The Lower Olentangy ecosystem covers two miles of the Olentangy river between Dodridge Avenue and the confluence with the Scioto River. The 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. The USACOE continues to review those comments and will incorporate them into the final version of the report. The USACOE is moving forward with testing of sediments near the dam but may not have enough funds remaining to finalize the report at this time.

Completion of the project from report finalization through construction depends on federal funding that has not yet been committed to the project. The USACOE requested $1.2 million in funding for 2008 toward removal of the dam, but the funding was cut from legislation prior to President Bush signing the bill in January 2008. It is unclear whether Congress or the White House removed the funding. The City continues to look for partners to fund the project.