2017 年 73 巻 4 号 p. I_85-I_90
Mangla reservoir is reducing its storage capacity due to sedimentation. The sedimentation rate may increase in future due to climate change. This study will provide the changes in sediment yield in Mangla watershed caused by climate and land use changes in future. The areas of watershed under high annual soil loss have identified using Universal Soil Loss Equation (USLE). Adapting proper land use types, it will be possible to reduce the soil loss and hence reduce the sediment load into the reservoir.
Estimations with CMIP5 rcp 4.5 climate scenario gave 12% increase in average annual sediment yield in late 21st century. Similarly, the increase in sediment yield due to future land use change arisen by expansion in urban and agricultural lands is 5% of that in present. Future sediment yield can be effectively reduced by 21% by transforming mosaic vegetation above 2000m and bare areas above 3000m elevation to forests. Contour cropping conservation practice for agricultural lands has found effective in reducing 4 to 5 percent of sediment yield in near future. These adaptation measures will help in enhancing the useful life of the reservoir by 31 years.