Macro rain water harvesting network to estimate annual runoff at Koysinjaq (Koya) district, Kurdistan region of Iraq

Macro rainwater harvesting techniques (Macro RWH) are getting more popular to overcome the problem of water scar-city in arid and semi-arid areas. Iraq is experiencing serious water shortage problem now despite the presence of Tigris and Euphrates Rivers. RWH can help to overcome this problem. In this research RWH was applied on Koya city in its districts, North West Iraq. Twenty two basins were identified as the catchment area for the application of RWH tech-nique. Watershed modeling system (WMS), based on Soil Conservation Service - curve number (SCS-CN) method, was applied to calculate direct runoff from individual daily rain storm using average annual rainfall records of the area. Two consecutive adjustments for the curve number were considered. The first was for the antecedent moisture condition (AMC) and the second was for the slope. These adjustments increased the total resultant harvested runoff up to 79.402 *106 m3. The average percentage of increase of harvested runoff volume reached 9.28%. This implies that water allocation is of the order of 2000 cubic meter per capita per year. This quantity of water will definitely help to develop the area.Validerad; 2013; 20131014 (nadhir