جستجوی مقالات مرتبط با کلیدواژه « شماره منحنی رواناب » در نشریات گروه « مهندسی آب »

Nowadays, in order to reduce the effect of unwanted factors and gather information related to land cover, vegetation indices were used. In this study, the effects of NDVI and VI indices on land cover and runoff curve number of Mansourabad watershed were investigated by using Geographic Information System (GIS) and Remote Sensing (RS). Land cover map was prepared by using vegetation indices and Landsat satellite images. In addition, the results of classification of these two indices and corresponding percentage with surveying data were compared. After that, runoff curve number map was prepared by combining land cover map with land use and soil hydrology group maps and by utilizing SCS table in the GIS environment. To assess the accuracy of each curve number map obtained from each index, runoff peak discharges computed by HEC_HMS model were compared by the measured amounts. The result of the classification showed that NDVI index with Kappa coefficient equal to 0.83 was better than the VI index with Kappa coefficient equal to 0.74 for land cover. These results were verified by lower error percentage between the measured and observed maximum discharge for NDVI index.

Geographic information systems and remote sensing techniques have been increasingly applied in watershed runoff estimation in recent years. In this research, the runoff curve number map of Birjand’s Mansourabad watershed, eastern Iran, was prepared using geographic information system (GIS), landsat images, and the Indian remote sensing (IRS) images based on the factors of hydrologic soil group, land use, land cover, and the hydrologic conditions. The land cover map was determined using Normalized Difference Vegetation Index, (NDVI); the watershed land use map was produced by satellite data; and the hydrologic soil group map was produced using field survey and watershed soil, slope, geology, and land use maps. Results showed that during the period of 2002 to 2006, land coverage density has decreased and consequently the curve number of watershed and its runoff production potential has increased.