 0 05 17 42 20 Troce ADP087 8 HT, 50-100 Clay 190 76, 1 75 0 05 041 5 15 0 02 0 18 9 50 Tiace 0 59 083 ADP120 9 HT, Clay 190 76 18 0 05 041 554 50 7 38 74 44 46 39 53 57 63 1 82 9 2 37 3 84 0 03 0 03 0 31 51 70 Trace s s w w w >150 ADP082 10 HT, 100-150 Clay loam 118 77 1 67 2 1 5 95 87 61 44 0 32 37 50 37 s 46 46 46 68 1 09 2 19 ADP139 11 HT< <50 Clay loam 143 6 1 65 06 01 5 38 93 28 51 0 05 0 39 14 70 Trace E/S 6-15 0 23 HT. 1 74 0 05 041 71 ADP169 12 loaiso Clay 190 76 59 78 100 89 3 63 0 09 0 27 38 60 3 35 S 0 79 ADP168 13 HT. 50-100 Clay 190 76 1 27 0 05 041 5 52 61 22 14 HT, 50-100 Sandy clay loam 143 6 0 02 08 0 51 5 81 24 17 75 58 18 1 2 99 4 62 0 07 04 17 90 Trace 68 68 05 ADP123 004 0 24 10 90 Trace s s 6-8 08 15 SHi Sandy clay loam 190 76 15 0 05 041 55 ADP010 32 26 70 4 1 71 0 05 012 12 80 Trace w 24 0 56 100150 ADP074 18 SH, Sandy loam 118 77 1 68 2 21 6 27 25 35 108 88 5 23 0 04 03 68 30 Trace E 50 100 8 15 0 77* ADP074 17 SH, >150 i oam 1168 1 1 6 12 62 17 48 34 5 22 0 03 0 74 5 60 Trace E 8-15 0 39 ADP112 M >150 Sandy loam 118 77 2 1 4 97 21 91 79 87 4 48 0 11 0 25 7 50 Trace W 2-6 0 97 ADP001 Water Works Design & Supervision Enterprise In Association with Interconttnentil Consultants and Technocrats Pvt Ltd 50Executive Summary Arjo Dedessa Irrigation Project May 2007 s. No Mapping unit EH Soli depth (cm) Texture class of top soil AWC mm/m BD grcm IR cm/br HC m/day PH CEC meg/100g of soli top 25cm BS % OC % lop 25 cm EC ds/m top 100 cm TN % top 25m PiO, top 25cm CaCoj % Drainage class Slope % ESP top 100 cm% Represent! tive Profile No 19 K, 50 100 Heavy clay 242 47 15 0 04 0 08 58 47.87 76 46 2 69 0 05 0 13 11 90 Trace M 4-6 06 ADP110 20 Kj >150 Heavy clay 242 47 1 66 0 04 0 08 5 63 54 04 80 9 0 59 0 05 0 04 65 20 90 M 4-6 1 07 ADPO43 21 K, >150 sandy clay loam 143 6 1 69 08 0 51 75 26 33 88 4 3 23 0 04 0 18 13 80 86 M 4-6 1 35 ADP007 22 K< 110 Loam 118 8 1 69 1 6 02 54 83 43 4 28 0 09 0 21 67 10 • M 4-6 061 ADP096 23 B >150 Clay 190 76 18 005 041 62 49 04 100 4 1 91 0 63 0 53 20 00 67 M 46 11 ADP014 24 Si >150 Heavy clay 242 47 1 73 0 04 0 08 58 508 99 7 304 0 04 0 19 37 53 Trace P 01 08 ADP060 25 s. >150 Clay 190 76 1.87 005 041 53 28 7 75 57 2 34 0 03 22 00 Trace P 0-1 1 02 ADPO72 26 Sj >150 Heavy clay 242 47 1 44 04 0 08 56 51 65 64 5 3 15 0 05 0 14 017 47 60 Trace P 1-2 27 s« >150 Silty loam 104 90 1 76 08 T2 5 26 44 96 65 93 3 42 03 03 7 50 Trace P 12 065 076 ADP106 ADP145 28 Ss >150 Clay 190 76 1 45 0 05 041 5 82 44 8 100 3 2 45 0 05 021 21 90 P 1-2 1 06 29 St 110 Heavy clay 242.47 1 39 0 04 0 08 5 85 65 04 963 4 24 0 06 0 27 33 80 Trace Trace 1 2-4 0 76 ADP031 30 Sv >150 Heavy clay 242 47 0 04 0 08 6 03 52 5 53 9 4 15 011 021 24 00 Trace 1 2-4 1 18 ADP013 31 S. >150 Clay 190 76 0 0 05 041 6 29 54 9 2 85 0 06 021 21 70 Trace 1 2 11 ADP009 32 Di >150 Clay 190 76 1 76 0 05 041 6 32 54 49 71 98 9 3 0 05 20 70 95 1 2-4 2-4 17 ADP032 33 D, >150 Heavy clay 242 47 1 76 004 0 08 5 91 94 91 28 0 05 0 72 0 17 19 62 8 14 1 2-4 0 92 ADP061 34 D, 100 150 Heavy clay 242 47 17 0 04 0 08 61 49 77 53 37 95 1 1 31 0 08 0 14 14 00 5 1 24 1 31 ADP044 35 Ab, 100 150 Clay 190 76 1 75 0 05 041 5 75 34 28 104 8 27 0 07 0 14 48 99 Trace P 12 0 83 ADP098 36 Abj >150 Silty loam 190 76 1 77 02 041 5 69 32 66 104 8 3 37 0 05 0 2? 27 63 Trace 1 24 0 82 ADP101 37 Ab, >150 Clay 190 76 1 73 08 041 5 82 44 13 81 9 3 14 0 04 02? 27 74 Trace 1 2-4 16 ADP100 Water Works Design & Supervision Enterprise in Association with Intercontinental Consultants and Technocrats Pvt Ltd. 51Executive Summary Arjo Dedessa Irrigation Project May 2007 s. No Mapping unH Eft Soil depth (cm) Texture class of top soil AWC mm/m BD g/cm’ IR cm/bf HC m/day PH CEC meg/100g of soil top 25cm BS % OC % Top 25 cm EC ds/m top 100 cm TN % top 25m PiO> top 25cm CaCo3 % Drainage class Slope % ESP top 100 cm% Represents tlve Profile No 38 AU >150 Heavy day 242 41 17 0 04 0 08 5 91 52 100.8 2 02 0 08 0 15 16 10 Trace I 2-4 1 04 ADP040 39 Abs >150 Heavy clay 24247 1 68 0 04 0 08 5 42 55 41 85 5 3 34 0 15 0 25 72 00 Trace P 1-2 0 85 ADP041 40 Smi >150 Clay 190 76 1 63 0 05 041 5 88 56 77 88 37 3 33 0 06 0 23 26 83 173 I 2-4 1 92 ADP121 41 Sma 10^150 Clay 190 76 1 71 0 05 041 621 44 6 95 72 3 6| 011 0 27 17.60 67 P 0-1 3 87 ADP151 E = Excessively drained S = Somewhat excessively drained M = Moderately well drained W = Well drained I = Imperfectly drained Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd 52Executive Summary Arjo Dedessa Irrigation Project 13. LAND SUITABILITY May 2007 The land evaluation has been carried out in accordance with the FAO frame work for lano evaluation. The suitability of land for irrigated agriculture nas been determined by rating land quality of each soil- mapping unit, wmch is relevant to the land utilization type The FAO Framework encompasses three levels of land suitability classes These are as follows At highest levei there are two suitability oraers, including Suitable and Not Suitable At second level the suitability orders are divided in to three ciasses, these are ■ Highly Suitable S1 ■ Moderately Suitable S2 ■ Marginally Suitable S3 The order not suitable has two classes. ■ Currently Not SuitaDie N1 ■ Permanently Not Suitable N2 At third or lowest level there are a number of classes, wnich reflect the kind of limitations that restrict the suitability of land for specific land use. The present study has given more attention to the suitability of the command area for medium to high scale of irrigated agnculture development. The major Kind of iand use considered for the iand cultivation is imgated agnculture development in the study area particularly in the command area using surface and/or pressurized irrigation system. A number of Land Utilization Types (LUTs) were identified and defined in terms of their response to imgation, socio-economic situation, marxet availability, expected advantage of the government for national and regional agricultural development The following crops have Deen proposed for the command area: nee, soybean, wheat, maize, vegetables (tomato, onion), sugarcane, forage (alfalfa), cotton, banana, coffee and mango. Land use requirements are conditions of iand required by a LUT for sustainable development and they are expressed in terms of crop requirements. The requirements for crop, depend on the land characteristics and land qualities, which will be required to meet for acceptable yields of a particular crop. Water Works Design & Supervision Enterprise 53 la Association with Iitercontlnental Consultants and Technocrats Pn Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 Land use requirements also include a set of limiting values or class determining factors. Class- determining factors are those factors that affect the performance of Land Utilization Type (LUTs) on a land unit and which can be used as basis for classifying the suitability of land unit for a given use. The limiting factors observed in the study area are identified by letter symbol. In case of the present study the following parameters are identified as class determining factors workability, texture, topography, soil depth, water logging and vegetation cover Lana units have been described in terms of their characteristics and their qualities. A land characteristic is a fairly simple attribute that can be measured or estimated such as soil texture, effective soil depth, water logging, topography and ability of soil to retain nutrient The assessment of land suitability for irrigated agriculture has been assessed based on iand qualities and land characteristics Based on land characteristics and land qualities 45 land mapping units have been identified. Land suitability classes, sub-classes rating and their extent are available at Table 13.1. Suitability is a measure of now well qualities of iand units match the requirement of particular form of land use. Matching iand use to land unit is essence of land evaluation. The land suitability maps have been prepared at 1:10,000 scale separately for all LUTs considered. The results of land evaluation showing area suitable for different crops are presented in Table 13.2 The black heavy clay soils due to their physiographic position, where these sols are located (level and nearly level slopes; and their inherent physical and chemical characteristics they pose a problem of poor drainage ano workability. Therefore the provision of drainage is a must in the Vertisol of the command area. It can be managed by properly designed surface drainage system such as construction of comber-beds and broad-beas ana by increasing the organic matter content. Water Works Design & Supervision Enterprise 54 la Association with Intercontinental Consultants and Technocrats Pvt Ltd.DACLUUtC OI1UUU*1J Arjo Dedessa Irrigation Project Table 13.1 Crops Suitability of Arjo-Dedessa Command Area May 2007 Mapping Area Rice Wheat Maize Vegetable Pasture Sugercane units Ha % Surface Overhead Surface Overhead Surface Overhead Surface Overhead Surface Overhead Surface Overhead H, 2031.7 5.54 N2k/w/d N2k/w/d N2m/w/k S3m/w/k N2w/k S3m/w/k N2w/k S3w/k N2w/k s3m/w/k N2w/k S3m/w/k H, 289.19 0.79 N2k/w N2k/w S3z/w/k S3z/w/k S3z/w/k S3z/w/k S3z/w/k S3zA7w S3rw/k S3z S3w/k/c S3w/k'c H, 149.3 0.41 N2k/w N2k/w N2w/k S3d N2w/k S3n/w N2w/k S3z/r/w N2w/k S3z/r/w N2w/k S3e H« 52.17 0.14 S3 mA S3 mA S3m/z S3m/z S3m/z S3m/z S3z/m S3z/m S3m S3m S3m S3m/z/n H, 339.86 0.92 N2w/k N2w/k N2w/k S3m/e N2w/k S3c N2w/k S3e N2w/k S3d/e N2w/k S3e H« 247.5 0.67 N2w/k N2w/k N2w/k S3d/e N2w/k S3e N2w/k S3c N2w/k S3d/e N2w/k S3c H7 , ____ HTj 75.83 0.21 N2w/k N2w/k S3m/w/k S3m S3w/k S3m S3m/\v/k S3m S3m/w/k S3m S3m/w/k S3m 1115 84 3.02 N2w/k N2w/k Nlz Nlz Nlz Nlz S3z/w/k S3z Nlz Nlz S3w/k S2c/r/k HTi 3295.28 8 95 N2w/k N2w/k S3z/w/k S3z S3w/k S2w/k S2zA/e S2z/w/k S3w/k S2e/d/z S3w/k S2c/w/k ht3 131.8 0 36 N2w/k N2w/k N2w/k S3r/w/k N2w/k S3m/w/k N2w/k S3m/w/k N2u/k S3m/d/e N2w/k S3w/k?c HT, 232.49 062 N2w/k N2w/k N2w/k S3w/k N2w/k S3m/w/k N2w/k N2r N2w/k S3r/z/c N2w/k S3r/w/k HT, 64 44 0 18 N2w/k N2w/k N2w/k S3d/w/k N2w/k S3w/k N2w/k S3w/k/e N2w/k S3d/e N2w/k S3w/k'e HT* 185 5 0.5 N2w/k N2w/k N2w/k S3z/w/k N2w/k S3w/k N2w/k S3w/k/e N2w/k S3d/c N2w/k S3w/k/e HT, 105.7 0.29 N2w/k N2w/k N2w/k S3z/w/k N2w/k S3w/k/e N2w/k S3mw/k N2\v/k S3d/c N2w/k S3w/k e SHj 234 38 0.63 N2w/k N2w S3z S3z S3z S3z S3z S3z S3z S3z S2c/n/z S2c/z/k SH s 223 7 . 13.55 0 61 N2w/k N2w/k N2w/k S3r/w/k N2w/k S3w/k/e N2w/k S3m/w/k N2w/k S3w/k N2w/k S3m/w/k SHj 004 N2w/k N2w/k N2w/k S3w/k N2w/k S3w/k/c N2w/k S3m/w/k N2w/k S3w/k/c N2w/k S3w/k/e M 230 89 063 N2z/w N2z/w Nlz Nlz Nlz Nlz Nlz Nlz Nlz Nlz S3n/w/k S3m/z/n K« 467.66 1.27 N2w/k N2w/k S2z/r/w S2z/r/w S3w/k S2z/r/w S3z/r/w S3z/r/w S3z/r/w S3w/z/c S3w/k S2c/z/r Ki 39 91 0 11 N2w/k N2w/k S3w/k S2zA7w S3w/k S3n/w S3z/r/w S3z/n S3n/z/r S3n/zA S3n/w/k S3n/w 1 137 78 3.1 N2w/k N2w/k S3m/w/k S3m/w/k S3m/w/k S3m/w/k S3m/w/k S3m/w/k S3m/w/k S3w/k/e S3m/w/k S3m/w/k ------- K. 429 77 1.17 N2w/k N2w/k S3m/w/k S3m S3m/w/k S3m S3m/w/k S3m S3m/w/k S3mw/k S3m/w/k S2c/wA B 1241.75 3.38 N2w/k N2w/k S3w/k S2z/w/k S3m/w/k S3d S3w/k S2z/t/w S3w/k S3w/k/e S3w/k S2c/wA S, 1160 74 3.14 S3d S3d S3d S3d S3d S3d S3z/r/w S3d/r/w S3d/zA> S3d/z'w S3d S3d Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt. Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 S> 1308.32 3.55 S3d S3d S3d S3d S3d S3d S3z/d S3z/d S3d/z S3d/z S3d S3d s, 1320.4 3.59 S3d S3d S3z/d S3z/d S3d S3d S3d/z/r S3z/r/d S3d/z/w S3//z/r S3d S3d S« 411.21 1.12 S3d S3d S3m/z/d S3m/z/d S3d S3d S3d/z/r S3z/d S3d/z S3d S3d S3d S, 274.7 0.75 S3d S3d S3d S3d S3d S3d S3d/ S3d S3d S3d S3d S3d S. 324.5 0.88 S3d S3d S3d S3d S3d S3d S3d/z/w S3d/z/i Sd/z/u S3d/z/w S3d S3d s, 1721.86 4.67 S3d S3d S3d S3d S3d S3d S3d/z/w S3d/z/r Sd/z/w S3d/z/w S3d S3d Si 1880 36 5.1 S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d D, 1332 66 3.61 S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d D. 466.47 127 S3d S3d S3d S3d S3d S3d S3d/z/r S3z/d S3d/z/w S3d/z/w S3d S3d D> 79 17 022 S3d S3d S3d S3d S3d S3d S3d/z/r S3d/z/r S3d/z/w S3d/z/w S3d S3d Ab, 174.7 0.47 S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d A th 348.15 0.95 S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d A th 1150.21 3.12 S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d Ab, 736 2 S3d S3d S3d S3d S3d S3d S3d S3d S3d/z/w S3d/z/w S3d S3d Ab, 5668 0.15 S3d S3d S3d S3d S3d S3d S3d S3d S3d/z/w S3d/z/w S3d S3d Ab. 812.7 2.2 S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d Smi 334.3 0.91 S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d Sni2 482.75 1.31 S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d S3d Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt. Ltd. 56Executive Summary Arjo Dedme Irrigation Project Table 13.2 Crop* Suitability of Arjo-Dedessa Command Area May 2007 Rice Wheat Mabe Sugarrane Vegetable Pasture Suitability Over Over Over Over Over Ovei Class Head Surf Head Surf. Head Surf. Head Surf Head Surf Head Surf Ha Ha Ha Ha Ha Ha Ha Ha Ha Ha Ha Ha SI 1160.8 1160 8 S2 528.6 1011 4 1749.5 5006.1 6356.5 234 4 5986 5 234.4 4538.3 S3 12922.7 12440 23627.4 21643.3 20370.7 21643 20367 3 22042.8 20736 5 24795.2 20838 5 21621 4 Sub Total Suitability 14612.1 14612.2 25376.9 21643.3 25376.8 21643 26723 8 22277.2 26723 25029.6 25376 8 21621 4 N1 231 1347 1347 1346 9 660 8 1347 1368 9 N2 12111.6 1116 3733 6 3733.5 3785 7 1694 1 3733 6 Sub Total 12111.6 12111 6 1347 5080.6 1347 5080 4 4446.5 1694 1 1347 5102 5 Suitability Grand Total 26723.7 26723.8 26723.9 26723 9 26723.8 26723 4 26723 8 26723.7 26723 26723.7 26723 8 26723 9 Water Works Design & Supervision Enterprise In Aiioclation with Intercontinental Consultants and Technocrats Pvt Ltd. 57Executive Summary Arjo Dedessa Irrigation Project 14. AGRICULTURAL PLANNING May 2007 The scope, approach and methodology of the study for Agricultural Planning include various broad aspects in view of the existing farming systems and socio-economic situations of the area, existing crops, livestock, cropping system, production practices etc. in the light of the prevailing soils and climatic conditions and the feasibility and prospects of enhancement of productivity and production by introducing the irrigated production system The previous studies made by USBR (1964), WAPCOS (1990) and BCEOM (1999) have been reviewed and their relevant findings pertaining to the project command have been appropriately used in agricultural planning while considering the economic crops and other enterprises to be included in the cropping system The major textures of the soils vary from sandy loam to clay for reddisn brown soil and clay to heavy clay for vertisols The soil depth ranges from 50 to 500 cm with pM value of 6 75 The land is fertile and appears to be productive The average cultivable land