Knox Cattle Company Dam Repair

Knox Cattle Company Dam (KCCD) is a Class I high hazard dam located in the City of Mount Vernon, Knox County, Ohio. The dam is currently owned by a local home owners’ association and the contract to evaluate and rehabilitate the structure is being administered by the City of Mount Vernon. The dam was originally constructed as a farm pond and was modified in 1999 to serve as a stormwater facility to support residential development. In 2008, the dam was classified as a Class I structure by ODNR Dam Safety as a result of development downstream of the dam within the inundation limits. The dam features a 6-inch diameter riser and primary spillway conduit with an emergency spillway weir along the left abutment. The current dam configuration does not provide adequate spillway and/or storage capacity to convey the probable maximum flood without overtopping the dam embankment.

During the Preliminary Design Phase, multiple alternatives were developed to address the deficiencies with the dam that included options to repair the structure and maintain as a Class I dam structure, as well as two alternatives to remove the dam from ODNR Dam Safety jurisdiction. To avoid the costly rehabilitation options, the client opted to pursue the option to deregulate the structure. The final design included the replacement of the primary spillway with a new concrete riser and larger primary spillway conduit, and construction of a causeway to establish an upper and lower pool. With this configuration the storage capacity of the dam was reduced to less than 15 acre-feet (removing the structure from ODNR jurisdiction) and allowed the facility to control stormwater for up to the 100-year design event and maximize the pool surface area.

AK Hydro coordinated all necessary environmental, historical, and construction permit to support the project. While developing the preliminary design alternatives, the owner has selected a responsible contractor and has established a guaranteed maximum price to rehabilitate the structure. AK Hydro is providing construction administration and inspection services to ensure that the project is completed in accordance with the drawings and specifications. Construction is anticipated to be completed by the end of summer 2026.