|ABOUABDILLAH, AZIZ - National School Of Agriculture|
|DE GIROLAMO, ANNA - Water Research Institute|
|OUESLATI, ONS - Water Research Institute|
|MAATAOUI, A - National School Of Agriculture|
|LO PORTO, ANTONIO - Water Research Institute|
Submitted to: Journal of Water Resource and Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2014
Publication Date: 12/5/2014
Publication URL: http://handle.nal.usda.gov/10113/61278
Citation: Abouabdillah, A., White, M.J., Arnold, J.G., De Girolamo, A.M., Oueslati, O., Maataoui, A., Lo Porto, A. 2014. Evaluation of soil and water conservation measures in a semi-arid river basin in Tunisia using SWAT. Journal of Water Resource and Protection. 30(4):539-549.
Interpretive Summary: The Merguellil catchment (Central Tunisia) is a typical Mediterranean semi-arid basin which suffers from regular water shortage. In recent decades, the government has allocated funds to construct dams and contour ridges for water harvesting that have impacted the regional streamflow. The work presented here tries to simulate erosion and regional streamflow using the Soil and Water Assessment Tool. It predicts that contour ridges are responsible for a 32% reduction in surface runoff and 21% less streamflow. These structures also increase aquifer recharge by 50% and reduce sediment losses by 26%. The model is a valuable tool to aid decision makers in the management of water harvesting structures in semi-arid regions.
Technical Abstract: The Merguellil catchment (Central Tunisia) is a typical Mediterranean semi-arid basin which suffers from regular water shortage aggravated by current droughts. During the recent decades the continuous construction of small and large dams and Soil and Water Conservation Works (i.e. Contour ridges) have taken place within this watershed. However, little is known about the effect of these water harvesting systems on the water balance components of arid or semi-arid basins. The work presented here tries to simulate the current water balance using the Soil and Water Assessment Tool (SWAT-2005) model and the impact of the contour ridges on water balance components and erosion. Large dams were modelled as reservoirs, small dams as ponds, and contour ridges as potholes that fill with water and increase the percolation into the aquifer. The model was rather successful in reproducing water flow. It predicts that contour ridges produce on a yearly basis a reduction of 32% and 21% in surface runoff and total water yield, respectively and an increase in aquifer recharge of 50%. At the same time, retention of a high quantity of sediment (+26%) was predicted.