A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to activities involving land under the ocean are necessary and proper for the following reasons: Land under the ocean provides feeding areas, spawning and nursery grounds, and shelter for many coastal organisms related to marine fisheries and wildlife. Destruction of eelgrass beds (Zostera marina) will harm scallop production. Eelgrass beds also buffer against climate change by sequestering carbon and diminishing wave energy during storms. Nearshore areas, and in some cases offshore areas, of land under the ocean help reduce storm damage, erosion, and flooding by diminishing and buffering the high-energy effects of storms. Submerged sand bars dissipate wave energy. Such areas provide a source of sediment for seasonal rebuilding of coastal beaches and dunes. The bottom topography and sediment type of nearshore areas of land under the ocean are critical to erosion control, storm damage protection, flood control and resiliency. Water circulation and flushing rates, distribution of grain size, water quality (including but not limited to turbidity, temperature, nutrients, pollutants, salinity, and dissolved oxygen), and the habitat of wildlife, finfish, and shellfish are all factors critical to the protection of significant wildlife habitat and marine fin and shell fisheries. Land under the ocean in an unobstructed state is important to recreational swimming, fishing, and shellfishing, to recreational boating and sailing, to commercial fishing and shellfishing, and to wetland scenic views.
(2) 
Disturbance to benthic habitats have been shown to impact the following interests of the Wetlands Protection Act:
(a) 
Protection of wildlife habitat.
(b) 
Protection of marine fisheries (particularly juvenile cod and other species).
(c) 
Protection of land containing shellfish.
(d) 
Storm damage prevention.
(3) 
The maintenance of the productive benthic habitats not only assures the continuance of the habitats themselves, but also plays a direct role in supporting fish and shellfish stocks by providing a major food source. The young shellfish in the planktonic larval stage that are produced in large quantities during spring and summer are an important source of food for the young stages of marine fishes and many crustaceans. When a resource area is found to be significant to the protection of land containing shellfish under 310 CMR 10.34(3), and is also significant to marine fisheries, the following factors are critical to the protection of those interests:
(a) 
Shellfish;
(b) 
Water quality;
(c) 
Water circulation; and
(d) 
The natural relief, evaluation or distribution of sediment grain size of such land.
(4) 
Under 310 CMR 10.25, the jurisdiction of the Conservation Commission extends into the nearshore areas of land under the ocean, extending seaward to a point where the land is at a depth of 40 feet below the level of the ocean at mean low water in Cape Cod Bay, and to a depth of 80 feet below mean low water in all other areas.
(5) 
Under 310 CMR 34(4), “any [activity on] land containing shellfish shall not adversely affect such land or marine fisheries by a change in the productivity of such land caused by:
(a) 
Alterations of water circulation.
(b) 
Alterations in relief elevation.
(c) 
The compacting of sediment by vehicular traffic.
(d) 
Alterations in the distribution of sediment grain size.
(e) 
Alterations in natural drainage from adjacent land, or changes in water quality, including, but not limited to, other than natural fluctuations in the level of salinity, dissolved oxygen, nutrients, temperature or turbidity, or the addition of pollutants.
(6) 
No activity may adversely affect land containing shellfish in the following manner:
(a) 
The turbulence generated by hydraulic dredging significantly increases turbidity levels. High turbidity levels attenuate light, which is necessary for photosynthetic process responsible for the primary productivity and oxygen regeneration of the water.
(b) 
The suspended sediments settle on shellfish beds, smothering existing shellfish and altering the quality of the benthic environment essential for spat (mollusk larvae) settlement.
(c) 
Resuspension of bottom sediments causes redistribution of sediments, alteration in sediment grain size distribution and causes changes in bottom topography relief, elevation and grade, including the creation of depressions in the bottom. Settlement of sediments into depressions can create deep pockets of highly fluid like sediment which may not be able to physically support shellfish or which can become anoxic and therefore not support shellfish.
(d) 
Disturbance of sediments during the period of shellfish larval settlement hinders or prevents the effective settlement of shellfish larvae. Hydraulic dredging has also been shown to adversely impact the interest of storm damage prevention, by uprooting vegetation and undermining the stability of land under the ocean. The underwater “terrace” contours of the trenches created by hydraulic dredging contributes to erosion of the adjacent beach, coastal dunes and banks during storm events.
(7) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering or building upon land under the ocean, the Commission shall find that such land is significant to the protection of the following interests: flood control, erosion control, storm damage prevention, fisheries, shellfish, wildlife, significant wildlife habitat, recreation, resiliency and wetland scenic views. These findings may be overcome only upon a clear showing that the land under the ocean does not play a role in protecting any of the interests given above and only upon a specific written determination to that effect by the Commission.
