Wetlands, ponds, and streams are significant natural resources
of the City because of their size or functional values, such as flood
storage, wildlife habitat, and the enhancement of water quality and/or
quantity. The preservation of these water resources promotes the general
public health, safety, welfare and convenience in our community. In
particular the regulations of the Conservation Overlay District (CO
District) are intended to:
A. Maintain and enhance the quality and quantity of surface waters and
groundwater by preserving the ability of wetlands to filter pollution,
trap sediment, retain and absorb chemicals and nutrients, and produce
oxygen.
B. Minimize expense to the City and the public in providing and maintaining
essential services and utilities, such as wastewater collection and
treatment, drainage facilities, and public water supply, which may
arise because of the inappropriate use of land within the CO District.
C. Minimize impacts to existing land uses and lots (see §
275-12.5, Exemptions; preexisting residential structures, uses and lots).
D. Prevent the destruction of, or significant changes to, those wetland
areas, related water bodies and adjoining land which provide flood
protection; protect persons and property against the hazards of flood
inundation by assuring the continuation of the natural flow patterns
of streams and other watercourses; and provide for nutrient attenuation
and augmentation of stream flow during dry periods.
E. Encourage those uses that can be appropriately and safely located
within the CO District.
F. Protect native wildlife habitat and natural vegetation upon which
a variety of upland and aquatic species are dependent for purposes
of breeding or sustenance.
The overlay district shall include rivers, lakes, ponds, perennial
streams, vernal pools, all jurisdictional wetlands and the surrounding
upland areas of each of these resources.
In all cases the more restrictive buffer shall be used.
Buffer
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Location
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75 feet
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Cocheco River, Salmon Falls River and Isinglass River from the
ordinary high-water mark of the river
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50 feet
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Named streams and surface water from the ordinary high-water
mark listed in Table I below
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50 feet
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Edge of jurisdictional wetland consisting of very poorly drained
soils1
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50 feet
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Edge of jurisdictional wetland consisting of poorly drained
soils1
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50 feet
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Vernal pools2
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Notes:
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1.
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The precise location of a wetland boundary in any particular
case must be determined by on-site inspection by a New Hampshire certified
wetland scientist.
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2.
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Vernal pools that shall be identified by a New Hampshire certified
wetland scientist and may be subject to review by the Conservation
Commission.
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[Amended 3-5-2019]
The edge of wet of these wetlands shall be determined by the
delineation process set forth in the Corps of Engineers Wetlands Delineation
Manual, 1987, and the most recent version of the Regional Supplement
to the Corp of Engineers Wetland Delineation Manual: Northcentral
and Northeast Region. When there is a dispute in the boundary, the
landowner may appeal the decision to the Planning Board with written
recommendations by the Conservation Commission.
The following are exempt:
A. All wetlands less than 1/2 acre in size, except vernal pools.
B. Wetland conditions resulting from the following: constructed drainage
structures, including but not limited to swales, ditches, and basins;
actively maintained agricultural/irrigation ponds; and septage lagoons.
C. Notwithstanding other provisions of this article, the construction
of additions and extensions to one- and two-family dwellings and accessory
residential uses shall be permitted within the CO District provided
that:
(1)
The dwelling or residential use lawfully existed prior to the
original adoption of the Conservation Overlay District on October
7, 2003;
(2)
The proposed construction conforms to all other applicable ordinances
and regulations of the City of Rochester; and
(3)
The dwelling or use continues in its present use.
D. Lots of record, except that any lot requiring subdivision (i.e.,
that creates two or more lots) or minor site/site plan review must
meet the requirements of this article.
E. Preexisting subdivisions and site plans. Exemptions:
(1)
Subdivisions, site plans and planned unit developments approved
by the Planning Board and existing at the time of passage of this
article shall be exempt from this article, as governed by the provisions
of RSA 674:39.
(2)
Completed applications approved by the Planning Board are exempt
from this article herein.
(3)
Condominium conversions where there are no improvements proposed
to the site are exempt from this article.
F. This article becomes applicable in the following situations:
(1)
Nonresidential site plans for additions, expansions, or changes
in use.
(2)
Site plans for new commercial, industrial, or multifamily development.
As used in this article, the following terms shall have the
meanings indicated:
BUFFER
The protected upland areas adjacent to wetlands and surface
waters in the Conservation Overlay District other than the wetlands
themselves.
