Boneyard Creek Flow Restrictor Study
The Boneyard Creek is located within Champaign and Urbana, Illinois, and serves as the primary conduit for transporting storm- water runoff out of Champaign-Urbana and the University of Illinois. Increased runoff caused by urbanization in the area has resulted in numerous damaging floods throughout the history of the two towns and the University. An effort is currently underway to improve the channel and floodplain characteristics within Champaign and the University of Illinois campus in order to reduce the flooding that occurs during an intense storm event.
One of the identified bottlenecks for the channel as it enters the U of I campus from Champaign is the Wright Street culvert. In this area, the channel passes underneath a building before experiencing a drastic reduction in cross-sectional area as it enters the culvert. It is necessary to understand the role that the culvert system plays during flood events.
To this end, a 1 to 16 scale physical model, based upon Froude similarity, was constructed. The model was initially calibrated against existing stage data for several storm events. The model was then tested with the initial channel geometry in place for a wide range of discharges in order to provide a basis with which to compare all future channel modifications. The second phase of testing involved examining the effects of the City of Champaign’s Lamar Improvements upon flows within the modeled reach. Also examined was the role of a flow restrictor that is proposed for the Wright Street culvert, as well as the effects of downstream construction on flows through the culvert. The final phase of testing involved implementing the U of I Improvements to the channel and floodplain, including a floodwall to be located along the east side of Wright Street.
The Lamar Improvements increased the ability of the culvert to convey flow, decreasing stages within Campustown while increasing the risk of downstream flooding. The flow restrictor tended to over-restrict the flow, causing undesirably increased stages within Campustown, while decreasing the flood risk on campus. The U of I Improvements nearly achieved the desired level of protection for both Campustown and the U of I Campus, but there are some undesirable effects associated with the floodwall and flow restrictor that need to be examined further.