Harpeth River Restoration
As part of a jointly funded project via the National Fish Passage Program, the totality of this project is removing a lowhead dam and restoring the immediate area to riffle/run habitat for the benefit of improved water quality and native fish habitat in the Harpeth River, TN. (Photo: Harpeth River Restoration)
The Harpeth River drains nearly 900 sqmi in middle TN and flows through one of the fastest growing regions in the country. It is a state designated Scenic River in Davidson County, within 30 minutes of downtown Nashville. The river is one of the most archeologically and historically significant rivers in the state. In addition, the Harpeth is incredibly biodiverse. Below the lowhead dam site, 54 species of fish have been recorded, as well as two federally listed endangered species of mussel (the Tan Riffleshell - Epioblasma florentina walkeri and the Pink Mucket Pearlymussel - Lampsilis abrupta). Restoring the river to a free-flowing state is crucial to the survival of these species
The problem:
The project area is listed on the 303(d) list for siltation and habitat alteration, nutrient enrichment and low dissolved oxygen. Low dissolved oxygen particularly above a 6.2 foot lowhead dam has been measured to be below state standards, and fish are unable to migrate freely past the dam in the river. TMDLs have been produced for both of these impairments. In the headwaters, agricultural activity and failing septic are the primary causes for low dissolved oxygen, siltation and habitat loss.
The objective:
The aquatic resources objective of this project is to restore almost 2 miles of impoundment back to natural riffle/pool habitat that will benefit species of concern found in the subwatershed, improve dissolved oxygen which currently falls below standards during the summer low-flow season and reduce sediment load from in-stream erosion processes.
A video on the Harpeth River Restoration Project
This project was completed in April of 2013, and was given the 2013 Governor's Environmental Stewardship Award as well as the National Fish Habitat Partnership "10 Waters to Watch" Award for the year 2012. The removal of this dam has made the Harpeth River one of the only rivers in Tennessee that is entirely free flowing.
The lowhead dam was removed, restoring 2 miles of in-stream habitat back to pool/riffle structure, reconnecting 35 miles of in-stream habitat. Natural Channel Design methods were used to replace the dam with double cross-vane low boulder structure to restore a natural riffle/ run and pool habitat. Eroding banks were stabilized, and vegetation was planted in the previously impounded area.
Restoration Accomplishments: 2 miles of in stream habitat restored via dam removal
Species Benefited:
Tan riffleshell (Epioblasma florentina walkeri)
Fantail darter (Etheostoma flabellare)
Blacknose dace (Rhinichthys atratulus)
Smallmouth bass (Micropterus dolomieu)
Slenderhead darter (Percina phoxocephala)
Spotted bass (Micropterus punctulatus)
Rock bass (Ambloplites rupestris)
