Sedimentation in small dams. Estimating the impact of catchment conservation, check dams and sediment bypassing in reducing dam siltation rates

The British Government's Department for International Development commissioned HR Wallingford to carry out a study to develop guidelines presenting appropriate methods for predicting, and where possible reducing, siltation rates in small communal dams in semi-arid zones in Eastern and Southern Africa. Small dam designers must be able to use these methods; they need simple procedures to carry out assessments rapidly, may not have software skills or computers, and may only have access to very limited local data. A capability to estimate the impact of measures to reduce small dam sedimentation rates is needed to enable the sedimentation lifetime of dams to be estimated at the planning and design stage of small dam projects. This report describes approximate methods for carrying out these calculations. The measures considered are check dams, soil and water conservation measures and sediment bypassing.