HomeMy WebLinkAboutSD-22-10 - Supplemental - 0500 Old Farm Road (33)Gilman & Briggs Environmental
1 Conti Circle #5, Barre, VT 05641
Ph: 802-479-7480; team@gbevt.com
MEMORANDUM
To: Andrew Gill
From: Art Gilman
Date: 1 March 2022
Re: Class Three wetlands on the Eastview project (O’Brien Home Farm property)
This memo regards three wetland areas at the eastern end of the fields on the Home Farm property that
have been determined to be Class Three wetlands by the Vermont District Wetland Ecologist (Tina
Heath). Note. these wetlands are not connected to the large wetland along Potash Brook that borders the
eastern edge of the property but are in low-lying fields. I assisted my colleague Errol Briggs in
delineating the more northerly ones in 2019, and my colleague Patti Greene-Swift and I delineated the
southerly one in August 2021. They are all very similar in nature.
Note, the northerly two of these three wetlands were evaluated in Errol’s letter dated 14 December 2020.
Here, I discuss them all together.
Wetlands are characterized by three parameters, described here:
• Soils. The two northerly sites are underlain by hydric (“poorly drained”) Enosburg & Whately
soils – which are described as coarse-loamy or sandy soils over clay. The southern wetland is
underlain by Covington silty clay, also a hydric, “poorly drained” soil. These soils are capable of
supporting wetland vegetation.
• Plants. All sites are mowed fields and have a dominance of grasses, sedges, and rushes of species
that are suited to wetness e.g., reed canary grass (Phalaris arundinacea), redtop grass (Agrostis
gigantea), and soft rush(Juncus effusus).
• Hydrology. These sites have very limited drainage areas (i.e., there is little drainage into them),
have no outlets, and act as sumps (rainfall and snowmelt only leaves by evaporation and by
percolating into the soil). They are not connected to or associated with streams, ponds, or any
open water.
I evaluated them collectively with two evaluation protocols: the Vermont Wetland Evaluation form and
the US Army Corps of Engineers “Highway Methodology Workbook Supplement” wetland function-
value form. Both of these forms found very limited functions or values. Both forms are attached to this
letter for your review.
The Vermont Wetland Evaluation form rated only two of ten functions present—and both at a “low
level.” These were 1) “Water Storage for Flood Water and Storm Runoff,” which is present because the
wetlands have no outlets, but low because they have small watersheds and have flat topography that
would not provide much storage capacity; and 2) “Surface and Groundwater Protection”/“Nutrient
Removal,” which function is present because the wetlands are fully vegetated (i.e, with hay grasses) but
low because, again, they have a very small area of potential inputs of nutrients, and no known sources of
sediments or toxicants.
The Army Corps of Engineers worksheet showed a similar result, but found them significant only
fornutrient removal, and again, that at a low level. They only retain nutrients from runoff that enters
them, and the watershed that enters these wetlands is extremely small and isolated.
These results are in accord with the State of Vermont’s position that they are Class Three wetlands, i.e.
that they do not have functions and values that are significant enough to warrant protection under the
Vermont Wetland Rules.
The only functions that they serve, nutrient retention, is because they capture a small amount of runoff
from adjacent and are able to uptake nutrients because they are fully vegetated. It must be noted in the
context of the Development Review Board’s decision whether to preserve these areas or to allow for their
alteration to become gravel wetlands, and ponds for stormwater treatment, that surrounding these
wetlands with development and isolating them from their already limited watersheds, will remove any
water from flowing to them (as that water will be diverted to stormwater treatment practices). If these
wetlands are not receiving flows of water from their surroundings, there will be no opportunity for that
function even if the physical land that now has some limited significance remains.
The question of whether these wetlands “could become” Class II wetlands has been asked, and is used as
a basis for regulating Class IIII wetlands beyond the State’s current rules. The Class III wetlands being
discussed would not developinto Class II wetlands without manual intervention, should the undeveloped
land simply be maintained as it currently is in perpetuity. For some frame of reference, below is what sort
of intervention might be required to make these wetlands Class II:
First, they could become so with significant investments in terms of abandoning agricultural use,
earthworks (plugging ditches both east and west of the southernmost wetland) and extensive plantings,
especially of trees. I am not a hydrologist and no testing has been done, but the hydrology does not appear
substantial enough—there is not enough water—to support extensive, “wetter” wetlands with any open
water components such as permanent ponds or permanent streams.
