Rainfall Recharge Wells for Groundwater Sustainability in Qatar

Groundwater sustainability is a vital issue for people on planet earth. Qatar is known for its scarcity of renewable water resources including groundwater. In the last decades, there has been an escalating trend in groundwater abstraction to provide resources for social and economic development in the country. Currently, almost all water demand for municipal and industrial demand is provided by desalination while agriculture demand is almost entirely met from groundwater with a total abstraction of about 218 Mm3/year (90% of total pumping). In 2009, a comprehensive assessment was carried out to study natural and artificial rechargeArtificial recharge of groundwater and define scenarios and designs for increasing artificial rechargeArtificial recharge. In order to design and develop an optimal artificial rechargeArtificial recharge scheme for future investments, an array of measurements and tests were carried out, including an assessment of the performance of pre-existing recharge wellsRecharge well and how these and new recharge wellsRecharge well could be optimised. Field and laboratory measurements were done for relevant parameters, and water balance modelling using the relatively simple SWAT2005 model was carried out, including rainfall-runoff and recharge analysis. Mapping the level and quality of groundwater indicated its extensive degradation. To augment the natural recharge, a total of 313 pre-existing passive artificial rainfall recharge wellsRainfall Recharge Wells facilitating the infiltrationInfiltration of ponding water in natural landscape depressions were identified across Qatar. However, data indicated that only 166 of these sites are located in favourable depressions and the remaining wells are not. The modelling results indicate that artificial rechargeArtificial recharge from the existing recharge wellsRecharge well and from natural rainfall recharge is 10.6 and 89.4 Mm3/year, respectively. For optimal design, modelling results indicate that a total of 1,502 recharge wellsRecharge well (1,388 as new wells) are required in favourable depressions to infiltrate the storms, typically around 20 mm within a 5-days period, which will augment the groundwater by 33.5 Mm3/year. Our recent estimation of groundwater resourcesGroundwater resource in Qatar indicates that an abstraction volume of about 150 Mm3/year leads to an equilibrium status under recent conditions of recharge. Comparing to actual abstraction volume (227 Mm3/year), this confirms the need for further increasing water supply and reducing demand. This work needs to be complemented by reviewing the design of existing recharge wells and using historic long-term data from monitoring networks complemented with advanced national 3D groundwater modelling for more accurate estimation. The goal is to manage natural and artificial rechargeArtificial recharge to support the achievement of groundwater sustainability in Qatar. Other alternatives sources such as treated sewage effluent and desalination to be considered as well.