An Integrated Approach for Impact Assessment of Water Harvesting Techniques in Dry Areas: The Case of Oued Oum Zessar Watershed (Tunisia)

Abstract

In the arid regions of Tunisia, considerable investments are being made to maintain the old water harvesting techniques and introduce new ones to capture the scarce amount of rainwater (100 mm to 230 mm annually) for agricultural and domestic purposes. However, no detailed assessment of the multiple effects and the costs and benefits of these techniques have been made so far. This paper summarizes the results of an in depth investigation of the multiple impacts (runoff mobilization, ground water recharge, agro-socio-economic impacts) of the water harvesting works undertaken in the watershed of oued Oum Zessar (southeastern Tunisia). The importance of interdisciplinary and integrated approaches was revealed through this detailed impact assessment and economic evaluation. In fact, the profitability of the water harvesting works depends largely on the criteria chosen. However, further refinements are needed to better include all possible impacts (positive and negative) that occur as a result of the installation of the water harvesting structures.

A Methodology to Assess and Evaluate Rainwater Harvesting Techniques in (Semi-) Arid Regions

“…Although the results are very similar, Method 2 gives a slightly higher score for the jessour in Sub-catchment 2 (jessour 10-16) and Sub-catchment 3 (jessour [1][2][3][4][5][6][7][8].…”

“…Water 2016, 8,198 14 of 23 farmers. The volume of collected water in each storage area and maintenance and construction costs of the jessour/tabias were used to calculate the cost per cubic meter of water, which was then classified and scored.…”

“…Each dyke has a spillway (menfes if the spillway is located on one or both sides and masref if the spillway is located in the middle of the dyke) to regulate water flow between dykes (see Figure 2). Water 2016, 8,198 4 of 23 …”

Hydrogeochemical characteristics and assessment of drinking water quality in Zeuss–Koutine aquifer, southeastern Tunisia

“…The southern Tunisian region is semi-arid and arid with a mean annual rainfall of 100-230 mm and evaporation rates of 1,300-1,600 mm per annum, and the climatic water balance is almost negative year round (Ouessar et al 2004). The average annual rainfall decreases from north to south from approximately 1,300 to less than 200 mm.…”

Classification methods for detecting and evaluating changes in desertification-related features in arid and semiarid environments

“…Sand encroachment is one of the most serious environmental problems in south Tunisia and previous research shows that several unwary human activities have contributed to the intensification of this process, namely overgrazing, change in land use, and disturbances triggered by inappropriate agricultural practices or changes in socioeconomic policies. In the Oum Zessar study area of southeastern Tunisia, sand encroachment represents the main threat for the agro-pastoral activities, being the main branch of the economy of the whole Dahar-Jeffara Plain Medenine area (Ouessar 2007;Hanafi and Jauffret 2008;Sghaier et al 2010;Ouerchefani et al 2013;Ouessar et al 2004;Afrasinei 2016). Since soil salinization is the second most important land-degradation indicator in this area, it was also taken into account in the classification analysis of this study.…”