How “leaky” should a leaky dam be? Insights from physical modelling at a white-water rafting course
Date:
Anthony Jones 1, Julia Knapp 1, Sim Reaney 2, and Ian Pattison 3 1 Department of Earth Sciences, Durham University, United Kingdom (anthony.d.jones@durham.ac.uk) 2 Department of Geography, Durham University, United Kingdom
3 School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, United Kingdom
Leaky dams, particularly those constructed from large woody material, are increasingly implemented in headwater streams to reduce runoff rates by enhancing channel roughness, slowing flow velocities, and creating temporary water storage during high-flow events to desynchronise flood peaks within catchments. Despite significant progress in modelling the hydraulic and hydrological effects of leaky dams through flume experiments and field studies, design guidance for the construction of leaky dams still needs to be improved. A key challenge in optimising designs is the limited availability of high-resolution pre- and post-intervention data in the field, particularly for extreme flood events, which constrains systematic evaluations of leaky dam performance. Enhanced observational studies are critical to validate the effectiveness of leaky dams and refine design strategies.
This study presents a controlled field experiment conducted at the Tees Barrage International White Water Centre, Stockton, UK, utilising a 300-meter white water rafting course to simulate flow events and evaluate the performance of three leaky dams under a range of flow conditions (up to 8.8 m³/s). Two dam designs were tested: (1) engineered dams constructed from pre-cut commercial timbers with consistent dimensions and (2) natural dams made from locally sourced pine timbers. The “leakiness” of the dams was systematically varied by adjusting timber spacings in increments of 10 mm to 100 mm.
Results demonstrate that both leaky dam designs effectively delayed flood peaks compared to the no-dam scenario. Engineered dams outperformed natural dams, delivering greater flood peak delays with better control of cross-sectional blockage. Smaller timber spacings further enhanced peak delays, with engineered dams achieving a 345-second delay and natural dams a 219-second delay relative to the no-dam scenario. Additionally, the study highlights the likely impact of debris accumulation over time on dam performance.
This research underscores the value of controlled artificial channels for generating precise, repeatable data on leaky dam performance under extreme flow conditions and provides a high-resolution dataset for in-channel hydrodynamic modelling. The findings advocate for further design-focused testing to optimise leaky dam configurations for improved flood mitigation, offering valuable insights for practitioners and researchers.
How to cite: Jones, A., Knapp, J., Reaney, S., and Pattison, I.: How “leaky” should a leaky dam be? Insights from physical modelling at a white-water rafting course, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-720, https://doi.org/10.5194/egusphere-egu25-720, 2025.