MODEL ENVIRONMENTAL RESOURCE AREA PROTECTION
STANDARDS FOR SUBDIVISIONS
Introduction. The VLCT Municipal Assistance Center has developed model environmental
resource area protection standards for subdivisions that provide language incorporating
environmentally sensitive and efficient uses of the land through the regulation of new parcel
layout and site design. These standards were developed as a work product of our grant-funded
water resources program and are offered as options for municipalities considering resource
protection beyond what is required by state law. For this reason, they do not necessarily reflect
VLCT’s municipal policy. Source materials for the model standards included state and federal
requirements and guidance, as well as technical reports and land use regulations from the towns
of Bolton, Braintree, Fayston, Marshfield, Norwich, Stowe, Waitsfield, Williston, and
Woodstock.
In general, subdivision standards control the location and pattern of new development, i.e., the
way land is divided up to accommodate land uses and necessary supporting infrastructure.
Zoning regulations, on the other hand, focus on the type and density of development allowed in
specific districts within the community. Chapter 117 of Title 24 authorizes municipalities to
adopt zoning regulations either as a separate bylaw or as part of a unified development bylaw
that also includes subdivision regulations. Likewise, subdivision regulations may be adopted in
the absence of zoning, but are usually tied to related dimensional and density requirements
typically found in zoning regulations. For municipalities without zoning, subdivision regulations
can be an excellent means to protect environmental resource areas.
The primary principle behind these model subdivision standards is that sensitive and ecologically
important places should be identified and set aside for protection prior to establishing building
sites, roads, and lot boundaries. In addition to providing essential habitat and connectivity for
animal movement and migration, protected environmental resource areas also provide essential
benefits to humans such as stormwater management, improved resilience to flooding, water
quality protection, and air purification – so-called “ecosystem services.” These model
subdivision standards minimize impacts to environmental resources through two primary
approaches: (1) excluding a specific list of environmental resources from designated building
envelopes, and (2) providing low impact development (LID) design strategies as the primary
means of pre- and post-development stormwater management.
Local governments have broad legal powers to adopt regulations they deem necessary to prevent
negative impacts from development. Requiring land to be set aside for environmental protection
is not unconstitutional as long as there is a legitimate public objective such as water quality
protection, or protecting public safety from flooding and streambank erosion. In the case of
Lucas v. South Carolina Coastal Council, the U.S. Supreme Court said that regulations cannot
deprive a property owner of “all economically beneficial use.”
How to Use this Document. As stated above, the following model subdivision standards are
intended to offer municipal officials bylaw language to achieve environmental resource
protection for those municipalities, or for specific areas within those municipalities, in which
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environmental resource management is a priority. Careful review of these standards is necessary
before incorporating the language into town bylaws and insuring compliance with the municipal
plan and any other ordinances and policies. We have included references to Vermont state law as
well as state and federal environmental regulations in this document. Due to the complexity of
these topics and land use regulation in general, we strongly recommend legal review of bylaws
or other documents prior to adopting these model standards or the definitions of terms provided
in this document.
The model subdivision standards are organized into four sections:
I. Application and Review Process
II. General Standards for Environmental Resource Area Protection
III. Stormwater and Erosion Control
IV. Open Space Standards
Within each category, you will find model standard language as well as additional explanatory
notes in bracketed italicized text. A municipality may decide to adopt specific standards or the
entire standard tailored to its needs. These models are designed to work under either scenario.
Section V includes definitions for 23 technical terms used in the model standards and a list of the
municipal land use regulations used as resources. Be careful to evaluate whether your town
bylaws include definitions for any of these terms and whether the current definitions match those
included here.
If you have any questions, please contact Milly Archer, VLCT’s Water Resources Coordinator,
at marcher@vlct.org or 800-649-7915.
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Model Environmental Resource Area Protection Standards for Subdivisions
I. The Application and Review Process
[These application requirements would be added to the town’s subdivision application and
review procedures in accordance with the requirements set forth in Chapter 117 sections 4418,
4463, and 4464.]
