Arjo Dedessa Irrigation Project Feasibility Study Summary

Project Components

Component	Description
Primary Canals	Right Primary Canal (7 sheets) and Left Primary Canal (9 sheets) with detailed longitudinal profiles
Secondary Canals	Including RS-16, RS-17 with longitudinal profiles
Tertiary & Quaternary Canals	Multiple canals with detailed designs (RT-16 series, etc.)
Drainage System	Secondary and tertiary drains (RDS-15, RTD-16 series, RTD-17 series)
Structures	Head regulators, cross drainage structures, spillways, and service roads

Key Drawings and Maps

Drawing No.	Description
AD-F-irr & Drail ./01	Administrative units map of project area
AD-F-irr & Drail ./03	Soil map of command area
AD-F-irr & Drail ./05	Layout of canal system
AD-F-irr & Drail ./14-16	Typical cross-sections for primary and secondary canals
AD-F-irr & Drail ./15	Cross-sections of Right Primary Canal at 0.555km and Left Primary Canal at head reach

Technical Specifications

• Slopes: Ranges from 0.0002% to 0.641% for different canal sections
• Roughness coefficient: 0.0225 (Manning's n)
• Typical dimensions:
  • Primary canals: Bed width varies, full supply depth ~0.5-1.0m
  • Secondary canals: Smaller dimensions than primary
  • Tertiary canals: Typically 750mm width
• Materials: Various soil types identified including clay, sandy clay loam, and heavy clay

Project Features

• Command area with detailed land suitability analysis
• Reservoir and dam components
• Integrated drainage system parallel to irrigation canals
• Service roads and farm access roads
• Multiple turnouts for field channels

Design Standards

The project follows standard irrigation engineering practices with:

• Detailed longitudinal profiles showing ground levels, full supply levels, and canal bed levels
• Cross-sections showing cut-and-fill requirements
• Hydraulic particulars including discharge, velocity, and slope for each section
• Freeboard requirements specified (typically 0.6m above full supply level)