Impact of planned water resource development on current and future water demand in the Koshi River basin, Nepal

TLDR

The Koshi Basin’s water resources are largely untapped, and the effects of proposed development on current and future demand remain unquantified. This study evaluates the impacts of 11 proposed hydropower and water‑storage projects in the basin. We estimate that 29,733 GWh of hydropower could be generated annually and 8,382 million m³ of water could be stored, enough to meet the current unmet demand of 660 million m³ and the projected unmet demands of 920, 970, and 1,003 million m³ for population, agriculture, and industry by 2050.

Abstract

The water resources of the Koshi Basin (87,311 km2) are largely untapped, and while proposals for their development exist, their impacts on current and future water demand are not quantified. The current study is the first to evaluate the impacts of 11 proposed development projects for hydropower generation and water storage. We find that 29,733 GWh of hydropower could be generated annually and 8382 million m3 of water could be stored. This could satisfy unmet demand in the current (660 million m3) basin situation and in future scenarios – i.e. population, agricultural and industrial growth – that are projected to have 920, 970 and 1003 million m3 of unmet demand, respectively, by 2050.