A. Meeting with Town Planning and Zoning Staff. All applicants should meet with the
administrative officer prior to preparing an application for subdivision approval in order to
receive guidance on the application and review process and the subdivision standards in
effect.
B. Sketch Plan Review. Prior to submitting a preliminary subdivision review application, the
applicant must attend the sketch plan review hearing with the [AMP] to discuss information
that must be submitted in conformance with these standards. The applicant is not required to
bring any formal plans to the sketch plan review conference, but should be prepared to
discuss different approaches to subdivision design and provide an informal outline of the
location and the environmental resource areas as described below.
C. Preliminary Subdivision Review. The applicant must submit the following two documents
with the preliminary plat in addition to those required in accordance with Section ____ of the
Town of __________’s subdivision application requirements.
1. Environmental Resource Area Inventory. The applicant shall provide an
environmental resource area inventory of baseline information on the elements of the
natural landscape, including steep slopes, tree canopy, floodplains, rivers, lakes and
ponds, wetlands, significant wildlife habitat, greenway corridors, fields, soil types and
natural drainage ways, ridgelines, and cultural features such as designated historic sites,
known archaeological sites, and scenic views. These elements may be listed in the town
plan as well as on existing maps on the websites of the Agency of Natural Resources
(ANR), the U.S. Geological Survey (USGS), and the Federal Emergency Management
Agency (FEMA).
2. Five-Step Design Process. The applicant shall submit a document verifying that the
following five-step design process was completed in the following order when creating
the preliminary plat:
Step 1. Identify the environmental resource areas.
Step 2. Identify the potential development areas.
Step 3. Identify building sites and envelopes within potential development areas.
Step 4. Lay out roads, driveways and utilities.
Step 5. Identify proposed lot boundaries.
[This five-step design process is based on the concept of “conservation subdivision
design” in which the most significant natural and cultural resources on a given tract of
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land are identified and protected, thereby establishing the most suitable building
envelopes from a preservation viewpoint. This approach is credited to Randal Arendt, a
noted conservation planner.]
D. Final Plat Review. The applicant shall submit the following items with the final plat in
addition to the items required in accordance with Section ____ of the Town of __________’s
subdivision application requirements:
1. A plan drawn to scale showing the location and number of lots, dwellings and their
building envelopes, the properties adjacent to and near the proposed subdivision location,
and the location and extent of all designated environmental resource areas and open space
areas to be conserved. Designated environmental resource areas and open space areas
shall be indicated with appropriate notation on the final plat.
2. A list of the permitted and restricted uses of environmental resource areas and areas of
open space shall be included on the recorded plat along with documentation ensuring that
the environmental resource areas and open space areas will not be subdivided in the
future. [Open space protection and its relationship to environmental resource areas are
discussed in Section IV.]
3. All major subdivision applications shall include the following information on a plan or
plans drawn to scale with supporting documents and technical details: [A major
subdivision results in the creation of four or more lots or creates more than an acre of
disturbed land.]
a. An erosion and sediment control plan that incorporates accepted management
practices as recommended by the Vermont Agency of Natural Resources in the
“Vermont Handbook for Erosion Prevention and Sediment Control” and the
“Vermont Stormwater Management Manual,” as most recently amended as of the
date of the application filing, and that includes provisions for the inspection and longterm maintenance of stormwater management and erosion control facilities.
b. A stormwater management plan identifying the construction disturbance areas and
demonstrating that stormwater runoff is minimized through the use of LID design that
employs strategies such as natural drainage systems and on-site infiltration and
treatment techniques to the greatest extent feasible. The plan shall demonstrate that
soils best suited for infiltration are retained and that areas consisting of tree canopy
and other natural vegetation are preserved in contiguous blocks or linear corridors to
protect the best stormwater management features identified in the environmental
resource area inventory as required in I.C.1.
c. The erosion and sediment control plan and the stormwater management plan shall be
prepared by a licensed Vermont engineer and include provisions for the inspection
and long-term maintenance of stormwater management and erosion control facilities.
