Excellent communication with the Village staff, residents, and a teamwork approach with the Contractor was the #1 reason the project was a success. The Village indicated they had minimal complaints from the residents during construction (all of which were weather related). In fact, they received several positive feedback responses from residents.
 

Excellent communication with the Village staff, residents, and a teamwork approach with the Contractor was the #1 reason the project was a success. The Village indicated they had minimal complaints from the residents during construction (all of which were weather related). In fact, they received several positive feedback responses from residents.
   
   

CASE STUDY:
Village of Wheeling, IL:
Cornell Avenue Dam Rehabilitation

Background
The Cornell Avenue Dam was constructed in 1970 as part of the Lake in the Winds Subdivision to control flood flows along McDonald Creek in the Village of Wheeling. The Dam had lived past it’s useful life and was in a critical stage of failure.

Consisting of three 60-foot long 71-inch by 107-inch corrugated metal pipe archs, the dam also included two 12 inch diameter concrete restrictor pipes located between the pipe arch culverts and approximately 2 feet below the arch inverts. The bottom of the metal pipe arches had completely rusted through and resulted in scouring away the pipe bedding materials. One restrictor pipe end had dislodged on the downstream end due to the scouring, and both restrictor pipes were completely plugged with debris. The concrete headwall on the upstream end of the culverts was also in poor condition with the south wingwall exhibiting excessive rotational displacement.

Cornell Avenue provided the only access to the residents of the Lake in the Winds and concern was mounting that continued deformation of the pipe arches and further erosion of the soils beneath the pipes could lead to a total collapse of the Dam and loss of emergency access for fire and police departments to serve this area.


Solution
In fall of 2005, Baxter & Woodman Consulting Engineers was hired to prepare a report outlining the condition of the Dam and alternatives to rehabilitate the structure. Several alternatives were considered from complete replacement to lining the pipe arches with High Density Polyethylene Pipe (HDPE). Replacing the pipes was the most costly alternative and would have led to many months of permitting. Coordination with the Illinois Department of Natural Resources confirmed the lining option would be considered a maintenance activity and permitting would not be required. The upstream headwall was recommended to be replaced and a new headwall on the downstream side was also included in the plans.


As the project proceeded with the installation of the new restrictor pipes, the existing CMP arches continued to deform. This resulted in the need to install a smaller HDPE pipe liner than originally designed. Extensive coordination with the contractor’s pipe supplier and the IDNR resulted in minimal delays. Weather was also a challenge on this project as the fall of 2006 was burdened with heavy rains. 24-hour pumping was required by the contractor to maintain the project schedule.


Results- Time/Money-Saving Innovations
The selected alternative to install the HDPE lining material saved at least 25 percent off the more traditional remove and replace culvert method. In addition, the innovative design to install the restrictor pipes immediately below the rusted CMP inserts saved significant construction time and allowed the roadway to remain open at all times.


Environmental Considerations

The Village is committed to preserving and protecting our environment. The following sustainable methods were utilized in an effort to conserve energy and minimize impact on the environment:


Best Management Practices
A debris screen was installed over the restrictor pipes to prevent debris from getting lodged in the pipes. A portable sediment tank was used during construction to collect excess sediment and protect the plants and wildlife downstream.


Preserved and protected trees
The eastside pipes were cut back approximately 5 feet to avoid right-of-way issues and protect trees located in the project vicinity.


Erosion protection was a priority
In order to fit within an environmentally constrained area, a new retaining wall and rip rap were installed.


Recycled materials were utilized
The original CMP pipe was reused by using the slip liner method for restoring the pipe to good working condition.