Thesis (M.Sc.) - Asian Institute of Technology, 1996

A thesis submitted in paitial fulfillment of requirements for the degree of Master of Science, School of Environment, Resources and Development

Nepal is a mountainous countly with thousands of subwatersheds. The main problem of Nepal is soil erosion, because of heavy concentrated monsoon rainfall, geologically young and slopy fragile mountains, rugged surface topography, uncontrolled grazing, high demand of food, fodder, fuelwood and shelter for over growing livestock number and population beyond the canying capacity, improper land use practices, deforestation, faulty rules and regulations forced to implement by govemment such as Forest Nationalization Act 2013, and inappropriate infrastrncture development such as road and in-igation channel constrnction along the vulnerable slope failure and plate tectonics sensitivity sites. The problem of soil erosion is big, which affects not only the countly but the region as a whole. It is urgent need to combat this problem as soon as possible. But, it is not feasible to implement SCWM programs all over the count1y immediately at once where it need; because of constraints in budget, manpower and technology. Therefore, prioritization of subwatersheds with simple and accurate methods is necessa1y for countly like Nepal. However, use of advanced technology such as integrated use of RS and GIS is necessa1y to simplify the things. Prioritization of subwatersheds is aimed to design excellent watershed management planning for betterment of mountainous people's living standard in sustainable way along with the best conse1vation of natural resources. Hence, watershed planning of the area is can-ied out with due consideration and compromization of three components : watershed p1fority, people's p1fority and implementation capacity. The results of research show that it is not necessa1y the method to be sophisticated to find out accurate results. Highly acceptable results are achieved successfully in this research with the application of simple methods. The area with high population, steep te1nin and sloping agifoulture terraces such as Bhainskatta Khola, Kusum I<hola and Hulangdi Khola subwatersheds have been found high Soil Erosion Status. The areas with steep slope but covered with good forest, have found medium Soil Erosion Status (e.g. Lower Tinau Khola subwatershed). The areas with gentle slope, dense forest cover and less population have found low Soil Erosion Status (e.g. Sukhajor I<hola Subwatershed). Watershed planning of the priority subwatersheds of the study area is also formulated for five years with due consideration of future implication of SCWM progi·ams in the area. Because the sudy area, Tinau I<hola watershed, lies in the middle pa1t of the countly, is approp1-iate for demonstration of SCWM progi·ams implementation.