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4. All minor subdivision applications shall include a plan that indicates the proposed limits
of disturbance noted in relation to the features and areas identified on the environmental
resource inventory. [A minor subdivision results in the creation of three or fewer lots and
disturbs less than one acre of land.]
E. To assist in evaluating an application, the [AMP] may require an independent technical
review at any point in the subdivision process of one or more proposed aspects of a proposed
development, prepared by a qualified professional acceptable to the [AMP] and funded by
the applicant. [This condition set forth in Chapter 117 § 4440(d) requires that the [AMP]
have procedures and standards in place for requiring an applicant to pay for reasonable
costs of an independent technical review of the application.]
II. General Standards for Environmental Resource Area Protection
[The following standards are not intended to imply that every piece of land has to be treated in
the same way, but it does put forward carefully thought-out rationales to account for the unique
attributes of each site. Supporting the building envelope limitations suggested in these model
standards with a thoughtful comprehensive town plan is a strong defense against any challenges
that applications are not being consistently reviewed.]
A. All subdivisions shall be designed and configured to preserve the features and areas
identified on the environmental resource area inventory.
B. All lots shall have a designated building envelope. The extent of construction, clearing, and
yard area shall be designated to limit the location of structures, parking areas, and associated
site improvements to the building envelope. The [AMP] may also require the identification of
specific building footprints if, in its judgment, such information is needed to determine
conformance with these standards.
C. Environmental resource areas shall not be included in a building envelope. Specifically,
building envelopes shall be located to exclude the following environmental resource areas:
1. Areas mapped as Floodplain by FEMA or ANR.
2. Areas within a mapped river corridor.
3. For streams without mapped river corridors, the building envelope shall exclude land 50
feet from streams with watersheds less than or equal to two square miles and 100 feet
from streams with watersheds greater than two square miles. The distance shall be
measured horizontally from the top of slope where the channel runs adjacent to a valley
wall or high terrace, and from the top of bank where the channel has access to its
floodplain. (See table and graphic on page 6.)
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≤ 2 sq. miles
> 2 sq. miles
Valley
Slope
Any
≥ 2%
> 2 sq. miles
< 2%
Watershed
Minimum Setback Width
Setback Measured From
50 ft.
100 ft
one half meander belt width
plus buffer width
top of bank or slope
top of bank or slope
meander centerline
[Source: Vermont Agency of Natural Resources River Corridor Protection Guide]
Measuring Top of Bank and Top of Slope
top of slope
top of bank
4. Wetlands, in conformance with state regulations.
5. Lake shoreland within 125 feet of the mean high-water level. [Source: VLCT Model Lake
Shoreland Protection District Bylaw and Technical Paper.]
6. Land characterized by slopes at or greater than 15%, prominent knolls, and ridgelines.
7. Significant wildlife habitat. Based on the Environmental Resource Inventory required
under Preliminary Subdivision Review, the [AMP] may require the submission of a
wildlife habitat assessment, prepared by a wildlife biologist or comparable professional,
to identify potentially impacted habitat and provide recommended management
strategies. The [AMP] may also consult with Vermont Fish and Wildlife Department staff
prior to issuing a decision.
8. Natural drainage ways that aid in stormwater management and a 25-foot vegetated buffer
from the edge of the drainage way.
D. Lots shall be configured to maintain contiguous tracts of undeveloped land on adjoining
parcels, where feasible.
E. Roads, driveways, and utilities shall be designed to avoid the fragmentation of identified
natural areas and wildlife habitat and shall be shared where practical.
F. The preservation, planting, and/or maintenance of riparian buffers, trees, hedges, ground
cover, and other vegetation in one or more areas of land to be subdivided may be required by
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the [AMP] in the following instances: [For more information, see VLCT’s Model Riparian
Buffer Ordinance and Technical Paper.]
