River Flow Estimation for Ungaged Stations Using Gis Model

Geographic information system (GIS) has had a great progress in river engineering in recent years. Most of new developed softwares in this area have the GIS abilities or are able to interact with GIS software. The application of GIS in this area is mostly for pre and post processing of input and output data. In this research, water flow of river has been estimated in an ungaged point using ArcView. GIS has been used to calculate the physiographical characteristics of watershed, flow accumulation, flow directions, etc. Its high speed in estimating these characteristic which are lengthy in other methods, is its main advantage. For this research, Gharahsoo watershed in west of Iran has been selected. All calculated data was compared with the measured data in order to verify the method. The river water flow in the ungaged point was calculated using the information extracted from produced layers and water flow measurements in upstream and downstream stations. In order to control and verify the results, estimating the flow was made for a gaged station considering it as an ungaged station. Then, the results were compared with measured data in that station. Also, water flow in the same station was estimated using a time series analysis with ARMA model to compare the results of two forecasting methods.