ABSTRACT
Bastora basin was located in northern part of Iraq about 20 km in northeast of Erbil city. It locates between latitudes (36o15’17” to 36o19’36” N) and longitudes (44o10’19” to 44o27’33” E). Bastora basin has a catchment of 236.4 km2 area, and length is 29.25 km with the basin perimeter is 97.73 km. According to tectonic division Bastora basin locate in high folded and low folded zones. The basin bounded by Permam Mountain in the north and Safin Mountain in the east and plain area toward the south with Greater Zab River to the west. The highest altitude is 1940 m in the eastern part and the lowest is 606 m in the southern (a.s.l). Based on the morphometric analysis by using DEM (3m) resolution this basin consist of 6th stream orders and 587 stream numbers, with elongated drainage basin morphology. The drainage density and drainage texture for the basin is 1.77km-1 and 6.0 no/km respectively. Bastora River reaches the mature stage, and has the V-shape and an asymmetrical Bastora basin valley. Rainfall, relative humidity, temperature, wind, sunshine and evaporation were used. The mean annual rainfall for Bastora basin is 597.9 mm/year, with mean annual temperature is 18.1Co and average annual evapotranspiration for the basin is 1835 mm/year. Study area has a semiarid to arid climate condition, with cold and rainy in winter and hot and dry in summer seasons which is affected by Mediterranean anticyclones system. Based on the Soil Conversation System method, the surface runoff reaches 195 mm/year and groundwater budget is 24.5 m3 /year. The soil type of Bastora basin is (type B) and curve number is (CN=72) according to hydrological modelling results. Based on Horton model equation and double ring methods, the infiltration rate estimates is 195.75 and 18.25 mm/hr respectively.
The main result of Running of Watershed Modelling System (WMS) 11.1 are basin slope is 0.1549 m/m, with maximum stream slope is 0.0179 m/m and watershed modelling area is 236.07 km2. Based on monthly water discharge in the basin hydrograph profile and peak flow hydrograph in April is 1.034 m3/sec.