1. To provide an undisturbed, vegetated buffer between developed and undeveloped
portions of a subdivision to protect water quality and/or other natural features identified
in the Environmental Resource Area Inventory;
2. To provide stormwater infiltration and management in accordance with stormwater
management and erosion control standards;
3. To provide screening of development that increases privacy, reduces noise and glare, or
otherwise softens and/or lessens its visual impacts;
4. To provide wind barriers and to reduce heat loss or gain as appropriate;
5. To preserve existing trees, tree lines, hedgerows, and wooded areas of particular natural
or aesthetic value to the site or significant wildlife habitat; and/or
6. To establish buffers or barriers between incompatible land uses.
III. Stormwater Management and Erosion Control Standards
Temporary and permanent stormwater management and erosion control measures shall be
incorporated into subdivision design and layout to control surface runoff, sedimentation, and
water pollution on-site and downstream from the proposed subdivision. Factors to be considered
in determining the types of controls necessary shall include pre-development site and runoff
conditions, vegetation and ground cover, slope and drainage patterns, soil types, the percentage
of land covered in impermeable surfaces, distances to streams and other surface waters, and
impact on adjoining properties.
A. Low Impact Development (LID) Design. Applicants shall use LID design strategies as a
primary means of stormwater management. Where LID design is not practical due to site
constraints or other factors, the applicant shall document the reasons why LID was not
utilized and explain why the proposed stormwater management approach is advantageous.
[See VLCT’s Model Low Impact Development Stormwater Management Bylaw and
Technical Paper.]
B. Stormwater Management and Sediment and Erosion Control Standards.
1. Minimize Land Disturbance. Development shall require the least amount of vegetation
clearing, soil disturbance and duration of exposure, soil compaction, and topography
changes as possible.
a. Environmental resource areas and open space areas shall be retained, preferably in
contiguous blocks or linear corridors for the protection of the best stormwater
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management features identified in the environmental resource area inventory. To the
extent feasible, soils best suited for infiltration shall be retained.
b. There shall be no soil compaction except within the approved building envelope,
which shall be identified and delineated in the field with appropriate safety or
landscape fencing. In areas outside the building envelope there shall also be no
storage of construction vehicles, construction materials, or fill, nor shall these areas
be used for circulation. [The building envelope should be sized to accommodate
necessary compaction incurred during development.]
c. River corridors, riparian buffers, and forested lands located on steep slopes are
priority areas. Clearing them shall be prohibited in order to protect significant wildlife
habitat and prevent erosion and sedimentation resulting from stormwater runoff.
d. Impervious surfaces and building envelopes shall be minimized. Where feasible,
development shall be clustered to minimize site disturbance and preserve large areas
of undisturbed open space to infiltrate stormwater runoff.
2. Manage Water, Prevent Erosion, and Control Sediment During Construction.
a. Runoff from above the construction site shall be intercepted and directed around the
disturbed area.
b. Within the construction site, water shall be controlled and allowed to infiltrate. Rock
check dams shall be installed before excavation or fill activities begin. Hay bales shall
not be used as check dams due to their high failure rates.
c. The amount of sediment produced from areas of disturbed soils shall be minimized by
using control measures such as vegetated strips, diversion dikes and swales, sediment
traps and basins, check dams, stabilized construction entrances, dust control, and silt
fences.
d. Immediate seeding and mulching or the application of sod shall be completed at the
conclusion of each phase of construction or at the conclusion of construction. The
[AMP] may require project phasing to minimize the extent of soil disturbance and
erosion during each phase of site development.
e. The applicant shall follow the erosion prevention and sediment control practices for
construction that occurs from October 15th to May 15th found in the most recent ANR
standards for winter construction (“The Low Risk Site Handbook for Erosion
Prevention and Sediment Control” [2006]).
IV. Open Space Standards
[In addition to environmental resource area protection, these model subdivision standards
include language that protects open space areas. Traditionally, open space areas are used for
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neighborhood recreation, stormwater management facilities, or conservation purposes and are
the result of alternative site planning techniques that concentrate dwelling units in a compact
area to reserve undeveloped space elsewhere on the site. However, because the term “open
space” can describe many types of open areas, these model subdivision standards make a
distinction between open space areas and environmental resource areas.]
