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New Hampshire Department of Environmental Services

What are the requirements to mitigate by wetland restoration or creation?

NHDES has adopted ratios for how much mitigation is required based on the type of resource if mitigation is proposed by wetland restoration or creation.

Resource Type Creation Ratio
(resource created: size of impact)
Restoration Ratio
(resource restored: size of impact)
Bog N/A 2 :1
Tidal Wetlands 3 :1 2 :1
Forested 1.5 :1 1.5 :1
Undeveloped Tidal Buffer Zone N/A 2 :1
All Other Jurisdictional Areas 1.5 :1 1 :1

What information needs to be submitted for proposed wetland restoration or wetland creation?

For mitigation by wetland restoration or creation, the following items need to be addressed and provided:

  • Evaluate the functions of the areas proposed to be impacted and those functions compensated through the proposed mitigation package. A functional assessment notes data collected on the area that includes land use; soil types; habitat; Natural Community Classification in accordance with the Natural Community Systems of New Hampshire (2005), prepared by DRED-NHB and The Nature Conservancy; presence of any rare, special concern, or state or federally listed threatened or endangered species, including flora, fauna, or migratory species, and; and presence of exemplary natural communities identified by the DRED-NHB.
  • Landowner consent if restoration is on a different property from the development site.
  • A summary of the proposed restoration/creation measures, construction procedures, timing.
  • An explanation of how the proposal creates hydrologic conditions or land connections that will restore or create the desired wetland functions or values.
  • Detailed engineering plans with existing and proposed grades, predicted water fluctuations and proposed wetland cover types.
  • A planting proposal, source of soils to be used, erosion controls to be installed, and an invasive species control plan if applicable.

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