Document Type : Research Paper
Authors
1 River Engeering, Soil Conservation and watershed management Research Institute , Agricultural Research , Education and Extension Organization (AREEO), Tehran, Iran
2 Department of Civil Engineering, Islamic Azad University, Najafabad Branch, Najafabad, Isfahan, Iran
3 Associate Professor, River Engineering and Coastal Protection Department Soil Conservation and Watershed Management Research Institute
Abstract
This study experimentally evaluates the performance of individual check dams in mitigating flood peaks using a 1:10 scale physical model of Sijan stream, testing 90 scenarios under controlled laboratory conditions. The research systematically examines how stream characteristics (number of check dams and their sediment conditions) and inflow parameters (peak discharge and hydrograph time base) influence flood control effectiveness. Results demonstrate that check dams reduce peak discharge by 5-16% and increase time lag to peak by 17-21%, with performance highly dependent on flood magnitude and duration. For floods with return periods increasing from 2 to 10 years, the peak reduction efficiency decreases from 16% to 5%, revealing structural limitations against higher energy flows. The hydrograph time base emerges as a critical factor - when exceeding the watershed's time of concentration, peak mitigation drops from 17% to 5% and time lag decreases from 35% to 8%, indicating reduced effectiveness for prolonged flood events. These trends are attributed to flow dynamics: larger floods overwhelm structural resistance, while extended durations lead to control saturation and steady flow dominance. The study develops three robust empirical relationships (R² = 0.81-0.92) through dimensional analysis to quantify check dam impacts on hydrograph modification, providing practical tools for watershed management. However, the derived equations require site-specific calibration for application beyond the Sijan stream due to their dependence on local channel geometry and roughness characteristics. These findings offer valuable insights for designing check dam systems, highlighting their conditional effectiveness and the importance of considering both flood magnitude and duration in watershed management strategies. The research contributes to improved flood control planning by quantifying performance limitations under varying hydrological conditions.
Keywords
)