The effect of flood-mitigation reservoir configuration on peak-discharge reduction during preliminary design

Study region The study considers synthetic river catchments representative of Mediterranean regions, with high impervious coverage and real rainfall time series. Study focus Stormwater studies often require rapid procedures to estimate which reservoir configuration reduces peak discharge to desired levels. Such estimates help identify and evaluate potential reservoir sites or assess the efficiency of existing ones. This paper provides simplified relationships to quantify the effects of the bottom outlet type and reservoir stage-storage curves on peak discharge reduction immediately downstream of a single reservoir. New hydrological insight for the region The proposed relationships fit the numerical results of detailed flood-routing simulations for 36 configurations. Results showed that the reduction effect could vary by 175% more, depending on the reservoir configuration. The proposed formulae allow a rapid evaluation and comparison of the reduction effect offered by different reservoir configurations without applying the standard reservoir-routing procedure, which should then refine and verify the design.