Modeling the Supply of Sediment Retention Ecosystem Service (Case study: Eastern Part of Gorgan-Rud Watershed)

Ecosystem services are benefits that people obtain from ecosystems. Soil retention is one of the most important ecosystem services. The capacity of ecosystem to maintain soil can be estimated by quantifying this services. In this study, version 3.0.0 of the InVEST software was used to map this ecosystem service in the eastern part of Gorgan-Rud watershed. The InVEST model employs the Universal Soil Loss Equation (USLE) for estimation of the soil loss in which R is the rainfall erosivity, K is the soil erodibility factor, LS is the slope length-gradient factor, C is the land use/cover and crop management factor and P is the support practice factor. Soil retention was estimated through the RKLS-USLE equation. Findings revealed the total soil loss potential varied between 0 and66.3 (t/ha). The sum of soil retention in sub watershed varied between 0.5 to 4530.2 (t/ha). Forest cover provided the main supply of this service in the study area. In comparison with other hydrological models, this model requires minimal input data, but at the same time produces useful outputs.