Alternate: Balancing Funding with Flood Risk Reduction

The City of Waco, TX (City) is experiencing chronic flooding within the area known as the Brook Oaks Neighborhood. As with most municipalities, they lack adequate funding to meet all their flood resilience targets. The City conducted a stormwater master planning effort to understand two main items: 1) the amount of infrastructure needed to meet all their targets and 2) the most impactful infrastructure they could implement with their current funding. The Brook Oaks Neighborhood is an 830-acre neighborhood located near the center of the City. It is served by both open channel and pipe stormwater infrastructure. Most of the pipe infrastructure drains into the main open channel (Barron's Branch) and discharges into the Brazos River. PC-SWMM 1-dimensional(D)/2-D modeling software was selected for the project. The stormwater master planning found that the majority of the stormwater infrastructure does not meet their newest targets. One of their newest targets is that all the stormwater runoff from events up to the 25-year, 24-hour remain within the stormwater conveyance system. The proposed solutions to meet this target include a mix of detention, open channel modifications, and storm sewer and box culvert reconstruction. These solutions serve as a long-term flood risk reduction plan for the neighborhood. Planning level cost estimates were generated to understand the magnitude of funding needed to implement infrastructure needed to meet this target. The cost far outweighs the available funding. Following that effort, model results were reviewed to understand where the most impact could be made with the available funding. Several areas experience flooding during even the 2-year, 24-hour event. Solutions were developed for these highest risk areas. This set of solutions is the short-term flood risk reduction plan for the neighborhood. This presentation will present the methodology, approach, and results of the short-term and long-term stormwater master planning. By creating this two-tiered approach, the City and the residents of the neighborhood can understand what can be done now versus what is ultimately needed for long-term flood risk reduction.