Using Tiered Floodplains for Resilient Outfall Restorations
Rebecca Oaks, PE
Nora Howard, PE
Rummel, Klepper, & Kahl (RK&K)
Baltimore, MD
The Anita C. Leight Estuary Center in Harford County is unique in many ways: it is a public park with pedestrian access that is located within the critical area and flows directly into the Bush River. It is not unique in one way though- it has gotten severely eroded by flashy urban flows over the last decade. Like so many of our urban outfalls, the tributary to Bush River at the Anita Leight Estuary Center has had dramatic erosion and downcutting over the last decade mostly due to increases in stormwater runoff and peak flows. This left the site with 900 linear feet of large eroded banks, little habitat opportunity, and major park impacts, including washed out trails and a failed bridge. The restoration design is intended to provide a stable stream restoration option that would reduce the erosion within the channel and provide a sustainable system that could improve ecological uplift while also providing capacity for the high flows coming from the stormdrain outfall.
During the original concept design, the intent was to restore the channel to its historic floodplain by filling the channel and then using a series of step pools sequences. During the modeling, however, it was found that by returning the flows to the original floodplain, the shears in the floodplain were very high due to high water depths, indicating that the classic priority 1 option was not a sustainable solution. The design team attempted several different iterations to create a design that would continue to convey the storms without adding erosive forces from high shears to the floodplain. Instead of just reconnecting the stream with its historic floodplain, the design team devised that it would actually be better not to fill the channel and bring it back to its historic floodplain, but instead to utilize the incised area to provide additional low storm floodplain benching that would pass lower storms and reduce the depth of flow in the floodplains. This presentation will focus on the iterative modeling process RK&K used to devise this system as well as preconstruction and post construction conditions at the site.
About Rebecca Oaks, PE
Rebecca Oaks, PE is a Project Manager at RK&K in the environmental, water resources department with 10 years of experience. She has a Bachelor of Science in Environmental Engineering from University at Buffalo and a Master’s of Science in Environmental Engineering from John Hopkins University. Rebecca is passionate about working in community spaces and restoring natural environments that work with communities to support habitat enrichment and water quality goals.
About Nora Howard, PE
Coming Soon