Located in west central Ohio, Indian Lake State Park is 5,800-acres in size and offers a variety of recreational opportunities, including boating, fishing, jet-skiing, swimming, hiking and camping. The 4,824-acre man-made lake was originally constructed in 1851 as part of the Miami and Erie canal system vital at the time for commercial transportation. By the time of the lake's completion in 1860, the use of canal systems were declining. In 1898, the Ohio General Assembly dedicated the lake as a recreation area.
An update to the Probable Maximum Flood (PMF) based on the 2013 update to the Ohio Probable Maximum Precipitation, resulted in the need to update the existing ogee weir with a crest length of 700-feet. The new labyrinth spillway increased the spillway capacity by 8% without increasing the head. The two-stage crest labyrinth spillway met state requirements for service spillway discharge to match existing spillway discharge up to the 100-year flood event. The new labyrinth spillway is the second longest in the United States of its kind at 701.5 lineal feet.
Ohio State Route 366 is located immediately downstream of the dam’s spillway. Previously the highly trafficked road bridge was protected by large riprap. The upgrade of the spillway offered the opportunity to also improve the collection channel from traditional revetment subject to continued maintenance, to a permanent engineered solution. ArmorFlex® Articulating Concrete blocks were selected for their reliability and speed of construction. ArmorFlex is an interlocking, articulating concrete block system with individual units of uniform size, shape, weight, and hydraulic capacity. Current ASTM standards, allowed the ArmorFlex system to be designed and installed with confidence. 22,621-square feet of ArmorFlex Class 45 block mattresses were installed in eight days and allows for unencumbered flow downstream of the spillway. It also provides erosion protection for the SR336 roadway embankments.
"Contech Engineered Solutions always provides professional support when we need it," stated Rob Kirkbride, P.E., Principal with Stantec. "For the Indian Lake Spillway project, this began during our design effort almost three years ago when we were looking at options for minimizing the potential for erosion downstream of the spillway. Contech provided clear recommendations on material selection and installation. Based on our discussions, Stantec was able to properly incorporate the ArmorFlex ACB’s into our construction plans and specifications. During construction, the Contech team provided excellent support when the ACB’s were being delivered and installed with a final product that looks incredible. Stantec looks forward to the next project that we can team up with Contech."