Assessment of Morphology and Soil Erosion Risk in Arain Macro -Watershed of Ajmer District (Raj.) Using RUSLE and Morphometric Parameters
Author : Dr. Shilpi Yadav, Narendra Kumar and Sabir Khan
Abstract :
The identification of priority areas for the establishment of control measures is one of the first objectives of conservation plans. The Watershed area of Arain Watershed is 1189 sq kms and located between 25055” N to 26030’ N latitude and 74050’’ E to 75015’ E longitudes. In this study, prioritization of sub-watersheds of the Arain Sub - Watershed has been done based on soil erosion risk. A methodology, based on Revised Universal Soil Loss Equation (RUSLE), has been applied using remotely sensed data, together with other ancillary data in a GIS environment. Based on the RUSLE model, the potential average annual soil loss of each parcel of land in the watershed’s ranges from 0 to 8437.21 t/ha/year. The result showed that moderate soil loss is observed in Six macro - watershed and rest of the macro watersheds fell under low soil erosion classes. About 15 – 20% of the macro- watershed fall in below the annual average soil loss of the entire watershed. On the other hand, Ground Truth has been also done for verifying this study and satisfactory results are achieved related to this study. Whereas, the quantitative analysis of morphometric parameters is found to be of immense utility in Sub-watershed prioritization for soil and water conservation and natural resources management at micro level. The present work is an attempt to carry out a detailed study of linear and shape morphometric parameters in 19 Macro Watershed of Arain Watershed and their prioritization for soil and water resource management. Topographic maps of 1972 on 1:50000 scale was utilized to delineate the drainage system, thus to identify precisely water divides using Geographic Information System (GIS). Following Strahler’s stream ordering scheme, it has been found that in Arain Watershed the total number of streams is 1711 belonging to different stream orders with the highest order of 7. The study has shown that the Arain Watershed is in conformity with the Horton’s law of stream numbers and stream lengths. The prioritization was carried out by assigning ranks to the individual indicators and a compound value (Cp) was calculated. Watersheds with highest Cp were of low priority while those with lowest Cp were of high priority. Thus, an index of high, medium and low priority was produced. The highest priority zone consists of 9 macro watersheds, medium of 8 and low of 02 Sub-Watershed. High priority indicates that these macro-watersheds are susceptible to greater degree of erosion and application of soil conservation measures becomes inevitable to preserve the land from further erosion and to alleviate natural hazards.
Keywords :
Soil Erosion, Arain Sub - Watershed, RUSLE, Morphometric Analysis, Prioritization, Remote Sensing and GIS.