B. 
Performance standards. Land under the ocean shall be presumed significant to an interest protected by the Bylaw as referenced in Subsection A; therefore, the following regulations apply:
(1) 
Dredging shall be designed and carried out using the best available measures as determined by the Commission so as to have the least possible adverse effects or changes in marine productivity caused by changes in, or resulting from suspension or transport of pollutants, sediment transport, smothering of bottom organisms, accumulation of pollutants by organisms, destruction of habitat or nutrient source areas, or changes in water circulation and water quality.
(2) 
All dredging shall use best available measures to minimize adverse effects caused by changes in bottom topography resulting in an increase in height and velocity of waves hitting the shore, localized changes in circulation patterns or in changes in sediment transport which affect natural replenishment of beaches or maintenance of channels.
(3) 
Residential piers shall be constructed so as not to change shoreline movement of sediment, harm shellfish resources, obstruct commercial shellfishing, or obstruct the reserved public rights of fishing, fowling, navigation, or passage. Residential piers shall be constructed so as to withstand projected sea level rise and associated impacts based on the best available scientific data and modeling during the cradle-to-grave life of the structure. Residential piers shall not displace public moorings without written approval from the Harbormaster. No solid-fill piers shall be permitted.
(4) 
Construction of commercial piers shall be in compliance with Chapter 139, Zoning, of the Code of the Town of Nantucket and shall not affect sediment transport, and shall not destroy or pollute fisheries and shellfish habitat or nutrient source areas for those resources. Commercial piers shall be constructed so as to withstand projected sea level rise and associated impacts based on the best available scientific data and modeling during the cradle-to-grave life of the structure. No solid-fill piers or new residential piers shall be permitted.
(5) 
Best available measures, as determined by the Commission, shall be used to minimize adverse effects of a commercial or residential pier on the interests protected by the Bylaw.
(6) 
Aquaculture projects shall be undertaken pursuant to such means as may be established by the Commission so as to have the least possible adverse effect on wildlife, erosion control, storm damage prevention, flood control, recreation, resiliency or public access. No destruction of habitat or areas where shellfish feed, or change in water quality or circulation in any manner which adversely affects productivity of marine fisheries or shellfish beds shall be permitted.
(7) 
No new bulkheads, groins or coastal engineering structures shall be permitted to protect structures constructed or substantially improved after August 1978. Bulkheads may be rebuilt only if the Commission determines there is no environmentally better way to control an erosion problem. An alternatives analysis must examine living shorelines or in appropriate cases the moving of the threatened building. If either of these methods is feasible then the bulkhead or groin may not be rebuilt. Other coastal engineering structures may be permitted only upon a clear showing that no other alternative exists to protect a structure built prior to September 1978, but not substantially improved, from imminent danger. The use of any or all forms of coastal engineering structures requires an appropriate annual mitigation plan and implementation to ensure no adverse impacts as set forth by the Commission. Mitigation shall reflect current and future needs to ensure no adverse impacts.
(8) 
Water-dependent projects shall be designed and performed so as to cause no adverse effects on wildlife, erosion control, marine fisheries, shellfish beds, storm damage prevention, flood control, recreation, resiliency and aquatic vegetation.
(9) 
No activity that disturbs benthic habitats shall occur within the waters under the jurisdiction of the Nantucket Conservation Commission without a proper filing before the Conservation Commission.
(10) 
Taking of shellfish or finfish by mechanical means including but not limited to trawls, drags, rakes and hydraulic gear with the assistance of machinery is prohibited within Nantucket waters. This does not include the use of bay scallop dredges, manual rakes or other hand-operated devices for the collection of shellfish or baitfish with or without the use of scuba gear.
(11) 
No activity on land under the ocean which is not water-dependent shall be permitted by the Commission, except activity allowed pursuant to a waiver from these regulations, as set forth in § 390-3F.
