Water from Small Dams

Usually, soil for building the sidesis excavated from the borrow pitand off-loaded on the upstreamside of the dam wall, while soilexcavated from the spillway(s) isoff-loaded on the downstream sideof the dam wall. This helps reducethe distance soil needs to bemoved.The depth of spillways are measured fromnylon strings drawn over the spillways.The upward curved crest (top of the dam wall) should have its various heights marked outusing sticks or poles inserted along the edges of the crest. Soil is thereafter added to thecrest until the final correct height and curvature of the convex crest is achieved.7.8 Completing the construction of an earth damUpon completion of a dam wall with its convex crest and with an allowance for settling,its sides and crest are made even and smooth using shovels. Trees and bushes in thereservoir are cut down and removed. Holes made by rodents in the floor of the reservoirare filled in with soil and the ground smoothened.Larger stones should be placed along the side of the spillway that faces the dam wall toprotect it from erosion. Smaller stones can be embedded in mortar between the largerstones to form a low stone masonry wall.Medium-sized stones should bepacked on the lower side of thedownstream side of the dam wallto form a rock-toe (or backtoe)drain and grass planted betweenthe stones.The stone apron will preventerosion of the dam wall by waterand soil seeping out through theback.Grass with runners is planted on the upstream sideof a dam wall, while stones are packed onto thedownstream side.50