The Application of Watershed Delineation Technique and Water Harvesting Analysis to Select and Design Small Dams: A Case Study in Qara-Hanjeer Subbasin, Kirkuk-NE Iraq

Abstract

The rainwater harvesting technique is one of the solutions to overcome the effect of water shortage crises in arid and semi-arid regions. In this study, the feasibility of using small dams in water harvesting has been examined at Qara-Hanjeer sub-basin that lies east of Kirkuk, N-Iraq with a surface area of 503.88 Km2. Watershed boundary for entire basin has been delineated comparatively by mask method, using hydrology toolset in ArcGIS (10) software. Direct surface runoff is calculated using Soil Conservation Service Curve Number method based on data from Kirkuk meteorological station for the period (1995-2020), information obtained from land use map, and soil type, the basin is divided into six zones with different CN values, Moreover, for average annual rainfall (334.33 mm/year), water surplus was 190.2 mm and surface runoff was 25.77 mm representing 7.708 % of the total rainfall. The runoff depth was 167.03 mm/year and the total annual harvested runoff is 12.99x106 m3 Several temporary and semi-permanent check dams could be built across the valleys, with height (< 3m.). These dams are of low cost, reduce the loss of runoff water, improve agriculture, tourism and add impetus to the ecosystem programs in Qara-Hanjeer city.