Application of GIS and RS in the plating of the Areas Prone to Floods by the Use of SCS Model in Larestan Varband River Catchment Area
Subject Areas : GeopoliticMarzieh Moghali 1 , Parviz Kardavani 2
1 - ندارد
2 - ندارد
Keywords: Exposure to the floods, SCS, IRS, Remote measurement, Curve Number, Organization of geographic dat,
Abstract :
This research was carried out in the catchment basin of Varband River in Larestanlocated in Fars Province in an area of 925.5 km2 by the use of IRS satellite pictures andthe measurer P6 (2006) so that through the use of the software ERDAS8.7, the localcorrections of the related pictures with 15 points and Afain equation with RMSE=0.42 andradiometric corrections with the algorithm of the equivalent rectangles were implemented.The best band combination was selected by the use of a suitable index factor and we usedthe classification under the supervision of the Maximum Similarity Probability Algorithmin order to provide the utilization map. The utilization layers were estimated 0.90 and 0.88by the use of general correctness test and Kapa statistics respectively. The co-precipitationmap was prepared in the environment of ARCGIS9.2 by the use of TPSs algorithm andaltitude-precipitation gradient as well as the map of Curve Number by the use of the mapof hydrologic and utilization groups. The height of the catchment basin slope,inappropriateness of formations, high evaporation and perspiration, soft soil tissue,severity of thundershower, utilization change, low compression of the covering crown andpoorness of pasturelands are among the effective factors in the exposure of the catchmentbasin to the floods. The analysis of each morphometric parameter of the catchment basinindicate that slope, area, shape, time of concentration, and percentage of waterwaycompression are the major effective factors in the exposure of the catchment to the floods.The presence of the rainfalls with duration of 15 minutes for 6-hour thundershowers arethe main factors in the destruction of soil structure and acceleration in the cumulativecurrent of the surface flowing water in Varband catachment basin . The phating map ofthe catchment exposure poteantial to the floods were offered in four classes of very low,low, average, and high. The results of this research showed that the whole productiveflowing water in this catchment basin is 42283746.6 m3 from which the sub-basins M, K,and A with 11.7, 11.3, and 10.01percent have a high exposure respectively and those of Cand G with 4.3 and 5.3 percent have the lowest exposure to the floods respectively.