(12) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to activities involving coastal beaches and tidal flats are necessary and proper for the following reasons: Coastal beaches and tidal flats aid in storm damage prevention, erosion and flood control; and coastal resilience in buffering inland areas from climate change impacts including but not limited to sea-level rise and increased storm frequency; serve as a source of sediment for downdrift coastal resource areas; serve to provide wildlife habitat to rare, endangered, and otherwise significant wildlife; serve to protect and provide habitat for marine fisheries and shellfish; and serve to provide important wetland scenic views and recreation. Coastal beaches dissipate wave energy by their gentle slope, their permeability, and their granular nature, which permit changes in beach form in response to changes in wave conditions. Coastal beaches serve as a sediment source for dunes and subtidal areas. Steep storm waves cause beach sediment to move offshore, resulting in a gentler beach slope and greater energy dissipation. Less steep waves cause an onshore return of beach sediment, where it will be available to provide protection against future storm waves. A coastal beach at any point serves as a sediment source for coastal areas downdrift from that point. The oblique approach of waves moves beach sediment alongshore in the general direction of wave action. Thus, the coastal beach is a body of sediment which is moving along the shore. Coastal beaches serve the purpose of storm damage prevention, erosion control, and flood control by dissipating wave energy, by reducing the height of storm waves, and by providing sediment to supply other coastal features, including coastal dunes, land under the ocean, and other coastal beaches. As relative sea level continues to rise, and possibly accelerate as predicted, it is important to provide source material to allow these inter-tidal and sub-tidal areas to vertically accrete and continue to reduce storm damage, increase flood control, protection of land containing shellfish, and protection of wildlife habitat. Interruptions of these natural processes by man-made structures and/or activities reduce the ability of the coastal beach to perform these functions. Tidal flats are important to the protection of marine fisheries because they provide habitats for marine organisms, such as polychaete worms and mollusks, which in turn are food sources for fish. Tidal flats are also sites where organic and inorganic materials are entrapped and then returned to the photosynthetic zone of the water column to support algae and other primary producers of the marine food web. Coastal beaches and flats serve as important habitats for a wide variety of wildlife, including but not limited to coastal birds, turtles, shellfish and finfish. In particular, they are used by coastal birds for feeding areas and nesting sites. The natural erosional and depositional cycles, sediment grain size, water quality (including but not limited to turbidity, temperature, nutrients, pollutants, salinity, and dissolved oxygen) and circulation, and elevation of the land surface are all features of wildlife habitat which are critical characteristics for the protection of wildlife. Characteristics of coastal beaches and flats which are critical to the protection of marine fisheries, and shellfish and their habitat include: distribution of sediment grain size, movement of sediment, water quality (including the characteristics given above) and circulation, and beach relief and elevation. Characteristics of coastal beaches and flats which are critical to storm damage prevention, erosion control, or flood control and coastal resilience include sediment volume and form, their ability to respond to wave action, natural erosional and depositional cycles, and wave intensities. Characteristics of coastal beaches and flats which are critical to recreation are topography, sediment grain size, water quality (including the characteristics given above), water circulation rates and patterns, unobstructed access along shore, natural erosional and depositional cycles, and wave intensity. Characteristics of coastal beaches which are critical to wetland scenic views are natural erosion and deposition cycles, relief and elevation, sense of openness, and solitude. Land within 100 feet of a coastal beach or tidal flat is considered to be important to the protection and maintenance of coastal beaches and tidal flats, and therefore to the protection of the wetland values which these areas contain.
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering, or building upon a coastal beach or flat, the Commission shall find that the beach or flat is significant to the protection of the following interests: flood control, erosion control, storm damage prevention, fisheries, shellfish, wildlife, recreation, resiliency and wetland scenic views. These findings may be overcome only upon a clear showing that the beach or flat does not play a role in protecting any of the interests given above and upon only a specific written determination to that effect by the Commission.
B. 
Performance standards. A coastal beach, tidal flat or land within 100 feet of a coastal beach or tidal flat shall be presumed significant to the interests protected by the Bylaw, as referenced in Subsection A; therefore, the following regulations shall apply:
(1) 
The provisions of § 390-6B(1) through (8) (regarding land under the ocean) shall apply to coastal beaches and tidal flats.
(2) 
No new bulkheads, groins or coastal engineering structures shall be permitted to protect structures constructed, or substantially improved, after August 1978. Bulkheads may be rebuilt only if the Commission determines there is no environmentally better way to control an erosion problem. An alternatives analysis must examine a green infrastructure alternative such as a living shoreline or in appropriate cases the moving of the threatened building. If either of these methods is feasible then the bulkhead or groin may not be rebuilt. Other coastal engineering structures may be permitted only upon a clear showing that no other alternative exists to protect a structure built prior to September 1978, and not substantially improved, from imminent danger. The use of any and all forms of coastal engineering structures requires an appropriate annual mitigation plan and implementation to ensure no adverse impacts as set forth by the Commission. Mitigation shall reflect current and future needs to ensure no adverse impacts to the littoral system or adjacent coastal beach and/or coastal dunes.
(3) 
Dredging projects in flats must be done in accordance with such procedures as the Commission determines would disturb the absolute minimum amount of habitat possible for both the borrow site and the area in which spoils are placed.
(4) 
Clean fill of compatible grain size may be used on a coastal beach but not on a tidal flat, only if the Commission authorizes its use, and only if such fill is to be used for a beach or dune nourishment project. All possible mitigation measures shall be taken, as determined by the Commission, to limit the adverse effects of the fill.
