Many communities across the U.S. suffer from routine and severe flooding due to a combination of riverine impacts and old, undersized stormwater collection systems, especially in urban areas. But how many communities develop detailed hydrologic and hydraulic models of both systems on a watershed scale and use these models to transform their downtown with holistic flood mitigation solutions that truly redefine urban drainage? The City of Fayetteville NC had the vision and financial commitment.

With its 12.0 square mile area and a stream length of 9.5 river miles, the Blounts Creek Watershed is the largest and most developed of the City’s watersheds. A Master Plan was prepared for this watershed that included detailed 1D and 2D hydrologic and hydraulic models using HEC-RAS (riverine) and ICM (collection) system; performing a field assessment of high priority stream reaches; and identifying issues and problem areas using the modeling and field assessment results to inform required mitigation with new proposed drainage solutions.

The primary and secondary system models were run under several design storms and the results were mapped together to enable the City to fully understand how the systems impact each other and identify concern areas of significant surface flooding and structure impacts. Each concern area was scored based on criteria outlined by the City to quantify street flooding, structure flooding and roadway overtopping. The scoring was used to define and inform the prioritization and scheduling of improvement projects.

One of the proposed solutions identified in the Master Plan that provides the greatest flood mitigation and risk reduction in the Blounts Creek watershed is the Person/Russell St Bridges Improvements and Stream Enhancement project. It is a large-scale primary system improvement that provides flooding relief to a significant number of low to moderate income homes, allows future secondary system improvements to meet level of service requirements, and provides an opportunity for community enhancements and nature-based solutions within the stream corridor to improve resiliency.

This presentation will step through the overall program and vision of the City in establishing and implementing the watershed master plan program. It will also detail the process used and proposed project developed to cost effectively provide holistic improvements, mitigate stormwater flooding and improve livability in downtown Fayetteville.