The following is a of thumb classification for selecting the type of structure for the particular watershed area. Watershed Purpose of Classification Structure Area Interventions This is the area that On slopes greater a) Contour Trenching. Protection the water source than 25%, and plantation of grasses, shrubs originates from. and trees native to the area Usually on steeper b) Where boulders are available, slopes, erosion is contour bunding with boulders. high in this area and It is might be good idea to go for the water runs off permanent vegetation through quickly. If the water planting local species and flows too quickly, perennial grasses. streams On slopes between Contour staggered Trenching downstream will 10-25% get silted. To avoid On slopes less than Earthen Contour Bunding. 30X40 this, certain 10% model is better than contour structures may be bunding because it is very built which slow difficult to follow a contour down the flow of while constructing earthen water. Erosion can bund, and mistake in following also be checked by bund can result is breaking of planting grasses, bund. shrubs, trees and permanent forest cover. Drainage This is the local area bed slopes> Brushwood checks between 20% the ridge Gabion structures where velocity and farm, that is, and volume of peak run-off is where the water too high for loose boulder flows down to the structures farm. There local will bed a slopes < 5% a) Earthen dams, which serve as gentler slope. This percolation reservoirs in the area too will have upper catchment. erosion and b) Sand-filled bag structures in siltation. Structures to check the velocity of built here will also stream flowwhere sand is locally be intended to available check erosion and c) Gabion structures where avoid siltation of velocity and volume of peak water bodies is too highfor loose boulder downstream. To do structures this, drainage stream a) naala training, including channels are embankments deepening channels and raising deepened and severely eroded embankments,along sections of
The following is a of thumb classification for selecting the type of structure for the particular watershed area. Watershed Area Purpose of Interventions Classification Structure This is the area that the water source originates from. Usually on steeper slopes, erosion is high in this area and the water runs off quickly. If the water flows too quickly, streams downstream will get silted. To avoid this, certain structures may be built which slow down the flow of water. Erosion can also be checked by planting grasses, shrubs, trees and permanent forest cover. On slopes greater than 25%, a) Contour Trenching. Protection and plantation of grasses, shrubs and trees native to the area b) Where boulders are available, contour bunding with boulders. It is might be good idea to go for permanent vegetation through planting local species and perennial grasses. On slopes between 10-25% Contour staggered Trenching On slopes less than 10% Earthen Contour Bunding. 30X40 model is better than contour bunding because it is very difficult to follow a contour while constructing earthen bund, and mistake in following bund can result is breaking of bund. Drainage This is the area between the ridge and farm, that is, where the water flows down to the farm. There will a gentler slope. This area too will have erosion and siltation. Structures built here will also be intended to check erosion and avoid siltation of water bodies downstream. To do this, drainage channels are deepened and local bed slopes> 20% Brushwood checks Gabion structures where velocity and volume of peak run-off is too high for loose boulder structures local bed slopes < 5% a) Earthen dams, which serve as percolation reservoirs in the upper catchment. b) Sand-filled bag structures in to check the velocity of stream flowwhere sand is locally available c) Gabion structures where velocity and volume of peak is too highfor loose boulder structures stream embankments severely eroded a) naala training, including deepening channels and raising embankments,along sections of
IPPE_manual_v4.docx