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Technical Assistance

Explore data, learn about New Hampshire’s wetlands, and find resources to plan your project.

NHDES provides technical assistance for anyone who has a project in New Hampshire that will impact a wetland area. When planning a project that may impact a wetland, surface water or upland area, it’s important to understand how the natural functions and values, plus the local natural processes, could be affected. Use these resources to help avoid and minimize jurisdictional impacts, complete your Wetlands Permit Application, find information on wetlands identification and assessment, and visually screen for some of the nearby natural resource areas using the online data and mapping tools.

 A turbidity curtain containing suspended sediment. Photo shows turbid water on one side of the curtain and clean water on the other side.

Avoidance and minimization is a practice for preserving wetlands resources wherever practicable. For a wetlands application to be approved, the applicant must demonstrate that the project adequately avoids and minimizes impacts to wetlands. Practicing avoidance and minimization in project planning and design will reduce costs to applicants and facilitate streamlined decisions from NHDES. The Wetlands Best Management Practice - Techniques for Avoidance and Minimization Manual includes examples and details to help permit applicants plan a project to adequately avoid and minimize impacts to wetlands.

Project-Specific BMP Manuals


lily pads and flowersThe resources listed below will help you find wetlands scientists in New Hampshire and provide valuable information related to wetlands identification and assessment.

erosion controlThe resources listed below will help you visualize and access data and GIS information.

Prime Wetlands in New Hampshire Communities

Under RSA 482-A:15 and administrative rules Env-Wt 700, individual municipalities may elect to designate wetlands as “prime-wetlands” if, after thorough analysis, it is determined that high-quality wetlands are present. Typically, a wetland receives this designation because of its large size, unspoiled character and ability to sustain populations of rare or threatened plant and animal species. Field and “desk top” data are used for the evaluation process.

After high value wetlands are identified, the municipality holds a public hearing before the residents of the community to vote on the designation. Once the municipality approves the wetlands for designation as prime, the municipality provides to the NHDES Wetlands Program a copy of the study and tax maps with the designated prime wetlands identified. NHDES reviews the submission from the municipality to ensure that it is complete and in accordance with Env-Wt 702.03.

Once the town's prime wetland submission is considered complete and approved, NHDES will apply the law and rules that are applicable to any future projects that are within the prime wetland or the 100-foot prime wetland buffer.

Review the Wetlands Permit Planning Tool (WPPT) for town prime wetland and prime wetland buffer maps to determine if your project is within these town designated protection areas. The original files can also be found at the town municipal offices.

Be aware that the town may have other local buffers or setbacks that are not addressed under the prime wetland or prime wetland buffer statute or rules.

Vernal Pools

A vernal pool depicted in all four seasons.Vernal pools are those wetlands and temporary ponds that typically have ponded water only part of the year. Because the pools are temporary, they provide critical habitat for certain wildlife to breed and complete their life cycle. Many of the animals that breed in vernal pools live in the upland areas around the pool during the non-breeding season. When pools dry, wood frogs migrate to forested upland areas that are as much as 1,000 to more than 2,000 feet from their breeding pools. Mole salamanders will migrate to forested uplands that are 1,000 feet from their breeding pools. Vernal pools are a resource protected from unregulated alteration under the NHDES Wetlands law and rules. The rules provide definitions of vernal pool, primary vernal pool indicators and secondary vernal pool indicators.

Typically, a vernal pool:

  • Forms in a shallow depression or basin.
  • Holds water for at least 2 continuous months following spring ice-out.
  • Cycles annually from flooded to dry conditions, although the hydroperiod, size, and shape of the pool might vary from year to year.
  • Has no permanently flowing outlet.
  • Lacks a viable fish population.
  • Supports one or more primary vernal pool indicators, or three or more secondary vernal pool indicators.

Look at the USC Vernal Pool Field Guide for information on the many species considered vernal pool indicators.

The following documents can be used to identify and document vernal pools