(5) 
No part of any septic system shall be placed in shifting sands or on a coastal beach. The septic leach facility shall be at least 100 feet from the spring high tide line.
(6) 
Proposed projects which are not water-dependent shall maintain a 25-foot undisturbed buffer zone with no greater than 50% of the area between the 25-foot buffer zone and 50-foot setback disturbed. All structures which are not water-dependent shall be located at least 75 feet from a coastal beach.
Exception: Structures shall be permitted down to the 50-foot setback provided that the undisturbed buffer zone is enhanced by 1.5X the structural area between the 50-foot setback and 75-foot setback in a manner contiguous with the undisturbed buffer zone. Any constructed bioswale shall count against this area so long as it is contiguous with the original undisturbed buffer zone. All structures in existence at the enactment of this performance standard will only be required to meet this requirement upon any expansion of the structure based on the area of expansion.
(7) 
In areas of eroding shoreline, the distance from all buildings to the coastal beach shall be at least 20 times the average annual shoreline erosion or 100 feet, whichever is less. The average annual shoreline erosion rate shall be determined by averaging the annual erosion rate over a 150-year period ending the date the NNOI was filed or, if no NNOI was filed, the date construction began. If erosion data are not available for the 150-year period, the Commission shall determine the average annual erosion rate from such lesser time period for which erosion data is available. A second annual average annual shoreline erosion rate shall be determined by averaging the annual erosion rate over a ten-year period ending the date the NOI was filed, or if no NOI was filed, the date construction began to determine if erosion has accelerated. If erosion has accelerated over the contemporary time period, the higher erosion rate shall be used to determine mitigation requirements for the application. In cases where documentation can be provided to show that the use of the ten- or 150-year period is inappropriate to existing shoreline characteristics and trends, alternate shoreline change rates may be used when based on a preponderance of credible evidence.
(8) 
Vehicular access for existing houses or for recreational use shall be as unpaved ways and shall be done in accordance with such procedures as the Commission determines will minimize any adverse effect on the beach and the interests of the Bylaw.
(9) 
Fertilizers shall be used in accordance with the Best Management Practices for Landscape Fertilizer Use on Nantucket Island (a copy of which is attached to these regulations as Appendix A[1]).
[1]
Editor's Note: Appendix A is included as an attachment to this chapter.
(10) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to activities involving coastal dunes are necessary and proper for the following reasons: Coastal dunes, including coastal dune fields, aid in storm damage prevention, erosion and flood control; protect land in coastal areas from storm damage and flooding; serve as a sediment source for beach and intertidal areas; serve to provide wildlife habitat to rare, endangered, and otherwise significant wildlife; and serve to provide important wetland scenic views and recreation. Coastal dunes aid in storm damage prevention, erosion control, and flood control by supplying sand to coastal beaches. Coastal dunes do not significantly inhibit transport of pollutants into groundwater. Coastal dunes protect inland coastal areas from storm damage and flooding by storm waves and elevated sea levels because such dunes are higher than the coastal beaches which they border. Vegetated cover contributes to the growth and stability of coastal dunes by providing conditions favorable to sand deposition. On retreating shorelines, the ability of coastal dunes bordering a coastal beach to move landward at a rate of shoreline retreat allows these dunes to maintain their form and volume. Characteristics of coastal dunes which are critical for storm damage prevention, flood control, and erosion control include: ability of the dune to erode and change in response to coastal beach conditions; dune volume, sediment grain size, and slope; dune form, which can change with wind and natural water flow; amount, continuity, and density of vegetative cover; wildlife habitat and ability of a dune to move landward and laterally. Coastal dunes are important habitats for a wide variety of wildlife, particularly turtles and birds for feeding and nesting areas. The amount of vegetation, dune height and slope, sediment grain size, and degree of isolation from human-caused disturbances are all features of dunes which are critical characteristics for the protection of wildlife. Characteristics of coastal dunes which are critical to wetland scenic views are dune form, slope, elevation, size of dunefield, proportion and scale of dunes in relationship with other land forms. Land within 100 feet of a coastal dune is considered to be significant to the protection and maintenance of coastal dunes, and therefore to the protection of the wetland values which these areas contain.
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering or building upon a coastal dune, the Commission shall find that the dune is significant to the protection of the following interests: flood control, erosion control, storm damage prevention, prevention of pollution, resiliency, wildlife, and wetland scenic views. These findings may be overcome only upon a clear showing that the dune does not play a role in protecting any of the interests given above and only upon a specific written determination to that effect by the Commission.
B. 
