Adaptive Infrastructure Management: A Case Study for Stream Restoration
Kayla Kernich, PE, CFM
Thomas & Hutton
Greenville, SC
Thomas & Hutton was retained by the City of Columbia to design and permit a protection plan for the exposed 42” sanitary sewer line that crosses under a tributary to the Congaree River along the West Columbia Riverwalk in Lexington County, SC. Due to vertical channel erosion, the existing sewer line had become exposed at the bottom of the channel and posed a major potential environmental and asset management risk should it become structurally compromised due to further erosion.
Since it was not possible to lower the gravity sewer line to provide additional cover, the City of Columbia proposed protecting it in place using stream restoration measures. To meet these objectives, five rock cross vanes were proposed along the tributary upstream and downstream of the pipe crossing in order to add fill on top of the pipe, provide grade control, and to encourage sediment deposition over the existing sewer line. Coir matting, live stakes, and native plantings were proposed for further grade control and bank stabilization.
As part of the due diligence for this project, Thomas & Hutton also performed an H&H study to assess the total watershed draining through the tributary in order to not negatively affect upstream or downstream of the project area. A no-rise analysis was performed for the Congaree River using FEMA’s effective model and the proposed grading plan.
T&H obtained all necessary local, state, and federal permits and construction easements for the project. The collaboration between the City of Columbia and West Columbia proved vital to obtain all permits and easements. Additionally, it was also extremely important to provide a well-designed and detailed plan set, as well as have an engineer on-site during the construction process in order to make sure the intricate design was followed and that the park could still be utilized during the construction process. In the end, the project went smoothly and was a great example of how using green solutions and natural stream channel design principles can solve problems with exposed infrastructure all while keeping the public’s health, safety, and well-being in mind.
About Kayla Kernich, PE, CFM
Kayla Kernich is a Water Resources Engineer at Thomas & Hutton in Greenville, SC. She graduated from Clemson University with a Bachelors in Biosystems Engineering and a Minor in Sustainability. Kayla has nearly six years of experience in planning, designing, and permitting water resources-related projects. These projects range from large scale ones, such as island-wide drainage studies and watershed-level hydrologic & hydraulic (H&H) studies for FEMA, to small-scale projects including culvert drainage improvements and stream stabilization. She is experienced in the application of various types of hydrologic, hydraulic, and water quality models. Additionally, Kayla has certifications in stream morphology, natural channel design principles, and stream bank repair (from NCSU’s River Course program). She is a licensed Professional Engineer in the state of South Carolina and a Certified Floodplain Manager. Outside of work, Kayla enjoys cheering on the Clemson Tigers, being outdoors, and volunteering.
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