Second, to optimize future functions and values, they would have to placed in a larger restoration setting,
ideally within a forested setting, which would mean the entirety of the north field, and the southern field
at least between the two ditches, would have to be part of the effort of earthworks and plantings – in the
buffer zone as well as in the wetland proper.“Wetland mitigation projects” such as undertaken by, e.g.,
Ducks Unlimited, are often very costly, on the order of $100,000+ per acre. Even so, I suggest that these
wetlands would not achieve a level of function and value that a DU-sponsored wetland project would be
expected to achieve.
The newly adopted South Burlington Development Regulations make a specific exception for impacts to
Class III wetlands associated with stormwater treatment. See Section 12.06(D)(2)(a)(i). At Eastview, the
Applicant is proposing just that. The placement of stormwater treatment is in the natural low areas where
these wetlands are located.
The stormwater treatment proposed has two components, a forebay consisting of standing water and a
treatment practice consisting of a gravel basin planted with wetland plants, where infiltration of
stormwater can occur. The primary purpose of stormwater treatment mirrors the significance of these
wetlands themselves, i.e., nutrient removal and stormwater storage. However, the proposed gravel
wetlands will likely have more significant values than the current wetlands because they will have an
open water component. Additionally, we have worked with the Applicant to expand the forebay to be
roughly double the size required. This will increase the amount of standing water, and will provide a new
and potentially significant habitat for aquatic organisms that do not currently exist on the site. In one of
our projects, South Village, we have found stormwater ponds to be of significance for wildlife,
supporting breeding birds and amphibians., and I suspect that the gravel wetlands will have higher
function and value for wildlife than the currently-existing wetlands do, as well as performing their own
stated function of capturing sediments.
VERMONT WETLAND EVALUATION FORM
Wetland ID#:___________________________ Project #:____________________
Date: ____________________ Investigator:_______________________________
SUMMARY OF FUNCTIONAL EVALUATION:
Each function gets a score of 0= not present; L = Low; P = Present; or H = High.
1.Water Storage for Flood Water and
Storm Runoff
6.Rare, Threatened, and Endangered
Species Habitat
2.Surface & Ground Water Protection 7.Education and Research in Natural
Sciences
3.Fish Habitat
4.Wildlife Habitat
8.Recreational Value and Economic
Benefits
9.Open Space and Aesthetics
5.Exemplary Wetland Natural
Community
10.Erosion Control through Binding and
Stabilizing the Soil
Note:
o When to use this form: This is a field form to help you compile data needed to evaluate the
10 possible functions and values of a wetland as described in the Vermont Wetland Rules.
All information in this form is replicated in the applications for both wetland determinations
and wetland permits.
o Both a desktop review and field examination should be employed to accurately determine
surrounding land use, hydrology, hydroperiod, vegetation, position in the landscape, and
physical attributes.
o The entire wetland or wetland complex in question must be evaluated to determine the
level of function in all ten (10) categories for accurate classification. A wetland complex can
be defined as a series of interconnected wetland types.
o The surrounding upland and outflow area of the wetland should be examined to determine
land use, development, nearby natural resources, and hydrology. The surrounding land use,
previous development, and cumulative impacts may play a role in the current function of the
wetland. For best results please read all descriptions prior to scoring activity.
o Evaluation: The first portion in each section determines whether the wetland does or does
not provide the function. If none of the conditions listed in the first section are met, proceed
Vermont Wetland Evaluation Form Jan. 2019
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to the next section. If any of these conditions are met, determine if the wetland provides this
function at a higher or lower level based on the information listed in the subsequent sections.
o Presumptions: Please note that many wetlands are already presumed to be significant
under the Vermont Wetland Rules. A wetland is presumed to be significant if:
o The wetland is mapped on the VSWI map
o The wetland is contiguous to a VSWI mapped wetland
o The wetland meets the presumptions of significance under Section 4.6
o The wetland has a preliminary determination that it is Class II
Vermont Wetland Evaluation Form Jan. 2019
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1. Water Storage for Flood Water and Storm Runoff
Function is present and likely to be significant: Any of the following physical and vegetative
characteristics indicate the wetland provides this function.
Constricted outlet or no outlet and an unconstricted inlet.
Physical space for floodwater expansion and dense, persistent, emergent vegetation
or dense woody vegetation that slows down flood waters or stormwater runoff during
peak flows and facilitates water removal by evaporation and transpiration.
If a stream is present, its course is sinuous and there is sufficient woody vegetation to
intercept surface flows in the portion of the wetland that floods.
Physical evidence of seasonal flooding or ponding such as water stained leaves,
water marks on trees, drift rows, debris deposits, or standing water.