Performance standards. A coastal dune, coastal dune field, or land within 100 feet of a coastal dune or coastal dune field shall be presumed significant to the interests protected by the Bylaw as referenced in Subsection A; therefore, the following regulations shall apply:
(1) 
No coastal revetments or coastal engineering structures of any type shall be constructed, rebuilt, or repaired.
(2) 
Proposed projects which are not water-dependent shall maintain a 25-foot undisturbed buffer zone with no greater than 50% of the area between the 25-foot buffer zone and 50-foot setback disturbed. All structures which are not water-dependent shall be located at least 75 feet from a coastal dune.
Exception: Structures shall be permitted down to the 50-foot setback provided that the undisturbed buffer zone is enhanced by 1.5X the structural area between the 50-foot setback and 75-foot setback in a manner contiguous with the undisturbed buffer zone. Any constructed bioswale shall count against this area so long as it is contiguous with the original undisturbed buffer zone. All structures in existence at the enactment of this performance standard will only be required to meet this requirement upon any expansion of the structure based on the area of expansion.
(3) 
No excavation or disturbance of vegetative cover shall be allowed on a coastal dune unless the area is completely restored, replanted, and stabilized to its original form and volume.
(4) 
Fill may be used only if the Commission authorizes its use and only if such fill is to be used for beach and dune nourishment projects.
(5) 
No part of any septic system shall be placed in shifting sands or on or in a coastal dune. The septic leach facility shall be at least 100 feet from the upland edge of a coastal dune or coastal dune field.
(6) 
Any activity allowed on a coastal dune or within 100 feet of a dune shall be restricted to such activity that is determined by the Commission not to have any adverse effect on the dune by altering the ability of wind or waves to remove sand from or deposit sand on a dune; by disturbing vegetative cover in a manner sufficient to destabilize the dune; by causing any modification of the dune form and slope which would increase the potential for erosion, storm or flood damage; by interfering with landward or lateral movement of the dune; or by causing the rate of sand removal to increase through man-made means or structures.
(7) 
No activity shall be permitted, other than the maintenance and repair of a structure existing on the effective date of these regulations, that will result in construction of a building upon a coastal dune or within 50 feet of any coastal dune.
(8) 
Any pedestrian or elevated walkway must be designed as determined by the Commission so as to minimize disturbances of vegetative cover.
(9) 
Fertilizers shall be used in accordance with the Best Management Practices for Landscape Fertilizer Use on Nantucket Island" (a copy of which is attached to these regulations as Appendix A[1]).
[1]
Editor's Note: Appendix A is included as an attachment to this chapter.
(10) 
Vehicular access for existing homes or recreational use shall be as unpaved ways and shall be done in accordance with such procedures as the Commission determines will minimize any adverse effect on the dune and the interests of the Bylaw.
(11) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to activities involving barrier beaches are necessary and proper for the following reasons: Barrier beaches are composed of tidal flats, beaches, and dunes. As such, barrier beaches perform the same functions and are critical to the same interests as referenced in § 390-7 and § 390-8 of these regulations and therefore these provisions shall also apply to barrier beaches. Barrier beaches protect landward areas from flooding and erosion because they provide a buffer to storm waves and to sea levels elevated by storms. Barrier beaches protect from wave action such highly productive areas as dunes, tidal flats, salt marshes, estuaries, lagoons, harbors, salt ponds, and freshwater marshes and ponds, which are in turn important to fisheries, shellfish and wildlife habitat. Barrier beaches are maintained by the alongshore movement of beach sediment caused by wave action. The coastal dunes, beaches, and tidal flats of a barrier beach are made up of sediment supplied by wind action, storm wave overwash, and tidal inlet deposition. Barrier beaches in Massachusetts undergo a landward or alongshore migration caused by the landward and alongshore movement of sediment by wind, storm waves, and tidal current processes. The continuation of these processes maintains the volume of the landform which is necessary to carry out its storm and flood buffer functions. The ability of barrier beaches to respond to wave action, including storm overwash sediment transport, is critical to the protection of wetlands values of barrier beaches.
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering or building upon a barrier beach, the Commission shall find that the barrier beach is significant to the protection of the following interests: flood control, erosion control, resiliency, water pollution, storm damage prevention, fisheries, shellfish, wildlife habitat, recreation, and wetland scenic views. Barrier beaches shall be found significant to private water supply and groundwater if there are existing houses with wells on or near the barrier beach or if the barrier beach abuts, creates, or protects a swamp, freshwater marsh, or pond. These findings may be overcome only upon a clear showing that the barrier beach does not play a role in protecting any of these interests given above and only upon specific written determination to that effect by the Commission.
B. 
