SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Effectiveness of contour farming and filter strips on ecosystem services 
Authors:Gathagu, J.N., K.A. Mourad and J. Sang 
Article ID:1312 
URL (non-DOI journals): 
Broad Application Category:hydrologic & pollutant 
Primary Application Category:BMP assessment 
Secondary Application Category:sediment loss and transport 
Watershed Description:840 km^2 combined Thika-Chania River system, located in southwest Kenya 
Calibration Summary: 
Validation Summary: 
General Comments: 
Abstract:The failing ecosystem services in Thika-Chania catchment is manifested in the deterioration of water quality, sedimentation of reservoirs, and subsequent increase in water treatment costs due to high turbidity. The services can be restored by implementing relevant soil and water conservation practices to enhance flow regulation and control sediment yield. The impacts of contour farming and filter strips on water and sediment yield were evaluated using Soil Water and Assessment Tool (SWAT), Texas A&M University, USA. Sediment calibration and validation was achieved using data obtained from a bathymetric survey. Model parameters were adjusted to simulate the conservation impacts of contour farming and filter strips. Results indicated the average annual sediment yield as 22 t/ha at the outlet of the catchment and average annual surface runoff of 202 mm. The simulation results showed that filter strips of 5 m width would reduce the average annual sediment yield from the catchment by 54%. The efficacy of filter strips in reducing sediment yield was observed to increase with increasing filter width. Three-meter filter strips and contour farming reduced the average annual sediment yield at catchment outlet by 46% and 36%, respectively. It was concluded that the implementation of contour farming and filters strips reduced sediments by 63% from the base value. Water yield at the sub-basin level was only influenced by contour farming. The total water yield at the catchment outlet experienced no significant change 
Keywords:Thika-Chania catchment; sedimentation; SWAT; calibration; validation; Kenya