occupies 36.76 percent and cultivated land 17 65 percent of the total area of all woredas of the project command. A numDer of cereals, pulses, oil seeds and other crops are being cultivated under ramfed production system Meteorological characteristics are favorable for growth and productivity of many field crops, horticulture and other useful plants and trees There are 170 kebeie administrations in 05 woredas but only 18 percent of this are covered under project command and reservoir The average household size ranges from 4 8 to 5.2 persons per household. Though there are number of schools, but the poor existing facilities have hampered the quality of education. Majority of fanners (more than 50%) own 1 1 to 2.0 hectare of land in project command The facilities of health coverage, potable water supply, road and other infrastructures are very poor or lacking in many pans of the command area. This is creating the problems of many diseases like malaria, intestinal parasites etc, along with transpon and marketing. Women are the main work force in agriculture and household activities but they are being discriminated in decision-making, education, community participation etc, in spite of the women Affair Policy 2004 having provision of abolition of gender discnmination. The major source of income (96%) of the farmers is crop production. Currently the major problem of the farmers is food insecurity due to low farm productivity, land degradation and erratic rainfall. The production ano Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 58Executive Summary Arjo Dedessa Irrigation Project May 2007 productivity status of crops have been given for the country Oromiya Region and Project command woredas. The average productivity of food grain is the highest in the region but the iowest in project command The existing cropping pattern and crop-wise productivity indicate the nignest yield from maize and the lowest from Soybean. The proper information on vegetable crops, fruits ana coffee are not available Currently only local varieties or land races with poor genetic potential are being grown by the resource-less farmers The farming is at subsistence level and traditional. The improved technologies have not reached to the farmers due to poor extension service The farmers are rarely using improved varieties, quality seeds, fertilizers, agro-chemicais, farm implements and improved tools The credit facilities are poor and farmers with low resources have no risk Dearing capacity Hence, the farm productivity is very low The livestock production is also important in the project command mainly due to mixed farming system. The oxen are the major source of draught power out more than 30 percent farm holders do not have even the oxen, some have only one ox and only about 35-40 percent have a pair of oxen. In general, the livestock number per household is very high with limited feed and fodder resources resulting in low productivity per animal. There is no genetic up - gradation program of the livestock in project command The fishery development is also negligible. On the basis of existing status of farming system in the project command, the mam constraints identified are the inadequate input supply (variety seeds, fertilizers, agro chemicals) farm implements, shortage of draught power problem of drainage, frequent natural hazards, poorly developed research-extension linkage inadequate extension service, poor marketing system and low market pnce of produce, problem of adequate rural credit facilities, inadequate transport net work and problem of health of farmers and their families and livestock specially cattle due to various diseases. Keeping in view the production potential of the project command, soils, climate and Ethiopian government policy towards agriculture called Agricultural Development Led Industrialization (ADLI) to attain self sufficiency in food, production of cash and industnal crops for export and import substitution by full and efficient utilization of land and water resources while maintaining ecological and environmental balance etc. suitable cropping pattern, cropping system and crop rotations have been selected with inclusion of most appropriate and potential crops of high quality. The crop calendars have been prepared for calculation of their actual water requirements under irrigated production systems Looking Water Works Design & Supervision Enterprise In Auodatton with Intereontinatal Consultant) and Technocrats Pvt Ltd. 59Executive Summary Arjo Dedessa Irrigation Project May 2007 at the present low cropping intensity of the project command, it has been suggested to have cropping systems involving two crop rotations to provide high and sustainable yield Accordingly it has been further proposed to make use of semi-dwarf, photo-insensitive, medium duration hign quality varieties, particularly of cereals that nave greater degree of water and nutnent-use efficiency and good marketability The crop rotations of 126 to 138 percent cropping intensity are proposed to be taken initially in a phased manner but with the further need, expenence and population pressure in the area, they may be raised to the level of 156 to 173 percent or even more. It has been further proposed to integrate the crop production system with horticulture, livestock, fisnery. forestry and other allied disciplines of production for sustainable yield with eco-friendly environment The crop water requirement of each crop included in rotations and cropping pattern has been calculated following the procedures recommended in FAO publications for calculation of reference evapotranspiration (ETo) by using Pennman Montieth Approach (FAO Irngation & Drainage Paper No.46) Suitable crop coefficients were selectee for different stages of growth to calculate crop water requirements by considenng the agricultural practices, climatic parameters, cropping pattern, crop calendar, cropping intensities etc The crop production technologies of important field and horticultural crops have been given importance considering the irrigated production system with optimum inputs and production practices to achieve reasonable yield per hectare based on the information available from IAR, personal expenence of the consultant and from other countnes having similar growing conditions and agro-climate The major corps included are nee, wheat, maize (cereals) sunflower groundnut, sesame ^oilseeds), Field peas, chick peas, soybean. Hancot bean. Faba bean (Pulses), potato, onion carrot, tomato, cabbage (vegetable), sugarcane (sugar crop), Alfalfa, Napier grass (forages) and coffee (stimulant crop) along with grassland management and agroforestry The post harvest losses of various important crops including horticultural crops, their prevention, and method of value addition along with post harvest operations are described briefly. These include important crops, fruits, vegetables, animal products etc. The possibilities of various rural based agro-industries for more income and employment have been discussed briefly The rural based storage system to prevent part of the post harvest loses are also discussed. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 60Executive Summary Arjo Dedessa Irrigation Project May 2007 In the process of crop buageting, the cost of cultivation of important food crops under irrigated production system involving improved production technologies have oeen worked out to project the expected income. Simultaneously tne cost of cultivation of the crops under existing farm situation in rainfed production system have Deen also calculated to compare the benefits. Among all the crops, nee appears to be the most economical. The status of agricultural research in the region has been bnefly discussed. Though Bako Agricultural Researcn Center (BARC) has done good work for rainfed agriculture involving crops, livestock along with soils covenng vanous aspects but the work on irrigated agriculture is very limited Moreover the BARC is only partly representing the conditions of project command for technology generation. There are a few suo-centers near or inside the command conducting researcn exclusively on coffee Water Works Design & Supervision Enterprise li AssocUUob with lntereontineaui Consultants and Technocrats Pvt Ltd. 61Executive Summary ArjoDedessa Irrigation Project 15. LIVESTOCK Livestock rearing in the area persisted for many years because May 2007 a) The resources are an integral pan of the economy of the people b) They serve mainly as live bank accounts, source of power for traction, source of milk and meat and as cash income to cover family expenses c) Considerable number of livestock is also supplied to the central market for meat consumption and expon • No systematic breeding is practiced (no performance recording, evaluation and genetic selection; • The majority of the livestock depend on unimproved natural pasture. • Livestock management practices are based on simple traditional methods and no attempt was made to improve the quality of feed and increase livestock productivity per individual animal Major constraints to livestock productivity include: a) Inadequate supply of improved technologies (improved breeds and forage crops) b) Lack of adequate infrastructure c) Lack of rural credit and saving facilities d) Shortage of budget e) Lack of know-how in modem livestock breeding Three livestock development options are proposed for the project area These include: Tsetse and Trypanosomiasis control, small-scale dairy cattle production and small-scale fattening programs When the proposed developments are put into practice the following major improvements will be attained: a) Increased milk yield b) Reduced mortality and morbidity rates. c) Increased birth rate (calving, lambing, kidding rates). d) Increased growth rates e) Improved reproductive performance f) Increased off-take rates and increased income. Water Works Design & Supervision Enterprise Id Association with Intercontinental Consultants aid Technocrats Pvt Ltd. 62Executive Summary Arjo Dedessa Irrigation Project May 2007 Hence, food security will be sustained and there will be increased living standard of the people To realize the proposed livestock developments, the following recommendations are forwarded: • upgrade the knowledge of farmers about livestock breeding, record keeping, management and feeding through training ano demonstration • Expand and strengthen credit facilities tor the purchase of in-calf-heifers, steers for fattening and milking equipments • implement suitable land use planning so that farmers properly utilize their land get enough livestock feed and grazing • Estaolish transportation, communication ano marketing infrastructures in the Woredas and with the other neighboring Woredas as well as regional ano central livestock market routes • Establish required number of veterinary clinics with manpower and medicines. • Expand and implement livestock technologies sucn as Al, bull service improved forage varieties and/or seeds to the project areas • Construct new water resources ano over diversions, and maintain ano properly utilize the already available water resources for livestock and crop production. Water Works Design & Supervision Enterprise Ii Association with Intercontinental Consultants and Technocrats Prt Ltd. 63Executive Summary Arjo Dedessa Irrigation Project May 2007 16. FISHERY DEVELOPMENT Ethiopia depends greatly on its inland water Dodies for fish supply to its population The total maximum harvestaoie annual fisn potential is 44.030-49 030 t/yr which consists of average 72%. 15% and 13% for lakes, rivers ano reservoirs respectively The riverine fishery has Deen ignored and least Known except some assistance whicn has been offered to the River Baro fisheries in Gambela Region. However, it is suggested that most rivers contain fish stocks, which are not currently exploited The country’s fish resource has been under exploited as only 10,007 tons have been harvested during 2004/05, which is 20-23% of total potential. This landing account 85% for major lakes, 9% for reservoirs and small water bodies, and the rest is for nvers. In 2003 the Fisheries Resources Development and Utilization Proclamation No 315/2003 have been declared at Federal level Following this Proclamation the Amhara National Regional State and Southern Nation Nationalities Peoples Regional State have declared their own respective regional proclamations However there is no effective fish resource control currently. The ADbay River is the major river of Ethiopia. The main tributaries of the AbDay River are Anger, Beles, Chemoga, Dabana, Dabus, Didessa, Dinaer Gemma, Guder and Wenchit. The exploitable potential fish resource of Abbay River ana its tributanes is estimated as 2000-2500 ton per year. The perennial rivers, which are easily accessible by fishermen, are Dabus, Didessa, Dabana and Anger. Their exploitable potential of these rivers is estimated as 700-800t/yr Didessa River is one of the main tributaries of Abbay River, which has fish resources and has active river fishery at different segment of river channel. The existing fishery is depending on the culture of society, which relates to the ethnic group Most of the time, the fishery is exclusively for subsistence with the intensity varying in the different segments of Didessa River and its tributaries. Despite the presence of huge fish resource in the river, there is no subsistence or commercial fishery developed currently in project area. