The tabia earthen dyke is a water harvesting technique used in the foothill and piedmont areas. Tabia floodwater spreading systems are usually installed on gentle slopes either at the foot of mountains, adjacent to or within wide riverbeds in lower part of the watershed, where the gradient does not exceed 3 %, and the soils are relatively deep. Tabias comprise a dyke (50 – 150 m in length, 1 – 1.5 m in height), a spillway (central and/or lateral) and an application area. Fruit trees and annual crops are commonly grown using tabia. Besides their benefits for water harvesting, tabias reduce soil erosion and have a positive effect on groundwater recharge.

The tabia runoff-water harvesting technique is widely practiced in central Tunisia. Usually tabias are installed on the piedmont, where the slope does not exceed 3% and where the soil is relatively deep. Ancient remnants of tabias have been found in the region of Gafsa (south west Tunisia). The system was adopted by people living at the neighboring foothills and plains of the central and southeastern regions of Tunisia, following the transformation of their pasture to cultivated fields. (Mekdaschi & Liniger 2013)