Underwood Creek Downtown Daylighting Project
Elm Grove's Segment of Underwood Creek
The Underwood Creek Watershed drains 18 square miles in 12 linear miles of stream throughout Brookfield, Elm Grove, and Wauwatosa. The section of the creek that runs through downtown Elm Grove was channelized and covered with a parking lot in the 1960’s. This concrete confinement channeled the water under the parking lot and under Sendik's before it reappears and flows alongside the 890 building.
What is Daylighting?
The process of re-opening a waterway that has been artificially channeled underground in a pipe.
Why Do We Need to Daylight Underwood Creek?
This enclosure built in the 1960s was not permitted by the Village nor sanctioned by the Wisconsin Department of Natural Resources (WDNR). When this channelized segment was evaluated during preliminary engineering of the Flood Management Project, it was determined to be insufficient for high water flow and would lead to flooding if not removed. The WDNR, as a condition of the permit issued for the rest of the Flood Management Project, required the Village to actively pursue funding to accomplish the future daylighting of Underwood Creek, as they determined it to be a previously unpermitted structure and therefore not eligible for any repairs. The ultimate goal has to be replacement. If not addressed soon, the deteriorating channel and parking lot above will collapse.
In 2003, the Village began the Underwood Creek Flood Management project to reduce the risk of flooding in Downtown Elm Grove during large scale rain events. The Flood Management project was successfully tested during a heavy rainstorm in June 2008 and several times since then, during which no overland flooding of any downtown structures occurred.
What is the Proposed Solution?
The Village of Elm Grove has worked with engineering firms and the Army Corps of Engineers to gain approval for a solution to the current enclosure. This new solution utilizes a design incorporating natural elements that will help to restore the waterway's natural path and provide a habitat for native fish and wildlife species, while providing floodwater storage during high-flow events.
View the proposed rendering below!
What are the Benefits of the New Solution?
The new design brings back a natural ecosystem. The area of stream bed just below the surface is called the Hyporheic Zone and it is critical for regulating stream temperature. This area also serves as an energy source for the stream (see video below). Restoring a natural stream bed will allow nutrients produced in the stream bed to interact with life in the water and under the surface, which will restore overall habitat health. Additionally, the planned design includes the incorporation of toe wood, which are wood branches placed underwater beneath the stream banks. The algae that grows on this wood provides food for small fish and the area between the branches of the toe wood under these stream banks form a calmer area where fish can escape the fast currents during high-flow events. A natural stream will also allow Salmon and Northern Pike to swim all the way upstream to spawning beds in Brookfield. Finally, the new plan is compliant with the regional floodwater protection plan. Daylighting of other streams around the country has shown that people are attracted to the new natural environment, and this has a positive economic impact on the nearby businesses.
For more information on the Hyporheic Zone and its benefits, check out this video.
Where have we gotten funding from so far?
Through continuous efforts, the Village has successfully secured grant funding for final stream channel design and engineering from the Milwaukee Metropolitan Sewage District (MMSD), local property owners, and the grant funds listed below.
Additional grant funding opportunities are currently being pursued for the second phase of the project: Underwood Creek relocation and construction. This project will be paid with funds from the Storm Water Fund and monies received from TID #2, so there will be no increase in property taxes to homeowners due to this project.
Construction? The new Daylighting design will keep the businesses affected by construction in mind each step of the way.
Parking? There will be coordination with the property owners to maintain approximately the same number of parking spaces. However, the parking lot is on private property, and the final design of the parking lot will be up to the property owners.