Optimizing hydropower generation with reservoir level management in humid regions

It is well known that water management practices can have a significant impact on the climate and hydrology of a region. As a rule, the average flow downstream decreases due to the construction of new hydropower plants and the operation of new dams, as evaporation increases in the upstream dams. However, this is not the case in every situation. This study shows that dams in humid areas such as Brazil can help to increase river flow. This phenomenon occurs due to the high humidity and low wind conditions in the region, which leads to low evaporation in the reservoirs. At the same time, full reservoirs help to maintain high humidity around the reservoirs, which increases precipitation in the catchment. To test this hypothesis, water storage and hydropower generation data from Brazilian catchments in the Southeast region were used. Reservoir data are compared with future hydropower generation to investigate the correlation between the two variables. We find that the operation of reservoirs has a significant impact on Brazilian river flows. On average, the annual hydropower potential of a catchment with a full reservoir is 111 % higher than with empty reservoirs. To increase the flow of the river, the study proposes solutions to fill the reservoirs after an energy crisis and keep the reservoirs at full capacity. • First study to analyze reservoir storage impact on hydropower generation in humid regions. • Demonstrates significant increase in river flow and hydropower potential. • Minimum reservoir levels can increase the river flow in the catchment area by up to 110 %. • Recommends optimal reservoir filling order for maximizing hydropower generation.