Asadzadeh et al. (2026) Water detention structures as a flood mitigation strategy: A case study of the Elgin Creek Basin

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2026
• Date: 2026-03-14
• Authors: Masoud Asadzadeh, Nursultan Umirov, Sung Joon Kim
• DOI: 10.1016/j.ejrh.2026.103347

Research Groups

• Department of Civil Engineering, University of Manitoba, Winnipeg, MB, Canada
• Manitoba Environment and Climate Change, Government of Manitoba, Winnipeg, MB, Canada

Short Summary

This study developed a computationally efficient, system-scale modeling framework to assess flood risks and evaluate water detention structures for mitigating road washouts in data-scarce Prairie basins. It identified five strategically located detention dams that collectively eliminate road washout risk for floods up to the 100-year return period in the Elgin Creek Basin.

Objective

• To develop and demonstrate an integrated, computationally efficient modeling framework for evaluating the effectiveness of distributed water detention structures in reducing flood risk and protecting vulnerable road infrastructure in data-scarce Prairie basins.
• Hypotheses: (i) MODSIM-DSS can accurately reproduce network flow dynamics and identify vulnerable road–stream intersections; (ii) distributed detention structures significantly attenuate peak flows and reduce spill volumes; and (iii) a small subset of strategically placed detention structures provides disproportionate basin-scale protection.

Study Configuration

• Spatial Scale: Elgin Creek Basin, Manitoba, Canada, covering approximately 499 square kilometers with a total length of about 40 kilometers.
• Temporal Scale: Simulations of 1-month (May) flood events with 2-, 5-, 10-, and 100-year return periods, using a 5-minute time step for hydrologic modeling and a 15-minute time step for integrated water management modeling.

Methodology and Data

• Models used: MODSIM-DSS (core integrated water management model), HEC-HMS (hydrologic model), HEC-RAS (hydraulic model), QGIS (Geographic Information System), ACPF (Agricultural Conservation Planning Framework) toolbox for ArcMap.
• Data sources:
  • High-resolution topography from Light Detection and Ranging (LiDAR) data (10 cm vertical accuracy, 1 m horizontal resolution).
  • Synthetic streamflow time series generated by HEC-HMS for various flood return periods.
  • Geometric data for HEC-RAS, including river cross-sections derived from LiDAR and hydraulic structure information provided by Surface Water Management (SWM).
  • Culvert design parameters (diameter, material, length, loss coefficients, Manning's roughness) based on field observations and Federal Highway Administration guidelines.

Main Results

• Computational Efficiency: The framework completed one-month flood simulations (15-minute time step) in less than five minutes on standard hardware, demonstrating significant efficiency compared to high-resolution hydrodynamic models.
• Model Validation: MODSIM-DSS results at the basin outlet showed high agreement with HEC-HMS (Nash-Sutcliffe Efficiency > 0.98, Percent Bias < 0.25%). The simulated 100-year flood accurately reproduced all eight road washout locations observed during the 2011 flood (estimated 83-year return period).
• Existing Infrastructure Performance:
  • Under a 5-year flood, one road (R10) overtopped, resulting in a 4% network washout risk and 0.72 million cubic meters of spill.
  • Under a 10-year flood, six roads overtopped (17% risk), with R10 experiencing 8.47 million cubic meters of spill.
  • Under a 100-year flood, eight roads overtopped (33% risk), with R10 having the highest spill volume at 52.41 million cubic meters. Road washouts were attributed to limited upstream detention capacity and insufficient culvert conveyance, exacerbated by tributary inflows.
• Effectiveness of Proposed Detention Structures:
  • Sixteen detention structures proposed by SWM reduced peak flows at R10 by 25% (from 8 cubic meters per second to 6 cubic meters per second) during a 100-year flood, but a substantial spill volume of 45.87 million cubic meters persisted.
  • Five strategically located detention dams (PC78, PC10, PC15, PC152, PC272) were identified as indispensable. These structures collectively reduced peak flow at R10 by approximately 75% (from 8 cubic meters per second to 2 cubic meters per second) during a 100-year flood, eliminating road washout risk at R10 and protecting critical downstream sites.
  • This intervention led to an increase in upstream inundation extent from approximately 866,000 square meters to 2,216,000 square meters at specific sites, highlighting a trade-off between downstream protection and upstream storage.

Contributions

• Introduces the first application of MODSIM-DSS as a decision-support tool for optimizing distributed detention dam placement to mitigate flood-induced road washouts in data-scarce Prairie basins.
• Develops an integrated, computationally efficient modeling framework that combines HEC-HMS, HEC-RAS, QGIS, and MODSIM-DSS, enabling rapid scenario-based assessment of flood mitigation strategies.
• Provides a scalable methodology that captures culvert-controlled routing and backwater effects, crucial for infrastructure-focused mitigation planning in low-relief, data-limited regions.
• Demonstrates that a small number of strategically placed detention structures can disproportionately enhance the reliability and resilience of rural transportation networks against extreme flood events.
• Addresses a critical policy challenge by offering an efficient decision-support tool for improving flood resilience under increasing climate variability and fiscal constraints.

Funding

• University of Manitoba Research Grant Program [URGP-324497]

Citation

@article{Asadzadeh2026Water,
  author = {Asadzadeh, Masoud and Umirov, Nursultan and Kim, Sung Joon},
  title = {Water detention structures as a flood mitigation strategy: A case study of the Elgin Creek Basin},
  journal = {Journal of Hydrology Regional Studies},
  year = {2026},
  doi = {10.1016/j.ejrh.2026.103347},
  url = {https://doi.org/10.1016/j.ejrh.2026.103347}
}