Kansas Department of Transportation
When erosion along Turkey Creek, a major urban drainage channel in Johnson and Wyandotte counties in Kansas, had the potential to disrupt the heavily traveled I-35 corridor, KDOT turned to GBA’s Stream Team for a long-term solution. Their efforts are paying off.
Stream Bank Restoration Designed to Prevent Erosion Along I-35
Flowing towards downtown Kansas City along the I-35 corridor, Turkey Creek has experienced dramatic changes because of urban development in the floodplain and subsequent channelization projects intended for flood control. In part because of these manipulations, the stream had moved a total of 67 feet toward the interstate within a period of eight years, prompting KDOT to take a fast-track approach to design, permitting, and construction of stabilization techniques. KDOT selected GBA’s Stream Team to provide geomorphology analysis and natural channel design solutions that would ensure long-term stability and sustainability for this portion of Turkey Creek. GBA's stream specialist Paul Miller, P.E., CFM, headed up the firm’s efforts on the project with a support team consisting of biologists, geologists, and engineers.
According to Miller, the Stream Team completed reach surveys that included profile, cross sections, sediment transport characteristics, and vegetative inventories. Collected data was then combined with mapping resources of geology and historic hydrology to define the current morphologic state of Turkey Creek at the project site. “This enabled us to estimate future changes in the stream so that our design recommendation would work with the natural tendencies of the system, improving long-term sustainability,” Miller said. The team provided conceptual design alternatives that included evaluating floodplain hydraulics, environmental permitting requirements, cost estimates, and lifecycle analysis. The selected design called for localized stream restoration by modifying channel length, depth, and cross section. The design called for using a mixture of stone and vegetated bank revetments to protect the interstate highway, overbank grading to offset floodplain impacts and restore floodplain connectivity, in-stream weirs to control localized stream beds, and deep-rooting woody vegetation to create natural roughness and reduce bank stress. The plan also called for permanent water quality features, reusing on-site materials and vegetation as much as possible while maintaining improvements outside the “clear zone.”
To help ensure that the project was constructed as intended, GBA’s Stream Team provided construction administration, assisting KDOT and the contractor with plan interpretation, construction techniques, and sequencing. It was recommended that performance be monitored over a three-year period to define management actions necessary to maintain the desired outcome for the project during the vegetative establishment phase.
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