A hydrologic-economic-agronomic model with regard to salinity for an over-exploited coastal aquifer

Abstract

The present work considers a management model for the sustainable development of an exploited coastal aquifer of the Gaza Strip, which includes different demands depending on water quality types into a regional hydrologic-economic-agronomic model. The uniqueness of this study is its consideration of two-separated demand functions one for fresh water and the other one for saline water, as well as effect of saline-water quality relationship on agriculture. This study identifies the optimum infrastructure of desalinated seawater and treated wastewater to fresh and saline levels. It also allocates water of different qualities (fresh and saline) among water sectors and between districts. Results show several important management outcomes: (i) the shadow value of saline water for all districts is larger than the cost of treating brackish water to fresh level is $0.30/m3. Therefore, the desalination of saline groundwater water to saline water level may be beneficial in Gaza districts. (ii) The shadow value of fresh water for all districts is larger than the cost of desalination ($0.6/m3). Accordingly, the desalination of brackish water to fresh water level is also beneficial. (iii) The areas of potential crops that use treated wastewater to saline level are proportionally increased to reduced abstraction from groundwater. Moreover, the sensitivity analysis indicated that, reduced abstraction from the groundwater would better allocate scarce water among competing users and better predict infrastructure sizing to fresh and saline treatment levels.