COS 192-6 - Economic developement meets environmental sustainability: Wetland restoration project for Volkswagen state industrial access road construction project

Friday, August 11, 2017: 9:50 AM
B114, Oregon Convention Center
Thomas J Becktold III and Jeff T Hoilman, Infrastructure/Transportation, ARCADIS U. S., Inc., Chattanooga, TN

In 2013, a state industrial access (SIA) road was proposed to be constructed directly through the center of a 57-acre mature, bottomland forested wetland designated as a Known Exceptional Tennessee Waters (KETW) by the Tennessee Department of Environment and Conservation (TDEC). The proposed SIA road was 1.4 miles in length and varied in width depending on the elevation of the road and the amount of required fill material. The proposed project faced many challenges, such as: How to obtain permits/approval from each of the state and federal regulatory agencies? How/where can we offset any unavoidable wetland impacts? How to avoid direct/indirect impacts to any state and/or federally-listed species? How can we guide the project outcome to be used as a community-based environmental education platform for future generations? Wetland delineations were performed using the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Eastern Mountains and Piedmont Region (Version 2.0). Stream determinations were performed using the Hydrologic Determination Field Data Sheet Tennessee Division of Water Pollution Control (Version 1.4).


Through creative thinking and early collaboration/coordination with each regulatory agency, a solution for each challenge was developed. Specifically, a thorough investigation of the project area yielded the discovery of an existing gravel road through the KETW wetland, of which could be utilized to cross with minimal additional impacts. The ability to utilize the alignment of the existing gravel road with a slight re-design of the SIA road ultimately reduced the impacts from approximately 8 acres to 0.75 acres. It was also discovered that a portion of the KETW wetland had been previously covered with fill material during the initial site development. After exploratory soil test pits confirmed the presence of hydric soils, a proposal was made to restore this portion of the KETW wetland in order to offset the unavoidable 0.75-acre impact from the road crossing. To further the deal, it was also proposed to place the restoration site, the entire 57-acre KETW wetland, and an adjacent buffer area in a Permanent Conservation Easement totaling 75-acres. The regulatory agencies accepted the proposal and reduced the mitigation ratio from 8:1 to 2:1. Since the completion, the restoration site has proven to be an ideal setting for various environmental education programs.