ORDINARY HIGH-WATER MARK
The line on the shore, running parallel to the main stem
of the river, established by the fluctuations of water and indicated
by physical characteristics such as a clear, natural line impressed
on the immediate bank, shelving, changes in the character of soil,
destruction of soil, destruction of terrestrial vegetation, the presence
of litter and debris, or other appropriate means that consider the
characteristics of the surrounding areas. Where the ordinary high-water
mark is not easily discernible, the ordinary high-water mark may be
determined by the Department of Environment Services. Source: Comprehensive
Shoreland Protection Act, page 7 from the State of New Hampshire web
page, 1998.
OVERLAY DISTRICT
A zoning district superimposed on one or more established
underlying zoning districts to impose supplemental restrictions on
uses in these districts.
POORLY DRAINED SOIL
As defined by high-intensity soil maps for New Hampshire
sponsored by the Society of Soil Scientists of Northern New England
Special Publication No. 1, September 2002.
[Amended 3-5-2019]
VERNAL POOLS
A.
Temporary bodies of water that flood each year for a few months
during the spring and summer. Vernal or "spring" pools fill up with
melting snow and early rains, then usually dry up by mid to late summer.
Some relatively deep pools may remain flooded for a few years but
become completely dry in seasons with very low rainfall. Autumnal
pools fill during the fall with rising groundwater.
B.
Because vernal pools are not permanently flooded, they do not
support fish populations and thus provide safe breeding sites for
several amphibian and invertebrate species, including wood frogs,
spotted salamanders, and fairy shrimp. These species have evolved
life cycles that depend on temporary pools.
C.
Vernal pools vary in size, ranging from several square feet
to several acres. They can be found in a variety of sites, such as
isolated depressions in the woods, kettle holes, and gravel pits.
Many are within larger wetlands, such as oxbows in river floodplains
and pools in forested swamps or scrub-shrub wetlands. Their common
characteristics are the absence of fish, temporary flooding regime,
and the presence of vernal pool species. Suitable pools must have
enough leaf litter and other debris to provide food sources and cover
for the species that breed in them. Source: ASNH Conservation Fact
Sheet: Vernal Pools.
VERY POORLY DRAINED SOIL
As defined by high-intensity soil maps for New Hampshire
sponsored by the Society of Soil Scientists of Northern New England
Special Publication No. 1, September 2002.
[Amended 3-5-2019]
WETLAND
As defined by the National Food Security Act Manual (Soil
Conservation Service, 1994) and the Corps of Engineers Wetlands Delineation
Manual (1987) and the most recent version of the Regional Supplement
to the Corp of Engineers Wetland Delineation Manual: Northcentral
and Northeast Region, those areas that are inundated or saturated
by surface water or groundwater at a frequency and duration sufficient
to support, and that under normal circumstances do support, a prevalence
of vegetation typically adapted for a life in saturated soil conditions.
Wetlands include, but are not limited to, swamps, marshes, bogs and
similar areas.
[Amended 3-5-2019]
Buffers are applied irrespective of lot lines and municipal
boundaries, except (as shown in the below diagram) that when a wetland
is bounded by City Class V or a state or federal highway, existing
at the time of passage of this article, buffers are not applied to
properties directly across the right-of-way.
Conditional use approval may be granted by the Planning Board
(RSA 674:21, II) after proper public notice and public hearing.
A. The following uses are allowed with a conditional use approval:
[Amended 12-6-2022]
(1)
Roads and other accessways; drainageways; pipelines, power lines
and other transmission lines; docks, boat launches, and piers; domestic
water wells (and associated ancillary pipes and equipment); and replacement
septic tanks and leach fields.
(2) Solar collection systems or associated vegetative clearing. In addition,
evidence shall be submitted that no alternative location is available
on the property, and that all of the following conditions are found
to exist:
(a)
The proposed construction is essential to the productive use
of land not within the CO District.
(b)
Design and construction methods will be such as to minimize
impact upon the wetlands and will include restoration of the site
consistent with the permitted use.
(c)
There is no feasible alternative route on land controlled by
the applicant that does not cross the CO District nor has less detrimental
impact on the wetlands. Nothing in this section shall limit the applicant
from exploring alternatives with abutting property owners.
