Runoff, Sediment and Nutrients Loss from Two Small Watersheds in Eastern Plateau and Hill Region of India

Hydrologic behaviour of many small watersheds around the world are changing mainly due to alterations in land use land cover, and creating new regimes of hydrologic response by driving changes in runoff, sediment and nutrient dynamics. In this study, response of two small watersheds, Plandu and Keribanda, located in eastern plateau and hill region (EPHR) of India was assessed in terms of runoff, sediment and nutrient loss. Daily discharge at the outlets of watersheds was monitored, and water samples were collected at weekly intervals during the monsoon seasons of the years 2015, 2016, and 2017. Water samples were analysed for sediment, Nitrogen (N), Phosphorous (P) and Potassium (K) concentrations. The peak discharge rate from the Plandu and Keribanda watersheds ranged between 5.35 m³.s⁻¹ to 8.58 m³.s⁻¹, and 8.41 m³.s⁻¹ to 11.79 m³.s⁻¹, respectively. The Plandu watershed yielded 47.4 % higher sediment yields compared to the Keribanda watershed on account of extensive agricultural activities duringthe monsoon season. The Plandu watershed also recorded higher N (1.17 kg.ha⁻¹.y⁻¹) and P (0.19 kg.ha⁻¹.y⁻¹) losses; however, theK loss (22.92 kg.ha⁻¹.y⁻¹) was higher in the Keribanda watershed. Linear regression models were also developed between rainfall-runoff (R²: 0.86-0.89), runoffsediment yield (R²: 0.82-0.88), N, P, and K loss with runoff volume(R²: 0.82-0.94). The findings of this study would aid in devising informedpolicies for soil, water and nutrient management strategies at the watershed scale.