نوع مقاله : پژوهشی
نویسندگان
1 استادیار، بخش تحقیقات حفاظت خاک و آبخیزداری، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان ایلام، سازمان تحقیقات، آموزش و ترویج
2 استادیار، گروه پژوهشی مهندسی حفاظت خاک و آب، پژوهشکده حفاظت خاک و آبخیزداری، سازمان تحقیقات، آموزش و ترویج کشاورزی، تهران، ایران
3 استادیار، بخش تحقیقات حفاظت خاک و آبخیزداری، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی خوزستان، سازمان تحقیقات، آموزش و ترویج
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Gully erosion is one of the most important water erosion's in which a large amount of soil is washed away. This type of erosion, in addition to producing a lot of sediment and as a result of filling dams and reservoirs, makes a wide range of lands unusable and changes the overall appearance of the land. One of the important issues of Ilam watershed is gully erosion. In this research, the ability Wight of Evidence and Dempster- Shafer models were used to determine the thresholds and zoning of gully erosion sensitivity. Using Google Earth images as well as field visits, 331 ditch locations in Ilam watershed were identified and recorded, and their distribution map was prepared. Spatial data of gully erosion distribution were divided into two random training (70%) and experimental (30%) groups. 23 factors affecting the occurrence of gully erosion according to the research records were used in the analysis of the gully erosion threshold. The output results of the layers, weighting and classification and integration in the two models of weight witness and Dempster- Shafer are the extraction of the zoning map of gully erosion sensitivity. The validation and efficiency results of the models based on the ditch distribution map of 70% of the ditches for training the models and 30% of the calibration and validation of the models showed that the area under the system performance characteristic curve (ROC) and the area under the graph (AUC) showed that the Dempsterschie Shafer fer model with an explanation coefficient of 934/ 0 and the control weight model with an explanation coefficient of 0.932 have an acceptable percentage of the area under the curve, which indicates the high performance of both models in the region. Based on the results of statistical analysis, the threshold of gully erosion in rains of 100 to 750 mm, the type of shale and marl rock, the height of 500 to 1500 meters, the density of waterways is 0.7 to 2.3 km per square kilometer, inspatisoil or lithic calcifert soils, the slope is 12.5%. Geographical direction: 67.5 to 292.5 degrees, watershed drainage area: 0.1 square kilometers, slope length: 20 to 200 meters, land use: agricultural and garden land, normalized vegetation difference index: 0.075 to 0.50, light shade analysis: 55/ 0 to 0.77 percent, topographic humidity index 3.5 to 8.14 percent, convergence and curvature indices -0.1 to 0.1, distance from the Stream 25 to 200 meters, vertical distance from the drainage network 0 to 400 meters, and the type of climate is ultra-arid and semi-arid, in the watershed. Ilam was determined.
کلیدواژه‌ها [English]
)