City of Colorado Springs Integrated Catchment Modelling, USA
- Alastair Sheppard
- Aug 14, 2024
- 3 min read
What our customers say:
“Linking the 1D urban solver to the Flood Modeller 2D solver provided the team with valuable insights into surface flow patterns within the sub-basin once the drainage system capacity was exceeded. This integration allowed for a comprehensive comparison between the existing inlet capacity and the overland street conveyance, helping to identify when different locations became at risk of flooding.”
Flood Modeller was utilised to model the Little Shooks Run drainage basin in the City of Colorado Springs. Leveraging the 1D urban solver, built on the FEMA-approved EPA SWMM model, this advanced tool enabled the simulation of flood water on the surface while dynamically linking to the subsurface drainage system. This seamless integration allowed water to flow effortlessly between the surface and subsurface during simulations.
By employing the 1D urban solver, locations at risk of flooding were swiftly identified when the subsurface drainage system exceeded capacity. This powerful capability also facilitated the efficient exploration of various flood mitigation solutions.
The model outputs provided invaluable guidance to developers and City officials, aiding them in enhancing the existing drainage and street conveyance systems throughout the basin.
Modelling Overview
To undertake this analysis, it was essential to dynamically model both the subsurface drainage and surface water flows. A 1D urban model was constructed for the Little Shooks area and linked to a Flood Modeller 2D model.
The 1D urban model simulates the subsurface drainage system for various storm events. When the subsurface drainage system exceeds capacity, flow is routed out of the 1D urban model through manholes and onto the 2D model. Due to the dynamic linkage between the models, any flow diverted from the 1D urban system into the 2D system can move across the surface and re-enter the 1D system if there is available capacity within the subsurface drainage network at other locations.
Key Facts
Enhanced understanding of surface flow routes: Linking Flood Modeller’s 1D urban and 2D solvers provided a clearer picture of surface flow routes.
Identification of flood risk locations: The model pinpointed areas at risk of flooding when the subsurface drainage system exceeded capacity.
Investigation of culvert blockage impacts: The effects of culvert blockages on system capacity were thoroughly examined.
Effective exploration of mitigation options: Various flood mitigation strategies were efficiently explored.
Improvement of existing drainage system: Modelling facilitated enhancements to the drainage system throughout Colorado Springs.
Results & Benefits
Linking the 1D urban solver to the Flood Modeller 2D solver provided the team with valuable insights into surface flow patterns within the sub-basin once the drainage system capacity was exceeded. This integration allowed for a comprehensive comparison between the existing inlet capacity and the overland street conveyance, helping to identify when different locations became at risk of flooding.
The modellers utilised the model to analyse how blockages in a culvert within the sub-drainage basin reduced the capacity of the local system, causing water to be discharged onto the surface upstream. The model demonstrated that in some locations, water could flow overland and re-enter the drainage system downstream of the blockage, while in other areas, water leaving the sub-drainage system ponded and could not re-enter. This linked model was therefore crucial in understanding how the subsurface drainage basin influenced the surface water conveyance of floodwaters.
The model was then applied to test the impact of various potential solutions to reduce surface flooding. These solutions included incorporating additional inlets into the drainage system, adding storage facilities, and increasing pipe capacity. The outcome was a set of effective approaches that could be adopted by City officials and planners to mitigate flood risk from intense thunderstorm events in the Little Shooks Run drainage basin.