Performance standards. A barrier beach or land within 100 feet of a barrier beach shall be presumed significant to the interests protected by the Bylaw as referenced in Subsection A; therefore, the following regulations shall apply:
(1) 
No coastal revetments or coastal engineering structures of any type shall be constructed, rebuilt, or repaired.
(2) 
Fill may be used only if the Commission authorizes its use and only if such fill is to be used for beach or dune nourishment projects.
(3) 
No septic system or buildings shall be constructed on a barrier beach. Buildings which pre-exist these regulations may be maintained and repaired. Existing septic systems may be maintained, repaired and upgraded to the best available measures. No expansion of septic systems shall be permitted.
(4) 
Excavation of sand around existing houses may be permitted, but no new projects shall be permitted which will require periodic sand removal for maintenance. All disturbed areas (including blowouts) shall be stabilized through planting of vegetation. The evacuated sand must be retained in the area and be part of the barrier beach.
(5) 
Vehicular access for existing houses or for recreational use shall be unpaved roads and shall be done in accordance with such procedures as the Commission determines will minimize any adverse effect on the barrier beach.
(6) 
No excavation or disturbance of vegetation shall be permitted on a barrier beach unless the area is completely restored, replanted, and stabilized to its original form and volume.
(7) 
Fertilizers shall be used in accordance with the Best Management Practices for Landscape Fertilizer Use on Nantucket Island (a copy of which is attached to these regulations as Appendix A[1]).
[1]
Editor's Note: Appendix A is included as an attachment to this chapter.
(8) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to activities involving coastal banks are necessary and proper for the following reasons: Coastal banks may serve as a source of sediment for other coastal landforms, including beaches, dunes, tidal flats, barrier beaches, and land under the ocean; act as a vertical buffer which protects upland areas from storm damage, erosion, and flooding; provide wildlife habitat to common as well as rare, endangered, and otherwise significant wildlife; and serve to provide important wetland scenic views. Coastal banks composed of unconsolidated sediment and exposed to wave action serve as a major source of sediment for other coastal landforms, including beaches, dunes, and barrier beaches. The supply of sediment is removed from banks by wave action. It is a naturally occurring process necessary to the continued existence of coastal beaches, coastal dunes, and barrier beaches. These areas dissipate storm wave energy, thus protecting structures and coastal wetlands landward of them from storm damage, erosion, and flooding. Coastal banks, because of their height and stability, may act as a buffer or natural wall, which protects upland areas from storm damage, erosion, and flooding. While erosion caused by wave action is an integral part of shoreline processes and furnishes important sediment to downdrift landforms, erosion of a coastal bank by wind and rain runoff, which plays a minor role in beach nourishment, should not be increased unnecessarily. Disturbances to a coastal bank which reduce its natural resistance to wind and rain erosion cause cuts and gullies in the bank, and decrease its value as a buffer. As relative sea level continues to rise, and possibly accelerate, Coastal Banks’ role in providing sediment to inter- and sub-tidal areas, and as a physical barrier to storm damage, flood control, and protection of wildlife habitat also increases. Vegetation tends to stabilize a coastal bank and reduce the rate of erosion due to wind and rain runoff. Vegetated banks are critical to reducing wind and rain erosion and for providing important habitat and biodiversity. A particular coastal bank may serve both as a sediment source and as a buffer or it may serve only one role. Coastal banks provide habitat for wildlife, particularly nesting birds. Characteristics of coastal banks which are critical to wildlife are bank steepness, height, stability, soil size and compaction, and vegetative cover and diversity. Characteristics of coastal banks that are critical to wetland scenic views are bank form, slope, elevation, proportion and scale in relationship to other landforms, vegetative characteristics and diversity, wildlife and habitat, and a sense of presence and solitude. All coastal banks are defined as primary coastal banks for the purposes of Town of Nantucket bylaws.
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering, or building upon a coastal bank, the Commission shall find that the bank is significant to the protection of the following interests: flood control, erosion control, resiliency, storm damage prevention, wetland scenic views, and wildlife. These findings may be overcome only upon a clear showing that the coastal bank does not play a role in protecting any of the interests given above and only upon a specific written determination to that effect by the Commission.
B. 
Performance standards. Coastal banks or land within 100 feet of a coastal bank shall be presumed significant to the interests protected by the Bylaw as referenced in Subsection A; therefore, the following regulations shall apply:
(1) 
No new bulkheads, coastal revetments, groins, or other coastal engineering structures shall be permitted to protect structures constructed, or substantially improved, after August 1978. Bulkheads and groins may be rebuilt only if the Commission determines there is no environmentally better way to control an erosion problem. An alternatives analysis must examine living shorelines or in appropriate cases the moving of the threatened building or infrastructure. If either of these methods is feasible then the bulkhead or groin may not be rebuilt. Other coastal engineering structures may be permitted only upon a clear showing that no other alternative exists to protect a structure that has not been substantially improved or public infrastructure built prior to September 1978 from imminent danger. The mitigation provided for use of any structure to protect against erosion must have no adverse impact on adjoining coastal beach, coastal dune, barrier beach, or coastal banks.