(d)
Economic advantage is not the sole reason for the proposed location
of the construction.
(e) If clearing is required within the Conservation Overlay District
to reduce shade and improve the function of a solar collection system,
a vegetative management plan shall be submitted with a conditional
use permit.
B. Buffer reductions.
(1)
Lots which are subject to the requirements of this CO District as defined in §§
275-12.2 and
275-12.3 above may be allowed a buffer reduction of no more than 1/2 of any required buffer subject to all applicable provisions of this chapter, in the following situations:
(a)
Expansion of existing structures may be permitted for lots located
in the Industrial, DC, OC, and HC Districts.
(b)
Construction of a new structure may be permitted for lots located
in the Industrial, DC, OC, and HC Districts.
(2)
All the following conditions shall be met to allow buffer reductions:
(a)
The structure for which the exception is sought cannot feasibly,
after consideration of all reasonable alternatives, be constructed
on a portion or portions of the lot which lie outside the CO District,
or the application of the CO District eliminates greater than 50%
of the buildable area located on the parcel or, in the judgment of
the Planning Board, the proposed site layout would result in a significantly
higher quality design.
(b)
The proposed structure and use must be consistent with the purpose
and intent of this article and provisions must be made to ensure that
drainage from the structure will not adversely impact any wetlands.
(c)
There shall be no impervious areas for parking within the reduced
buffer for which the conditional use approval is sought.
(d)
The maximum building coverage is limited to 50% of the outer
half of the buffer zone, as shown in the diagram below.
(e)
Best management practices must be demonstrated to the satisfaction
of the Planning Board.
Buffer Reduction Examples
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(3)
Buffer reduction may also be obtained explicitly by issuance of a NHDES dredge and fill permit, per §
275-12.10, Dredge and fill permits.
C. Administration
of conditional use approvals.
(1)
The application shall be referred to the Conservation Commission
for review and comment prior to the Planning Board making any final
decision. In acting on the application, the Board shall consider any
report received from the Commission. The Board shall then vote either
to approve the application as presented, approve it with conditions,
or deny it.
(2)
Prior to the granting of any conditional use approval under Subsections
A and
B of this section, the applicant may be required to submit a performance security in a form acceptable to the Planning Board, depending on the scale of the proposed use and potential threat to the wetlands. The security shall be submitted in a form and amount with surety and conditions satisfactory to the Planning and Development Department to ensure that the construction will be carried out in accordance with the approved design. The security shall be submitted to and approved by the Planning and Development Department prior to the issuance of any permit authorizing construction.
(3)
The Planning Board may require the applicant to submit a wetlands
impact assessment when necessary to evaluate an application made under
this article. The cost of this assessment shall be borne by the applicant.
(4)
As outlined in RSA 676:4, I(g), the applicant may also be assessed
reasonable fees to cover the cost of other special investigative studies
and for the review of documents required by particular applications,
reviews by the City's legal counsel, and any third party wetlands
consultant as may be required by the Planning Board.
CO District mitigation shall be provided in the same watershed,
if required by the Planning Board, at its discretion, with consideration
of recommendations by the Conservation Commission.
Any variance or appeal to the Zoning Board of Adjustment shall be in accordance with RSA 676:5 and Article
4 of this chapter. Prior to holding a public hearing on an appeal or variance, the Zoning Board shall forward a copy of the plan and application to the Conservation Commission for review and comment. The Conservation Commission shall, after reviewing the plan and application, forward any appropriate recommendations to the Zoning Board of Adjustment for its consideration.
Any wetland or part of any wetland consisting of very poorly
drained soils shall not count toward the minimum lot area or density
requirements of any property in any zoning district.
Table I
Named Streams and Surface Water Table
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Axe Handle Brook
(Rickers and Howard Brooks)
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Heath Brook
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Hurd Brook
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Willow Brook
AKA Wardley Brook
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Clark Brook
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Baxter Lake
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Rochester Reservoir
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Hanson Pond
AKA Squamanagonic Pond
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Little Long Pond
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Champlin Pond
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No name pond south of Champlin Pond
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Note: The above streams have been identified in the Water Resource
Management and Protection Plan, prepared by the Southern New Hampshire
Planning Commission, dated February 1991 and on file in the office
of the Planning Board, as listed in Table I.
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