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pn. Ltd. 64Executive Summary Arjo Dedessa Irrigation Project May 2007 The Didessa Rivers owes its abundant fish to the varied habitats it has to offer, its vast catchments and wet and dry seasons. Fish and other aquatic animals use this range of habitats for spawning, feeding and coping with seasonal changes in water levels The nver is fish migration corridors connecting upstream spawning nabitats with downstream nursery nabitats, ano dry season reruge habitats in the mainstream with wet season feeding habitats on the floodplains The Didessa River ecosystem and fishery is in natural condition, out there are a number of possible threats in the future to the fishery that must be understood and addressed otherwise the fishery could be decimated. These threats mainly come from environmental modification by proposed project such as habitat loss due to deforestation and degradation of catcnments, Dlockage of the route of migratory fish species, introduction of new fish species and pollution. One of the major impacts of a dam is cnange in the natural patterns of seasonal flow. The impacts are felt in the channel of the nver and in the new water body (reservoir) that is formed The downstream impacts of dams on rivers can affect the river immediately below the dam, and may persist for considerable distances downstream Substantial cnanges occur to biota below a dam. The most direct of these is the blocking of the pathway by which invertebrates and fish travel upstream and downstream This Dlockage will severely affect all fish species. This may result in the complete elimination of species dependent on migrations upstream for breeding or at least a drastic change in their abundance The short distance effects will include change of temperatures and quality of water, ano discharge by hipolimnion or metalimion water layers of the reservoir. The long distance effects will include decreasing the seasonal inundated area. Both adversely affect the aquatic life In general, broad measures are needed to develop and exploit the potential for fishenes which will become available with the creation of reservoir and construction of canal system Research and resource monitonng will be very essential for fishenes in Didessa River, proposed reservoir and canal system. These will take into account environmental modification that will have effect on reverine environment and subsequently on up and down stream fisheries. Water Works Design & Supervision Enterprise In Allocation with Intercontinental Consultants and Technocrats Pvt Ltd. 65Executive Summary Ar jo Dedessa Irrigation Project May 2007 There are a number of constraints and threats in fisnery sub sector The cross-sectoral issues for the sustainability of fisheries in relation to environment include lack of appropriate plans for the development of river and lakeshore areas, pollution, degradation of catchments etc. The positive impact of the project is creation of large water bodies, which will increase fish resources. The estimated annual harvestable potential is 557 t/yr These will crate job opportunities for 140 people as full time fishermen and provide high quality protein food for communities to improve their live hood and quality of life In addition to these at the back of every fisnerman will benefit at least four persons and this will increase the beneficiaries four times i.e. 560 persons Totally about 700 family head persons or 3500 parsons will be benefited directly from the reservoir To increase fish productivity in reservoir following tecnmcal measures should be taken for long-term Denefits; clearance of some portion of the bottom reservoir before it is impounded, proper water level management to optimize the working curve for specific purpose of fishenes, control of aquatic vegetation, and provision of structure for fish pass at dam The irrigation canals will also have great potential for capture fisheries and aquaculture The capture fishery in irrigation canal will be exposed to unmanageable exploitation The particular case to project area needs measures to protect the fish fingerlings from entering into irrigation system from reservoir mainly during dry season. Aquaculture/fish farming can be developed for a wide variety of production systems in the proposed reservoir irrigation canal and Didessa river catchments However, pr.ority should be given to capture fisheries and aquaculture for medium term development prospects. Because, the development of capture fishery takes time to exploit fully In conclusion, these fragile resources encompass a number of challenges such as degradation and modification. The adverse effect of dam will have two main consequences, losses/decreases of the fish species and losses of its biodiversity Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 66Executive Summary Arjo Dedessi Irrigation Project May 2007 Much efforts are needed if the fishery sector is to develope all its available potential in the reservoir and canal system in particular and, Didessa river catchments in general. The proposed mitigation measures should be properly implemented at the right time and necessary follow up their effectiveness should be made through well planned monitoring program In addition to this, creation of effective linkages with appropriate institutions to protect these fish species througn shielding environment from degradation ano pollution is also essentially required. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pit Ltd. 67Executive Summary Arjo Dedessa Irrigation Project 17. AGRICULTURAL MECHANIZATION May 2007 The mechanization of agricultural operations is considered to be very important in the study of Arjo-Deaessa irrigation Projects It is expected to play a very key role in improving the productivity of irrigated agriculture, leading to the increased economic benefit to tne farmers Currently traditional tools and implements are being used for various field operations like field preparation, sowing, interculturai, harvesting and threshing but with the introduction of irrigated agriculture it will be necessary to use improved tool and implements, of coarse depending on the availability of credit facilities This may include animal ana tractor operated cultivators and disc harrow for seea bed preparation, seed-drill or seed cum fertilizer drill and planter for line sowing with fertilizer application and mechanical power thresher or manually operated thresher for thresnmg. improved serrated sickles for harvesting the crops is also important. With the advancement of technologies and enhancement of yield over a period of time, the farmers may be required to use drip and sprinkler imgation system in commercial crops and aiso use combine harvester Even if they are not in a position to afford heavy farm machinery like tractor, disc plough and combine harvester, they will be in a position to utilize the services on custom higher basis Over a penod of time in place of bullock drawn farm machinery and equipment; the farmers will be in a position to accept tractors, power tillers, Imgation Pumps, mechanical thresher and sprayers. Modernization of agriculture requires appropriate matching machinery for ensuring timely field operations and effective application of agncultural inputs. It also requires machinery for reducing drudgery in agriculture. Traditionally farmers are using only indigenous ploughs and other tools in rainfed agriculture with very low cropping intensity of 20-25% but due to introduction of irrigated agriculture, the cropping intensity is likely to increase in phases from 25% to a level of more than 170% Hence, different level of mechanization as discussed here under is required for achieving the timely farm operations resulting in enhanced production and productivity Water Works Design & Supervision Enterprise la Association with lntorconOnental Consultants and Technocrats Pvt Ltd. 68Executive Summary Arjo Dedessa Irrigation Project 2007 Land development and tillage machinery : It involves clearing of land, leveling ano grading so as to perform field operations properly and apply seed fertilizer or manure ana irrigation water uniformly Initially axe, hoe, pick-axe, spade, crowbar and neavy duty ploughs can oe used. As and wnen. advancement ana income increases tractor, tractor-drawn scrapper, leveler, terrace float and smoother can be used for large scale mechanized land cieanng. leveling, construction of farm ponds and laying of irrigation and drainage systems Also, bulldozers, excavators, aumpers and trencher could be used for some of the operations like laying suosurface drainage pipe Equipments for Seed-Dea Preparation : Country plough is the most popular traditional implement for seed bed preparation today, using draught animals Though it has a low output and requires more number of tillage operations, the small farmers are using it more conveniently With the introduction of irrigated agriculture and increased cropping intensity, initial introduction of bullock or animal operated cultivator disc harrow mould board plougn, puddler disc harrow cum puddler will help in timely completion of farm operation. In due course, the improved tractor-operated machinery namely sweeps, cultivator disc harrows, mould board ploughs, disc ploughs, puddler and rotavators can be introduced for demonstration at government farms and at the fields of big farmers for their popularization. Seeding and Planting Machinery : Traditional methods of sowing include manual broadcasting, opening furrow by country plough and dropping seed by hand behind the plough in furrows. Small areas are sown by dibbling the seed i.e. making holes or slits by a stick or tool and dropping seed by hand in small area. In manual seeding, it is not possible to achieve uniformity in distribution of seed. A farmer may sow at a desired seed rates, but the interrow and intrarow distribution of seeds is likely to be uneven, resulting in clumps of plants or gaps in the field. The line sowing not only saves the seed but also facilitates regulated application of fertilizer near the root zones. Besides, it helps in easy control of weeds through use of mechanical weeders. It is, therefore, important to introduce multi-row mechanically metered seed drill and seed cum fertilizer drill operated by bullocks. This can be developed to suit specific crops. Subsequently, tractor-drawn seed cum fertilizer drills can be introduced with further increase in cropping intensity The functions of well designed seed drill or planter are to Water Works Design & Supervision Enterprise 69 la Association with Intercostinoital Consultsiti and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 meter seeds of different sizes and shapes, place the seea in the acceptable pattern of distribution in the field as well as place it accurately and uniformly at the desired depth in the soil and cover the seeds and compact the soil around it to ennance germination and seedling emergence. Improved seed cum fertilizer drills are provided with seed and fertilizer boxes, metenng mechanism, furrow opener covering devices, ground drive system and controls for regulation of seed and fertilizer rates. Most of the seed cum fertilizer drills are provided with a pointed tool to form a narrow slit in the soil for seed deposition Application of Organic, farmyard and green manures: Organic manures are available from products of farming and allied industries derived from plant ano animal sources These contain both major and minor nutnents in small quantity These are applied in comparatively large quantity per unit area and have direct effect on plant growth. Usually these are applied manually by the farmers and ploughed in deep placement in band However it would be more advantageous if it is applied by using proper equipment. Bullock drawn cart operated applicator can be used. The tractor- tailor type of farm yard applicator can also be used as it is used in other countnes Equipments for Intercultural and plant protection Weed control in imgated and rainfed agnculture mainly during rainy season is a senous problem ano yield is adversely affected in the range of 20 to 60%, if not controlled. The uprooting of weeds and use of indigenous tools take 300-700 man nour to cover one hectare area. Use of long handle wheel hoe and peg type weeders reduces this weeding time to 100-125 hours/ha. Bullock operated weeder and cultivator can also be used to control weeds. The advantages of using improved weeding tools are reduction in weeding time, human efforts and efficient operation. Different designs of low-cost had-operated sprayers and dusters are available which can also be used for plant protection. Subsequently after more intensification of cropping intensity more efficient power operated sprayers, aero-blast sprayers, tractor operated air assisted sprayers and ultra low volume sprayers can be used particularly for plant protection in commercial crops like coffee, fruits etc. Harvesting and threshing Machinery : Harvesting with sickle (local) followed by threshing with animal trampling of crops is the most popular system prevalent with the small farm holders. Traditional sickles take more time and energy in harvesting Traditional bullock trampling is arduous and time consuming. In irrigated agriculture, introduction of Water Works Design & Supervision Enterprise In Association with Intorconttnoital Consultants and Technocrats Pvt Ltd. 70Executive Summary Arjo Dedessa Irrigation Project May 2007 manually operated threshers will reduce the time and improve the quality of produce like fodder In due course with change in economy mechanical thresner of varying power range ( 5 to 15 HP) could be introduced not only to thresh the grain but also to provide, good quality fodder for cattle teed This can be owned by big farmers or could be used on custom hiring basis In general for threshing of paddy, pedai operated paddy threshers are quite good and reduces drudgery and also the loss of grains In large farm areas, with high intensity of crops combine harvesting can be adopted on custom hire basis provided the farmers have limited economic use of straw In areas where worx force is not available in adequate numbers, and also to reduce the turn-around time to facilitate increased cropping intensity harvesting with combine harvester is recommended. