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Environmental Division - Natural Resources Office

Ecology Section Wetland Mitigation and Wetland Banking Program; Monitoring Program

James K. Polk Building, Suite 900
505 Deaderick Street
Nashville, Tennessee 37243-0334
Phone: 615.253.2472
Fax: 615.741.1098

Mike Williams, Supervisor

Wetland Mitigation Program Banks and Sites

The Tennessee Department of Transportation (TDOT) replaces unavoidable wetland impacts through a process referred to as compensatory mitigation, whereby wetlands that are impacted through permitted activities are replaced by restoration or enhancement of a wetland site.

Compensatory mitigation typically occurs in advance of or concurrent with the impact and may be comprised of on-site mitigation, off-site mitigation or a combination of the two. On-site mitigation attempts to replace the wetlands functional capacity lost as a result of the highway project on the same site or in the immediate vicinity of the impacts; however, on-site mitigation is not always possible due to lack of suitable restoration sites.

The Tennessee Department of Transportation (TDOT) replaces unavoidable wetland impacts through a process referred to as compensatory mitigation, whereby wetlands that are impacted through permitted activities are replaced by restoration or enhancement of a wetland site.

Compensatory mitigation typically occurs in advance of or concurrent with the impact and may be comprised of on-site mitigation, off-site mitigation or a combination of the two. On-site mitigation attempts to replace the wetlands functional capacity lost as a result of the highway project on the same site or in the immediate vicinity of the impacts; however, on-site mitigation is not always possible due to lack of suitable restoration sites.
If mitigation cannot be accomplished on-site, the impact may be mitigated off-site at a mitigation site or a formal mitigation bank, pending approval by the regulatory agencies and/or Mitigation Banking Review Team (MBRT). The mitigation sites and mitigation banks are typically larger former wetland sites that have been restored with the purpose of being used to offset wetland losses from multiple projects. Currently, TDOT uses seven mitigation sites/banks, which are located throughout the state. Restored Wetland Near Jackson, Tennessee.
Restored Wetland Near Jackson, Tennessee


Wetland Mitigation Sites/Banks Used By TDOT
Wetland Banks


Monitoring Program
When streams are relocated, wetlands are temporarily affected, or vegetation is planted, the regulatory agencies require TDOT to monitor the success of the affected resource, generally for five years. Field surveys are conducted which address specific characteristics and a report is produced and submitted to ensure that the mitigation is successful. Remedial activities are undertaken if problems are found, as shown below.

Photo of unnamed tributary to West Harpeth River.
Unnamed tributary to West Harpeth River; looking upstream at culvert outlet; 2004
Photo of unnamed tributary to West Harpeth River.
Unnamed tributary to West Harpeth River; looking at “Protected Area Do Not Mow” sign; trees line newly designed channel at culvert outlet (in center left at toe of slope); 2006
Photo of unnamed tributary to West Harpeth River.
Unnamed tributary to West Harpeth River;
looking upstream at culvert outlet; 2007