  Citation: Aljawzi, A.A.; Fang, H.; Abbas, A.A.; Khailah, E.Y. Assessment of Water Resources in Sana’a Region, Yemen Republic (Case Study). Water 2022, 14, 1039. https://doi.org/10.3390/w14071039 Academic Editor: Stephane Couture Received: 17 January 2022 Accepted: 23 March 2022 Published: 25 March 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). water Article Assessment of Water Resources in Sana’a Region, Yemen Republic (Case Study) Alhasan Ahmed Aljawzi 1 , Hongyuan Fang 1, *, Abdullah A. Abbas 2 and Ebrahim Yahya Khailah 1,2 1 College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou 225009, China; aljawzi100@gmail.com (A.A.A.); ebrahimkhailah@gmail.com (E.Y.K.) 2 Civil Engineering Department, College of Engineering, Thamar University, Dhamar 504408, Yemen; engaaabbas2011@gmail.com * Correspondence: hyfang@yzu.edu.cn Abstract: 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 Mm 3 (million cubic meters), respectively. In Sana’a basin, groundwater abstraction increased significantly from about 25 Mm 3 in 1970 to around 330 Mm 3 in 2020, while groundwater recharge was about 80 Mm 3 in 2020. The estimated water demand for domestic use was in the range of approximately 106–128 and 199–241 Mm 3 in Sana’a governorate, whereas in Sana’a city, it was in the range of about 249–302 and 607–737 Mm 3 for 2020 and 2040, respectively. The estimated agriculture water demand was between 1.14 and 1.53 Bm 3 in 2007, and declined to 801 Mm 3 and 1.16 Bm 3 (billion cubic meters) 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 Mm 3 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 region. Keywords: Sana’a region; rainfall; surface water; groundwater; water crisis 1. Introduction Water is the basis of life, an essential input for social and economic development, and an essential element of environmental sustainability. Agriculture for food production is considered one of the most significant pressures on freshwater resources. Where consid- ered, agriculture is responsible for over 80% of worldwide freshwater withdrawals (up to 90% in some fast-growing economies) [1,2]. Food demand is expected to rise by 70% by 2050 owing to the projected global population expansion of 2–3 billion people within the next 40 years [3]. On the other hand, natural disasters caused damage of 2–15% of Water 2022, 14, 1039. https://doi.org/10.3390/w14071039 https://www.mdpi.com/journal/water