چکیده:
In the field of erosion and sediment supply using remote sensing data in Iran, few studies have been conducted. Therefore, due to the importance of accurate assessment of the erosion phenomenon and the lack of measurement stations, the MPSIAC technique was used from remote sensing for studying the target basin. The Sefidab basin lacks previous studies in the field of erosion and sediment, and the aim of this study is to estimate erosion and sediment using satellite data and compare the results obtained from these data with hydrometric station statistics. Using Landsat TM satellite data and Russian Cosmos (KFA-1000) data, and geometric correction of images with the GPS system, band 7 was used to prepare the geological layer, the combination of bands 4 and 3 was used to prepare the vegetation index, the combination of bands 5 and 2 was used to prepare the soil moisture layer, and the combination of bands 4, 3, and 2 as False Color Composite and Color Composite was used to identify land use (with digital image processing). To evaluate the soil layer, surface and riverine erosion, Cosmos data were used. By analyzing these data, the specific sediment amount in the basin using the Modified MPSIAC method was estimated to be about 4 tons per hectare per year, which shows a difference of about 1.3 percent compared to the statistics obtained from the hydrometric station (95.3 tons per hectare per year). A slight difference is observed between the results obtained from satellite data and the hydrometric station statistics. This issue indicates that the use of satellite data, in addition to high speed and accuracy, also reduces time and financial costs. Therefore, the use of satellite data in the assessment of erosion and sediment in inaccessible basins lacking ground information in the country is recommended.
خلاصه ماشینی:
The Sefidab basin lacks previous studies in the field of erosion and sediment, and the aim of this study is to estimate erosion and sediment using satellite data and to compare the results obtained from these data with the statistics of the hydrometric station.
Research Method To evaluate erosion and sediment in this sub-basin and assess the 9 factors of the modified PSYAC model, using the equations of this model (Table 1), the research method can be summarized in the following stages: Library studies (reviewing existing resources in university libraries and research centers).
(10) (Refer to the page image) Figure 3 Histogram of the cover index using Landsat TM bands 3 and 4 in the Sefidab sub-basin Evaluation of the land use layer To prepare this layer from satellite data, first, Color Composite images were created using bands 2, 3, and 4 with the combination of bands 2, 4, 3 (B.
(Refer to the page image) Map 4 Final class map in Sefidab basin Table 11 Determining the value of factors obtained with satellite data in the Pasiak model Using the final equation (Equation 7) of this model, the annual specific sediment yield of the basin was evaluated in tons per square kilometer per year, considering the average soil bulk density (1.
(Refer to the page image) Table 15 Specific erosion and sediment rates in Sefidab basin By comparing the obtained sediment with the hydrometric station data; the annual sediment evaluated using the remote sensing technique was approximately 21604/4 tons per year, which shows a difference of about 1/3 percent compared to the value obtained at the hydrometric station.
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