Butajira Irrigation Project Summary
Project ID: h/82/304
Location: Approximately 25 km west of Ziway, Ethiopia
Date: April 1987
Cooperating Organizations: Government of Ethiopia, Food and Agriculture Organization (FAO) of the United Nations, United Nations Development Programme
Project Background
The Butajira Irrigation Project was initiated following the devastating drought of 1985 to conserve water and provide relief against future droughts. The project focuses on a dam site on the Moja River identified during reconnaissance visits, with potential storage capacity exceeding 200 million cubic meters and an irrigable area over 6,000 hectares.
Key Components
1. Topographical Survey
Surveys completed for dam site, reservoir area, and command areas. Benchmarks established along the Moja River for orientation.
2. Land Resources
Approximately 3,000 ha of suitable land identified with potential to expand to 6,000 ha. Soils are deep, fertile volcanic ash soils with some drainage concerns.
3. Water Resources
Mean annual inflow estimated at 75 million m³. Reservoir capacity curve developed. Alternative dam sites investigated to optimize irrigation potential.
4. Crop Water Requirements
Calculations for major crops (maize, wheat) including evapotranspiration, effective rainfall, and irrigation efficiency (40% overall). Annual water requirement approximately 1,300 mm/ha.
5. Irrigation System
Furrow irrigation recommended as primary method due to topography and soil conditions. Details provided on furrow slopes, lengths, flow rates, and application methods.
6. Phased Development Plan
| Phase | Area | Elevation | Water Delivery Method |
|---|---|---|---|
| I | 100 ha | below 1,812 m | Gravity |
| II | 900 ha | below 1,820 m | Pumped (self-generated power) |
| III | 3,000 ha | below 1,825 m | Pumped (grid power) |
7. Infrastructure
- Low level main canal with 1:2,000 gradient
- Pipeline and pump station for Phase II development
- Main, secondary and field canals
- Drainage systems (subsurface and surface)
- Roads and support buildings
Key Findings and Recommendations
- Project area shows good potential for irrigation development with suitable soils and water availability
- Additional dam site investigations needed, including core drilling to assess foundation conditions
- Hydrological data collection recommended to verify water availability estimates
- Detailed topographical surveys required for full project area
- Furrow irrigation recommended as most suitable method for local conditions
- Phased development approach proposed to match water availability with infrastructure development
Appendices
The full report includes detailed appendices covering:
- Soil Report
- Geological Report for Moja Dam Site
- Reservoir Simulation
- Water Quality Results
- Soil Test Results