Dabus Irrigation Study and Design Project - Technical Specifications Summary
1. Project Overview
The Dabus Irrigation Development Project is located in Benishangul Gumz National Regional State, Ethiopia, approximately 55 km east of Asosa town. The project involves the construction of complete irrigation infrastructure for an irrigable area of 10,000 hectares.
Key Components:
- Conveyance and distribution systems with clay/geomembrane lining
- Associated structures (night storage reservoirs, road culverts, bridges, etc.)
- Infield drainage and flood protection system
- Service, access, and field roads
- Land leveling of irrigation fields
2. Project Location and Physical Information
| Parameter | Details |
|---|---|
| Location | Right and left bank of Dabus River, boundary of Menge and Oda Bildiglu weredas |
| Coordinates | 10°02' to 10°14' N and 34°51' to 35°02' E |
| Altitude | 850 to 1,100 meters above sea level |
| Access | Near Fudindu kebele market town with all-weather gravel road connection to Asosa |
3. Technical Specifications
3.1 Earthworks
Detailed specifications for:
- Channel and dike construction
- Excavation and disposal methods
- Compaction requirements (95% of maximum dry density for embankments)
- Impermeable clay lining specifications
3.2 Concrete Works
| Concrete Class | 28-day Strength (N/mm²) | Minimum Cement (kg/m³) | Max Water/Cement Ratio | Application |
|---|---|---|---|---|
| A (C-30) | 30 | 380 | 0.45 | Prefabricated elements |
| B1 (C-25) | 25 | 350 | 0.45 | Reinforced concrete cast in situ |
| C (C-15) | 15 | 250 | 0.60 | Binding concrete to structures |
3.3 Structural Steelworks
Includes fabrication and erection of:
- Slide gates and flat gates with operating devices
- Emergency shutters/stoplogs
- Trash-racks with guide profiles
- Handrails and bridge components
- Water conveyance pipelines
4. Environmental and Quality Considerations
Key Requirements:
- Water quality standards for irrigation and household use
- Soil conservation measures during construction
- Protection of existing vegetation and settlements
- Strict quality control for materials and workmanship
- Compliance with ASTM and other international standards
5. Project Implementation
5.1 Contractor Responsibilities
- Submit detailed work plans and schedules
- Provide all necessary equipment and materials
- Maintain quality control through testing and inspections
- Coordinate with other contractors working on related projects
5.2 Engineer's Role
- Approve all designs, materials, and work methods
- Conduct inspections and quality control tests
- Monitor progress and compliance with specifications
- Approve all changes to the original design
6. Appendices and Reference Data
The document includes detailed appendices with:
- Location maps of the project area
- Groundwater chemistry data
- Monthly climatic data and evapotranspiration calculations
- Flood estimates for various return periods
- Soil characteristics and hydraulic properties