RiskHydro developed an integrated 1D–2D PCSWMM model to support the Duffyfield Canal Restoration Master Plan in New Bern, North Carolina. The model represents nearly 2 square miles of urban watershed, including the Duffyfield Canal and connected drainage system, stormwater pump stations, overland flow paths, and the influence of elevated Neuse River water levels within a single hydraulic framework. The project is funded through the North Carolina Resilient Coastal Communities Program (RCCP), administered by the North Carolina Department of Environmental Quality’s Division of Coastal Management.
Using rain-on-grid modeling, RiskHydro evaluated existing and future flood conditions, quantified how downstream water levels affect drainage throughout the neighborhood, and tested conceptual improvement strategies ranging from pump station improvements and interior pumping to regional stormwater storage and distributed neighborhood-scale stormwater controls.
RiskHydro also supported the project’s community engagement by turning the technical model into an interactive tool residents could explore themselves. At public meetings, residents moved between present-day rainfall scenarios, elevated river conditions, future conditions with sea level rise, and proposed improvements while comparing the model results with flooding they have experienced firsthand. Their feedback provided another source of information for the master-planning process and helped identify drainage features and problem areas that may not be fully represented in existing mapping.
| Location New Bern, NC | Client Type Municipal |
| Client City of New Bern | Service Area Stormwater & Watershed Planning |
| Project Type Flood Resilience & Stormwater Master Planning | Partnership Year 2025-2026 |
| Project Status In Progress |
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Flooding in the Duffyfield neighborhood is not controlled by rainfall alone. The canal drains toward the Neuse River through a low-lying system of storm drains, road crossings, pump stations, wetlands, and downstream conveyance features. When receiving-water levels rise, gravity drainage becomes restricted and the existing pumping system can become less effective, allowing runoff to accumulate within the neighborhood.
That interaction makes the problem difficult to understand using conventional pipe calculations or isolated flood maps. The City needed a model that could represent rainfall, underground drainage, canal conveyance, pump station operation, surface flooding, and elevated downstream water levels together.
The project also needed to communicate those complicated interactions clearly to residents who experience the flooding. A successful master plan had to combine technical analysis with local knowledge of streets, ditches, pipes, and drainage paths that may not be apparent in available mapping.
RiskHydro developed a fully integrated 1D–2D PCSWMM model that represents runoff generation, storm drain conveyance, canal hydraulics, pump station operation, and surface flooding within one connected system.
Rainfall is applied across the two-dimensional model domain, allowing the model to simulate where runoff enters the drainage network, where pipes and culverts become overwhelmed, how water moves across streets and developed areas, and how downstream water levels influence the system.
RiskHydro evaluated a range of present-day and future flood scenarios along with five conceptual improvement strategies:
The model was also adapted for community engagement. At the Duffyfield Canal Restoration public meeting, RiskHydro provided an interactive flood-model display that allowed residents to move directly between scenarios and see how flood conditions changed with rainfall, downstream river levels, future conditions, and proposed improvements.
Rather than simply presenting completed maps, the model became a discussion tool. Residents identified locations where modeled flooding matched their experience and shared information about drainage paths and infrastructure that could be carried forward into the planning process.
The modeling showed that elevated downstream water levels are an important control on flooding within the Duffyfield watershed. Under compound conditions, higher receiving-water levels restrict gravity drainage, reduce the effectiveness of the existing drainage system, and increase the potential for interior flooding and roadway impacts.
The future-condition analysis also showed that these interactions become increasingly important as downstream water levels rise. RiskHydro then used the model to compare five conceptual improvement strategies:
The analysis provided a consistent basis for comparing how each strategy affects flood depth, inundation extent, structural exposure, roadway access, and performance under both rainfall-driven and compound flooding conditions. It also demonstrated that the alternatives address different parts of the flooding problem and can provide complementary benefits.
The resulting model gives the City a defensible planning tool for comparing alternatives, communicating flood risk, incorporating community input, and identifying which strategies should be advanced for further engineering as the restoration master plan moves forward.
Integrated 1D–2D rain-on-grid hydraulic modeling using PCSWMM
Existing, compound, and future-condition analysis
Pump station, canal, storm drain, and overland-flow simulation
Five conceptual flood-mitigation strategies evaluated
Building and roadway flood-impact mapping
“RiskHydro has become our go-to partner for complex hydrologic and hydraulic modeling needs. Their team has an excellent eye for detail, is incredibly responsive, and delivers a final product that is both technically sound and easy to understand.” – Luke Baker, PG, Water Resources Lead, TRC Engineers, Inc.
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