DETERMINATION OF BASE-FLOW COMPONENTS FOR REZAN AT REZAN GAUGING STATION

Rezan River is a tributary of the Greater Zap River which is the principal source of water for domestic and agricultural use in the Barzan area. The length of the river is about 85 km with total drainage area reaches 1158 km² in Iraqi part. The Rezan River is of great importance for Iraqi Kurdistan Region; because it provides Greater Zab River with about 1,37 billion m³ / year which represent about 8,2% of its total discharge. The mean daily discharges data for the last ten years are available. The result of hydrograph analysis for the water years shows better understanding of the flow characteristics of Rezan River, it is necessary to understand its base flow components characteristics and their relations to the total stream flow and geology of the river basin due to the importance of base flow in the dry season where all the water flow in the river is from base flow. Tens of villages depending on the river during the summer for irrigation as well as to supply water for domestic uses for reconstruction of destroyed villages along the river course, and have significant role in developing agricultural activity in the area. The quantitative information and analysis of base flow are also important in developing and future planning of the area where most activities are related to agriculture.