Hyla Ecological Services Analyzes the Proposed Wetlands Ordinance

We would like to present this analysis of the proposed wetlands ordinance as prepared by Hyla Ecological Services. The author is Dr. Bryan Windmiller (PDF of curriculum vitae). This analysis, available as a PDF, is being circulated today to members of Northampton’s City Council.

Preface for Councilors

To: Northampton City Councilors

From: Coalition to Save Northampton’s Wetlands

Date: September 20, 2007

Re: Review by Hyla Ecological of the proposed Wetlands Ordinance

We respectfully submit for your review the attached report by Hyla Ecological Services commissioned by the Coalition to Save Northampton’s Wetlands. Also attached is author Bryan Windmiller’s curriculum vitae.

Respected for its scientific and unbiased wetlands impact assessments, Hyla Ecological Services offers important insights into both the language and substance of the proposed Wetlands Ordinance that could have far-reaching implications for wetlands protection in our City:

In summation, I find that proposed Ordinance would effectively lessen the current protections of wetland resource areas in Northampton against injurious encroachment by construction projects. The wording would provide applicants with the means to argue that projects in many areas of Northampton would qualify for reduced wetland setbacks, often as small as 10 feet from the wetland edge. Existing scientific evidence makes it very clear that setbacks of less than 50 feet from wetland edges almost inevitably result in the degradation of the wetland resource.

We feel that the observations contained in this report will help Northampton craft a clearer Ordinance, and will improve the Conservation Commission’s ability carry out its work. In providing you this analysis, we, your constituents, ask to be treated with the same consideration as you and the Ordinance Committee recently granted to other interested parties, including the Chamber of Commerce. Thank you.

Cc: Conservation Commission c/o Paul Wetzel

Excerpts from Dr. Windmiller’s Analysis

…The current Northampton Wetlands Protection Ordinance makes no reference to a nonencroachment zone surrounding jurisdictional wetlands in its brief performance standards (Section 24-10). However, I have been informed that, in October 2003, the Northampton Conservation Commission adopted an official policy of enforcing a 50-foot setback policy for proposed construction in upland areas adjacent to statutory wetlands. This policy has, to my knowledge, constituted a de facto performance standard that has generally been rigorously applied by the Commission since its adoption…

Given the uniformity with which the current 50-foot no encroachment policy is applied throughout Northampton, the net result of adoption of the Proposed Ordinance would therefore be to permit work closer to wetlands than is currently the case in projects that meet certain conditions…

There has been a great deal of scientific inquiry into the importance of wetland buffer zones. Many studies have demonstrated that buffer zones of upland vegetation surrounding wetland areas are critical to the maintenance of the integrity and functionality of the wetlands. I have, for example, authored several studies demonstrating the direct link between the diversity and abundance of vernal pool amphibian populations and the extent of forested upland buffers maintained around the pools. In short, the consensus of the scientific literature is clearly that the value and functions of wetlands are severely compromised when buildings, roads, lawns, fields, etc, are constructed too close to the wetland edges. Negative consequences to wetlands of insufficient setbacks from wetland edges include:

  • changes in wetland temperature
  • increased frequency and severity of flooding
  • increases in abundance of exotic invasive species
  • increases in pollutant loads
  • increased rate of sediment deposition
  • increased fecal coliform counts
  • increases in nutrient levels and in nutrophillic nuisance vegetation
  • increased levels of direct human disturbance and trash accumulation
  • altered distribution of native wetland plant and animal species
  • decreased diversity in native wetland plant and animal species.

…The following summary findings, excerpted from Castelle et al., 1992 are particularly germane to this discussion:

Buffer effectiveness increases with buffer width. As buffer width increases, the effectiveness of removing sediments, nutrients, bacteria, and other pollutants from surface water runoff increases. (p. 43)

Buffers of less than 50 feet in width are generally ineffective in protecting wetlands. Buffers larger than 50 feet are necessary to protect wetlands from an influx of sediment and nutrients, to protect wetlands from direct human disturbance, to protect sensitive wildlife species from adverse impacts, and to protect wetlands from the adverse effects of changes in quantity of water entering the wetland. (p. 44)

Buffer widths effective in preventing significant water quality impacts to wetlands are generally 100 feet or greater. (p. 44)

Buffers from 50 to 150 feet are necessary to protect a wetland from direct human disturbance in the form of human encroachment (e.g., trampling, debris). (Pp. 44-45).
Also, of particular significance are the results of a field evaluation study of wetland buffer effectiveness in the Puget Sound area of Washington State conducted [by] Sarah Spear Cooke. These findings are summarized in Castelle et al., 1992:

Buffer function was found to be directly related to the width of the buffer. Ninety-five percent of buffers smaller than 50 feet suffered a direct human impact within the buffer, while only 35% of buffers wider than 50 feet suffered direct human impact. Human impacts to the buffer zone resulted in increased impact on the wetland by noise, physical disturbance of foraging and nesting areas, and dumping refuse and yard waste. Overall, large buffers reduced the degree of changes in water quality, sediment load, and the quantity of water entering the adjacent wetland. As a rule, buffers were subjected to a reduction in size over time. Of 21 sites examined, 18 were found to have reduced buffer zones within one to eight years following establishment. (P. iv, bold-type added).
In my own experience, as a scientist, consultant, and conservation commissioner, construction that takes place closer than 50 feet from a wetland edge inevitably results in some degree of degradation to the adjacent wetland. The degree of degradation is largely a product of the nature and intensity of the construction and the relative vulnerability of the adjacent wetland…

