WH Main Where Category Options use Description appropriate Disadvantages Dams characterized by being Stocking Hillsides with gentle High earthwork to water dam situated on a gentle slope sloping catchment storage volume ratio catchment area on a hillside Small Earth Dams Dams characterized by having a Potentially sandier soil at Stocking Having a well defined Charcot dam well defined narrow gully leading gully way. Heavy siltation natural narrow gully to an excavated circular reservoir from gully runoff. For tree planting in Closed grid of diamond shapes or Negarim situations land is Trees open-ended "V" s formed by small limited to small scale. catchment uneven or only a few earth ridges, with infiltration pits tree are planted Microcatchment Not suitable for uneven (short slope) For crop or tree planting terrain. Requires new Earth bunds on contour spaced at Contour in semi-arid technique of land 5-10 meters apart with furrow especially where soil preparation and planting, upslope and cross-ties fertile and easy to work therefore may be problem with acceptance Suitable for situation Long low rock dams across valleys gently sloping valleys Very site-specific and needs Permeable slowing and spreading floodwater are becoming gullies considerable stone as well rock/check dams as well as healing gullies and better water as provision of transport spreading is required Does not impound much Flood water long Earth bunds set at a gradient, with For areas where water spreading water and maintenance high slope catchment crops a "dogleg" shape, spreading water is diverted from bunds in early stages after diverted floodwater watercourse onto crop construction Trapezoidal shaped earth bunds Widely suitable (in a capturing runoff from external variety of designs) for Labor-intensive and uneven trapezoid bunds catchment and overflowing around crop production in arid depth of runoff within plot. wingtips and semi-arid areas Critical site selection Narrow passage of a requires technical Concrete dam build on the saturating seasonal dry riverbed. expertise/equipment. More Stocking bedrock of a sandy riverbed, ground subsurface dam Avoids surface expensive than earth dams. water trapping water under the sand storage evaporation, Does not store as much surface of a dry riverbed contamination. water as regular surface dams
Category WH Options Main use Description Where appropriate Disadvantages Small Earth Dams dam Stocking Dams characterized by being situated on a gentle slope catchment area on a hillside Hillsides with gentle sloping catchment High earthwork to water storage volume ratio Charcot dam Stocking Dams characterized by having a well defined narrow gully leading to an excavated circular reservoir Having a well defined natural narrow gully Potentially sandier soil at gully way. Heavy siltation from gully runoff. Microcatchment (short slope) Negarim catchment Trees Closed grid of diamond shapes or open-ended "V" s formed by small earth ridges, with infiltration pits For tree planting in situations land is uneven or only a few tree are planted limited to small scale. Contour Earth bunds on contour spaced at 5-10 meters apart with furrow upslope and cross-ties For crop or tree planting in semi-arid especially where soil fertile and easy to work Not suitable for uneven terrain. Requires new technique of land preparation and planting, therefore may be problem with acceptance Flood water long slope catchment Permeable rock/check dams Long low rock dams across valleys slowing and spreading floodwater as well as healing gullies Suitable for situation gently sloping valleys are becoming gullies and better water spreading is required Very site-specific and needs considerable stone as well as provision of transport water spreading bunds crops Earth bunds set at a gradient, with a "dogleg" shape, spreading diverted floodwater For areas where water is diverted from watercourse onto crop Does not impound much water and maintenance high in early stages after construction trapezoid bunds Trapezoidal shaped earth bunds capturing runoff from external catchment and overflowing around wingtips Widely suitable (in a variety of designs) for crop production in arid and semi-arid areas Labor-intensive and uneven depth of runoff within plot. saturating ground storage subsurface dam Stocking water Concrete dam build on the bedrock of a sandy riverbed, trapping water under the sand surface of a dry riverbed Narrow passage of a seasonal dry riverbed. Avoids surface evaporation, contamination. Critical site selection requires technical expertise/equipment. More expensive than earth dams. Does not store as much water as regular surface dams
Uganda_-_Karamoja_Water_Harvesting_field_guide.docx