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 71Executive Summary Arjo Dedessa Irrigation Project 18. AGRICULTURAL MARKETING May 2007 The government of Ethiopia has recently given more emphasis on irrigated agriculture to ennance production and facilitate access to food for more than 50% of the populations laDeied food insecure and thereby generate foreign excnange that will contribute to the development of the country The strategy that the country is following. Agricultural Development Led Industrialization (ADLI) and the guiding strategic framework for the second phase Plan for Accelerated and Sustainable Development to End Poverty (PASDEP, 2005-2010) attaches the highest importance to the use of agricultural inputs and vigorous extension services to shift from subsistence production to market-led commercial production, and thereby by increasing farm productivity and alleviating poverty. The government is also committed to stabilize a sound price to producers and ensure a sustainaole increase in agnculture production and productivity Hence the government liberalized the socialist onented marketing system, which had discouraged the involvement of private traders (between 1975 and 1992) to improve the efficiency of agncultural marketing system. in view of role of irrigated agnculture in the production of high value crops, and that of agricultural marketing as a dynamic force in agncultural development, a detailed market study has been undertaken Accordingly, this market assessment was carried out for the proposed irrigation project areas Bedele and Jimma Arjo Weredas. as about more than 85% of the command area falls under these two woredas The assessment comprised, farmers in both weredas, market participants at all levels: wereda and regional levels, and governmental and non-governmental organizations The methodologies employed in the process were individual interviews, group discussions and field observations. Parallel to it relevant information was gathered from the secondary sources to enrich the assessments: private and governmental market participants were contacted for information, available published and unpublished literature and reports were also consulted The result of the assessment revealed that the utilization of inputs faces vanous problems like: rapidly escalating prices, untimely and inadequate supply and quality deterioration, traditional use of inputs and poor involvement of pnvate traders and credit institution in marketing system. Therefore, targeted subsidy and facilitating the conditions in which Water Works Design & Supervision Enterprise In Association with Intereoatlnental Consultants and Technocrats Pvt Ltd. 72Executive Summary Ar Jo Dedessa Irrigation Project May 2007 healthy competition flourishes are essential to bring about effective and efficient marketing system. The study also attested that rainfed farming is the dominant type of crop production covering about 95 and 94 % of the total cultivated area in Bedele and Jimma Arjo weredas. respectively Of which, cereals comprise some 70 and 80 % of the cultivated areas in Bedele and Jimma Arjo weredas, respectively The situation indicates that the areas are cnaractenzed by extensive agnculture. whicn has expanded at the expense of forests and woodlands. Therefore, the decision to implement the proposed irrigation is considered very appropriate, timely and justified to absorb the landless farmers and in accordance with the policy of the government The proposed culturabie command area is 13665 ha. and annually irrigated area is 24220 ha Thus there is tremendous increase over traditional irngation areas. On the average, as compared to the pre project periods, area envisaged for maize production during the project period will increase from 232.5 ha to 7000 ha Similarly, area projected to vegetables will increase from 224.06 ha to 1400 ha. On average, as compared to pre project penod, the seed requirement will increase from 278 to 30793 qt, while the demand for fertilizer will increase from 26577 qt to 39820 qt. Hence, ensuring a sound pnce, intensive extension service towards production and improving the efficiency of marketing are considered very essential to sustain the proposed irngated fanning According to the Report on Productivity by European Commission (2002) the productivities of cereals and puises were 11 54 and 6.74 qt. per ha. at national level However the productivity of cereals were estimated 93% and 92% below national average for Bedele & Jima woredas respectively The productivity of pulse in Bedeie & Jima woredas is 58% and 59% respectively The projection for the post project penods revealed that the productivity of cereals will increase by 4.73 times, while that of pulses by 1 96% times Therefore, the project would contribute to attain the ultimate aim of the government: secure food for the citizens, bring about a rapid economic development and thereby make poverty a history It was understood that marketing for agricultural outputs have suffered from following constraints: limited market participants that leads to lack of competition, non-existence of financial institution, except banks and inadequate capacity, in terms of knowledge, information and capital, especially lack of credit both for the producers and traders. Therefore, it is very essential to improve the efficiency of agricultural marketing in with the Water Works Design & Supervision Enterprise !■ Auodidoi with IntereontlBaiUl Coumltuts ud Tichaoents Pvt Ltd. 73Executive Summary Arjo Dedessi Irrigation Project May 2007 line in accordance with increase in magnitude & quality of output expected to result from the implementation of the project. Farmers in Doth the sample weredas have Deen recogmzea price takers because of their subsistence nature, overlapping of fertilizer and seed loan collection and taxes with the peak harvest periods ano casn need immediately after harvest for vanous social commitments The retailers also lack access to credit from the financial institutions due to lack of collateral, non-existence of financial institution and are obliged to take loan for a day and/or a week from wholesalers They are to deliver the products immediately and thus the actual and windfall Denefits go to the wnoiesalers and thus the retailers are discouraged to be involved in the transaction. The result of the market assessments reveals that the product produced in the anticipated project areas, especially coffee oil seed/ sesame and niger seed, faba bean, pea and sugar cane would deserve high demand Doth at home and overseas markets and encourage farmers to sustain the products because of its sound pnces It has been learnt that stable crops, teff, maize, sorghum, barley and wheat nave a guaranteed sustainable market due to the proximity of the anticipated project areas to heavy coffee producers and both weredas have Deen recognized as traditional suppliers of the mentioned crops to Gambella Region Therefore, computing a Value Cost Ratio and providing a vigorous extension service towards convincing farmers to produce high value crops are essential both for loan repayment and sustain the production. As regards fruits ano vegetables, despite the favorable environment in the wereads, the areas covered and production obtained are insignificant. Hence, a lot is expected from relevant parties to increase production, cnange the habit of consumption that is skewed to grains, link markets at close proximity ano elsewhere, through providing marketing information and encouraging private investors so as to invest for establishing processing plants. Indeed, inhabitants in the entire command area of proposed irrigation projects have been engaged in livestock reanng. However, they are not fortunate for the best use of the resources because cattle and equines are vulnerable to Tse-Tse fly infestation. Therefore, giving the maximum attention towards controlling ise-tse ano its consideration as an important component of the project is essential to increase livestock production. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt. Ltd. 74Executive Summary Afjo Dedessa Irrigation Project May 2007 ENVIRONMENTAL AND SOCIO-ECONOMIC ASPECTS Chapter 19 Environmental Impact Assessment Chapter 20 Public Health Chapter 21 Socio-economic Aspect Chapter 22 Organization and Management Chapter 23 Settlement Planning Chapter 24 Physical Infrastructure Chapter 25 Financial and Economic Analysis Water Works Design & Supervision Enterprise 75 In Association with Intercontinental Consultants and Technocrats Pvt LuLExecutive Summary Arjo Dedessa Irrigation Project 19. ENVIRONMENTAL ASPECTS May 2007 Experiences in Ethiopia and elsewhere have shown that large-scale dam and irrigation projects usually cause serious environmental and social consequences This nas been proved in many dam and irrigation projects Therefore, the need to incorporate Environmental impact Assessment (EIA) study during the planning ano implementation pnases of large-scale water resource projects has become a pressing issue to minimize the adverse impact on the environment One of the Ethiopia's rivers which nave vast potential for irrigation development is Dedessa, for which a potential dam site ano irrigation commano area nave been identified and feasibility study is being undertaken Environmental Impact Assessment study has been undertaken in order to ensure environmental sustainability of the project Policy and Legal Framework : As the major binding document for all other derivative national ano regional policies, laws ano regulations, the Constitution of the FDRE has several provisions, wnich have direct policy legal and institutional relevance for the appropnate implementation of environmental protection and resettlement action plans to avoid, mitigate or compensate the adverse effects of development actions including dam and imgation projects The overall goal of Ethiopia s water resources policy is to enhance and promote all national efforts towards the impact and optimum utilisation of the available water resources for socio-economic development on sustainable basis lhe policies, proclamations and guidelines relevant for environmental protection in Ethiopia have been reviewed and incorporated into the EIA study. Physical Environment : The Deoessa catchment is characterized by maimy undulating, hilly and mountainous topography with the low lying part having flat to gentle slopes. The geology of the project area is characterized mainly by crystalline rocks (igneous and metamorphic) which is covered by alluvial and colluvial soils. The dominant soils in the project area are ‘black cotton’ soils, which are heavy clay textured, poorly drained and cracking, and they occur on flat land form. In addition, reddish brown soils are found on sloping lands and hills Severe gully erosion is observed along access roads and it is caused by runoff concentrated by roadside drains, disturbance of the soil structure and clearance of the protective vegetation cover Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 76Executive Summary Arjo Dedessa Irrigation Project Ma 7 2007 3 The catcnment area of Dedessa sub-basin at the gauging station near Arjo town is 9,981 km2 and the mean annuai flow of Dedessa at this station is about 3.800 million m It has maximum flow in August and September (52% of the annual) and minimum flow in February and March (less than 15% of the annual). The mean annual flow of Dedessa river at the proposed aam site is estimated at about 2328 Mm Suspended sedimentation rates varying between 45 mg/lt to 1670 mg/lt were observed from Dedessa river The water quality of the river water is generally good and fit for imgation The rainfall in the Dedessa catchment is concentrated during June to September period with virtual drougnt from November through February The annual average rainfall ranges from less than 1500mm to more than 2000mm Bioiogicai Environment: The natural vegetation in the Dedessa Suo Valley is dominantly woodland savannah The sloping lands are dominantly covered by relatively dense woodland while the flatter areas are mostly covered by tall grasses The woodland vegetation mostly consists of Droad-leavea deciduous trees with the ground flora dominated by tall grasses, in addition, there are narrow strips of dense riverine forests along the banks of Dedessa and its tributaries Due to significant increase of human activities in last few years, the larger member of wild animals has migrated away from the project area probably to the downstream area where there are still some intact habitats However, some species of wild animats mainly primate species are still present in the area in significant numbers. Of the aquatic fauna Hippopotamus and Nile Crocodile commonly occur in the Dedessa river Socio - Economic Environment : The proposed project is located in Jimma, llubabor and East Weilega zones of the Oromia NRS. The imgation command, dam and reservoir areas extend over 30 Kebeies in 5 Woredas The majority of the population in the project area belongs to the Oromo ethnic group, and the remaining to the Amahara ethnic group. The source of livelihood for the community in the project area is subsistence agnculture Soil Erosion: Implementation of the project may cause significant soil erosion due to removal of the vegetation cover and destruction of the topsoil and exposure to runoff water erosion. The main causes will be construction of the dam. canals, drains, access and farm roads, clearing and leveling of the irrigation area, extraction of construction materials and establishment of construction facilities At present the landscape of most part of the project Water Works Design & Supervision Enterprise li Association with Intercontinental Consultants and Technocrats Pvt Ltd. 77Executive Summary Ar Jo Dedessa Irrigation Project May 2007 area is well protected by vegetation cover With increased erosion, the sediment loading or water bodies and irrigation structures will also be significant Proposed mitigation measures include execution of construction works in dry season, designing and construction of proper drainage structures, re-vegetation of affected areas, and keeping land clearing and disturbance to absolute minimum. Landscape and Visual Amenity* The major changes to the natural landscape will be related to creation of an artificial lake and extensive farmlands that would replace the relatively diverse natural landscape. Construction of the proposed dam would form an impoundment that would inundate about 85 Km2 area of land, replacing diverse terrestrial landscape by an artificial lake Creation of a reservoir ano irrigated farmlands (about 13665 na) will bnng a significant alteration in natural landscape In addition, exploitation of construction materials and disposal of spoil materials will affect the landscape Sedimentation: The mean annual sediment loads at the reservoir site is estimated at 0 78 Mm3 The creation of a reservoir will attenuate the sediment load that may lead to the sediment free water downstream. This may have a detnmental effect on downstream river channel of Dedessa river The 50 years accumulated total sediment load at the reservoir site is estimated to be about 38.78 Mm3 However this will not have an impact on the economic life of the structure as the reservoir capacity is much higher than the irrigation water demands due to the dam height required for attaining the desired head Impacts on Water Quality: Major impacts on water quality are related to high sediment loads dunng the construction phase and low sediment ratings downstream of the dam during the operation phase as well as due to modification of the natural nver hydrograph Water quality can also be affected by the residuals of agro-chemicals (chemical fertilizers and biocides) used in the irngation area and the catchment of Dedessa river Air and Noise Pollution: Air pollution will occur dunng the construction phase ansing from dust and exhaust emissions. The major sources of air pollution are fuel combustion in construction equipment, dusts generated from excavation activities and vehicular movements and fugitive emissions from crushing plant. There are sensitive receptors such as human settlements, health units and schools within the irngation command area, and along the possible route of access roads to the project site. