The Sio-Malaba-Malakisi river basin is shared between Kenya and Uganda. The Project was one of the three trans-boundary river basin management projects implemented under the framework of the Nile Equatorial Lakes Subsidiary Action Program (NELSAP) and managed by the Nile Basin Initiative (NBI). Its objective was to establish a sustainable framework for the joint management of the water resources of the Sio-Malaba-Malakisi river basin, and to prepare for sustainable development-oriented investments: in fact, the project assessed the potential and viability for multipur-pose water resources development in irrigated agriculture, hydropower generation, livestock development, water sup-ply, flood control and protection, drought mitigation, aquaculture, etc., together with the restoration of the associated sub-catchments.
Feasibility studies, detailed designs and tender documents for the following infrastructure were prepared:
1. An earthfill dam with clay core. Dam Type = Composite dam with central concrete spillway (45m long and 24m high) and rockfill clay core embankments, Dam Height = 24m, Reservoir Capacity = 3,900,000m³, Dam Length = 975m, Embankment Volume=970,000m3, crest length = 975m. The dam spillway is 36.6m wide, designed for a discharge of 215m3/s. The total reservoir volume equals 3.9Mcm. The design also included a small hydropower scheme of 260KW.
2. 1,700ha net irrigation area (2,267ha gross). The proposed system consists of two trapezoidal concrete canals of 24.4km total length. Distribution system of HDPE pipes, with a total length of 122km
3. At a preliminary stage, design of a drinking water system including a water treatment plant, to cover a total population of 20,000 capitals. The total demand is 12 l/s, which results to 1,036.8 m³/day (0.38Mcm/year).
The project included all the necessary specialized activities and studies required for the identification of the optimal scenario for the implementation of the planned infrastructure, such as Stakeholder Management Plan, Environmental Impact Assessment, Cost-Benefit Analysis, Financial Analysis, Watershed Management Plans etc.
The service covered the fields of:
-Feasibility Study. The hydrological analysis was elaborated using the HEC-HMS software, and took into con-sideration the climate change. The sediment analysis was elaborated using the Rusle method and GIS soft-ware.
-Detailed Design and Tender Document Preparation for the Sio-Sango Irrigation Development and Watershed Management Project.
-Detailed Design, Tender Document and Dam Safety Plans Preparation for Sio-Sango Dam (20m). The dam break analysis was carried out using the HEC-RAS modelling system.
– Development of irrigated agriculture of 1,700ha (Sio-Sango), Feasibility Study and Detail Study of HPP (0.26 MW) and Detail Design of a Water Treatment plant for a equivalent population of 20,000
-Environmental and social impact assessment
-Financial Model Execution