Streamflow routing at high temporal resolution: A distributed hydrological model with dam and weir impacts

The Geum River basin (9915.5 km 2 ) is the third-largest basin in South Korea including two multi-purpose dams and three multi-functional weirs. This study introduces LEESMORM, a distributed hydrological model designed for high-temporal-resolution streamflow routing that incorporates dam and weir operations. Applied to the Geum River basin, the model operates on a 1 km× 1 km grid with 10-minute time steps, simulating overland, unsaturated, and saturated hydrological processes. Calibration and validation were conducted using observations from 2013 to 2020. The LEESMORM demonstrates the feasibility of grid-based approaches for simulating streamflow dynamics and identifying drying trends in the Geum River basin. Streamflow modeling results at 10 gauging stations, including dam and weir locations, yielded coefficients of determination (R²) ranging from 0.56 to 0.94, Nash-Sutcliffe efficiency from 0.44 to 0.91, Root Mean Square Error from 1.13 to 3.61 mm/day, and percent bias from −13.94–42.50. For soil moisture, the average R² across 8 observation points was 0.41 (0.32–0.64 range), and for evapotranspiration at the Deokyusan flux tower, the average R² for the period was 0.66. These results highlight the importance of incorporating dam and weir releases to understand streamflow dynamics in regulated basins. The model’s fine temporal resolution provides valuable insights for water management, with potential future applications in smaller watersheds using finer grid resolutions to address localized challenges. • LEESMORM provides continuous streamflow simulations by tracking flow in small and medium-sized rivers. • The model uses kinematic waves, Penman-Monteith, and Darcy’s law to estimate hydrological factors. • Grid-based routing allows LEESMORM to simulate dam impacts at second-scale resolution. • Streamflow simulations at 10 stations showed high accuracy, with R² values between 0.56 and 0.94.