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ARTICLE XI - WETLANDS DISTRICT (W)
(Adopted March 14, 1989; Amended March 11, 2008, Amended March 9, 2010)
The Wetlands District is intended to protect the public health, safety, general welfare and property. This ordinance section for wetlands is intended:
1. To be a guide in the use of wetlands in Antrim,
2. To aid in the protection of persons and property from the danger of floods by preserving natural floodwater storage areas,
3. To encourage those uses that can appropriately and safely be located in wetlands areas.
B. The Wetlands District shall be considered as overlaying any other districts established by this Ordinance. Any use permitted in the portions of the district so overlaid shall only be permitted subject to all provisions of this Article. Any lot size established in the districts so overlaid shall only be permitted subject to the provisions of Paragraph E.2 of this Article. The Wetlands District includes all areas of wetlands identified by the use of soil surveys, examination of vegetation and/or shown on wetlands maps.
C. Wetlands as defined by this Ordinance within the Town of Antrim shall include:
1. Areas of retention of fresh water and their associated drainage ways (brooks, rivers, streams, ponds, or lakes),
2. Areas where the soil series are classified as “very poorly drained” or “poorly drained” by the most recent National Cooperative Soil Survey conducted by the U.S. Department of Agriculture Soil Conservation Service and titled Soil Survey of Hillsborough County New Hampshire-Western Part or other updated survey editions.
3. Areas where site-specific soils survey performed by a Town approved professional soil scientist locates poorly or very poorly drained soils not identified in the SCS published survey.
Areas where the vegetation community is dominated by water tolerant species (hydrophytes). The vegetation communities may include but are not limited to the following species:
Scrub/Shrub and/or Forested Wetlands are areas where the water table is at or near the ground surface for a significant part of the year. The vegetation communities consist mostly of trees and woody shrubs including, but not limited to:
Alders Poison Sumac
Arrow-wood Red Maple
Atlantic White Cedar Rhodora
Black Ash Sphagnum Moss
Black Gum Spicebush
Black Spruce Sweet Pepperbush
Buttonbush Tamarack (Larch)
Common Elder Willow
High-bush Blueberry Winterberry
Emergent Wetlands, Also known as marshes, wet meadows or fens are characterized by erect rooted, herbaceous hydrophytes. Vegetation is present and the soil is saturated for most of the growing season. Flooding may be seasonal, permanent, irregular or temporal. The vegetation community includes, but is not limited to the following:
Arums Poison Sumac
Bladderworts Pickerel Weeds
Cattails Sedges, including Bulrushes, Cotton-grasses
Duckweeds and Wool-grasses
Frog’s-bit Sweet Gale
Hydrophylus Grasses Water Milfoil
Bogs include areas where mosses cover substrates other than rock and where emergent shrubs or trees make up less than 30% of the area cover. The substrate is saturated to the surface. The water in a bog is practically devoid of oxygen and nutrients. Bogs usually develop in undrained glacial depressions. Typical plants include, but are not limited to:
Atlantic White Cedar Pink Laurel
Black Spruce Pitcher Plants
Bog or Buckbean Sedges
Bog Laurel Sheep Laurel
Bos-rosemary Sphagnum Moss
Cotton Grass Sundews
High-bush Blueberry Sweet Gale
Where it is alleged that an area has been incorrectly delineated as a wetland in Antrim, or that an area not so designated meets the criteria for wetlands designation, the Planning Board shall determine whether the regulations contained herein have application.
The Planning Board shall make its judgment under this section only upon the determination by a qualified professional soil scientist and/or biologist, or botanist on the basis of additional on-site investigation or other suitable research that the information contained on the most current Antrim Wetlands Map or SCS survey map is incorrect. This evidence shall be acceptable only when presented in written format by said scientists to the Planning Board. Any necessary testing or expenses incurred to clearly delineate questionable wetland areas shall be at the expense of the landowner or developer.
D. Permitted Uses:
1. Forestry, using the Best Management Practices as outlined in the 1979 Water Supply and Pollution Control Division booklet, “Erosion Control Guidelines for Timber Harvesting,” in order to protect streams from damage to prevent sedimentation.
2. Cultivation and harvesting of agricultural crops according to recognized soil conservation practices, including the protection of wetlands from pollution caused by the use and/or storage of fertilizers, pesticides, and herbicides used in such cultivation and sedimentation caused by erosion.
Wildlife refuges, parks, recreation uses consistent with the purpose and intent of this Ordinance such as nature trails and conservation areas.
