Groundwater Level Rise in Muscat Airport Area and Ways of Managing the Issue

Despite the arid climate and scare water resources, groundwater level rises in some areas of Muscat, the capital city of Oman. Consequent impacts have already been detected in manholes around the new runaway, where groundwater seepage into basements of utility lines. The objective of this study is to simulate the groundwater flow in the airport area, which then can be used to propose countermeasures for lowering the groundwater levels as applicable. There are 8 pumping wells and 16 monitoring wells were drilled around the runaway and the terminal building to conduct pumping test and to estimate the aquifer properties such as the transmissivity and specific yield. Estimated aquifer properties were then used to develop a three-dimensional groundwater flow model using MODFLOW software. Steady state model calibration and verification were done using two independent data sets in 15 monitoring wells in 2017 and 2018. Four pumping scenarios were considered for lowering the average groundwater level by 0.5m. Model results show that potential water volume that can be withdrawn from existing pumping wells with highest pumping rates is about 8.4% of water coming into the model from the upstream mountain area. It was estimated that altogether 24 pumping wells with the pumping rates vary from 222 to 1564 m 3 /day, are required to achieve the expected reduction. Two pumping scenarios were proposed to guide the operations in different situations. It is expected to carry out further investigations to calibrate the proposed pumping rates and to understand aquifer response for long-term pumping.