Erosivity index of urban storms: case study of two stations of Kermanshah.

Present research examine the erosivity index of precipitation Kermanshah Province, two stations belonged to west Region Water Company named old Kermanshah and new Kermanshah were used, the duration of statistical period being 13 and 19 years. Data on stations was prepared graphically and the extraction of storms was performed visually with 15 min temporal step. After descriptive data on storm was adjusted and arranged tabularly, their kinetic energies were calculated with Wischmier and Smith formula considering maximum intensity of 30 min. Next, they were placed in continuous 1-72 h rainfall groups. Resulting conclusions indicated that about 85% of storm were in 1-6 h continuations and 6 h continuations had the highest values of kinetic energy as well as of erosion index (R), but remained in very low erosion class; and old and new Kermanshah stations were placed in very low erosion class, with annual average of erosion index less than 500 MJ mm ha(-1) h(-1).