Assessing the Impact of Dam Spillway Releases on Flood Dynamics in Snow-Dominated Basins

Abstract

Effective management of dam spillway water releases is crucial for mitigating flood hazards in snow-fed basins. This study examines the April 2024 flood event that severely impacted Uralsk city and its surrounding areas in Kazakhstan. Using hydrological and hydraulic modeling, this study evaluates the role of upstream dam spillway releases in Russia as a primary driver of the flood event. Hydrological modeling was conducted using the HBV-light model, incorporating calibrated and validated streamflow data from ground stations. Snow water equivalent (SWE) and snow cover area (SCA) simulations were validated using ERA5-Land products. The flood extent and water depths were determined using the HEC-RAS two-dimensional (2D) hydraulic model, validated against satellite and drone imagery. Scenario-based analyses compare flood conditions with and without dam reservoir water contributions. The results indicate that an abrupt spillway release with a peak discharge of 2,170 m3/s increased the simulated flood inundation area by approximately 10% and locally increased flood depths by up to 1 m. These findings underscore the importance of proactive dam management in snow-fed basins to minimize flood risk. This study provides insights into the critical relationship between water resource management and flood dynamics, offering valuable guidance for sustainable development and flood risk mitigation in snow-covered regions.