Prioritizing Watersheds for Sustainable Development in Swan Catchment Area, Himachal Pradesh, India

Abstract

Land and Water resources form the base for development and utilization of other resources. The depletion and degradation of these resources has happened at a very fast pace in developing countries like India. Many resource development programmes have been undertaken in India to tackle the problem of land and water resources and have been applied generally on watershed basis. Thus, prioritization is essential for proper planning and management of natural resources for sustainable development. Mountain watersheds have attracted global concern due to the threat of serious environmental and socio-economic implications arising from natural resource degradation. Increasing recreational pressures within the mountains, demand for hydro-power, and increasing climatic variability are major concerns of present time Himalayas. Therefore, the basic objective of the prioritization of watersheds is proper management in the most vulnerable parts of the watershed so as to minimize the siltation rate in the active stream or reservoirs. The study area of Swan catchment falls under Una district. The river Swan has a total catchment of 140,000 ha out of which 120,000 (85.7 %) ha lies in the Himachal Pradesh. The river is fed by about 82 tributaries during its traverse in Himachal Pradesh. In district Una, river Swan flows through inter-mountainous valley. The study has used both primary and secondary databases. In the present study, the parameters considered for prioritization of watershed were from the natural resources thematic map data, including soil, drainage density, surface water prospects, groundwater prospects, irrigated area, forest cover and Land use land cover derived from satellite imagery and socio-economic data. In the present study, weightage system has been adopted for sub-watershed prioritization based on its factors and after carefully observing the field situation. The basis for assigning weightage to different themes was according to the relative importance to each parameter in the study area. The weightage system adopted here is completely dependent on local terrain and may vary from place to place. The prioritization results of study shows that 4 sub-watersheds SWL36, SWL6, SWR54, and SWR69 need very high priority, 29 sub-watersheds need high priority, 16 sub-watersheds fall in medium priority and 32 sub-watersheds fall in very low and Low priority.