Future of Drylands – An Overview of Evaluation and Impact Assessment Tools for Water Harvesting

Abstract

In the arid regions of Tunisia, huge efforts are being made in the construction and maintenance of water harvesting and soil conservation structures. A growing need for their evaluation and assessment of their impact is felt. To this end, a simple tool has been developed and applied to evaluate the structural stability of jessour, tabias and gabion check dams. The total gives a measure of the structure's present-day overall condition based oil physical inspection of a number of key characteristics vital to its functionality. The evaluation tool was applied to a random Sample of structures in Southern Tunisia, This paper also describes an adaptation and evaluation of the ArcView soil and water assessment model (SWAT) for the assessment of the hydrologic impact of water harvesting systems. Some modifications were made to the model code to adapt the model to the processes in the study area. Evaluation of the hydrologic goodness-of-fit of the model based on the observed and simulated runoff data in the study Site, Using four Statistical criteria, gave reasonable results.