Assessment of CN method in runoff Estemation using of GIS In Madarsu basin in Golestan province
Subject Areas :Ali Panahi 1 , Bohloul Alijani 2 , Hosein Mohammadi 3
1 - استادیار دانشگاه آزاد اسلامی واحد تبریز
2 - استاد دانشگاه تربیت معلم تهران
3 - استاد گروه جغرافیا دانشگاه تهران
Keywords: rain fall- runoff- curve number-geographical information system- Madarsu basin,
Abstract :
Every year, due to the penetration of cyclone and different air masses and also local conditions, the resultingflood phenomena causes extreme damage to the natural and economical resources. Sometimes, due to the floodwaves or high density of residual materials, hydrometric stations are damaged and consequently the recordeddata do not match to real data. Considering the lack of hydrometrical stations in most of the small watersheds,determination of runoff and maximum flood discharge requires a suitable method to estimate runoff and peakflow which to be used in flood and erosion control management plans. In this study empirical CN method isused.In this study, a principle of work method is applying of statistical data (5686 statistics year of climatologystations Robate ,Ghare bil, Cheshmekhan, Hagholkhaje, Dasht, Dashte shad, tangrah,Ghojmaz,Til abad,pishkamar, Galikesh and station hydrometric Tnagrah). Spatial data analysis and also using of satellite imagesfor gaining CN map in SCS model with GIS, in the next stage recognized applying the SCS equation, CN mapand precipitation layer which zones have the potential for creating of similar runoff.In this study, also due to assessment curve number CN choice several flood danger that the results shows thehigh correlation between curve number calculated and curve number observed and also resulted that use ofweight model in curve number calculate provided to consider all of effective factors in runoff existing and at theresult attain reliable estimate of runoff resulting the rainfall.
