Updates to the Louisville District Army Corps of Engineers Mitigation Policy

The Louisville District Army Corps of Engineers (USACE) recently released a guidance document regarding modifications and standardization of wetland and stream mitigation in areas regulated by the Louisville District which they are considering for future mitigation projects.  The document primarily discusses mitigation ratios and performance criteria in order to request release from further monitoring.

The document has been described as a “living document” allowing for modifications based on feedback from the public and as information is obtained from annual monitoring reports.  Early discussions with some staff at the Indiana Department of Environmental Management (IDEM) indicated that the document is being reviewed internally; therefore, Williams Creek has not confirmed if the IDEM will adopt the same guidance.  Williams Creek is continuing to coordinate with the USACE and IDEM regarding specific items of our concern regarding performance criteria.

A summary of the guidance document is below and a link to the document can be found here Louisville District Mitigation Policy_2017.  Wondering how this updated policy might affect your property?  Contact us with your questions.

Mitigation Ratio Comparison:

Establishment of wetland mitigation:

  • Forested Wetland = 3:1 from previous 4:1
  • Emergent/Scrub-shrub wetland to Emergent/Scrub-shrub mitigation = 2:1 from previous 2:1 (emergent) and 3:1 (scrub-shrub)
  • Emergent/Scrub-shrub wetland to Forested wetland mitigation = 1:1

Preservation of existing wetland is 10:1

Summary of Mitigation Concepts Clarification

  • Mitigation sites should look natural and should be designed to not require structural controls (i.e. no outfall controls, no deep excavations, berms, cells, etc.)
  • USACE will continue to not allow mitigation in areas being used for stormwater management.
  • If the 404 permit requires mitigation for conversion of forested to emergent wetlands for utility lines, mitigation would be required at a 1:1 ratio.
  • Section 10 and Section 404 impacts will continue to require mitigation for impacts over the prescribed thresholds.
  • Impacts associated with impoundments streams for the purpose of constructing a pond will consider both the dam and inundated waters as an impact.

Forested/Scrub-shrub Wetland Mitigation and Riparian Corridor Mitigation Performance Criteria

Clarified density of woody stems depending on installation of bare root saplings to 3-gallon trees.

 

Bare Root3-Gallon Container
Minimum 300 trees per acreMinimum 200 trees per acre
No species can exceed 20 percent of total population of planted species (minimum 5 species)No species can exceed 20 percent of total population of planted species (minimum 5 species)
Minimum 5 Year MonitoringMinimum 5 Year Monitoring
50 percent survival plant list75 percent survival plant list
No species may make up more than 15 percent of surviving stockNo species may make up more than 15 percent of surviving stock
50 percent of the surviving 150 trees must be 15 ft in height AND 3 inches dbh before release50 percent of the surviving 150 trees must be 15 ft in height AND 3 inches dbh before release
50 percent of the surviving 150 shrubs must be 3 ft in height before release50 percent of the surviving 150 shrubs must be 3 ft in height before release
Less than 5 percent of invasive/exotic species may be present and 0 percent of species from USACE specified listLess than 5 percent of invasive/exotic species may be present and 0 percent of species from USACE specified list

 

Emergent Wetland Performance Criteria
  • Planting plan should include a minimum of 10 species
  • Minimum 5 year monitoring
  • 75 percent of initial planted species shall be alive (Williams Creek assuming live plant material)
  • No one species may make up more than 20 percent of the total vegetative cover for the site
  • Less than 5 percent of invasive/exotic species may be present and 0 percent of species from USACE specified list
  • Combined surface area of open water and/or bare ground shall not exceed 10 percent
By | 2017-06-06T02:45:11+00:00 June 6th, 2017|In the News|0 Comments

About the Author:

“I especially enjoy projects which create economic and social value for a community; designs that catalyze change. I believe the outdoor spaces people interact in can influence them greatly in a positive or negative way. I have the opportunity to improve peoples’ experiences.”

Sarah Evans is a Professional Landscape Architect (PLA) with over 10 years of design experience working in the private and non profit sectors. Her specialties include park and trail design, recreation master planning, neighborhood creative placemaking, implementation of Crime Prevention Through Environmental Design (CPTED) principles, and marketing and event coordination. Prior to joining Williams Creek, Sarah served as project manager for the East 10th Street Civic Association, a non-profit organization focusing on the commercial revitalization of the Near Eastside in Indianapolis. Sarah holds a Bachelor of Science in Landscape Architecture degree from Arizona State University and is a licensed Professional Landscape Architect in Indiana.

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