Land use/cover and their change have an impact on watershed hydrology Human activities,such asrnsteep slope and reservoir buffer zone cultivation and urban land expansion at the expense of forestrnand wetland causes for the dynamism of the watershed in the study area. The study were undertakenrnto quantify water balance change, water quality change, reservoirs sedimentation, and degradationrnof forest and wetland, due to difference in land use/cover,slope gradient and soil types in Chanchornand Sorga sub-watersheds. The SWAT model was used to quantify hydrological components,rnsediment and nutrient loss and RUSLE model for soil loss estimation, sediment yield and subsequentrnsedimentation of reservoirs. Surface water quality was assessed by taking water sample from eachrnsurface water and analyzed in the laboratory for TN, TP, TSS, TDS, and PH. Three times historicalrnimages of 20 years were used to assess the effects of urban land expansion on the naturalrnenvironment (water, forest, and wetland). The combined impact of land use/cover, slope gradientrnand soil types on watershed hydrology were also estimated by the SWAT model. It is found that thernpredictive capacity of the SWAT model for hydrological and water quality variables was evaluatedrnby using recorded river flow and sediment yield and showed a good agreement with simulatedrnvalues. The result indicated that urban land produced more surface runoff (642mm) than other landrntypes, followed by cultivated land; it is because of the impervious nature of urban land and steeperrnslope and continues cultivation of farmland with no soil conservation practices. Forestland andrngrassland produced (621mm and 610mm) of surface runoff and water yield,respectively, asrncompared to cultivated and urban land because of their higher infiltration capacity,rnevapotranspiration and percolation in the study area. Human activities such as land cultivation andrnexpansion of urban built-up areas are the main factors responsible for change of the watershedrnhydrology in terms of change in water balance and water quality deterioration. The slope gradient,rnsoil type and land use/cover type also contribute for the change in water balance in the watershed.rnAs the slope increased from 0% to 20%, surface runoff and water yield increased in cultivated,rngrass, and forest lands and then declined, whereas it increased in urban land as the slope increasedrnbeyond 20%.. The combined effects of land use/cover and soil types had no significant impact onrnhydrological components. The highest soil loss produced in the cultivated land which accounted forrn76% (30.38ton/ha/yr) of the total soil loss and the least soil loss was recorded in the grass andrnforestland (15.33 & 17.08ton/ha/yr), respectively, in the study sub-watersheds. Agriculturerndominated sub-watershed produced 8524.34 t/yr and forest dominated sub-watershed larger arearnproduces 14909t/yr of sediment and subsequently result in sedimentation of the reservoir differently.rnAgriculture-dominated surface water was greater in total nitrogen, total suspended solids, andrnacidity than the other two land uses. Urban-dominated surface water was greater in total dissolvedrnsolids than others. Forestland and wetland continuously decreased from 17% and 14% in 1996 torn5.1% and 2.7% in 2016, respectively, due to an increased average in the annual urban growth raternby 3.6% in the past 20 years. Therefore, the study areas are exprinced in an increased mean annualrnlocal temperature, variability of rainfall and relative humidity, and surface water quality reduction.rnLand use/cover and its change, slope gradient, and lesser extent of soil types are the most influentialrnfactors in affecting the hydrology of the watersheds in terms of water balance, water qualityrnreduction, storage capacity loss of reservoirs and forest and wetland resource degradation.rnTherefore, appropriate land use practice and watershed management strategies should bernimplemented