(2) 
Piers shall be constructed in compliance with Chapter 139, Zoning, of the Code of the Town of Nantucket using procedures determined by the Commission to be the best available measures to minimize adverse effects on interests protected by the Bylaw.
(3) 
All projects shall be restricted to activity as determined by the Commission to have no adverse effect on bank height, bank stability, wildlife habitat, vegetation, wetland scenic view, or the use of a bank as a sediment source.
(4) 
Elevated walkways designed not to affect bank vegetation shall be required for pedestrian passage over a bank.
(5) 
Proposed projects which are not water-dependent shall maintain a 25-foot undisturbed buffer zone with no greater than 50% of the area between the 25-foot buffer zone and 50-foot setback disturbed. All structures which are not water-dependent shall be located at least 75 feet from a coastal bank.
Exception: Structures shall be permitted down to the 50-foot setback provided that the undisturbed buffer zone is enhanced by 1.5X the structural area between the 50-foot setback and 75-foot setback in a manner contiguous with the undisturbed buffer zone. Any constructed bioswale shall count against this area so long as it is contiguous with the original undisturbed buffer zone. All structures in existence at the enactment of this performance standard will only be required to meet this requirement upon any expansion of the structure based on the area of expansion.
(6) 
The septic leach facility of a septic system shall be constructed at least 100 feet from the top of the coastal bank and shall not be located within the face of the coastal bank.
(7) 
In areas of an eroding coastal bank, the distance from all new structures to the coastal bank shall be at least 20 times the average annual erosion rate or 100 feet, whichever is lesser. The average annual erosion rate shall be determined by averaging the annual erosion over a 150-year period ending with the date the NOI was filed or, if no NOI was filed, the date construction began. If erosion data are not available for the 150-year period, the Commission shall determine the average annual erosion rate from such lesser time for which erosion data is available. A second annual average annual shoreline erosion rate shall be determined by averaging the annual erosion rate over a ten-year period ending the date the NOI was filed, or if no NOI was filed, the date construction began to determine if erosion has accelerated. If erosion has accelerated over the contemporary time period, the higher erosion rate shall be used to determine mitigation requirements for the application. In cases where documentation can be provided to show that the use of the 150-year period is inappropriate to existing coastal shoreline characteristics and trends, alternate shoreline change rates may be used with the approval of the Commission.
(8) 
All permits issued for the substantial improvement of an existing building or new construction of buildings under the Bylaw within 100 feet landward of the top of a coastal bank shall contain the specific condition that no coastal engineering structure of any kind shall be permitted on an eroding bank in the future to protect the project allowed by this permit, except those coastal engineering structures allowed by a waiver issued pursuant to § 390-3F of these regulations.
(9) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to activities involving salt marshes are necessary and proper for the following reasons: Salt marshes serve to support marine organisms, including finfish and shellfish; serve to provide critical wildlife habitat; serve to remove pollutants from surrounding waters; serve to aid in erosion control and storm damage prevention; and are important to fishing, shell fishing, recreation, and wetland scenic views. A salt marsh produces large amounts of organic matter. A significant portion of this material is exported as detritus and dissolved organics to estuarine and coastal waters, where it provides the basis for a large food web that supports many marine organisms, including finfish and shellfish. Salt marshes also provide spawning and nursery habitat for several important estuarine forage finfish. Salt marsh plants and substrate remove pollutants from surrounding waters. The network of salt marsh vegetation roots and rhizomes binds the sediments together. The sediments absorb chlorinated hydrocarbons and heavy metals such as lead, copper, and iron. The marsh also helps retain nitrogen and phosphorous compounds which can cause algal blooms and changes in ocean plankton and plant communities, particularly eelgrass. The underlying peat serves as a barrier between fresh groundwater landward of the marsh and the ocean, thus helping to maintain the level of the groundwater. Salt marsh cord grass and underlying peat are resistant to erosion and dissipate wave energy, thereby providing a buffer that reduces wave damage and coastal erosion. A saltmarsh is an important feeding and spawning area for many types of fish and aquatic and terrestrial wildlife. The marsh, including its creeks and open water, also provides important shelter for many aquatic and migratory birds. Marshes help absorb pollutants, but there is a careful balance of nutrients and pollutant input which, if exceeded, will result in accumulation of pollutants and/or changes in the marsh community. Because the marsh is the basis for such a large food web, bioaccumulations of pollutants and toxins can mean that relatively low levels of pollutants may be detrimental. Some of the characteristics of salt marshes which are critical to their health and ability to protect wetland values include: the growth, composition, and distribution of salt marsh vegetation; the amount of flow and level of both tidal and fresh water; the water quality (including but not limited to turbidity, temperature, nutrients, pollutants, salinity, and dissolved oxygen) of both tidal and fresh water; the presence and depth of peat; rate of marsh productivity; and the diversity of the animals and plants making up the marsh community. Salt marshes provide excellent areas for bird watching, canoeing, and hunting. The ability for salt marshes to migrate landward as sea levels rise is critical to enhancing the resiliency of coastal areas. Characteristics of salt marshes that are critical to wetland scenic views are water quality, vegetative characteristics, and a sense of presence, expanse and biodiversity.
