Input data set: Reservoirs and dams (Group III)

Future hydropower dam locations under ISIMIP3b Group III scenarios.

Future dam locations are based on the methodology of Gernaat et al. (2017), which identifies sites suitable for hydroelectric power plants at near-global coverage. Here we apply the methodology for multiple combinations of GCMs and global hydrological models (GHMs). We further combine it with projections for future hydropower usage from integrated assessment models (IAM), i.e. taking into account the projected expansion of hydropower caused by rising energy demands and/or climate change mitigation.
Briefly, run-off simulated by WaterGap2-2c (Müller Schmied et al., 2016, 2021) at 0.5° x 0.5° resolution is downscaled based on high-resolution topographic data, yielding 15’’ x 15’’ discharge data. Exploring a large number of potential sites (every 25 km along every river), the optimal type (river vs. diversion canal power plant) and dimensions of a hydropower plant at a given site are identified using an optimization approach, aiming for lowest-cost electricity generation. We rank potential locations by their electricity production costs, leading to a cost-supply curve for the expansion of hydroelectric power supply. Given the extension of hydropower capacity projected in an IAM (REMIND, Ref.) analysis of the respective scenario, we populate potential dam location sites (starting from the site with cheapest electricity generation) until the projected generation capacity for a given year is reached. This is repeated for each time step of the hydropower demand scenario (i.e. every 5 or 10 years).

In the corrected version released in May 2026, potential dam locations with unrealistically large reservoir volumes were excluded as unrealistic. To address potentially unconstrained dam construction in remote areas, a cost-of-electricity (COE) cutoff at 10 ct/kWh was applied, assuming dams with electricity costs above this value are unlikely to be built. In addition, potential dam locations with defined reservoir volumes larger than 300 km3 (3 x 10^11 m3) were removed. The dam scenarios were then recalculated by mapping the remaining potential dam locations to the REMIND hydropower demand projections. The corrected files replace the previous version.

Users who downloaded the ISIMIP3b Group III reservoirs and dams files before the May 2026 correction should update to the current files. The excluded very large reservoirs were likely related to known limitations in the hydropower dam model input data, including local misalignment between HydroSHEDS v1.0 elevation data and hydrological data, and potentially too small population-displacement and land-value costs in remote areas.

For ISIMIP participants, these files are available for download on the DKRZ cluster server using the path /work/bb0820/ISIMIP/ISIMIP3b/InputData/socioeconomic/reservoir_dams/