Estimation of Impact of Artificial Groundwater Recharge in Small Islands Using a Numerical Modeling Approach

Abstract

There are many small islands all over the world which face scarcity of drinking water. Recharge is an important factor which controls the available freshwater lens. In addition to natural recharge, artificial recharge can be used to increase the freshwater lens volume. The objective of this study is to identify the impact of artificial recharge in small islands. Three islands in the Maldives were selected for this study. A model was developed by using SUTRA (Saturated Unsaturated TRAnsient Model) with Model Muse as graphical user interface and calibrated until the percentage difference between simulated and observed freshwater lens volume is less than 10%. The impact of artificial recharge was identified by increasing the recharge rate by 5% and 10% of annual rainfall and simulating the previously calibrated model. The freshwater lens thickness and volume increase with artificial recharge. With 5% of annual rainfall as artificial recharge, the freshwater lens thickness of Dharavandhoo, Henbadhoo and Bodufulhadhoo island increased from 5.2 m to 6.9 m, 2.6 m to 4m and 1.5 m to 2.7 m, respectively. Based on these results, it can be concluded that artificial recharge will be a sustainable solution to overcome the scarcity of drinking water in small islands.