الملخص

This study aims for building a database of the morphometric characteristics of the valley of Koysenjaq basin throughout the analysis of the digital elevation model (DEM), using a range of geographic information systems, such as (Arc GIS v. 10.3), (Global Mapper v.18), as a means of measuring raster, linear and areal elements. They integrate together to produce a large number of variables and morphometric measurements. The study has adopted digital elevation model data accuracy of distinctive accuracy (14) meters in addition to a range of maps and satellite images. The basin is located in the southeast southeast of Erbil Governorate and has a small area of about (549.56) km2, with a length of (34.26) km and long Perimeter compared with its large area (133.92) km. The basin has characteristics of different morphometric features as a result of the different climate change, geological nature, morphology, and characteristics of the soil, which indicates that the basin is at the beginning of its geomorphological cycle. The quantitative analysis shows that the value of the elongation is (0.68), circulation is (0.38) and the form factor is (0.46). This means that it is rectangular, and irregular in shape, and it obvious from the study of the characteristics of terrain that the value of basin relief is high (28.27) m/km, and passes in the early stage of maturity according to hypsometric integration value. The study shows the characteristics of the drainage network in the basin consists of (433) tributary distributed (6) arranged according to Strahler classification with low-density drainage (1.13) km/km2 and stream frequency for basin (0.78) stream/km2. This indicates that the number of tributaries of water is few compared with the area of the basin, so that the basin was not exposed to floods.  The study recommends the use of more geographic information systems in determining the extent of seasonal drainage of the basin valleys in order to control the future flood risk, and good planning of the investment of these valleys in different fields through the construction of dam at the end of the basin for the purpose of harvesting water, and conducting morphometric studies compared to other river basins in Erbil Governorate to understand in detail its morphometric properties.