Survey the Tarval Drainage Watershed Hydro Geomorphology and Hydrology Indicators

The rivers physical and morphological properties survey and study is one of the first and most important actions in hydrological plans design and implementation. The aims of this research is Tarval drainage basin physical, hydrological, hydrographic and hydro geomorphology's traits surveying using software and statistical methods in order to access the appropriate information's to planning and implementing the constructions and watershed management plans. Tarval stream is the Caspian Sea sub basin that its drainage basin area from confluence location with Ghezel Owzan is 6955 km2. According to present statistics from 1971 to 2011 years the annual average of meteorology and synoptic basin temperature are 12.5 centigrade degree and annual precipitation is 352 mm that shows semi-arid situation of basin climatologically. The result shown that the drainage net densities in this basin is low and the number of streams per unit area is few. By considering the study area dispersal coverage and is some cases are high-density, the runoff coefficient is 0.35 percent and the basin delay time is 1.65 hours, and its time of concentration is 2.75 hours. The results shows that by considering the factors such as precipitation rate, basin low slope, little discontinuous seed sediment, the basin runoff amount is very low and precipitation of this area speedily drops down. For this reason the soil erosion percentage in this basin is so little and be controllable. In addition, the flood debit curvy changes with time passing have a slight curve that represent the basin immunity against flooding.