Volume 5, Issue 1 (6-2018)                   Jsaeh 2018, 5(1): 1-16 | Back to browse issues page

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Asgari S, GHANAVATI E, Shadfar S. Evaluation of landslides on sedimentary quantitative of Ilam Dam Watershed. Jsaeh. 2018; 5 (1) :1-16
URL: http://jsaeh.khu.ac.ir/article-1-2630-en.html
1- Soil Conservation and Watershed Research Department, Ilam Agricultural and Natural Resources Research and Education Center, AREEO, Ilam, Iran and student of Kharazmi University Tehran, Iran
2- Prof Associate Prof Associate in Department of Geomorphology, Faculty of Geography, Kharazmi University, Tehran, Iran , ezghanavati@yahoo.com
3- Prof Associate Samad Shadfar., Prof Associate in Department of Soil Conservation and Watershed Research Agricultural Research ,Education and Extension Organization (AREEO), Tehran,
Abstract:   (332 Views)

 Quantitative assessment of landslide sedimentation in the ILAM dam Basin

Information on the accurate volume of landslides and sedimentation in landslides is a research necessity, with the assumption that the bulk of sediment accumulated in the ILAM Dam (located between , E and , N) is related to the surface landslides of the basin. Although the role of landslides in erosion, sediment transport and sedimentation of slippery basins is confirmed and different experts understand and determine the relationship between the fluctuation of slopes and the fluctuation system in many respects more important than other areas. Because according to the results they can assess the widespread environmental changes, but comprehensive research on the scale of catchment basins has done very little (Harvey 2002). So far, the study of wet landscapes in Iran has been more sensitive to the factors, their sensitivity and their hazards, and there has been no study on the sedimentation of landslides.

Data and Method
First, using a geomorphologic system methodology with topographic maps of 1: 50000, geological map of 1: 100000, aerial photography1: 20000, Landsat TM1988 ETM2002,2013 satellite imagery, and Google Earth in the GIS environment in the following sub-basins and landslide events at the following levels The basin was drawn. The discharge data of the water and sediment flow of three hydrometric stations GOLGOL,CHAVIZ and MALEKSHAHI Station were provided from the waters of the ILAM province. Two models of estimated MPSIAC and EPM models have been used to estimate soil erosion and subsoil sedimentation. The Moran spatial correlation model was used to introduce the spatial pattern of landslides, and the fuzzy logic model was used to determine the relationship between the dependent landslide to the independent variables and the potential risk of landslide hazard in the basin. In order to elucidate the quantitative results of landslide sedimentation, empirical models of estimation of sediment erosion, hydrological model of discharge curve and sediment, observational statistics of sediment during statistical period, landfall time occurrence in compliance with the hydrometric station sediment peak during the statistical period of computation Estimated a small amount of sedimentation of the landslides of the ILAM dam basin.
Result and Discussion
The spatial correlation model of Moran showed that the data have spatial correlation and cluster pattern. The average total sediment production in the MPSIAC model in the GOLGOL basin was estimated to be 13.3 tons per hectare per year under the CHAVIZ basin of 10.3 tons per hectare for one year and 4.00 tons per hectare in the sub-basin MALEKSHAHI. Using hydrological model of discharge-sediment curve, the mean sediment was calculated during the statistical period at the hydrometric station of the sub-basin of GOLGOL 18.8 ton per hectare, the station CHAVIZ 10.4 tons and the station MALEKSHAHI 0.9 tons of sediment per hectare per year was calculated. According to the results of the research methodology, the observation of the sediment in the two stations of GOLGOL and CHAVIZ compared to estimated sediment is related to the events occurring in these two sub-basins.
The data of 16 active landslides were recorded. Under the GOLGOL basin, 9 landslide events occurred, and in the CHAVIZ basin, 7 landslide events, the time of landfall occurrence recorded with sedimentary peaks, the length of the statistical period, the precipitate in the sub-basins was almost synchronized. Average relationship between suspended period of the statistical period - average of the peak delayed flight time of the statistical period coinciding with the occurrence of landslide = the amount of suspended load of landfall occurrence in the basin.
The amount of suspended land slip under the GOLGOL 75088.19 - 315.85=74772.34
Landing slope under the Chavez Basin 19907.30 - 20.24=19887
The area of the sub-basin is about 29,000 hectares and the active landslide area is about 100 hectares. According to the calculations, 77772.34 tons of suspended sediment is a sedimentary passage passing at the GOLGOL hydrometric station, which shows with a coefficient of 1.4 times the suspended sediment load of approximately 104681 tons of landslide sedimentation in this sub-basin, which shows the amount of sediment yield 100 hectares of landslide, so each landslide hectare had an average of 1046. 81 tons of sediment deposited at the GOLGOL hydrometric station. The area under the Chavez Basin is about 14000 hectares and the active landslide area of this sub-basin is about 65 hectares. According to the data of the discharge data, the sedimentation of the Chavez hydrometric station is 19887 tons of suspended sediment load, which shows a 1.4 equivalent of 27842 tons of landslide sedimentation in this sub-basin, equivalent to a slope of 428.33 tons per hectare.
According to the calculations, it is concluded that in the sub-basin of flowering GOLGOL, 37.35% is equivalent to 4.9 tons per hectare per year, the increase of sediment is related to landslide events. As a result, 28.2 tons of sediment per hectare were introduced in one year Dam reaches ILAM. The results showed that in the CHAVIZ sub basin, 38.2 percent is equivalent to 4.6 tons per hectare per year for the increase of sediment related to landslide events. As a result, an amount of 14.5 tons of sediment per hectare has entered ILAM dam in one year. In the sub-basin MALEKSHAHI, there was no increase in sediment during the period without active landslide occurrence. A total of 1237314 tons of landslide deposition have entered the ILAM Dam. To control this threat, the appropriate action by the executive office for sustainable development should be applied.

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Type of Study: Research | Subject: Special
Received: 2017/02/21 | Accepted: 2018/06/12 | Published: 2018/06/12

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