A. Minimum Open Space Requirement
1. The minimum acreage of open space required to be set aside is either 40% of the gross
acreage of land in the proposed subdivision or 40% of land protected as environmental
resource areas as defined in these standards, whichever is greater. [The standard
percentage of protected space for Conservation Subdivision Design is from 35% to 70%
of the gross acreage of land in the proposed subdivision. The percentage chosen by a
municipality should be based on local needs and circumstances in order to achieve the
desired result of protection for the purposes outlined in the introduction.]
2. When the protected environmental resource areas are less than 40% of the gross acreage
of land in the proposed subdivision, additional land shall be set aside to make up the
difference and be protected as open space.
3. Any subsequent subdivision of a parcel that meets the level of environmental resource
and open space protection provided in (1) and (2) above under prior approval pursuant to
the subdivision regulations is not subject to successive 40% open space set-asides.
4. Open space areas shall be configured to be contiguous with environmental resource areas
on adjacent parcels where feasible.
B
Permitted Uses of Open Space
1. Conservation of archeological and historical sites.
2. Stream and wetlands restoration.
3. Walking, bicycle, or horse riding trails, provided they are constructed of pervious
materials.
4. LID stormwater management practices or facilities that require incorporating or
establishing open space areas – such as vegetated swales, constructed wetlands and
bioretention cells or rain gardens – provided they are located outside the environmental
resource areas.
5. Other uses deemed appropriate by the [AMP] that are protective of the environmental
resource areas.
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C. Prohibited Uses of Open Space
1. Any use that obstructs or damages environmental resource areas.
2. Roads, parking lots and impervious surfaces, except as specifically authorized.
3. Storage of equipment and placement of structures.
4. Deposition of debris (including grass, leaves, brush, construction debris, refuse, etc.).
5. Excavation or filling.
V. Definitions
[Terms used in these model subdivision standards defined below were compiled from a number
of sources that included Vermont Statutes Annotated, federal and state agency regulations,
samples found in existing municipal bylaws listed below, and other resource documents.]
Appropriate Municipal Panel (AMP). Any municipal body or panel designated in the bylaw to
review development applications or to hear appeals. An AMP may include a planning
commission, board of adjustment, development review board, or in some cases the legislative
body.
Building Envelope. The area on a lot that encompasses development as defined below.
Development. Any human-made change to improved or unimproved real estate, including but
not limited to the construction, re-construction, conversion, structural alteration, relocation, or
enlargement of any building or other structure, or of any filling, grading, paving, excavation,
earth moving, tree removal, storage of equipment or materials, or the extension or use of land.
Environmental Resource Area. Any natural area that must be mapped and documented prior to
subdivision approval, including floodplains, river corridors, wetlands, streams, lakes, riparian
buffers, forested areas, significant wildlife habitat, greenway corridors, fields, well-drained soils
and natural drainage ways, steep slopes, ridgelines, and scenic views. The environmental
resource areas characterize the most sensitive and ecologically important places in the Town of
__________.
Floodplain. The area that will be inundated by the flood event having a 1% chance of being
equaled or exceeded in any given year as determined by the Federal Emergency Management
Agency. The 1% annual chance flood is also referred to as the base flood or 100-year flood.
Fluvial Erosion Hazard Area. The land area adjacent to stream channels subject to fluvial
erosion processes or other channel adjustments as delineated on a current Fluvial Erosion
Hazards Area Map.
Fragmentation. A process of dividing continuous forests into isolated patches of forest.
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Greenway Corridor. A linear corridor of undeveloped tree canopy and other natural vegetation
that follows distinct geologic and cultural features and provides connectivity for animal
movement and plant migration.
Impervious Surface. A constructed hard surface that either prevents or retards the entry of water
into the soil and causes water to run off the surface in greater quantities and at an increased rate
of flow than prior to development. Examples include roads, rooftops, out buildings, decks, paths,
patios, parking areas, and concrete, asphalt, or gravel driveways.
Low Impact Development (LID). The use of site and subdivision design techniques in
coordination with stormwater management engineering to mimic a site’s pre-development
hydrology by using design techniques that infiltrate, filter, store, evaporate, and detain runoff
close to its source.
