Rain Water Harvesting and Supplemental Irrigation at Northern Sinjar Mountain, Iraq

Abstract

Iraq is facing water shortages and the problem is becoming more serious with time. Despite this fact, none of the farmers had used Rainwater Harvesting (RWH) technique yet. The main aim of this research is to contribute to solving the problem of water shortage of Iraq by finding effective results in terms of saving significant runoff water for irrigation purposes. Macro RWH was applied at Northern Sinjar Mountain in Iraq, where macro is indicator for large catchment area. Runoff volume was determined by applying the watershed modeling system (WMS) for six selected basins with total area of 614.19km2 for the study period of (1990-2009). The volume of harvested water ranged (0.6-42.4) × 106 m3 for all six basins together for the study period. A linear programming technique was adopted to optimize the irrigated area for three scenarios of irrigation, 1/ supplemental irrigation (SI) 100%, 2/ deficit irrigation (DI) 50%, 3/ deficit irrigation (DI) 25% of full irrigation requirements. The results of calculation of irrigated area ranged between 14.5-3663.7 for SI 100%, 33.0-39827.1 for DI 50%, and 20.1-7314.0 for DI 25% hectares respectively. These results reflect useful value of RWH and its influence to increase the irrigated area in the studied region.