Environmental Erosion Research Journal

One of the most important main environmental problems is soil erosion and its affects. Eutrophication, low oxygen levels and `high nutrient (nitrogen and phosphorus) concentrations in reservoirs, channel and other water courses, is a common water pollution feature. Phosphorus (P) is one of the major plant nutrients and also the major nutrients controlling eutrophication of surface water. The aim of current study was to quantities evaluation of the effect soil erosion on available phosphorus loss in Kojour watershed. Discharges resulting from storm events were sampled at one fixed point of river using the manual sampler. Results showed that minimum and maximum phosphorus loss through 7 rainfall events was 321and 6707 g respectively with an average value of 2620 g. Soil erosionThe result of modeling among phosphorus loss, sediment yieldrate in this period was dramatically affected on the loss of phosphorus. The result of modeling among phosphorus loss, sediment yield and runoff volume indicated that phosphorus loss didn’t estimate by discharge, while sediment concentration can estimate loss of phosphorus with estimation error of 26%. The results could facilitate the application of given methods obtained in the present study to other ungauged watershed with similar conditions and leading to the suitable soil and water management

During the construction of road networks large area of forests and rangelands will be destroyed in the road path and its margins. This process causes massive amount of soil and rock move from its site and on adjacent lands will be accumulated, that causes increasing environmental degradation. One of the most important problems due to forest roads making is increasing of different erosion forms in around of roads, sediment yield resulting of vegetation destroy, soil structure ruin, run off velocity increasing and slope instability. In this research, sediment due to existence roads of different land use was estimated in a part of Kojour (Experimental Forest of Tarbiat Modares University) using of SEDMODEL and GIS. The results show that without considering sediment delivery ratio, erosion in this road network is about 11682.23 ton/year. With attention to sediment delivery ratio based on distance from road, sediment yield from these roads is 423/07 (71/8 %) and 165/98 (28/17 %) ton due to road surface, lateral ditch and cut slope respectively. Meanwhile with attention to sediment output that is 10560 ton, percent of sediment due to road network is about 5/57 %, whereas area of this road is about 0/31 percent of total area