Major Subdivision. A subdivision of land resulting in the creation of four or more lots or
creating more than an acre of disturbed land.
Mean High Water Level. The normal summer (June 1 to September 15) water level in lakes,
measured in feet above sea level, as determined by an average of water level readings available
over time as established by the State of Vermont.
Minor Subdivision. A subdivision of land resulting in the creation of three or fewer lots and
disturbing less than one acre of land.
Open Space. The portion of a subdivision not occupied by structures, buildings, roads, rights-ofway, and parking lots that is undeveloped except for uses permitted in Section ____, and has
been set aside for permanent protection. Open space areas are less environmentally sensitive and
ecologically important than environmental resource areas, but can play an important role for
wide ranging species movement and provide a buffer for the more sensitive environmental
resource areas.
Ridgeline. The uppermost point of a ridge, hill, cliff, slope, or face, characterized by visual
dominance in the valley landscape.
Riparian Buffer. The land abutting a stream, lake, or wetland consisting of trees, shrubs, natural
ground cover, and an understory of plants that functions to filter runoff, control sediment and
nutrient movement, reduce erosion, and provide fish and wildlife habitat.
River Corridor. Lands adjacent to and including the river channel. The width of the river
corridor is defined by the lateral extent of the channel in equilibrium condition (called the
meander belt width), which is governed by valley landforms, surficial geology, and the length
and slope requirements of the river channel. The river channel is in equilibrium condition when
water flow, sediment, and woody debris are transported by the stream in such a manner that it
maintains its dimension, general pattern, and slope without unnaturally aggrading (raising) or
degrading (lowering) the channel bed elevation.
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Significant Wildlife Habitat. Those natural features that are essential for the survival and/or
reproduction of the native wildlife of the Town of ____________. This shall include but is not
limited to: (1) deer winter habitat; (2) habitat for rare, threatened, and endangered species; (3)
concentrated black bear feeding habitat; (4) moose habitat; (5) wetlands that provide critical
functions for wetland-dependent wildlife such as breeding and nesting habitat for wading birds,
waterfowl, and otter and vernal pools; (6) wildlife travel corridors, characterized by undeveloped
forested corridors, including forest cover reaching to road rights-of-way, which serve to link
large tracks of unfragmented forest habitat; (7) large areas of contiguous, unfragmented forest
that provide for a large number of species; (8) areas that provide an abundance of food and/or
maternity sites; and (9) habitat identified by the Vermont Department of Fish and Wildlife as
either significant wildlife habitat or necessary wildlife habitat in accordance with 10 V.S.A. §
6086(a)(8)(A).
Steep Slope. Land characterized by a gradient in excess of 15%.
Stream. The full length and width, including the bed and banks, of any watercourse, including
rivers, creeks, brooks, and branches and intermittent watercourses that have a defined channel
and evidence of water and sediment transport, even if such watercourses do not have surface
water flow throughout the year or throughout the channel. For purposes of these standards,
constructed drainage ways including water bars, swales, and roadside ditches are not considered
streams.
Structure. An assembly of materials for occupancy or use, including but not limited to a
building, mobile home, or trailer.
Subdivision of Land. The division of any parcel of land into two or more parcels for the purpose
of offer, transfer, sale, conveyance, lease, or development.
Wetlands. Areas that are inundated by surface or groundwater with a frequency sufficient to
support vegetation or aquatic life that depend on saturated or seasonally saturated soil conditions
for growth and reproduction. Such areas include but are not limited to marshes, swamps, sloughs,
potholes, fens, river and lake overflows, mud flats, bogs, and ponds, but exclude such areas for
growing food or crops in connection with farming activities.
Municipal Bylaw Resource Documents
Land Use and Development Regulations for the Town of Bolton; Braintree Unified Bylaw;
Town of Fayston Land Use Regulations; Town of Marshfield Subdivision Regulations; Town of
Norwich Subdivision Regulations; Town of Stowe Subdivision Regulations; Town of Waitsfield
Subdivision Regulations; Williston Unified Development Bylaw; and Town of Woodstock
Zoning Regulations.
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