Compensatory Mitigation for Streams and Wetlands
Activities associated with commercial, residential and agricultural land development, along with the construction of linear transportation systems and utility lines have the potential to significantly impact Tennessee's streams and wetlands. When these impacts cannot be avoided and/or minimized, and represents an overall net loss of water resource value, the Division of Water Resources requires permittees to offset their activities through compensatory mitigation.
Compensatory mitigation is the act of taking a degraded stream or wetland and returning the aquatic resource to a reference condition and/or improving the resource value of that feature. This may be accomplished through the replacement, restoration, and/or enhancement of degraded streams and wetlands.
The division has developed guidelines that detail the requirements for compensatory mitigation projects. (GUIDELINES July 2004)
Because authorized activities often require mitigation from both TDEC and the US Army Corps of Engineers (USACE), on June 1, 2016, an educational event focused on compensatory mitigation was held in conjunction with the USACE for the regulated community. The purpose of this event was to provide a review of existing USACE and TDEC regulatory authority, jurisdiction and compensatory mitigation requirements, as well as provide additional compensatory mitigation guidance. TDEC works closely with our federal counterpart to improve consistency, transparency, and efficiency of compensatory mitigation development within Tennessee.
For large, complex proposals, applicants seeking a Tennessee Department of Environment and Conservation (TDEC) Aquatic Resource Alteration Permit (ARAP)/Section 401 Water Quality Certification and a U.S. Army Corps of Engineers (USACE) Clean Water Act Section 404 Permit can request a regulatory coordination meeting, especially those in which permittee-responsible mitigation (PRM) is proposed. If you have a project proposal that you think may meet these requirements please visit our regulatory coordination page to obtain additional information.
Technical Resources and Links
- The US Army Corps of Engineers Compensatory Mitigation Public Facing Mapviewer Database
RIBITS (Regulatory In lieu fee and Bank Information Tracking System) was developed by the U.S. Army Corps of Engineers with support from the Environmental Protection Agency, the U.S. Fish and Wildlife Service, the Federal Highway Administration, and NOAA Fisheries to provide better information on mitigation and conservation banking and in-lieu fee programs across the country. RIBITS allows users to access information on the types and numbers of mitigation and conservation bank and in-lieu fee program sites, associated documents, mitigation credit availability, service areas, as well information on national and local policies and procedures that affect mitigation and conservation bank and in-lieu fee program development and operation.
- TDOT Environmental Mitigation Office
Compensatory mitigation is required for certain TDOT transportation projects, as part of the permitting process through the Tennessee Department of Environment and Conservation (TDEC) and the U.S. Army Corps of Engineers (USACE). The Tennessee Department of Transportation (TDOT) Environmental Mitigation Office is responsible for providing compensatory mitigation to offset unavoidable stream and wetland impacts from transportation projects through a process referred to as compensatory mitigation.
- TDEC Requirements and Process for In-System Mitigation
The Division places a high priority on, and has established rule and guidance that require and/or place preference on mitigation sites on impaired waters in close proximity to the site. In these circumstances the Division requires permittees to seek compensatory mitigation opportunities closer to the area of impact.
- Cumulative Impacts and the Common Plan of Development
TDEC regulations require the Division to evaluate…” whether the proposed activity is reasonably likely to have cumulative or secondary impacts to the water resource” for linear and non-linear projects. Where a single impact of a given scale might only require coverage under a general permit, multiple impacts of the same scale may require coverage under an individual permit, due to the cumulative effects. Similarly, large linear and non-linear activities often encompass multiple impacts that may, collectively, result in a net loss of water resource value if compensatory mitigation is not utilized to offset or compensate for the impacts. Therefore, TDEC must review applications from larger linear and non-linear activities that propose multiple impacts comprehensively at the outset of permitting to ensure that there is no net loss of resource value from individual or cumulative impacts. These projects are considered Common Plans of Development (CPD).
- Regional Curves
TDEC Division of Water Resources has worked (and continues to work) with Jennings Environmental, LLC to develop ecoregion based regional curves across the entire state. These regional curves were developed to assist practitioners in identifying the bankfull stage in ungaged watersheds and estimating the bankfull discharge and dimensions for river studies and natural channel designs. Regional curves relate bankfull channel dimensions (i.e., width, depth and cross-sectional area) and discharge to watershed drainage area. These tools can also be used as an aid in designing a pilot or low flow channel within flood control projects. TDEC Regional curves should only be applied where the project reach has the same Level III Ecoregion as the reaches that were used to generate the curve.
Current regional curves by ecoregion:
- Ecoregion 67 Ridge and Valley
- Ecoregion 68 Southwestern Appalachians & 69 Central Appalachians
- Ecoregion 71 Interior Plateau
(Additional curves are being developed for ecoregions 74, 64, and 66. The projected completion date is summer of 2017.)
Joint Outreach Event Presentations
- Overview of Compensatory Mitigation Within Tennessee - USACE
- Overview of Mitigation Banking Template - USACE
- Regulatory Mission & Efficiencies - USACE
- Dam Removal for Potential Credits - TDEC
- Regional Curves, Reference Streams, and Regionalization of the Stream Quantification Tool - TDEC
- Potential General Permit for Structural Discharges - TDEC
- General Permit for Minor Water Withdrawals - TDEC
Other Recent Regulatory Presentations on Compensatory Mitigation
- PRESENTATION: Permittee-Responsible Compensatory Mitigation Plan Guidance
- PRESENTATION: Draft Prospectus Submittal Guidance for Stream Mitigation Banks or Stream In-Lieu Fee Projects within Tennessee
- PRESENTATION: Draft Prospectus Submittal Guidance for Wetland Mitigation Banks or Wetland In-Lieu Fee Projects
- PRESENTATION: Overview of the 2008 Compensatory Mitigation Rule
- PRESENTATION: Overview of Bank and In-Lieu Fee Mitigation
- PRESENTATION: Overview of the Tennessee 401 Program
- PRESENTATION: Overview of the Tennessee Stream Mitigation Guidelines
- PRESENTATION: Overview of the US Army Corps of Engineers Regulatory Program