The Busse Woods Reservoir South Dam was constructed in 1975 to reduce flood damages during large scale floods up to the 100-year flood event. Since that time however, Elk Grove Village has historically sustained significant damages from Salt Creek flooding downstream of the Dam as a result of the lesser, more frequent storm events. The Village has sustained flood damages to public infrastructure, residences, commercial, and institutional land owners in recent events, including 2008, 2009, and 2013.
Modifications to the South Dam to improve its flood protection capability had been studied numerous times over the years with different modifications proposed. Concerns associated with the potential ecological impacts of alterations to the existing water levels in the Busse Woods Reservoir complex prompted further evaluation of existing conditions and options for floodwater management by WBK and the Village. The creation of storage and management of the timing of the flow events within the Busse Woods Reservoir complex was one option that provided a viable solution. This option involved the use of a movable gate.
WBK performed a concept level screening investigation using hydraulic modeling as a tool to guide selection of movable gate alternatives for refinement. During this concept phase, the initial emphasis was on determining the scope and scale of dam modification and pool lowering that would be required to meet the Village’s need for flood mitigation. At the screening level, WBK used the MWRD Unsteady HEC-RAS model previously developed by others to develop and compare alternatives. As the next step, the concept modification, previously developed in HEC-RAS, was evaluated to assess potential affects in downstream DuPage County communities using the County’s FEQ model. Extensive hydraulic modeling was then completed to develop a gate operation plan and subsequently integrated into DuPage County’s Salt Creek Flood Control program.
In parallel with the design/engineering analysis of the movable gate alternative, a number of ecological studies were completed to understand the current state of the ecological communities within the reservoir complex as they related to the planned operation of the movable gate. The innovative design of the moveable, hinged crest gate at the dam outlet provided storage for flood mitigation while not impacting sensitive environmental species upstream.
These analyses in conjunction with the design/construction plans prepared by WBK provided the project support and justification as WBK successfully navigated through the required regulatory process that included, but not limited to, the preparation of an Environmental Assessment as part of the NEPA process and permit application submittals to the USCOE and IDNR-OWR.
Construction of the hinged crest gate system and remote monitoring stations is complete. WBK provided the resident engineering services during construction and continues to work with Elk Grove Village and DuPage County in its operation and integration into the Salt Creek Flood Control Program.
The Busse Dam project has earned an ASCE Illinois Outstanding Civil Engineering Achievement <$10M award (2016) and an ACEC-Illinois 2017 Special Achievement Award.