Analysis of the Impact of Land Use Changes on Soil Erosion Intensity and Sediment Yield Using the IntErO Model in the Talar Watershed of Iran

Abstract

Land use change is known as one of the main influencing factors on soil erosion and sediment production processes. The objective of the article is to study on how land use change impacts on soil erosion by using Intensity of Erosion and Outflow (IntErO) as a process-oriented soil erosion model. The study has been conducted under land use changes within the period of 1991–2014 in the Talar watershed located in northern Iran. The GIS environment was used to prepare the required maps including Digital Elevation Model (DEM), geology, land use, soil, and drainage network. The climatology data including average annual precipitation and air temperature as well as the volume of torrential rain were extracted from the data of meteorological stations located inside and around the study watershed. The results indicates that, within the period of 1991–2014, the forest area decreased by 12,478.04 ha (6%), while the other land uses including rainfed agriculture, rangeland, irrigated agriculture, and residential area increased by 7248.25, 4481.05, 476.00, and 273.95 ha, respectively. The estimated outflow with 100 year return interval was 432.14 m³ s⁻¹ in 1991, which increased to 446.91 m³ s⁻¹ in 2014. It can be concluded that the probability of larger and/or more frequent floods waves in the Talar River is expected to increase. In addition, the amount of production of erosion material (gross erosion) in the watershed increased from 1,918,186 to 2,183,558 m³ yr⁻¹, and the real soil losses per year (sediment yield) of the watershed increased from 440,482.4 to 501,421.3 m³ yr⁻¹. The results clearly emphasized how the lack of appropriate land management and planning leads to increase the maximum flow discharge and sediment yield of the watershed.