Document Type : Research
Authors
1
Department of Watershed Management, Faculty of Natural Resources, Tarbiat Modares Universityدهلران خیابان انصارالحسین کوچه شهید شیری
2
Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Noor, Mazandaran, Iran
3
Department of Watershed Management, Faculty of Natural Resources, Tarbiat Modares University
10.22092/wmrj.2023.362691.1545
Abstract
Introduction and purpose: One of the most common types of soil degradation is soil erosion under the influence of rain and runoff factors. Soil erosion reduces the quality of the soil in the place of erosion, and also the sediment resulting from erosion causes problems inside and outside the watershed. Due to the high cost of measuring soil erosion and sediment yield, various models have been developed to estimate the intensity of these variables in different spatial and temporal scales. Among these, the revised universal soil loss equation (RUSLE) has been widely used in all parts of the world for reasons including the availability of data required for model input factors and the possibility of implementing it in a distributed format.
Materials and methods: The present study was conducted in order to estimate soil erosion using the RUSLE model on a monthly scale for 2021 in the Kasilian watershed. First, a distribution map of the five factors of the RUSLE model was prepared. Since the variables of vegetation cover and precipitation have a significant change on a monthly scale, therefore, the temporal changes of the mentioned factors lead to the dynamics of the watershed system and the monthly changes of soil erosion. Also, soil erodibility factors, topography and land management were considered as static factors. Finally, the five factors of the model were multiplied together in Arc GIS software and erosion distribution maps were prepared on monthly, seasonal and annual scales.
Results and discussion: According to the monthly, seasonal and annual distribution maps of soil erosion, the highest and lowest monthly soil erosion occurred in November and April with values of 1.13 and 0.13 tons per hectare, respectively. Also, the average intensity of soil erosion in spring, summer, autumn and winter seasons was 1.32, 2.74, 2.99 and 1.52 tons per hectare respectively. Therefore, spring and winter seasons respectively had the least and autumn and summer seasons had the highest share of annual soil erosion. It can also be said that more soil erosion has occurred in the second half of the year compared to the first half. Finally, the intensity of soil erosion in Kasilian watershed was estimated at 8.56 tons per hectare per year.
Conclusion and suggestions: The results showed that a large part of the study watershed has low erosion and only the steep slopes, especially with low vegetation, including rangelands and abandoned agricultural lands, are prone to accelerated soil erosion. Specifically, soil erosion has increased due to the conversion of forest and rangeland into agricultural and orchard and even residential land. Finally, it is suggested to prevent the land use change by using land management solutions and soil conservation measures, especially in high slopes.
Keywords
Main Subjects
)