A reservoir operation scheme for global river routing models

SummaryA global river discharge simulation was conducted that accounted for 452 individually operated reservoirs by locating them on the digital global river network map of TRIP, a global river routing model. An operating rule was determined for each reservoir using a newly-developed algorithm that used currently available global data such as reservoir storage capacity, intended purposes, simulated inflow, and water demand in the lower reaches. This algorithm reduced the root mean square error of reservoir release and river discharge simulations from that of earlier global river discharge simulations that neglected reservoir operations or substituted an algorithm for natural-lake outflow. The 2-year global simulation results indicate that reservoir operations substantially altered monthly discharge for individual basins (i.e., by more than 20%). Averaged over the continental scale, the maximum change in monthly river discharge varied from 0% to 34% and the changes in reservoir storage were small as a proportion of the total storage capacity.