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 78Executive Summary Arjo Dedessa Irrigation Project May 2007 Adverse Soil Modification: The soils of the project area are dominantly heavy clay soils, which are imperfectly drained and vulnerable to water-logging oue to irrigation A percneo water table due to surplus irrigation water may develop particularly in the areas of clay soils The potential for salinity and sodicity is low as the quality of both the soils and irrigation water is beiow the threshold values to cause adverse effects Loes of Vegetation and Habitats: The largest damages on natural vegetation will be caused Dy the reservoir and the irngation command area. The proposed reservoir will affect about 8500 na of land, of wnich about 32% is open grassland, 61% woodland and wooded grassland, 5% nvenne forest, ana the remaining 2% swamp area. The command area is estimated to be about 13665 ha, of wnich about 13% is open grassland, 69% woodland and wooded grassland, 4% nverine forest, and the remaining 14% cultivated lands and settlement areas. impacts on Wildlife: implementation of the project will bring loss of habitats that support a variety of wildlife species and displacement of wildlife In particular, the irrigation development ano reservoir will affect large areas of wildlife habitats, and disrupt habitat use patterns of the wild animals Resettlement: The reservoir to be created by the proposed dam will affect about 15 Kebeles located along the Dedessa river Totally about 7000 households are residing on the penphery of the inundation area and within 3 km distance from the reservoir The majority of these households may have to be resettled mainly due to health hazards from water related diseases, modification of the micro-climate ano the need to have a protected buffer zone around the reservoir Loss of Land: The proposed reservoir will occupy about 8500 ha of land; over 90% of which is covered by grassland and woodland that is currently used for livestock grazing and habitat for wildlife. The flat grassland areas along the Dedessa river, that are seasonally inundated, are important dry season grazing grounds for large animal populations. Loss of Communication Network: The proposed reservoir will affect four major over crossing points on the Dedessa river that are used by the local population for economic and Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 79Executive Summary Arjo Dedessa Irrigation Project May 2007 social interactions They are foot crossing points but wooden traditional boats are used at one of the crossing points during the wet season increased Risks of Water-related Diseases: During the construction period, there will be increased risks of the transmission of endemic diseases such as malaria ana onchocerciasis ano sexually transmitted diseases Among water related vector-borne diseases, malaria is the major concern during the operation of the aam and irrigation project Potential Positive Impacts : The irrigation project will have the potential to create a range of beneficial impacts. These include creation of job opportunities, increase of agricultural production and income levels of local farmers development of social and physical infrastructure, reservoir fishery development, flood control and potential for wildlife reserves in the buffer zone arouna the reservoir Conclusion : The implementation of the irrigation project will bring a number of beneficial as well as adverse impacts The significant negative impacts include loss of a large area of productive land and associated habitats, involuntary resettlement of local population, loss of traditional communication networks and impediment to movement of iocal population, health nazards from increased prevalence of water related diseases, reservoir sedimentation, soil erosion, landscape intrusion, displacement of wildlife, and deterioration of water quality Most of these impacts can be reduced to an acceptable level through a holistic planning ana implementation of environmental mitigation plan. The proposed project is well accepted by the local population with the expectation that the project would provide better opportunities to improve their livelihood and living standards, and solve the prevailing problems Recommendations : Among the main recommendations drawn from the EIA study are • Because of the significance of the impact on land resource, it is recommended that other possible option(s) shall be considered before final decision is made on the present option • Policy measures may be taken to designate representative habitats for ecosystems conservation. • A proper Resettlement Action Plan shall be prepared and implemented • The analysis for economic viability of the project shall include the value of the land lost due to the project especially the impoundment area. Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 80Executive Summary Arjo Dedessa Irrigation Project 20. PUBLIC AND ENVIRONMENTAL HEALTH May 2007 The major public and environmental nealth problems are found to be mfectious/communicabie diseases related to water borne diseases including malnutrition According to data obtained from the five Woreda Health Sector Offices, Malaria, Fever of un-known origin, Upper Respiratory Tract infections, Intestinal Parasite, Diarrhea. Rheumatic Pain, Gastritis, Anemia. Skin Infection, and Pneumonia are the major diseases prevailing in the project area and its environs Diarrhea and malaria are the leading cause of morbidity among the top ten reported diseases (diarrhea 14 6%, malaria 13 4% for all woreoasj Intestinal parasite stands thiro with about 11% while skin infections stand at 06 % Although, not recorded among the top 10 diseases schistosomiasis may be one of the major health concerns, as Deaaessa catchments have already been identified as one of the foci for this disease A survey of housenoid indicated that 72% of the respondents are producing sufficient food for their family althougn, nutritional value was not cieany indicated, while 28% of the respondents indicated that they are not producing sufficient food for their family wmcn may result in nutritional deficiencies. in general, lack of adequate and safe dnnking water and poor personal hygiene and environmental sanitation are believed to be responsible for the wide spread of intestinal parasites and water bome/related-diseases prevailing in the project areas The currently available health care facilities are few in numbers and low in quality Available facilities including health relateo practices are as follows- In the five Woredas, there are 39 health posts out of 64 health facilities, the highest being in Limu Seka, 13, wnile others have from 05 to 09 These are the front line health services There are also 15 clinics in the five woredas, operated either by public and/or private sectors Three health centres are available in three woredas out of five (Bedele, Jima Arjo and Limu Seka) and all of them are located in their respective towns. Currently, health services coverage ranges from 58% for Getchi to 75% for Jima Arjo. House hold sample survey of the community indicated that 79% have received health education and 98% of them agreed on immunization services. About 97% of the households agreed for the need of family planning with 66% of then using family planning Water Works Design & Supervision Enterprise la Association with Intercontinental Consultants and Technocrats Pvt Ltd. 81Executive Summary Ar jo Dedessa Irrigation Project May 2007 services The majority of the community members (98%) nave responded that they know about HIV transmission and 95% of tne respondents know HIV prevention methods The total numbers of human resources for health-professional and others- in the five woredas are 183 ana the ratio to the population stands at 2,826 Three laboratory technicians are available in three of the woredas, which makes 07% of the total of the three zones The number of environmental health workers in the project woredas is currently eight, 25% of the total for the three zones and 2 1% of the Regional State. These professionals are essential for the day to day monitoring of environmental health activities which is highly essential for the project areas Prevention/control Infectious diseases with a focus on vector control and other water borne/related diseases are cntical to mitigate potential health risks associated with any imgation projects. The essential requirement for vector control is the availability of more than one method of control that favours the action of another method. For such undertakings, an adequate knowledge of the biology ecology and behaviour of the vector and associated non-target organisms and numan behaviour must oe applied to ensure not only effectiveness in controlling the vector but also human safety and prevention of unacceptable side effect. For example, the measures available for the control and/or prevention of the transmission of malana through mosquitoes include the application of insecticides residual or non-residuai sprays from ground or air against adult mosquitoes, and remain the most effective measures to prevent malana transmission (WHO, 2006) Currently, in Ethiopia, spraying of residual insecticide, mainly DDT. is used with environmental management and these operations can be further strengthened with more emphasis on environmental management in the project areas to minimize the risk of vector resistance and danger of the insecticide to non-target group. Fortunately. WHO and Environmental Defense, which launched the anti-DDT campaign in 1960s. have endorsed indoor use of DDT for controlling malana (WHO/Washington, 15 September 2006). Another most important activity in controlling malaria is prompt diagnosis and the proper treatment of the disease. For this to be effective the ability and capacity to diagnose and Water Works Design L Supervision Enterprise In Association with Intercontineatal Consultants and Technocrats Pvt Ltd. 82Executive Summary Arjo Dedessa Irrigation Project May 2007 treat malaria cases require the strengthening of available healtn care facilities, malaria control program sectors with necessary human, finance and material resources Althougn, schistosomiasis has not been reported as one of the top 10 disease prevention of the spread of the disease into the project areas is highly recommended Schistosomiasis can be prevented and/or controlled by the treatment ana through the reduction of contact with water infested by vector snail. An adequate and timely diagnosis and treatment of patients with scnistosomiasis is the primary component of any control program. Effective nutrition education need to be included in a more extensive way in the field of nealth promotion by acting on the multiple factors which influence the nutritional and health states of the vulnerable group Moreover, coordination with existing agncultural nome agents ana NGOs working in the area can produce effective means of improving food production and nutntional status Standard health care facilities in the project areas are very few and those available are not equipped ana staffed accordingly As a result, they can not handle cases of different types locally and the available referral health facilities may be constrained with minor cases Upgrading and/or the strengthening of available health facilities with skilled human resources like microscopists and staffing them with well trained professionals are immediate requirements With these upgraded nealth facilities most of the cases can be handled and related health programs can be expanded. In conclusion, all concerted actions ana precautions have to be taken into account at the earliest with coordinated efforts from the national to the grass root levels with full community involvement and participation. Water Works Design & Supervision Enterprise In AssodnUon with IntercontlnenuJ Consultants ind Technocrats Pvt. Ltd. 83Executive Summary Arjo Dedessa Irrigation Project 21. SOCIO ECONOMIC STUDY May 2007 Productivity of rainfed farming has decreased, and the agricultural sector is now unable to provide the basic requirement to the farming people Traditional farming practices, environmental degradation, lack of external agro-mputs. impact of frequent drought, and a high population pressure nave aggravated the present food insecurity in Ethiopia. This implies the need of launching irrigation projects development based for achieving prime objectives of increasing crop yield and improving the living standard of the people Hence, over the past few decades, irngated agriculture has become more important. Several, previous studies have indicated the potential for developing irrigated agriculture in Dedessa sub-basin, wnich is located in Aooay basin Presently agriculture consists mainly of rainfea annual cropping. Crop yields are low and declining in the project area. Although available reports suggest that insufficient and erratic rainfall is an important reason for low production, there are a number of other factors that needs close examination. These are poor technology, lack of essential inputs, iow pnces and lack of incentives, poor marketing ano weak agricultural support services. Unless remedial measures are taken, the standard of living of the farmers will further decline, especially in view of the current rapid population growth rate of about 2.9 % per year The socioeconomic study is one of the major components of Feasibility Study for Arjo- Deoesa imgation project. The methodology has involved employing both primary and secondary data collection. Thus, related literatures nave been assessed, household survey conducted and public consultation also has been held with the community representatives of the area to collect relevant information ano understand attitudes at grass root level. The study primarily includes assessment of the administrative setups, demographic features of the area, examination of the current living conditions of the people, assessment of the potential socioeconomic impact of the proposed irrigation scheme, assessment of the situation of infrastructures and social services development and examining the attitudes of the would be beneficiaries and so on After analyzing all the collected data and information, a socio economic report has been prepared. The report also tnes to provide basic current information on the socio economic characteristics of the project area. Interpretation and recommendations included in the Water Works Design & Supervision Enterprise 84 In Association with Intcreonttaental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa ImgaUon Project May 2007 report are Delieved to be worthwhile for mitigating adverse impacts ana