The Lower Olentangy ecosystem covers two miles of the Olentangy river between Dodridge Avenue and the confluence with the Scioto River. The 5th Avenue Dam is one of six lowhead dams on the river within Franklin County. Lowhead dams prevent the development of a flow regime that is indicative of a natural, high quality ecosystem beneficial to fish and microinvertabrates. The dam is an eight foot high, 475 foot wide structure built in 1935. It was used as a source of cooling water for the Ohio State University power plant, which is no longer in operation.
The city offered to look at either modification or removal of the dam as a Supplemental Environmental Project as part of the settlement of an enforcement order and agreement with the Ohio Environmental Protection Agency. The agreement was reached to enhance water quality and stream habitat in this portion of the Olentangy River.
The Columbus department of Public Utilities in 2006 and 2007 worked in conjunction with the U.S. Army Corps of Engineers (USACOE), which conducted a feasibility study on restoration of the Lower Olentangy ecosystem, focusing on the 5th Avenue Dam. Public meetings were held in August 2006 and August 2007 at Goodale Park to explain the project and feasibility study, as well as to solicit stakeholder and community input to examine a variety of alternatives for dam modification and removal. A draft of the feasibility study was subsequently published for public comment in August 2007. In 2009, the USACOE sampled and tested sediments in the vicinity of the dam.
In October 2009, DPU contracted with Stantec Consulting Services Inc. to perform engineering services to determine sediment depths and compositions behind the dam, to evaluate the impact of dam removal on flood elevations, the impact of lowered normal water elevations on upstream bridges, the impact of lowered groundwater elevations on buildings located within the dam’s influence zone, and to perform bathymetric survey of the river bottom. In April 2010, Stantec submitted a draft report presenting results of their evaluations. This work was funded by a grant from the OEPA.
In October 2010, Stantec began preparing construction documents which were completed in May 2011. The project includes removing a portion of the lowhead dam and constructing stream improvements along the Olentangy River from the dam upstream to the Lane Avenue Bridge. The project will help restore natural river function, improve habitat for fish and other aquatic species and improve the riparian corridor. In July 2011, USACOE sent a letter informing the City the project met criteria for Section 404 Nationwide Permit (NWP) #27.
On-going work includes resolving outstanding floodplain issues associated with restoration of the stream banks with the Federal Emergency Management Agency (FEMA); coordinating construction activities with the university which has and will have numerous construction projects in the area; and finalizing the Ohio EPA environmental covenants among the affected entities. Given the outcome of the flood elevation review, additional efforts may be needed to mitigate the risk of increased flood impacts due to stream channel restoration work.
Following the evaluation of construction bids in May 2012, the cost of this project – including removal of a portion of the dam itself and extensive restoration of the area upstream from the dam – totals $6.9 million. Project funding sources include $500,000 through the Ohio Environmental Protection Agency’s 319 Grant Program, $3.1 million through the agency’s Water Resource Restoration Sponsor Program, $2 million from The Ohio State University and $2.1 million from the City of Columbus.
See project rendering (large file)
See projected views for completion, 5 years and 25 years after completion
See drawings of the existing & proposed river
Any questions or comments can be directed to:
Columbus Department of Public Utilities
• George J. Zonders at (614) 645-2926 or by email.
The Ohio EPA has completed a Limited Environmental Review for this project. The document may be viewed on Ohio EPA’s site or in hard copy from Ohio EPA. If you would like to receive either an electronic copy via e-mail or a paper copy of the document via U.S. mail upon its release, please contact Dan Halterman of Ohio EPA at (614) 644-3658 or by email.