Water scarcity is a prominent consequence of global climate change, presenting a significant challenge to the livelihoods of wide parts of the world, particularly in arid and semi-arid regions. This study focuses on Erbil Province in Iraq, where the dual effects of climate change and human activity have significantly depleted water resources in the past two decades. To address this challenge, rainwater harvesting (RWH) is explored as a viable solution. The purpose of this study is to make a suitability zone map that divides the study area into several classes based on the features of each area and its ability to collect rainwater. The map will then be used to find the best place to build different RWH structures. Seven different layers are used to make the RWH suitability zone map: rainfall, runoff, land use/cover (LU/LC), soil texture, slope, drainage density, and the Topographic Wetness Index (TWI). Each layer was assigned specific weights through the Analytical Hierarchy Process (AHP), considering its relevance to RWH. Results revealed four suitability classes: very highly suitable 1583.25 km² (10.67%), highly suitable 4968.55 km² (33.49%), moderately suitable 5295.65 km² (35.69%), and lowly suitable 2989.66 km² (20.15%). Notably, the suitability map highlights the northern and central regions as particularly suitable for RWH. Furthermore, the study suggested three suitable locations for constructing medium dams, six for check dams, and twenty-seven for farm ponds, according to the requirements of each type. These findings provide valuable insights for the strategic planning and effective management of water resources in the study area, offering potential solutions to the pressing challenges of water scarcity.

Water, being the basic resource for life on earth, is of great importance in arid and semi-arid regions, which face the direct impacts of climate change. This study aims to solve water scarcity for Baranti Plain farmers by constructing concrete canals using modern technology. The Baranti Plain is located approximately 25 km north of Erbil in Iraq and spans an area of 445 km². The Great Zap River flows through its northern region, with an average discharge of about 400 m³ per second. In response to the challenges faced in this area, the Ministry of Agriculture and Water Resources collaborated with the Food and Agriculture Organization (FAO) to gather essential data. This extensive dataset, covering the period from 2000 to 2021, particularly focuses on ground-level monitoring in September. Notably, the region experienced a significant decline in groundwater levels, totaling 23 m on average. Additionally, there was a 7.8% increase of urban expansion, and the number of wells increased from 257 in 2006 to 600 in 2021. To counter the diminishing groundwater levels and facilitate agricultural irrigation, a proposal was introduced to harness the waters of the Great Zap River. This plan involves channeling the river waters to the plain through a network of concrete canals known as the Baranati Project Plain. For precise planning, a digital elevation model (DEM) with a 12.5 m resolution was procured to analyze the area using GIS. This investigation revealed a height difference of 130 m between the Great Zap River and the Baranti Plain. Subsequently, the area was segmented into four zones based on its suitability for the project: highest, medium, low, and unsuitable. Notably, the combined areas of high, medium, and low suitability encompass 68% of the entire study region. The project’s next phase used a flow calculator to determine the channel’s shape, area, slope, and water requirements. The final phase involved analyzing annual rainfall data from three meteorological stations (Bastora, Ankawa, and Khabat), showing an average annual rainfall of 396 mm. The project has the capacity to irrigate more than 30,000 hectares of land, benefiting more than 1200 farmers. It is expected to stop the use of over 600 wells for irrigation and potentially raise groundwater levels by about 2.5 m annually. Our work revealed that addressing groundwater depletion requires implementing canals, rainwater harvesting, farmer education, modern irrigation, drilling restrictions, and supporting water.