tuning the envisaged project to its social context. The gross command area is estimated to about 17.825 ha falling mainly in Bedeie. and Jima-Arjo Woredas. very small portion of the irrigable area falls in Gecni woreda as well The net command area that lies on left bank is estimated to be about 7 450 ha (55%) wnile the part of the net command area that lies on nght bank of the Deddessa River, is aoout 6,215 ha (45%) It is located at about midway between the towns of Bedeie and Arjo The right bank of the command area lies in East Woiega Zone ^Jimma Arjo woreaa) ana the left bank command area lies in llluoabor zone (Beddelle. ana Gechi Woredas) The lower part of the potential irngable area is situated along the Deddessa River adjacent to the town of Arjo It can be accessed through all weather Bedeie - Nekemptie road It extends upstream on both sides of Dedesa River at about 32 km from Bedele-Nekemte Road Bridge The middle part of the command area, located on the left bank can be reached by a dry weather road from Bedeie The nght bank area can be accessed from Arjo-Beaele road It is located at about 10 km from Arjo -Bedeie road and 27km to the left from the main road to Bedaasa-Meta settlement area. The jpper part of the left bank command area can be accessed through Gechi It is located at about 39 km from Gechi -Chara -Cheti settlement area. The Ago Dedessa Dam site and reservoir area is located in Jimma Zone. The geographic position of the dam site (axis) in UTM is 257565 m E and 0907545 m N (E 36°48‘ 20” N 8°12' 20"). The reservoir area is estimated to be about 8,500 ha falling in Borecha and Limu seka Woredas. The Dam site is located at about 7km on the road from Limu- Genet to Atango and 16 km to the left from Dora elementary school to Mero (Moga private farm camp). The Dam axis is about 5km from Moga camp The reservoir area can be accessed through Jimma - Limu Genet- Atango all weather road It is located at about 103km from Jimma to Atango and 48 km from Atango to Deneba settlement area. Water Works Design & Supervision Enterprise la Association with Intercontinental Consultants and Technocrats Pvt Ltd. 85Executive Summary Arjo Dedessa Irrigation Project May 2007 The project impact zone consisted of five Woredas (Bedele Getchi Borecha, Jima-Arjo ano Limu-sekea) located in three zones (Eastern Welega, llluoaDor. ana Jima Zones) of Oromia Region There are 30 Kebeies whose area is falling either partially or fully in the command and reservoir area These Keoetes in number represent 18 percent of the total (170) Kebele administrations found in the five Woredas falling under the project impact zone. The thirty Rural Kebele Administrations have a total population size of 73,15. and out of which 38.617 (53 %) are males and 34.540(47 %) females. In other words, these Rural Kebie Administrations, which are falling in the project area (Command & Reservoir Area) are consisting 15% of the total rural population and Household size of the above-mentioned five Woredas falling under the project impact zone Further the average household size of the project area ranges between 4 8 and 5.2 persons per household while literature indicates about 6 6 for Oromiya region As is the case for most other rurai parts of the country, the majority of the inhabitants of the area are dnving their means of livelihood from mixed farming involving both crops production and livestock rearing. However both sectors are not able to satisfy even the subsistence requirements of the household and thus the proiongea poverty among peasant involving a lot of toiling is perpetuating On the other hand, the household survey has indicated that, out of the total surveyed households 96% denve their major source of income from crop production. This indicate that the farming system is dominated by crops production in the area. The distribution of educational institutions and student enrollment rate vanes among Woredas falling under the project impact zone. Lack of education institutions, high student drop out rate ensued from vanous sorts of socioeconomic problems, high student number per class, and lesser participation of girts in all school levels of the formal education systems are the major problems identified by respective representatives during the feasibility study. The health situation of the people and the existing health services with their facilities are not promising in the proposed project area According to data obtained from all Woredas Health Sector Offices. Malana. Upper Respiratory Tract Infections. Intestinal Parasite. Water Works Design L Supervision Enterprise 86 In Association with Intercontinental Consultants and Technocrats Prt Ltd.Executive Summary Ar jo Dedessa Irrigation Project May 2007 Diarrhea, Rheumatic Pain. Gastritis. Anemia. Skin Infection. Urinary Tract infections and Pneumonia are the major diseases, prevailing most commonly in the project area and its environs Most of the above-mentioned diseases are potentially preventaDle that can be alleviated mainly by promoting of Primary Health Care Program which of course is the major strategy stated on the National Health Policy of the country There is also scarcity of potable water provision in the study area The number of potable water supply schemes as well as the capacity and regularity of the services of schemes are found to be much short of meeting the demand of the population. Paradoxically the project area is rich in water resources (which is the very reason for its identification for the proposed project), while the vast majority of the people have no access as yet, to potable water in sufficient quantity and at reasonable distance. All the Worecas capitals in which the proposed command and reservoir areas fall are accessible by all weather roads, with the exceptions of Beaele and Gechi that have asphalt road link. The command area and the dam site are accessible only in dry periods In all the woreda capitals there are Postal as well as Telecommunication services with the exception of Yanfa Except Atenago and Yanfa Town, the remaining three-wereda capitals (Getchi, Bedele and Jimma Arjo/ have electric supply All Kebele Administrations in all the Woredas do not have access to telepnone service, electric power, and postal services Generally speaking, almost all rural keoeles of the Woredas are suffering from problem of in-accessibility. The process of examining the attitude of the people towards the project was treated in two ways. Household survey and public consultations. The nousehold survey revealed that out of the surveyed households 63 percent of the respondents have prior onentation about the project. 78% of the respondents accepted the project with expectation of sustainable production and then better income The respondents expressed their willingness to participate in the forthcoming construction phase in labor contribution (66%). monetary contribution (1%), labor and material contribution (88%). As is the case for most other parts of the country, women of the project area are suffenng from practical and strategic problems. For the purposes of addressing women’s problems. Water Works Design & Supervision Enterprise 87 In Association with Intercontinental Consultants and Technocrats Prt Ltd.Executive Summary Arjo Dcdessa Irrigation Project May 2007 Women’s Affairs Offices of each Woreda are striving currently to change the prolonged traditional and backward attitude of the people towards women. Similar to other development-oriented interventions, this project also will have its own plus ana minus sides in its positive side the project is expected to ensure sustainable food secunty promote family welfare, creates job opportunity, promote educational program, income generating scnemes for women, social service and infrastructural development, and generate agro industry developments To sum up. a long list of benefits can be described regarding the proposed project in addition to merits mentioned above However in order to ensure the accrual of these benefits, the project nas to be narmomzed properly with the existing social context. On the other nand, The Threat of Maiana, displacement of dwellers, loss of social services, are some of the major adverse impacts, for wmcn appropnate remedial measures are required to be undertaken. Dispensing the other details, it is estimated about 20,093 population size clustered in 3,945 households settled in the project area that will displaced in relation with the activities of the project Therefore, it will be worthwhile first to consider preparation of action plan for resettling the identified size of households and redistributing the land among the beneficianes In a nutshell, linkages between irrigation development and socio-economic conditions are many and have diversified impact, both positive and negative. Irngation projects are primarily conceived with and implemented to improve peoples welkoeing and economic conditions. Large numbers of people are likely to be benefited The Arjo dedesa Irrigation Project is one of the most valuable projects for the people in the area, Amhara Region and the country It will enable creation of a number of new employment opportunities, increase foreign exchange earnings and will help creation of market for other sectors Major constraints on developing the project would be impacts due to loss of grazing land, cultivable land, forests and displacement of residents from the reservoir and command areas Water Works Design & Supervision Enterprise 88 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 The study team has carried out field trip and assessed the views of the people towards the proposed project; investigated the overall socio-economic situations of the project area ano identified the potential impacts (positive or negative) due to the proposed project According to the socio-economic study findings, the project is found to De responsive (accepted by the majority of the people in the area) for the fact that the objectives of the project is designed /geared to improve the living standard of the project area in implementing the proposed project, the program should take into consideration people expectation and should be designed and negotiated with the concerned groups and their participation snouid be ensured Resettlement program have to be planned with the participation of all groups of the community (men, women s, religious leaders etc.) so as to mitigate losses and negative impacts and ootam the acceptance and effective involvement of all the people The pressing need of the majority of the population who live in the project area is lacking access and other social services such as access to training, education opportunities, health facilities access roads, and infrastructures facilities. Therefore, it would be better to have these services along with the proposed development This should be done with the involvement of the concerned people and in consultation and good communication with the local government and village leaders Development and dissemination of knowledge and know-how for irngated agncutture through extension and training for the farmers should be taken up An effective project monitoring and evaluation methodology and program have to be prepared for the successful implementation and operation of the project so that the objective of the project is achieved. Lastly as the area to be inundated is too large when compared to the total command area, i.e. 8,500 ha of land to be submerged under water to develop about 14.000 ha of land. This calls for looking other options of using the resources. In other word give due consideration for forgone benefits of the land to be submerged under water Water Works Design & Supervision Enterprise 89 In Association with Intercontinental Consultants and Technocrats Pn. Ltd.Executive Summary Arjo Dedessa Irrigation Project 22. ORGANIZATION AND MANAGEMENT May 2007 The main objective of Organization and Management Study is to assess current policies, practices and institutional arrangements with respect to irrigation development, management, operation and maintenance, to identify problems and strengths in the existing practices; ana to recommend an appropriate organization and management for the project The study is also aimed at iaying down prerequisites and frameworks for future transfer of the project to regional and local authorities and involvement of beneficiaries in planning, design, implementation, operation and maintenance. The methodologies adopted for acquiring relevant data and information for this study includes interviews, document reviews field visits and discussions with other technical specialists of the study team. The views and concerns of major stakeholders at Federal, Regional and Woreda levels have been also considered and incorporated in the analysis and recommendations of the organization and management study Organizational and Managements Recommendations : The organization and management of existing irngation projects in Ethiopia have little relevance to the envisaged Arjo-Diddessa Irrigation Project except the Koga Irngation Project, which is currently under construction. The proposed organization and management for the Koga irngation Project during its feasibility study vis-^-vis the current practice has been, therefore, critically reviewed and assessed in order to arrive at an appropriate conclusion necessary for recommending effective and efficient organization structure for the Arjo-Diddessa Project. The consultant has also reviewed the experience of other countries in Asia and Europe, through document reviews, to get in-depth understanding about the current trend and practices in irrigation system management. The organization and management recommendations are made in two pnases. For the planning, design and implementation phase; and for operation and maintenance pnase During the planning, design and implementation phase, the Ministry of Water Resources is the owner, and is primarily responsible for the proper and successful implementation of the project. The proposed organizational structure for this phase of the project is presented in Fig 22.1. Water Works Design & Supervision Enterprise la Association with Interconttnental Consultants and Technocrats Pvt Ltd. 90Executive Summary Ago Dedessa Irrigation Project May 2007 During the 2nd phase of operation and maintenance, the ownersnip management, of the project will be transferred to the Oromia Irrigation Development Authority The scheme with all its structures shall be under the control of the Region s Irrigation Development Authority A separate project office will be established under the Authority to carry out the management, operation and maintenance activities. The operation