Assessment of Water Resources in Sana’a Region, Yemen Republic (Case Study)

Yemen is a water-scarce country with inadequate freshwater, considerable groundwater depletion, and a lack of adequate surface water. This study aims to assess water resources and identify the current water situation in Sana’a region, which includes the governorate of Sana’a and the country’s capital, Sana’a city. A variety of data from different sources was collected and analyzed. Remote sensing (RS) and GIS techniques in combination with the Arc Hydro model were utilized. Water demand and supply for domestic and agricultural purposes were estimated. The results show that there is insufficient water to meet the needs of the region’s yearly population growth rates of 3.2 and 4.5% in Sana’a governorate and Sana’a city, respectively. The amount of observed rainfall varies spatially and temporally, ranging between 160 and 367 mm per year. There are 233 water structures, 168 dams, and 65 reservoirs, with a storage capacity of 64.65 and 0.24 Mm3 (million cubic meters), respectively. In Sana’a basin, groundwater abstraction increased significantly from about 25 Mm3 in 1970 to around 330 Mm3 in 2020, while groundwater recharge was about 80 Mm3 in 2020. The estimated water demand for domestic use was in the range of approximately 106–128 and 199–241 Mm3 in Sana’a governorate, whereas in Sana’a city, it was in the range of about 249–302 and 607–737 Mm3 for 2020 and 2040, respectively. The estimated agriculture water demand was between 1.14 and 1.53 Bm3 (billion cubic meters) in 2007, and declined to 801 Mm3 and 1.16 Bm3 in 2018 due to the reduction in the cultivated area by about 33% from 2007 to 2018, which was attributed to a lack of water. The estimated water deficit ranges between 500 and 723 Mm3 during 2007 and 2018. This study concluded that the estimated water supply and demand for the past 12 years from 2007 to 2018 resulted in a supply that was less than the demand in each year, indicating that the available water resources were insufficient to fulfill demand. The significant gap between water supply and demand means withdrawal from the stored groundwater. Thus, groundwater is at high risk. Constructing more water harvesting structures, adopting water conservation, water resource management, and making groundwater artificial recharge are recommended to meet the water demand and conserve non-renewable resources in the coming decades. The results obtained from this study would help decision makers to make appropriate plans to achieve the SDGs in Sana’a regio