Prioritizing sub-basin according to erosion and recognition of waterway sensitive reaches to erosion using field reconnaissance (case study: Babolrood watershed, Mazandaran province)

Erosion is inevitable and cannot be completely eliminated, but human activity can be cause of acceleration or reduction it. Babolrood watershed that located in Mazandaran province aren’t exception from it, this watershed according to Area, topography, geology, various land use need to be investigation and study from erosion, management of optimize of land use. In this research EPM model was used to erosion intensity zonation that have 4 factors such as watershed erosion coefficient (ψ), land use (Xa), soil and rock sensitivity coefficient related to erosion(Y) and average slope of watershed (I) for modeling erosion rate in a watershed. Since various effective factors have a different impact and importance degree in the erosion with take into account importance proportion each of the parameters categorize these parameters into different classes and exert according to above model in the GIS software standard operation for the mention layer. These layer were assimilated and were produced erosion intensity zonation map then by considering of model result and amount of sediment rate that estimated from model, we prioritize sub-basins to management threats. For evaluate the model results, 43 years of Ghorantalar station data were used. The correlation coefficient between observation and estimated equal to 0.91 was obtained. Also results of model with observation data was evaluated using binary t examination that not found significant difference in %95 confidence surface. In order to recognize and determine waterway sensitive reach related to erodibility and sediment yield results of model were used. By Field visited and GIS software recognized 150 sensitive reach in the case study, and exist from this 150 sensitive reach the most it in the Babolak sub-basin. Overall results showed that Babolak sub-basin in the Babolrood watershed have the most amount of sediment and erosion rate and most quantity of sensitive reach because have sensitive formation and low permeability of soil.