4. Open spaces as permitted or required by the Subdivision regulations or the Zoning Ordinance.
5. State approved wetland impoundments.
6. Construction of wells and water supply.
7. Dry hydrants and fire protection ponds.
E. Special Provisions
1. No septic tank or leach field may be constructed, repaired or enlarged closer than seventy-five (75) feet to any wetland.
2. No construction or ground disturbance shall occur within twenty-five (25) feet based on the recommendation of the Hillsborough County Soil Conservation Service of the wetland areas defined in this article, except for those items listed in Section G of this Article. This twenty-five (25) foot buffer zone shall be parallel to and surveyed from the edge of the wetland on a horizontal plane; for the purposes of protection the buffer zone shall be subject to the same regulations that apply to the filling and uses of wetlands.
3. The minimum dry land area must be contiguous and sufficient in size and configuration to adequately accommodate all required utilities such as sewage disposal and water supply, and leach field locations. This minimum contiguous dry land area shall be the required building site
with accommodating utilities thereon. All contiguous areas shall be a minimum of fifty (50) feet in width in order to be considered contiguous. (Adopted March 11, 2008)
F. Minimum Lot Size (Adopted March 10, 1992)
In areas not served by public water and sewer and where there are wetlands and/or steep slopes, the area of contiguous non-group 5, poorly drained soils, or non-group 6 soils, floodplain or very poorly drained soils, shall meet the following requirements:
1. Single-family homes with four bedrooms or less shall have 68,000 square feet with a slope less than 8%, 76,000 square feet with a slope 8 - 15%, or 86,000 square feet with a slope more than 15% and less than 25%
2. Single family homes with more than four bedrooms shall have 15% more area for each additional bedroom over and above that required for four-bedroom, single-family homes.
3. Duplex dwellings with a total of not more than five bedrooms shall have 95,000 square feet with a slope less than 8%, 100,000 square feet with a slope 8 - 15% or 120,000 square feet with a slope more than 15% and less than 25%.
4. Duplex dwellings with more than five (5) bedrooms shall have 15% more area for each additional bedroom over and above that required for a five-bedroom, duplex dwelling. (Adopted March 13, 2007)
Note: A variance may be granted based on the results of a High Intensity Soil Survey and the Model Subdivision Regulations for Soil Based Lot Size, Rockingham County Conservation District, June 1991.
G. Special Use Permit (Adopted March 10, 2005, Amended March 9, 2010)
The following uses are permitted within the Wetlands District only after obtaining a Special Use Permit from the Planning Board. All such uses must comply with other applicable ordinances and regulations of the Town of Antrim as well as state and federal regulations. In granting the Special Use Permit, the Planning Board may impose conditions to the extent the Board concludes such conditions are necessary to minimize any adverse affect of the proposed use on adjoining properties, and preserve the intent of this Ordinance. The Planning Board shall act upon the application in accordance with the procedural requirements of the Site Plan Review Regulations and RSA 676:4. This ordinance is an innovative land use control subject to the exclusive jurisdiction of the Planning Board.
1. Streets, roads and other access ways, utility right-of-way easements, including power lines and pipelines, if so located and constructed to minimize any detrimental impact of such uses upon the wetland.
2. Water impoundments.
3. The undertaking of a use not otherwise permitted in wetlands (that is not already listed in Section D of this Article), if it can be shown that it meets the purposes and intentions listed in Section A of this Article.
In granting the Special Use Permit, the Planning Board shall consider the following:
1. The Special Use Permit shall be conditioned upon the granting of a permit to cross the wetland issued by the New Hampshire Department of Environmental Services Wetlands Bureau.
2. Reports submitted by the Conservation Commission and the Water and Sewer Department if located in the Water and Sewer District prior to the public hearing or thirty (30) days having elapsed following referral to said commission and department without receipt of report.
3. All possibilities for the avoidance of the wetlands have been exhausted short of denying the creation of a legal building lot which meets all zoning requirements for the district.
4. The disturbance of the 25-foot buffer zone will not adversely affect the property involved or any abutting properties by creating a drainage problem.
5. Where water and other effluents leave a man-made drainage system, adequate measures, including but not limited to buffer zones and natural treatment swales, shall be provided to protect the wetland from pollution, erosion, or siltation.
6. Adequate erosion control, including but not limited to haybales, silt fences, and temporary rip-rap, shall be maintained before, during, and after construction (until site stabilization) to protect undisturbed wetland areas from intrusion and siltation.