Hydrologic or hydraulic study indicates wetland attenuates flooding.
If any of the above boxes are checked, the wetland provides this function. Complete the
following to determine if the wetland provides this function above or below a moderate
level:
Check box if any of the following conditions apply that may indicate the wetland provides
this function at a lower level.
Significant flood storage capacity upstream of the wetland, and the wetland in
question provides this function at a negligible level in comparison to upstream storage
(unless the upstream storage is temporary such as a beaver impoundment).
Wetland is contiguous to a major lake or pond that provides storage benefits
independently of the wetland.
Wetland's storage capacity is created primarily by recent beaver dams or other
temporary structures.
Wetland is very small in size, not contiguous to a stream, and not part of a collection
of small wetlands in the landscape that provide this function cumulatively.
Check box if any of the following conditions apply that may indicate the wetland provides
this function at a higher level.
History of downstream flood damage to public or private property.
Any of the following conditions present downstream of the wetland, but upstream of a
major lake or pond, could be impacted by a loss or reduction of the water storage
function.
1. Developed public or private property.
2. Stream banks susceptible to scouring and erosion.
3. Important habitat for aquatic life.
The wetland is large in size and naturally vegetated.
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Any of the following conditions present upstream of the wetland may indicate a large
volume of runoff may reach the wetland.
1. A large amount of impervious surface in urbanized areas.
2. Relatively impervious soils.
3. Steep slopes in the adjacent areas.
2. Surface and Ground Water Protection
Function is present and likely to be significant: Any of the following physical and vegetative
characteristics indicate the wetland provides this function.
Constricted or no outlets.
Low water velocity through dense, persistent vegetation.
Hydroperiod permanently flooded or saturated.
Wetlands in depositional environments with persistent vegetation wider than 20 feet.
Wetlands with persistent vegetation comprising a defined delta, island, bar or
peninsula.
Presence of seeps or springs.
Wetland contains a high amount of microtopography that helps slow and filter surface
water.
Position in the landscape indicates the wetland is a headwaters area.
Wetland is adjacent to surface waters.
Wetland recharges a drinking water source.
Water sampling indicates removal of pollutants or nutrients.
Water sampling indicates retention of sediments or organic matter.
Fine mineral soils and alkalinity not low.
The wetland provides an obvious filter between surface water or ground water and
land uses that may contribute point or nonpoint sources of sediments, toxic
substances or nutrients to the wetland, such as: steep erodible slopes; row crops;
dumps; areas of pesticide, herbicide or fertilizer application; feed lots; parking lots or
heavily traveled road; and septic systems.
If any of the above boxes are checked, the wetland provides this function. Complete the
following to determine if the wetland provides this function above or below a moderate
level.
Check box if any of the following conditions apply that may indicate the wetland provides
this function at a lower level.
Presence of dead forest or shrub areas in sufficient amounts to result in diminished
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nutrient uptake.
Presence of ditches or channels that confine water and restrict contact of water with
vegetation.
Wetland is very small in size, not contiguous to a stream, and not part of a collection
of small wetlands in the landscape that provide this function cumulatively.
Current use in the wetland results in disturbance that compromises this function.
Check box if any of the following conditions apply that may indicate the wetland provides
this function at a higher level.
The wetland is adjacent to a well head or source protection area, and provides
ground water recharge.
The wetland provides flows to Class A surface waters.
The wetland contributes to the protection or improvement of water quality of any
impaired waters.
The wetland is large in size and naturally vegetated.
3.Fish Habitat
Function is present and likely to be significant: Any of the following physical and vegetative
characteristics indicate the wetland provides this function.
Contains woody vegetation that overhangs the banks of a stream or river and
provides any of the following: shading that controls summer water temperature; cover
including refuges created by overhanging branches or undercut banks; source of
terrestrial insects as fish food; or streambank stability.
Provides spawning, nursery, feeding or cover habitat for fish (documented or
professionally judged). Common habitat includes deep marsh and shallow marsh
associates with lakes and streams, and seasonally flooded wetlands associated with
streams and rivers.
Documented or professionally judged spawning habitat for northern pike.
Provides cold spring discharge that lowers the temperature of receiving waters and
creates summer habitat for salmonoid species.
The wetland is located along a tributary that does not support fish, but contributes to
a larger body of water that does support fish. The tributary supports downstream fish
by providing cooler water, and food sources.
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4. Wildlife Habitat
Function is present and likely to be significant: Any of the following physical and vegetative
characteristics indicate the wetland provides this function.
Provides resting, feeding staging or roosting habitat to support waterfowl migration,
and feeding habitat for wading birds. Good habitats for these species include open
water wetlands.