and maintenance at the lower portion of the irrigation scheme, i.e tertiary and quaternary canals will be gradually transferred to the organization of local farmers under Participatory irrigation Management (PIM). The proposed organizational structure for Phase-ll, of Operation & Management is available in Fig. 22.2. Fig 22.1 - Proposed Organization Structure for the Planning, Design and implementation Phase -------------------------- Regional Steering Committee —- Planning, Follow Up and Evaluation Team : Administration and Finance Unit ---------------------------- Water Works Design & Supervision Enterprise 91 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 Figure 22.2 - The Proposed Organization Structure for Operation and Maintenance Phase Water Works Design & Supervision Enterprise In Association with Intoreontinatal Consultanu and Technocrats Prt Ltd. 92Executive Summary Arjo Dedessa Irrigation Project May 2007 Participatory irrigation Management: Participatory irrigation Management (PIM) has assumed importance because of its role in improving the water use efficiency ano quality of irrigation services in view of the followings • Huge financial requirement for irrigation sector ■ increasing demand for water under other sectors ■ Overall scarcity of water • Delay in irngation development ■ Adverse economic impact resulting due to aoove reasons Besides, there is a significant increase in demand for irrigation requirement as the irrigation facilities are being expanded considerably to meet the demand for the ever-growing population. PIM is aiso expected to play important role in improving the quality of irrigation services, whicn is essentially needed to obtain optimum agricultural production with available limited land ano water resources. Therefore it is proposed to introduce PIM into the proposed Arjo-Diddessa Irrigation Project, especially at micro irrigation level for operation & maintenance Training Requirement: Identification of training needs for the proper execution and operation of the project and for optimization of benefits from the irrigation scheme has been made in four categories depending on those involved in the implementation process. These are (i) Irngation Engineers including other supporting staffs that are responsible for the planning, design, implementation and operation activities (ii) Agnculturai scientists: including extension workers who are expected to provide assistances and guidance in the field of irrigated agnculturai farming to the farmers. (iii) Water users associations: These include the members and the officials of the Water User Associations proposed to be formed for introducing Participatory Irrigation Management. They are the representatives of the real beneficianes, i.e , fanners. (iv) Farmers: They are the beneficianes and the important stakeholders They are those who are going to optimize the agricultural produces with limited land and water resources. Water Works Design & Supervision Enterprise 93 bi Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 Operation and Maintenance : Large irrigation systems like Arjo-Diddessa Project require huge initial financial outlays as the purcnase of machineries for implementation and operation and maintenance are mandatory for which, external funds in the form of loan and grants will oe, therefore, needed Recurrent costs sucn as salary of local staff and cost of maintenance for the nead works, the primary ana secondary canals, however can be covered through allocating budgets by the regional government. Routine maintenance at the lower level of the scheme, tertiary and quaternary canals shall De covered through revenue from water charges to be collected and administered by the users themselves For maintenance costs beyond local capacity at tertiary and quaternary level, government assistance througn responsible authority, the irrigation Development Authority will be required Water Works Design & Supervision Enterprise Id Association with Intercontinental Consultants and Technocrats Pvt Ltd. 94Executive Summary Arjo Dedessa Irrigation Project 23. SETTLEMENT PLANNING May 2007 The major objective of the settlement planning study is to assess and analyze the impacts of the Arjo Dedesa Irrigation Project on natural and social environments vis-a-vis tne need for resettling certain proportion of the inhabitants of the project areas The most significant part of the study is establishing oaselme information on possible dislocation of people from the project area and related adverse impacts of the project so as to design mechanisms by which such occurrences are avoided or at least mitigated. The baseline information will also serve as a bencnmark against whicn future monitoring and evaluation of achievements of the resettlement program will be measured Qualitative research methoo with different techniques of data collection was used in this study The tecnmques included Key informant interviews, Focus Group Discussions review of literature ana documents, secondary data collection and on-site observation. As is common in any large scale development initiatives, it is inevitable that the implementation of this project will entail expropriation of land and certain magnitude of damage on properties of the people residing in the direct impact zones of the project The properties that may befall sucn carnages are categonzed into two categories These are communal properties ana individual properties and the resource category determines the type of compensation The major constraint related to development induced resettlement programs and compensation for damaged properties is not only the fact that most states have not yet signed legally binding international documents that provide specific or comprehensive rights for development displacees, but also that they have no national policies to deal with the problem. The World Bank was the first multilateral lending agency to adopt a policy for Resettlement and Rehabilitation (R4R) The Banks present policy is contained in the document "Involuntary Resettlement," Operational Directive (OD) 4.30 adopted in June 1990 Despite this constraint, however, there are a number of national legislations and legal provisions (besides the international treaties), which are relevant and applicable to resettlement processes and implementation. Water Worts Design & Supervision Enterprise In Association with lnurcondnontal Consultants and Technocrats Pvt. Ltd 95Executive Summary Ar Jo Dedeisi Irrigation Project May 2007 The Constitution (FDRE 1995) as well as the Civil Code contain articles which are relevant to development induced displacement and resettlement Moreover though mere is no guideline for resettling households to be displaced by large-scale irrigation development projects the resettlement and rehabilitation framework of Ethiopian Road Authority (ERA) which was published in February 2002 is also found relevant to development induced displacements in other sectors One area that calls for precaution m the implementation of large-scale projects is avoiding damage on communal properties especially those perceived as cultural heritage and/or those having religious significance The assessment reveaied that there are no such properties in both the reservoir and command areas Although there are a few mosques and religious centers within the recently established settlement areas they are newly built on a temporary basis and have no historical significance and are easily replaceable The few Churches in the old settlement areas (now mostly in the command area), which probably have mstoncal significance are also built on places not fit for irrigation or canai routes and access roads, such as picks of hills and thus could hardly be affected Moreover it is assumed that the project will take all technically possible precautions to avoid damage on such institutions in the same manner it did in the case of other projects There is therefore no need to replace such religious and cultural neritages even if it were possible to replace them Nevertheless available data showed that there are a numoer of schools, health facilities residence houses of DAs. and kebele offices, in the 30 project impact kebeies. which might be damaged at various levels and should be compensated for Of these 15 of each kind are within the reservoir area (in Umu Seka where the entire 4 Kebeies will be submerged and 11 kebeies from Borecha. where only parts of them will be submerged) While the vast majority (at least 80%) of the latter may inevitably be demolished, it is assumed that only 20% of those within the command area will have similar fate Based on this calculation the project might be obliged to build or rejuvenate a total of 15 schools. 15 health institutions 15 kebele offices and 15 DA houses Of these 7 from each kind are to be built In the 1 selected resettlement sites, while the remaining budget should be expended for either repairing or upgrading facilities and/or building new once within the command area where from people may not be dislocated Water Worki Decifn & Superrislon Enterprise lfl AuoelaUon with lntereentlnenui Connltanti and Technocrats Pvt Ltd %Executive Summary Arjo Dedessi Irrigation Project May 2007 Concerning people to be dislocated, it is estimated that about 6,375 people clustered into 1,275 households, are living in kebeles and/or villages that will De submerged Despite the fact that out of the 15 kebeies to be affected by the reservoir only 4 will be wnolly submerged, it is assumed that all residents would be resettled just to be on the safe side Accordingly the number of households to be displaced is 1,275. Of these 10% are estimated to have houses with roofs of corrugated iron sheet, while the rest have houses with grass thatched roofs On the other nand, the total estimated number of people living in the command area is 13,350. the number of households being 2.100 Given that most of these kebeles are sparsely populated and most are to be only partially affected, it is assumed that only 20% of the total population residing in these kebies might need to be resettled Moreover, it is assumed that there may De a possibility of accommodating some of them within the already existing settlements The number of households to be dislocated will thus amount to 420 Thus the total numDer of households to be resettled from the reservoir and command areas has been estimated as 1695 As the irrigated land is for the displaced people, it is proposed that no compensation for loss of land is to be made, instead resettlement site and the imgated farm will be provided. The compensation will rather De for costs of relocation (transfer), demolished houses, fences, and damaged/abandoned perennial crops and trees As observed, the houses in the area are of two types: Wood and mud wall with corrugated iron sheet roofs and predominantly wood and mud wall with grass roofs. Most of the houses have wooden fences and few perennial trees around the houses, except those owned by the recent settlers. The perennial trees are estimated to be 10-12 on the average and sometimes include fruit trees such as mango. Thus, two options could be proposed for resettling the would-be displaced households The first option is paying out money for the individual HHs for the houses and other properties to be demolished so that each HH will rebuild as he wishes in the area to be provided. The proposed payment rate based on previous experience is as follows Water Works Design L Supervision Enterprise 97 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 2 ■ Birr 1,200 per m2 for houses with corrugated iron sheet and wood and mud wall ■ Birr 600 per m for houses with grass root and wood and mud wall ■ Birr 80 for wooden fence per meter length. ■ Birr 1,000 for each HH assuming the cost of transferring and interruption. ■ Birr 60 for perennial trees ■ Payment for each HH to be displaced for the number of construction period (years in which farmers will not get benefit from the land) based on the average annual income of HH in their previous residence In the second option the project implementation authority will construct standardized residence for all the displaced households and provide the finished nouses. Still payment has to be made for transferring to the new site and for trees. The following criteria have been taken into consideration for resettlement site selection • The sites should be located on marginal lands (not suitable for irrigated agriculture within or out of the command area) • The settlement sites snould not be to far from the farm (not more than 5-10 KM) • The sites should as far as possible be closer to existing infrastructure and established services (markets, road, health services, education services, eiectncity, water supply teiepnone bank, administrative, etc.) • Probable sites for settlement should be acceptable to the community In accordance with these criteria, seven sites, 1 in Jimma Arjo, 1 in Limu Seka, 2 in Borecha 1 in Gechi, and 2 in Bedeie woredas have been selected at the penphenes of the command area from the respective directions of the relevant woreaas Besides compensation for the properties that the displaced people have to lose, both at individual and community levels, it is imperative that appropriate mechanisms of rehabilitating them are in place, indeed rehabilitation is understood as part and parcel of resettlement in current resettlement approach Rehabilitation measures may include provision of a package of support items and programs. Water Works Design & Supervision Enterprise la Association with Intercontinental Consultants and Technocrats Pvt Ltd. 98Executive Summary Arjo Dedessa Irrigation Project May 2007 The package may consist of provision of grain aid till the resettlers collect the first narvest after resettlement, provision of loans, provision of fertilizers and processed seeds tree or on credit, provision of training in soil and water management, livestock Dreeding, and other vocational training opportunities One crucial but often-negiected issue, in relation to development-induced displacement and resettlement, is gender consideration. In line with many research outputs a World Bank research demonstrates compellingly that greater gender equality translates into greater economic growth, less poverty and more sustainable development (World Bank 2001). It is therefore imperative to take all necessary a priori arrangements to ensure that women get the share they deserve not only from the project’s anticipated benefits, but also in terms of participating through out the process including playing of decision making roles Moreover deficiency in terms of capacity of worda Administrations to implement the resettlement program