Summary of the Upper Beles Irrigation and Drainage Scheme Feasibility Study
Overview
This document is Volume 4 of the Feasibility Study Final Report for the Upper Beles Irrigation and Drainage Scheme in Ethiopia, focusing on Soils, Land Use, and Suitability. The study was conducted by Halcrow Group Limited in association with Generation Integrated Rural Development (GIRD) Consultants, funded by the World Bank, and completed in May 2011.
Key Findings
1. Project Location and Goals
- Location: The Upper Beles Scheme is located about 30 km southwest of Lake Tana, within the Amhara and Benishangul-Gumuz Regions of Ethiopia.
- Goals:
- Promote sustainable smallholder-based irrigated agriculture.
- Reduce poverty and improve rural livelihoods.
- Enhance food security and involve the private sector in large-scale irrigation development.
2. Soil Survey Methodology
- Survey Area: 137,626 hectares.
- Methods:
- Soil auger survey (5,111 sites).
- Soil profile pits (306 described and classified).
- Laboratory analyses and in-situ tests (infiltration, hydraulic conductivity, etc.).
- Mapping: Produced Soil, Land Use, and Land Suitability maps at 1:100,000 and 1:20,000 scales.
3. Soil Types and Characteristics
| Soil Type | Percentage of Area | Characteristics |
|---|---|---|
| Vertisols | 50% | Deep cracking clays, poor drainage, moderate fertility |
| Nitisols/Luvisols | 14% | Deep red clay soils, well-drained and fertile but acidic |
| Cambisols | 5% | Brownish clay soils, associated with eroding land |
| Leptosols/Regosols | 31% | Shallow and/or stony soils, unsuitable for irrigation |
4. Land Use and Cover
- Rainfed Farming: Covers 32% of the study area, primarily on red clay soils and Cambisols.
- Natural Vegetation: Grassland (38%), woodland (22%), and riverine forest (5%).
- Challenges: 37% of rainfed farming occurs on land unsuitable for irrigation due to steep slopes or shallow soils.
5. Land Suitability for Irrigation
- Suitable Land: 55% of the study area (75,833 ha for surface irrigation, 76,008 ha for pressure irrigation).
- Classification:
- Suitable (S2/S3): Land with manageable limitations.
- Conditionally Suitable (N1): Requires soil conservation or drainage improvements.
- Unsuitable (N2): Steep slopes (>12%), shallow soils, or dissected land.
6. Recommendations
- Drainage: Essential for Vertisols to mitigate waterlogging.
- Soil Conservation: Required for slopes >3% to prevent erosion.
- Fertility Management: All soils need organic matter and nutrient inputs for sustained productivity.
- Irrigation Methods:
- Surface irrigation feasible on gentle slopes (<8% for Vertisols, <12% for non-Vertisols).
- Pressure irrigation (e.g., sprinklers) recommended for steeper slopes.
Conclusion
The study identifies significant potential for irrigated agriculture in the Upper Beles area, with over half of the land suitable for development. However, successful implementation will require careful management of soil limitations, drainage, and conservation measures to ensure sustainability and productivity. The findings provide a foundation for detailed planning and investment in the region's agricultural development.