Attleboro, MA: Evaluating and Protecting Vernal Pools; Stormwater Modeling

The Massachusetts Association of Conservation Commissions provides a convenient list of wetlands regulations from cities across the state. Here we excerpt and emphasize portions of Attleboro’s regulations, as adopted in 2004 (MS Word file).


The Ordinance recognizes Vernal Pools as a protected Wetland Resource Area. The area within 100 feet of the mean annual boundary of a vernal pool depression is considered to be part of the Vernal Pool resource area. In areas where there is a disagreement between the applicant and the Commission as to the presence or extent of a Vernal Pool, the burden of proof falls on the applicant. The Commission need not identify a vernal pool and vernal pool habitat locations prior to an application being filed with the Commission. The Commission may postpone vernal pool determination until an appropriate time of year or non-drought year. It shall be the applicant’s responsibility to identify the location of potential vernal pools and vernal pool habitats on the subject property during the application process. The Commission shall have the discretion to invalidate any Permit previously issued if the applicant failed to designate an area as a potential vernal pool site. The applicant may submit a Request for Determination of Applicability for the purpose of identifying whether a vernal pool exists on the subject site prior to submitting a Local Wetlands Permit Application.

4.7.1 Presumption of Vernal Pool Habitat

Vernal Pools are afforded protection under various State laws including the Massachusetts Wetlands Protection Act, Massachusetts Surface Water Quality Standards (314 CMR 4.00), Title 5 of the Massachusetts Environmental Code (310 CMR 15.00), and the Forest Cutting Practices Act Regulations (304 CMR 11.00). However, in most instances, Vernal Pools must have been certified through the NHESP or identified by a preponderance of credible evidence presented at a public hearing to be protected. The City of Attleboro’s Wetlands Protection Ordinance extends and expands upon this protection, and presumes Vernal Pool habitat exists if a wetland’s physical characteristics conform to the definition of a “vernal pool” set forth in Section 1.4 of these regulations.

Section 18-1.2 of the Ordinance identifies vernal pools as a Wetland Resource Area, and the definition for vernal pools provided in Section 18-1.3 of the Ordinance includes the area within 100 feet of the mean annual high water line of such a depression. This presumptive definition for vernal pools is based on systematic field observations showing that most basins that possess the above characteristics host breeding vernal species. These areas are essential breeding habitat, and provide other important wildlife habitat functions during non-breeding season as well, for a variety of amphibian species such as wood frog (Rana sylvatica) and the spotted salamander (Ambystoma macultum), and are important habitat for other wildlife species.

Vernal pools include depressions in uplands, temporary and/or permanent ponds in kettleholes, depressions in swamps and wet meadows, old river oxbows and other floodplain pools, and isolated Lands Subject to Flooding or Inundation, ranging from small depressions to multi-acre expanses. These pools are essential breeding sites for certain amphibians, which require isolated, seasonally wet areas without the presence of predatory fish. Most of these amphibians require areas of undisturbed woodlands as habitat during the non-breeding seasons. Some species require continuous woody vegetation between woodland habitat and the breeding pools. Depending on the species, during non-breeding seasons these amphibians may remain near the pools or travel one-fourth mile or more from the pools. Reptiles, especially turtles, often require areas along rivers to lay their eggs. Since amphibians and reptiles are less mobile than mammals and birds, maintaining integrity of their habitat is critical. Various kinds of animals, including several amphibian species and a number of invertebrate groups, occur or reproduce only in vernal pools. These animals often live their lives a quarter mile or more from the vernal pool and migrate to the pool only for a few days each year for breeding purposes. Many of these animals only return to their own birth pool to mate, therefore increasing the importance of protecting all vernal pools.

