Effectiveness of Contour Farming and Filter Strips on Ecosystem Services

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Effectiveness of Contour Farming and Filter Strips on Ecosystem Services. / Gathagu, John Ng’ang’a; Mourad, Khaldoon A; Sang, Joseph.

I: Water, Vol. 10, Nr. 10, 1312, 22.09.2018.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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Gathagu, John Ng’ang’a, Khaldoon A Mourad och Joseph Sang. "Effectiveness of Contour Farming and Filter Strips on Ecosystem Services". Water. 2018. 10(10). https://doi.org/10.3390/w10101312

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Gathagu, John Ng’ang’a ; Mourad, Khaldoon A ; Sang, Joseph. / Effectiveness of Contour Farming and Filter Strips on Ecosystem Services. I: Water. 2018 ; Vol. 10, Nr. 10.

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TY - JOUR

T1 - Effectiveness of Contour Farming and Filter Strips on Ecosystem Services

AU - Gathagu, John Ng’ang’a

AU - Mourad, Khaldoon A

AU - Sang, Joseph

PY - 2018/9/22

Y1 - 2018/9/22

N2 - 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.

AB - 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.

U2 - 10.3390/w10101312

DO - 10.3390/w10101312

M3 - Article

VL - 10

JO - Water (Switzerland)

JF - Water (Switzerland)

SN - 2073-4441

IS - 10

M1 - 1312

ER -