is also observed despite the fact that they are legally mandated to plan and implement all development initiatives as well as resettlement programs in accordance with the devolution of power and decentralization process issued in the proclamation No 455/2005 It follows then that the project has to plan and execute programs to the effect that the capacity of its local partners is adequately enhanced. One area of the problem related to this deficiency relevant to resettlement is assumed to be reluctance to recognize the legal entitlement of resettires to participate in the process and to claim their rights when they think these are violated Another important, but often lacking factor, is the commitment of officials and staff at all levels in the administration ladder. This is an issue that deserves close monitoring and prompt rectifying measures from all concerned bodies. Community structures, especially Idirs, could play important roles in assisting the smooth execution of the resettlement program. More specifically they can help to resolve possible conflicts, they can help to identify illegal claimants (people who are not residents of the project area), they can mobilize labor, and can be effective vehicles of information dissemination and awareness creation. It is therefore advisable that the local wo red a Water Works Design & Supervision Enterprise 99 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessa Irrigation Project May 2007 administrations involve and make use of these associations in activities related to the resettlement program. Equally important, may be even more so. is the direct or indirect participation of affected peopie in decision-making, implementation, operation, and evaluation of the resettlement program from the perspectives of both settlers and host populations The project is responsible for the overall implementation of the irrigation scheme and all activities that are related to this task in one way or another Besides the realization of the project, its major and challenging responsibility is ensuring that the project implementation is executed with little negative impact on the people and taking appropriate mitigating measures when such impacts are unavoidable. Therefore, besides the points suggested in the preceding pages, the following follow-up actions are recommenoed based on the findings of the assessment: ■ A longer and intensive fieldwork should be arranged to carry out investigation and detailed inventory of the properties of potential displacees and their resources, as well as identifying host communities and their potential, so that it would be possible to further improve the suggested resettlement and rehabilitation plan ana implement it in a more viable manner ■ An independent office which will have the mandate to mediate between the project ana the iocal people must be establishea for the success and smooth operation of the planned development. The independent office to be established may have higher decision-making body, may be a board, which will have members from relevant government offices, representatives of the community and the project implementation agency. ■ The rural development office (Agriculture office) should play crucial role in organizing the farmers introducing modem agricultural production technology suitable for farmers to be settled (Dairy poultry, bee keeping, horticulture, fishing, etc.) ■ A continuous training on different aspects of agricultural as well as other development activities has to be given including family planning, environmental protection, and sanitation for all members of the community, etc Water Works Design & Supervision Enterprise In Association with InttreontlnenU! Cansnltants and Technocrats Fvt Ltd. 100Executive Summary Arjo Dedessi Irrigation Project May 2007 ■ Follow up in terms of ensuring the enhancement of the community s awareness has to be seriously considered, and should not be undermined as it has been in the past ■ It is important to make use of the informal community leaders to oring the issue to the grass root level (to the vast majority of the community members including women and children) ■ The settlement plan has to consider the further capacitating of already constructed infrastructures and service giving facilities such as schools, health posts, ano veterinary posts, while providing new ones in the new settlement sites ■ The rural development office (the woreda agriculture office) together with the cooperative promotion office at the Zone level has to start preparing the ground for the establishment of cooperatives in the planned development area to efficiently implement the proposed development project. • Registration of households in each KeDele association has to be done as early as possible Otherwise, if late, may create problem by attracting people from Keoeies outside of the Kebeles currently considered • Active and genuine participation of the Communities of the project impact zones in all activities of the resettlement program should be ensured; ■ Ensure the full participation of women in the resettlement program, as well as implementation of other measures that would help mitigate gender —specific problems. The various stakeholders, especially the Administrations of the five project woredas ano the Project, should exert all possible energy and time for the successful implementation of the resettlement ano rehabilitation program by putting into action their responsibilities. Water Works Design & Supervision Enterprise 101 la Association with tatertontinntal Consultants and Technocrats Prt Ltd.5. S. S. S. 8.1B B B. IliiiiiwExecutive Summary Arjo Dedessa Irrigation Project 24. PHYSICAL INFRASTRUCTURES May 2007 The infrastructure study of the Dedessa irrigation Project includes access roads water supply and sanitation for resettlement sites, settlement shelters, energy school and health facilities and communication services The objectives of the infrastructure study includes assessment of existing infrastructure situation such as access roads, water supply and sanitation, energy, communication, housing, education and nealth facilities, etc, and proposing and recommending adequate infrastructure for resettlement sites and displaced people The methodology that has been adopted includes literature and map review, interviews, consultative meetings, data collection and direct observation The project area has very limited road accessibility, highly limited water supply and sanitation facilities, inadequate energy and communication services, poor education ana health facilities The Decessa Imgation project is expected to affect 1275 households (HHs) in reservoir area ana 2100 HHs in the command area Taking the household size as 5.1, the population to oe affected amounts to 6503 in the reservoir area and 10,710 in the command area. The affected HHs in the reservoir area (1275 HHs) will be fully displaced and will have to be resettled, while those in the command area (2100 HHs) will be partially displaced and it has been estimated that about 20% of the total house nold in the area will be displaced due to construction of the canal system and other proposed structures Thus the house nold to be resettled in the command area will be 420 only Therefore, the total HHs to be resettled comes to 1700 Five resettlement sites have been proposed, two on the right bank and three on the left bank of the Dedessa River Each site is to accommodate 340 HHs. The five resettlement sites that have Deen proposed are on the penphery of the command area. The sites have been selected such that people will not be very far from their farms Alongwith the infrastructure for resettlement of the displaced households from the submergence under the reservoir and the from the command area due to location of different components of the project, the infrastructure required for project staff to be engaged for the implementation as well as the operation and maintenance of the project has also been considered and provided for infrastructure consisting of access roads, water supply & sanitation, housing units for displaced people, as well as for project staff required Water Works Design & Supervision Enterprise In Association with bitercontinental Consultants and Technocrats Pvt Ltd. 102IllllllllExecutive Summary Arjo Dedessa Irrigation Project May 2007 for operation & maintenance of the project, energy supply schools, health facilities, etc has Deen developed and proposed Cost estimates for all infrastructures proposed nave been made, and the summary of costs is indicated below - Access Roads 128,700.000 Birr Water Supply & Sanitation 5 800,000 Birr Energy Supply 6.800,000 Birr Housing Unites 56.100.000 Birr Schools 1,000,000 Birr Health Facilities 600.000 Birr Housing for project staff 12. 680.000 Birr Grand Total 211,680,000 Birr The participation of the people to De settled is very vital in the planning and implementation of detailed resettlement programme The Provision of infrastructure in the project area is expected to create jobs for the iocal people during construction. Promotion of health, hygiene and education should De made among the settlers regarding the water borne and water related diseases Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 103Arjo Dedessa Irrigation Project May 2007 25. FINANCIAL AND ECONOMIC ANALYSES irrigati on developments have become progressively more expensive as less favorable sites are now being aevelopeo Therefore irrigation proposals require careful economic appraisal. The objectives of the present study are • To carry out financial analysis to determine the extent of financial viability or the project • To carry out economic analysis to measure the real contribution which the project will make to the national income in order to decide wnether it is worth while to invest in this project or not • To carry out sensitivity analysis in order to test the stability of the economic parameters The project with a capital cost of 1003.9 million ETB has been designed to serve a command area of 13665 ha It is proposed to raise ten most potential crops such as Rice. Wheat, Maize, Groundnut, Sesame, SoyDean, Cabbage Potato, Coffee and Alfalfa Apart from meeting the nousenoid food requirements crops like coffee and sesame will provide export earnings and Alfalfa will meet the fodder requirement of the livestock. Keeping in mind the capacity limitation of the smallholder a cropping intensity of 173% has been proposed at the full development of imgation resources. Economic life of the imgation project has been considered for 40 years Both the financial and economic analyses have been carried out by considering all the relevant costs and benefits ‘with ‘and without’ project. The costs and benefits have been considered in constant terms. The cash-flow has been discounted at 10%, the opportunity cost of capital. Prices used in the economic analysis are real prices reflecting the shadow paces for making adjustment in the market pnce distortions. Water Works Design & Supervision Enterprise la Association with Intercontinental Consultants and Technocrats Pvt Ltd. 104Executive Summary Arjo Dedessi Irrigation Project May 2007 Three possible scenarios nave Been considered nere for sensitivity test These are - A 5% increase in cost stream and no cnange in benefit stream - A 5% decline in benefit stream and no cnange in cost stream - A 5% decline in benefit stream and a 5% increase in cost stream The result of the financial analysis reveals that the NPV of the incremental benefits of the project is ETB 607 5 million, the BCR is 1 87 and IRR is 15.47% The result of the Economic analysis indicates that the NPV is ETB 1311.8 million, BCR is 3.173 and IRR is 22.06% Sensitivity analysis in both the cases - financial and economic - affects the result marginally, suggesting that the project is not only viable, but also very much stable In view of the results obtained in this evaluation study it is strongly recommended that the Arjo-Dedessa Irrigation Project may be implemented at the earliest to avail the cost over Increasing productivity of crops is the only realistic option to raise the living standards of the population and to ensure food security and poverty alleviation. It is now realized that irrigation provides the livelihood for large numbers of economically marginal people However, better imgation management is only possible with high levels of cooperation between farmers and imgation engineers as organizing efficient water distribution and application depends upon a strategic participatory approach. Therefore, an appropnate enabling environment is a necessary condition to achive the objectives of the Imgation Project. Our past experience has at times not shown desired results as anticipated in Feasibility study stage. Because of certain constraints the cropping intentisty as well as productivity levels were snort of the targets. Keeping this point in mind, it is suggested that a mission mode action plan may be followed along with the project intervention. The action plan should include: • Identification of issues and challenges in the context of efficient irrigation management • Creation of opportunity for shanng and learning from positive experiences on efficient irrigation management from national and international perspectives Water Works Design & Supervision Enterprise 105 In Association with Intercontinental Consultants and Technocrats Pvt Ltd.Executive Summary Arjo Dedessi Irrigation Project May 2007 • Formulation of grass roots initiatives for capacity building of stakeholders and building local leadersnip for irrigation sector management • Introduction of various management tools for upgradation capacity of the farmers and technical manpower including extension agencies • Establishment of database and weo-friendly networking for online dissemination of information and monitoring of activities • Promotion of innovative Public-Private Partnership (PPP) models for improving support services system in integrated land-water-environment management • Target the vulnerable groups for service delivery and empower them by formulating self-neip groups (SHG) and linking them with micro-credit institutions • Enlist Deneficianes contributions to O & M by cash and/or kind form for ensuring sustainability of project • Promotion of proper infrastructure or strengthening support services • Promotion of proper local level institutions such as Water users. Associations (WUAs), Micro-Financing institutions (MFIs), woreda / kebele level, agriculture promotion committees for ensuring timely and quality supply of inputs at fair prices Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd. 106
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