The presumption of vernal pool habitat may be overcome with the presentation of a preponderance of credible evidence, which in the judgment of the Conservation Commission, and if necessary its consultant, demonstrates that the wetland does not provide, or cannot provide, vernal pool habitat functions…

4.7.4 Timing of Evidence Collection.

Many of the indicators of vernal pool habitat are seasonal. For example, certain salamander egg clusters are only found between late March and late May. Wood frog chorusing only occurs between late March and May, and then only at night. Consequently, failure to find evidence of breeding must be tied explicitly to those periods during which the evidence is most likely to be available. Accordingly, in the case of challenges to the presumption of vernal pool habitat the Conservation Commission may require that the determination be postponed until the appropriate time period consistent with the evidence being presented. The Commission may also require its own site visits as necessary to confirm the evidence. It is the Commission’s intent that no applicant will be required to wait longer than 12 months for a vernal pool determination except in periods of Drought, in which case the Commission will make its determination as soon as it is practical or possible.


Wetland Resource Areas are important to the protection of Wildlife Habitat and in many cases Rare Species habitat. In addition, the near-upland areas around wetland resources often play important roles in determining and maintaining the Wildlife Habitat values of associated wetlands. While it is common to think of the protective or “buffering” value of buffer zones in terms of area undisturbed, habitat values may be equally affected by the configuration of the buffer zone perimeter, the inclusion or exclusion of specific topographical and ecological features (such as an abutting sandy knoll or tree canopy), etc. The potential presence of rare or endangered species and their specific sensitivity to proposed activities shall be considered by the Commission when evaluating proposed projects. The Conservation Commission shall consider evidence of the presence of such species or evidence of likely habitat. Prior designation of rare or endangered species habitat by the Massachusetts Division of Fisheries and Wildlife Natural Heritage Program (NHESP) is not necessary. The Commission may consult with the NHESP or other authorities, as it deems necessary for guidance and recommendations.

4.8.1 No Significant Adverse Impact On Wildlife Habitat

Wildlife Habitat serves a variety of functions in support of wildlife. Food, water, breeding space, shelter, security, movement and migration space, and connections to other habitat areas are all equally important. All of these Wildlife Habitat functions are presumed to exist in Wetland Resource Areas. Therefore, in accordance with the Ordinance’s fundamental purposes (see Section 18-1.1) no project proposed within Areas Subject to Protection may have a significant adverse impact — either project-specific or cumulative — on Wildlife Habitat.

For Wildlife Habitat purposes, a significant adverse project-specific impact is defined as an impact caused by work within a Wetland Resource Area that would under reasonable assumptions: (a) result in a measurable decrease in the extant wildlife populations or biological composition, structure, or richness on the site or in the vicinity exclusive of the present or future state of adjacent and nearby properties; or (b) impair, damage, destroy, or reduce in value for wildlife purposes certain specific habitat features.

Studies have shown that direct impacts from work – filling, grading, vegetation removal, construction
of barriers to movement, etc. – in resource areas can severely harm wildlife populations. For example, low stone walls, culverts or roadways bisecting a resource area can prevent amphibians that live in upland areas from reaching breeding pools, marshes, and streams. Or, removal of large snags (dead trees) can virtually eliminate nesting by barred owls, pileated woodpeckers, mink, etc. Accordingly, the Commission shall prohibit the placement of fences or other barriers to wildlife movement within and between resource areas and the destruction of specific habitat features.

Examples of protected habitat features include (but are not limited to):
• Large cavity trees;
• Turtle nesting areas;
• Existing nest trees for birds that reuse nests (e.g., great blue herons, osprey);
• Beaver dams, dens, and lodges;
• Mink or otter dens;
• Vernal pools and adjacent upland areas;
• Vertical sandy banks;
• Migration corridors that provide connectivity between wildlife habitats; and
• Sphagnum hummocks and pools suitable to serve as nesting habitat for four-toed salamanders.

Indirect impacts — the effects of human activities near wildlife habitat — may have equally harmful effects. Therefore the Commission shall take into account indirect effects on a project-by-project basis. For example, work within resource areas may be restricted within 100 feet of existing beaver, mink or otter dens, or within 200 feet of existing osprey or great blue heron nests.