The criterion: “Projects in certain infill areas” is vague and would be open to much debate. Neither the term “infill” nor the more specific phrase “certain infill areas” are defined in the proposed Ordinance. The word “infill” is of rather recent and specialized derivation, and generally unfamiliar. Definitions of “infill” available on the Internet vary widely. If this term is to serve as a meaningful condition by which projects might qualify for reduced non-encroachment zone widths, it must be tightly defined, ideally through reference to a mapped overlay. As currently drafted, the phrase invites applicants to argue that their particular lot is “infill” since there are other developed lots nearby, an argument that could presumably be applied to almost any site in Northampton…

…determining whether a mitigation project would result in the improvement of a wetland is a difficult, subjective, and inherently somewhat dubious undertaking. Again, the condition appears to invite applicants, through their consultants, to argue that their particular project would “improve” the adjacent wetlands. Such arguments are often specious and depend upon short-term, minor mitigation measures (e.g. the removal of trash, the removal of some exotic species, or planting some native wetland species), yet typically make no detailed accounting of the negative consequences of new construction close to the wetlands or of long-term maintenance and monitoring of any proposed mitigation measures. The wording, as proposed, would tend to put conservation commissioners in the difficult task of rebutting claims by paid consultants that the mitigation measures proposed would improve the subject wetland resources. In effect, the proposed Ordinance would shift some of the burden of proof for permitting diminished non-encroachment zones onto the Conservation Commission.

In summation, I find that proposed Ordinance would effectively lessen the current protections of wetland resource areas in Northampton against injurious encroachment by construction projects. The wording would provide applicants with the means to argue that projects in many areas of Northampton would qualify for reduced wetland setbacks, often as small as 10 feet from the wetland edge. Existing scientific evidence makes it very clear that setbacks of less than 50 feet from wetland edges almost inevitably result in the degradation of the wetland resource…

From my own experience, I recommend a simpler approach that maintains a 50-foot nonencroachment zone in all cases except for those carefully specified. If “infill” development is to be one such criterion for exception to the non-encroachment rule, it should be tightly defined, ideally through a mapped overlay. Moreover, the ordinance should give more guidance as to what constitutes suitable mitigation for closer encroachment upon wetlands. The standard of net “improvement” is almost impossible to measure and very unlikely to be attained.

Download the complete analysis as a PDF.

See also:

Proposed Changes to Northampton Wetlands Protection: Making Way for Infill

Mike Kirby: Compensatory Wetland on Carlon Drive Not Working
Today if you stand by the pond and look down into it, you’ll see the check dam is now about two feet underwater. You can’t even see where they planted the marshgrass and flowers. The area is under water. Even in a fairly dry summer, the detention pond is only about a foot and a half from the top of the bank. There’s no storage to speak of, no discharge, no filtering. As it is constructed now, grey water from the parking lots and the access street goes directly into the swamp and the Connecticut River.

Alex Ghiselin, Letter to Gazette: “Don’t let development encroach on our wetlands”
The failure of the storm water system built as a part of the Northampton High School renovation six years ago illustrates why protecting wetlands is so important. Silt has filled the retention pond so there is no capacity to slow a storm surge which now flows unimpeded into the Mill River and contributes to flooding downstream. This accumulated silt also raised the water table and spills ground water into nearby basements…

Connecticut River Watershed Action Plan: Remove impervious surfaces within 50 feet of streams

The Wetlands Policy Lawsuit that City Officials Are Afraid Of
We can accept that Northampton should have its key wetlands policies specified by ordinance. However, we disagree that the city needs to lock itself into a buffer zone policy that’s about as weak as any we can find in the state, and at variance with Northampton’s Flood Mitigation Plan of 2004 and its Open Space Plan of 2005. A more balanced ordinance will better serve the long-term interests of the people. Springfield, for example, calls for a 50-foot no-touch buffer zone around wetlands.

Wetland Values
Wetlands were long thought to be a nuisance because they were not suitable for development or most kinds of agriculture. We now realize that wetlands are not just valuable, they are invaluable. The following is a list of ways in which wetlands benefit people and the environment…

Flood damage control: Wetlands adjacent to rivers (riparian wetlands) can easily survive inundation by floodwaters and often actually benefit from regular flooding. Water that is allowed to flow over wetlands is slowed and partially absorbed, thereby reducing flood damage downstream. Wetlands are said to act as sponges because wetland soils can readily absorb
water, and depressions associated with wetlands can fill up. This has the effect of trapping and slowly releasing water that would otherwise rush into the channel and contribute to flooding downstream…

Water supply and groundwater recharge: Wetlands act as sources of water even in very arid regions. A properly functioning wetland can provide water for humans, livestock, and wildlife. Water flows out of wetlands and into the water table below neighboring habitats as these habitats dry out. This process is known as groundwater recharge, and helps habitats around wetlands survive drought. This slow release of stored water also helps rivers maintain flows in the summer.

Water purification: Not only do wetlands act as a sponge, they also act as a filter. Certain types of wetlands are efficient at removing toxins, and excess nutrients from surface and ground water… Wetlands also control sediment by decreasing the volume and velocity of flows during high water events which decreases channel erosion.