Habitat to support one or more breeding pairs or broods of waterfowl including all
species of ducks, geese, and swans. Good habitats for these species include open
water habitats adjacent shallow marsh, deep marsh, shrub wetland, forested wetland,
or naturally vegetated buffer zone.
Provides a nest site, a buffer for a nest site or feeding habitat for wading birds
including but not limited to: great blue heron, black-crowned night heron, green-
backed heron, cattle egret, or snowy egret. Good habitats for these species include
open water or deep marsh adjacent to forested wetlands, or standing dead trees.
Supports or has the habitat to support one or more breeding pairs of any migratory
bird that requires wetland habitat for breeding, nesting, rearing of young, feeding,
staging roosting, or migration, including: Virginia rail, common snipe, marsh wren,
American bittern, northern water thrush, northern harrier, spruce grouse, Cerulean
warbler, and common loon.
Supports winter habitat for white-tailed deer. Good habitats for these species include
softwood swamps. Evidence of use includes deer browsing, bark stripping, worn
trails, or pellet piles.
Provides important feeding habitat for black bear, bobcat, or moose based on an
assessment of use. Good habitat for these types of species includes wetlands located
in a forested mosaic.
Has the habitat to support muskrat, otter or mink. Good habitats for these species
include deep marshes, wetlands adjacent to bodies of water including lakes, ponds,
rivers and streams.
Supports an active beaver dam, one or more lodges, or evidence of use in two or
more consecutive years by an adult beaver population.
Provides the following habitats that support the reproduction of Uncommon Vermont
amphibian species including:
1. Wood Frog, Jefferson Salamander, Blue-spotted Salamander, or Spotted
Salamander. Breeding habitat for these species includes vernal pools and
small ponds.
2. Northern Dusky Salamander and the Spring Salamander. Habitat for these
species includes headwater seeps, springs, and streams.
3. The Four-toed salamander; Fowler’s Toad; Western or Boreal Chorus frog, or
other amphibians found in Vermont of similar significance.
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Supports or has the habitat to support significant populations of Vermont amphibian
species including, but not limited to Pickerel Frog, Northern Leopard Frog, Mink Frog,
and others found in Vermont of similar significance. Good habitat for these types of
species includes large marsh systems with open water components.
Supports or has the habitat to support populations of uncommon Vermont reptile
species including: Wood Turtle, Northern Map Turtle, Eastern Musk Turtle, Spotted
Turtle, Spiny Softshell, Eastern Ribbonsnake, Northern Watersnake, and others found
in Vermont of similar significance.
Supports or has the habitat to support significant populations of Vermont reptile
species, including Smooth Greensnake, DeKay’s Brownsnake, or other more
common wetland-associated species.
Meets four or more of the following conditions indicative of wildlife habitat diversity:
1. Three or more wetland vegetation classes (greater than 1/2 acre) present
including but not limited to: open water contiguous to, but not necessarily part
of, the wetland, deep marsh, shallow marsh, shrub swamp, forested swamp,
fen, or bog;
2. The dominant vegetation class is one of the following types: deep marsh,
shallow marsh, shrub swamp or, forested swamp;
3. Located adjacent to a lake, pond, river or stream;
4. Fifty percent or more of surrounding habitat type is one or more of the
following: forest, agricultural land, old field or open land;
5. Emergent or woody vegetation occupies 26 to 75 percent of wetland, the rest
is open water;
6. One of the following:
i. hydrologically connected to other wetlands of different dominant
classes or open water within 1 mile;
ii. hydrologically connected to other wetlands of same dominant class
within 1/2 mile;
iii. within 1/4 mile of other wetlands of different dominant classes or open
water, but not hydrologically connected;
Wetland or wetland complex is owned in whole or in part by state or federal
government and managed for wildlife and habitat conservation; and
Contains evidence that it is used by wetland dependent wildlife species.
If any of the above boxes are checked, the wetland provides this function. Complete the
following to determine if the wetland provides this function above or below a moderate
level.
Check box if any of the following conditions apply that may indicate the wetland provides
this function at a lower level.
The wetland is small in size for its type and does not represent fugitive habitat in
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developed areas (vernal pools and seeps are generally small in size, so this does not
apply).
The surrounding land use is densely developed enough to limit use by wildlife species
(with the exception of wetlands with open water habitat). Can be negated by
evidence of use.
The current use in the wetland results in frequent cutting, mowing or other
disturbance.
The wetland hydrology and character is at a drier end of the scale and does not
support wetland dependent species.