The purpose of the Ordinance is to protect for future generations of residents the natural wetland and water resources and amenities – including wildlife – we presently enjoy in Attleboro. The Ordinance protects Wetland Resource Areas from cumulative impacts as well as from immediate ones. Therefore, the Commission must be cognizant of the likelihood of cumulative impacts from work within resource areas. For Wildlife Habitat purposes a significant cumulative adverse impact is defined as an impact that would under reasonable assumptions result in a measurable decrease in the extant wildlife populations or biological structure, composition, or richness on the site or in the vicinity taking into account the projected impacts of future projects that could be proposed in the vicinity with similar, comparable, or other significant impacts and disturbance. This method for assessing cumulative impacts avoids the pitfall of placing an unreasonable burden of resource protection on subsequent applicants/projects in the vicinity while subsidizing those who are first to develop land. It allows the Commission to level the marginal impact of all proposed projects in the vicinity while ensuring appropriate protection – present and future – of the values and interests protected by the Ordinance.

A wildlife habitat assessment may be required for any project where alterations of Wetland Resource Areas totaling 2,500 square feet or more are proposed. This assessment shall be performed by an individual with at least a masters degree in wildlife biology or ecological science from an accredited college or university, or other competent professional with at least two years experience in wildlife habitat evaluation. The assessment shall include an evaluation of the potential importance of the given resource area to wildlife habitat and shall include an evaluation of potential impacts from proposed activities within the resource area(s) to wildlife habitat…


All proposed stormwater management systems shall at a minimum conform to best management practices specified in MADEP’s Stormwater Management Policy, the latest version of the Stormwater Policy and Technical Handbooks, and these regulations. Drainage calculations shall be provided when any change to the pre-development (existing) watersheds are proposed, and shall be prepared in conformance with the latest version of the Stormwater Policy and Technical Handbooks published by MADEP. All drainage calculations shall bear the stamp of a Professional Engineer, currently registered in the Commonwealth of Massachusetts.

Proposed projects must control and maintain post-development peak discharge rates from the 2,10,25 and 100-year frequency storm events at or below pre-development levels. The most widely used method for determining runoff volumes, peak discharge rates and storage requirements is the National Resource Conservation Service’s (Soil Conservation Service) Technical Release 55 (TR-55) program. This is the preferred method for projects with areas between one and 2000 acres. Another SCS method that may be more suitable for some projects is the Technical Release 20 (TR-20) program. Please note that the 24-hour, Type III distribution storm event must be analyzed when using all SCS methods. It is presumed that a decrease of more than 15% in either the peak rate or volume of runoff for the 2, 10, 25, or 100-year design storm events would impair the resource areas ability to function.

The discharge from any stormwater facility must be conveyed through properly constructed water courses to provide for non-erosive flows during all storm events. Rip-rap (or other approved energy dissipaters) shall be placed at all flared-end sections, pipe outlets, overflow weirs, drainage swales, and any other location at the discretion of the Conservation Commission. Rip rap shall be sized such that the stones will be able to resist movement due to discharge velocity.


Detention/Retention basins may be used to mitigate increases in surface runoff. Basins shall be designed in conformance with the MADEP Stormwater Policy and Technical Handbooks. In addition, basins shall include a pre-treatment device such as a forebay or water quality chamber capable of handling the “first flush” as described in the MADEP Stormwater Policy and Technical Handbooks…

See also:

Belchertown Wetlands Regulations
These Belchertown Wetlands Regulations, dated May 23, 2006, may provide guidance as Northampton debates its own regulations. It notes the benefits wetlands provide and regulates development that encroaches within 100 feet of a wetland. Developers are required to model watershed behavior during 2-, 10- and 100-year storms. Regulations of vernal pools are integrated into the general discussion of wetlands and buffer zones. This appears to make more sense than treating them separately, which is what Northampton’s City Council is preparing to do on September 6.

Intermittent Streams Merit a 100-Foot Buffer Zone in Hopkinton
Here is a bylaw from Hopkinton’s Wetlands Protection Regulations (PDF) requiring a 100-foot buffer zone around intermittent (and continuous) streams. We note that just such an intermittent stream, Millyard Brook, runs through the heart of the forest behind North Street that Kohl Construction intends to build on.