Item

Abstract

Retainment of sediment in lakes and reservoirs is a major problem that impacts drinking water supplies, irrigation, recreation, hydropower production, and flood control globally. The amount of sediments is likely to increase due to changing clime, e.g. increases in high intensity precipitation events. An ongoing challenge with assessing sedimentation at a large scale is that many basins are ungauged, and information about sediment management and decision making is not available. Large-scale dynamic hydrological models are fortunately becoming more commonly established as tools not only for flood forecasting and climate impact analyses, but also for estimating time-dynamic water fluxes and their transport into sea basins. One such tool is the dynamic, semi-distributed process-based rainfall-runoff and water quality model, Hydrological Predictions for Environment (HYPE, see https://hypeweb.smhi.se/). HYPE was recently updated to dynamically simulate (1) the effect of sediments on the available volume of lakes and reservoirs and (2) selected sediment management strategies. The new routines were tested on several reservoirs globally using different types of data for calibration: instream sediment concentrations (Banja in Albania), storage capacity loss (Enguri in Georgia), and upstream sediment yield (dams in Greater uMngeni River Basin in South Africa). The current annual rate of storage capacity loss varied greatly among cases (0.004-4.15%). The routines were then incorporated into SMHI’s pan-European model (E-HYPE) and calibrated against existing sediment concentrations. We present current and future losses of lake and reservoir storage and analyze sediment regimes in water bodies with water management structures such as hydropower or drinking water reservoirs.