Check box if any of the following conditions apply that may indicate the wetland provides
this function at a higher level.
The wetland complex is large in size and high in quality.
The habitat has the potential to support several species based on the assessment
above.
Wetland is associated with an important wildlife corridor.
The wetland has been identified by ANR-F&W as important habitat.
5.Exemplary Wetland Natural Community
Function is present and likely to be significant: Any of the following physical and vegetative
characteristics indicate the wetland provides this function.
Wetlands that are identified as high quality examples of Vermont’s natural community
types recognized by the Natural Heritage Information Project of the Vermont Fish and
Wildlife Department, including rare types such as dwarf shrub bogs, rich fens, alpine
peatlands, red maple-black gum swamps and the more common types including deep
bulrush marshes, cattail marshes, northern white cedar swamps, spruce-fir-tamarack
swamps, and red maple-black ash seepage swamps are automatically significant for
this function.
The wetland is also likely to be significant if any of the following conditions are met:
Is an example of a wetland natural community type that has been identified and
mapped by, or meets the ranking and mapping standards of, the Natural Heritage
Information Project of the Vermont Fish and Wildlife Department.
Contains ecological features that contribute to Vermont’s natural heritage, including,
but not limited to:
Deep peat accumulation reflecting a long history of wetland formation;
Forested wetlands displaying very old trees and other old growth characteristics;
A wetland natural community that is at the edge of the normal range for that
type;
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A wetland mosaic containing examples of several to many wetland community
types; or
A large wetland complex with examples of several wetland community types.
6. Rare, Threatened, and Endangered Species Habitat
Function is present and likely to be significant: Any of the following physical and vegetative
characteristics indicate the wetland provides this function.
Wetlands that contain one or more species on the federal or state threatened or
endangered lists, as well as species that are rare in Vermont, are automatically
significant for this function.
The wetland is also likely to be significant if any of the following apply:
There is creditable documentation that the wetland provides important habitat for any
species on the federal or state threatened or endangered species lists;
There is creditable documentation that threatened or endangered species have been
present in past 10 years;
There is creditable documentation that the wetland provides important habitat for any
species listed as rare in Vermont (S1 or S2 ranks), state historic (SH rank), or rare to
uncommon globally (G1, G2, or G3 ranks) by the Natural Heritage Information Project
of the Vermont Fish and Wildlife Department;
There is creditable documentation that the wetland provides habitat for multiple
uncommon species of plants or animals (S3 rank).
List name of species and ranking:
7. Education and Research in Natural Sciences
Function is present and likely to be significant: Any of the following characteristics indicate
the wetland provides this function.
Owned by or leased to a public entity dedicated to education or research.
History of use for education or research.
Has one or more characteristics making it valuable for education or research.
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8.Recreational Value and Economic Benefits
Function is present and likely to be significant: Any of the following characteristics indicate
the wetland provides this function.
Used for, or contributes to, recreational activities.
Provides economic benefits.
Provides important habitat for fish or wildlife which can be fished, hunted or trapped
under applicable state law.
Used for harvesting of wild foods.
Comments:
9.Open Space and Aesthetics
Function is present and likely to be significant: Any of the following physical and vegetative
characteristics indicate the wetland provides this function.
Can be readily observed by the public; and
Possesses special or unique aesthetic qualities; or
Has prominence as a distinct feature in the surrounding landscape;
Has been identified as important open space in a municipal, regional or state plan.
10.Erosion Control through Binding and Stabilizing the Soil
Function is present and likely to be significant: Any of the following physical and vegetative
characteristics indicate the wetland provides this function.
Erosive forces such as wave or current energy are present and any of the following
are present as well:
Dense, persistent vegetation along a shoreline or stream bank that reduces an
adjacent erosive force.
Good interspersion of persistent emergent vegetation and water along course of
water flow.
Studies show that wetlands of similar size, vegetation type, and hydrology are
important for erosion control.
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What type of erosive forces are present?
Lake fetch and waves
High current velocities
Water level influenced by upstream impoundment
If any of the above boxes are checked, the wetland provides this function. Complete the
following to determine if the wetland provides this function above or below a moderate
level.
Check box if any of the following conditions apply that may indicate the wetland provides
this function at a lower level.
The stream is artificially channelized and/or lacks vegetation that contributes to
controlling the erosive force.
Check box if any of the following conditions apply that may indicate the wetland provides
this function at a higher level.
The stream contains high sinuosity.
Has been identified through fluvial geomorphic assessment to be important in
maintaining the natural condition of the stream or river corridor.
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