EFFECT OF LAND USE ON RUNOFF AND EROSION AT HILKOT WATERSHED (MANSEHRA)

The study was conducted on runoff and erosion losses at Hilkot watershed, Mansehra, N. W. F. P, Pakistan, from January to December 1999. Main objective of the study was to determine runoff and erosion losses from four different land uses (I. e. on degraded, pasture, forest and agriculture plots), and to develop rainfall-runoff and runoff-soil loss relationships. All land use plots had same size (100-m2) but different plant cover, slope and soil texture. A collection system consisting of four drums was installed at the end of each land use plot to monitor runoff and erosion. Runoff and erosion samples were taken after every rainfall event. Results showed a strong relationship between rainfall and runoff on all land use plots. Higher rainfall-runoff relationship (R2= 0.62) was found in case of agriculture plot. In runoff-soil loss relationship resulting value of R2 (0.93 to 0.96) shows that there is a strong relationship between runoff and soil erosion on all plots. On degraded plot maximum 96% variability can be explained by runoff Maximum total soil loss (4.66 t/ha) was found on degraded erosion plot and minimum (0.30 t/ha) on pasture plot. Similarly, annual runoff was highest (756m 3/ha) in degraded land and minimum (226m/ha) in pasture land. &nbsp