MODELING THE WATERSHED AND ESTIMATION OF DESIGN FLOOD DISCHARGE FOR ALI AL-GARBI STORM WATER BY USING GIS

Abstract

In this study the GIS was applied with the aid of the spatial analyst extension’s hydrology tools, by using DEM (digital elevation model) to create the watershed and network stream. After delineation the watershed by using GIS, the area value of watershed for Ali al-Garbi water storm was equal to 44211.431 hectare, and the part of this watershed was lied in Iran(Illam governorate) but the major part of the watershed was lied in Iraq (Maysan governorate) .The intersection outlet point of watershed with the Ali al-garbi –Baghdad road, it had the coordinate (657830.15 E, 3595395.16 N), and represents’ the location of suggests culvert.Finally and easily, by using the rational method was estimated the design flood for the culvert was estimated equal to 122.80 m3/sec