CLIMATE CHANGE AND LAND USE DYNAMICS; PERSPECTIVE ON SOIL EROSION AND SEDIMENTATION PROBLEM IN PHEWA LAKE WATERSHED AREA OF NEPAL

摘要

Phewa watershed area is in a fragile physiographic region, which intense monsoon rainfall one of highest rainfall receiving watershed of Nepal. The Phewa lake watershed covers the area of 118.19 km~2 and lies on Western Development Region of the country. The objective of this study is to find the land use dynamics and climate change effects on soil erosion and sedimentation problem in the watershed. The Phewa lake watershed is located in a steep slope terrain of the Himalaya mountain range as high. The precipitation plays the important role for the soil erosion and sedimentation. 30 years data of rainfall is analyze and see the scenario of change in climate of the watershed and the change in land use in watershed area. Phewa lake watershed area has significant marked of land use change and analyzed by using GIS technique. The land use change is due to the opening of the roads in the hilly areas connecting to the Pokhara valley. Most of the land use changes are found in all categories of the land cover. The effect of land use change directly shown to the soil erosion and sedimentation in the Phewa Lake. Direct observation survey also shows the tremendous effect in soil erosion and sedimentation. Barren land is completely disappearing changing to other land use. The rate of change of land use agriculture decrease (0.49% per annum), forest decrease (0.12% per annum) and built-up area increase (0.135%) per annum. Most of the changes are in settlement, agricultural land, and forest and build up area in the watershed. Adaptation and management of the settlement policy for the environmental perspective is the way of minimize the effects of climate change and land use dynamics with respect to soil erosion and sedimentation. Lake conservation can play the important role for minimizing the soil erosion and sedimentation problem in Phewa Lake. The study shows that the land use change is continuous process from one aspect to another aspect: man and nature are its major agents for change of the landscapes in the watershed area of the Phewa Lake.