Assessment of runoff and soil loss from the selected watersheds in the Hindu-Kush Himalayan Region

This study was conducted to examine the key factors affecting runoff and soil loss in 5 watersheds located in the Hindu-Kush Himalayan Region, viz., China (Xi Chuang, XI), India (Bhetagad, BG), Nepal (Yarsha Khola, YK and Jhijhu Khola, JK) and Pakistan (Hikot, HK). Results showed that runoff and soil losses were higher in the months of May and September, when rainfall duration and intensity were higher in all the watersheds. Highest annual runoff was generated in JK watershed in all land uses while very low in BG and HK watersheds. Highest runoff was recorded from degraded land uses. Most of the runoff in all watersheds occurred in 2nd and 3rd quarter. In JK (92-96%), in HK (75-90%), in BG (83- 94%) and in XI (87-90%) runoff was recorded in 2nd and 3rd quarter. Annual soil loss from JK was recorded higher in degraded, forest, agriculture and pasture land uses, while it was very low in HK and BG watersheds. Soil loss in April to September was higher in almost all watersheds. In JK watershed (95-99%), in HK (80 to 90%), in BG (83-90%), in XI (90%) of soil loss occurred in 2nd and 3rd quarter of the year in all land uses. Highest runoff and soil loss was found in degraded plots because of less vegetation and loose soil, susceptible to erosion. In agricultural plots, runoff and soil erosion was higher during the periods when there was no crop canopy and soil was not compacted after ploughing. During the months when crop cover was good, there was less runoff and soil erosion. However, in pasture and forest plots, runoff and soil loss was minimum throughout because of good vegetation and well organic matter that increased the infiltration and reduced runoff and soil loss. It is suggested that good water management techniques be introduced to get maximum advantages of the present water resources in the watersheds.