Old Cheney Cutoff Stream Stability Project
The City of Lincoln Public Works Watershed Management Division and Kirkham Michael are working on the design of stream stability improvements to a small drainage way stream located in southwest Lincoln. The stream drains a watershed of roughly 200 acres in a largely residential area southeast of the 14th Street and Old Cheney Road intersection. The stream is experiencing erosion problems at the outlet of a concrete box culvert crossing under Rock Island Trail. The erosion has begun to threaten the stability of the culvert and the embankment of the Rock Island Trail approach to the bridge over 14th Street.
Project Location Map (402 K)
The proposed project to repair and stabilize the channel includes earthwork within the channel to repair the eroded banks and construction of a rock riprap stilling basin. The basin is designed to temporarily hold a pond of storm water runoff that slows the speed of water rushing out of the box culvert. By reducing the energy of the flowing water with the pool of water, the potential for channel erosion is greatly reduced. The large rocks in the riprap basin also help stabilize the channel banks to provide further erosion protection. The pool of water in the stilling basin will drain away once the runoff from the rainfall event stops. The project also features grade stabilization structures across the channel that prevent channel bottom erosion. Earthwork will be done within the channel including widening to form the stilling basin and transitioning the channel banks back to their natural shape and size. The project is anticipated to impact less than 200 feet of the channel.
The proposed project is expected to have a construction cost of approximately $90,000 which will be paid for using funds from voter-approved storm water bonds. The construction for the project will be completed in September 2013. Because the project site is located near Rock Island Trail, a short portion of the trail will be temporarily closed during construction but the bridge over 14th Street will remain open. This project is important to the City of Lincoln in order to protect the Rock Island Trail from damage caused by erosion and will ensure the trail remains in excellent condition for years to come.
Jared Nelson, City of Lincoln, Watershed Management
Mark Egger, PE, Kirkham Michael