Abundant Wildlife in Delaware’s Olentangy
Making River One of Ohio’s Best

Director Korleski watches the electrofishing demonstration with a group of 4th graders from St. Mary's School.

Stonecat madtom. Brindled madtom. Silver shiner. Banded darter. According to new Ohio EPA reports, these four pollution-intolerant fish species can now be found where the Central Ave. dam used to pool the Olentangy River in Delaware.

Before removal of the dam in 2008, Ohio EPA couldn’t find these four sensitive fish species because they need free-flowing water. Since initiating several collaborative efforts to restore and protect the river, Ohio EPA has found an abundance and diversity of fish and macroinvertebrates (for example, aquatic insects, mussels), including sensitive species, in the Olentangy.

For the first time in the watershed since the 1800s, Ohio EPA confirmed the first live population of Purple Wartyback mussels (listed as an Ohio species of concern) downstream of the Panhandle Road dam in 2007. The Ohio Department of Transportation’s removal of this dam last month is expected to foster a wider distribution of this freshwater mussel.

Perhaps a more dramatic ecological indicator of water quality improvements – and better fishing – in the Olentangy is the near doubling of aquatic insect communities and the repopulation of sensitive insects that serve as important food for fish.

Fish and Aquatic Insect Results Before and After Dam Removals

U.S. EPA Region 5 Water Division Associate Director Tim Henry and Ohio EPA Director Chris Korleski joined Delaware officials and students from St. Mary School and the Delaware Area Career Center at Mingo Park on Oct. 6 for a wildlife demonstration.

Ohio EPA biologist sample for fish near the former site of the Central Avenue Dam in Delaware.

“Coming face to face with the fish and other wildlife here today really makes this fun science lesson come alive for the students – and the rest of us, too,” Director Korleski said. “To the delight of biologists and fishermen, this surge of fish and aquatic insects in Delaware tells us the Olentangy is becoming one of Ohio’s best rivers.”

“At the heart of this Olentangy success story is the significant, measurable recovery of river life, thanks to the hard work, cooperation and watershed-wide approach of local, state and federal partners,” said Henry.

“For the first time in more than 50 years, more than 20 miles of the Olentangy that’s designated as a state scenic river in and near Delaware will be free-flowing once again,” said City Manager Tom Homan, referring to Delaware’s removal next year of two small dams at Stratford Rd. and U.S. Rt. 23 with Ohio EPA grants. Ohio EPA allocated Delaware a $100,000 U.S. EPA grant to remove the Central Ave. dam. The city removed the River St. dam in 2006, and ODNR’s Scenic Rivers Program removed the Dennison dam in 2004.

A Joint Effort to Restore and Protect the Olentangy River

The Olentangy River flows 93 miles through Richland, Crawford, Marion, Morrow, Delaware and Franklin counties before emptying into the Scioto River in downtown Columbus. The river is home to 54 fish species, like the state threatened Bluebreast and Spotted darters, and a variety of mussel species.

Low-head dams, failing home septic systems and agricultural and urban storm water runoff have impaired the Olentangy at some locations. Dams stop the river’s natural flow and create stagnant conditions for fish and aquatic insects, decreasing vital dissolved oxygen levels and increasing sedimentation that threatens habitat. Dams also create a vortex that can be deadly for swimmers and boaters. Septic systems, if not maintained, can leak sewage (and bacteria) into the river. Rains can wash manure, fertilizers, chemicals and silt from construction sites, farms, homes and gardens into the river.

This direct tributary to the Olentangy River is permanently protected as a result of a conservation easement at Camp Lazarus.

Local, state and federal partners have collaborated since 2004 to protect and restore the rapidly urbanizing Olentangy River watershed in and around Delaware through:

• six dam removals;

• a permit to control construction storm water runoff;

• enrollment of 10,000 farm acres in the Scioto Conservation Reserve Enhancement Program;

• land acquisition or implementation of conservation easements
  (for example, Preservation Parks of Delaware County partnered with
  Ohio EPA’s Water Resources Restoration Sponsorship Program to buy 235
  high-quality acres at Camp Lazarus and Big Run Preserve); and

• addressing bacterial concerns from raw or partially treated sewage.
  (The Delaware General Health District repaired/replaced 126 home septic systems with help from an Ohio EPA grant.)

Prior to these projects’ completion, four water quality monitoring sites in and around Delaware were not attaining the Olentangy River’s designation of warmwater habitat for aquatic life use. After these projects were implemented, fish scores for all monitoring sites improved and half the sites exceeded standards, meeting the designation of exceptional warmwater habitat. Additionally, aquatic insect scores increased by more than 40 percent at some sites.

More information about the Olentangy River’s recovery, including photos, maps, Ohio EPA reports, grant program information, and a lowhead dam removal fact sheet, is available through the online media kit.