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering, or building upon a salt marsh, the Commission shall find that the salt marsh is significant to the protection of the following interests: groundwater, erosion control, storm damage prevention, water pollution prevention, fisheries, shellfish, resiliency, wildlife, recreation, and wetland scenic views. These findings may be overcome only upon a clear showing that the salt marsh does not play a role in protecting any of the interests given above and only upon a specific written determination to that effect by the Commission.
B. 
Performance standards. Salt marshes or land within 100 feet of salt marshes shall be presumed significant to the interests protected by the Bylaw as referenced in Subsection A; therefore, the following regulations shall apply:
(1) 
Salt marshes shall not be filled.
(2) 
Salt hay may be harvested from a salt marsh only if performed in a manner which does not disturb the marsh substrate.
(3) 
No proposed project in a salt marsh, or in lands within 100 feet of a salt marsh, shall destroy any portion of the salt marsh, change species composition of the marsh, have any adverse effect on salt marsh productivity, pollute the salt marsh, or adversely affect water quality.
(4) 
Proposed projects which are not water-dependent shall maintain a 25-foot undisturbed buffer zone with no greater than 50% of the area between the 25-foot buffer zone and 50-foot setback disturbed. All structures which are not water-dependent shall be located at least 75 feet from a salt marsh.
Exception: Structures shall be permitted down to the 50-foot setback provided that the undisturbed buffer zone is enhanced by 1.5X the structural area between the 50-foot setback and 75-foot setback in a manner contiguous with the undisturbed buffer zone. Any constructed bioswale shall count against this area so long as it is contiguous with the original undisturbed buffer zone. All structures in existence at the enactment of this performance standard will only be required to meet this requirement upon any expansion of the structure based on the area of expansion.
(5) 
The septic leach facility of a septic system shall be at least 100 feet from the salt marsh.
(6) 
Piers shall be constructed and maintained using procedures determined by the Commission to be the best available measures to minimize adverse effects on the interests protected by the Bylaw.
(7) 
Elevated walkways shall be designed not to affect marsh vegetation or existing water circulation patterns.
(8) 
Materials cannot be stored or deposited on a salt marsh.
(9) 
Fertilizers shall be used in accordance with the Best Management Practices for Landscape Fertilizer Use on Nantucket Island (a copy of which is attached to these regulations as Appendix A[1]).
[1]
Editor's Note: Appendix A is included as an attachment to this chapter.
(10) 
A project which will restore or rehabilitate a salt marsh may be permitted; provided, however, that this section shall not be construed as to allow the alteration of one salt marsh on a given site by or contingent upon the restoration of another.
(11) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to the activities involving salt ponds are necessary and proper for the following reasons: Salt ponds provide excellent wildlife habitat. The high productivity of plants and phytoplankton provides food for shellfish, crustaceans, and juvenile fish. The bottom sediments and shallow water provide habitat for many bivalves. The ponds also serve as spawning and nursery areas for crabs and fish. The productivity of salt ponds and the food web they support provide ideal habitat for many types of wildlife, particularly various ducks and shore birds. The enclosed nature of the ponds also provides shelter for wildlife. Salt ponds and the area around them provide the public many recreational opportunities and wetland scenic views, including: shellfishing, fishing, sailing, swimming, hunting, and wildlife observation. Because of their semi-enclosed nature, salt ponds are sensitive to pollution or nutrient inputs. These inputs can change the plant and animal species composition of the pond, and thus can be detrimental to fish, shellfish and wildlife. Bioaccumulation through food webs can also create dangerous levels of pollutants or toxins for wildlife and humans. Characteristics of salt ponds which are critical to various wetland values include water circulation, distribution of sediment grain size, amount of freshwater and saltwater inflow, productivity of plants, and water quality (including but not limited to amounts of dissolved oxygen, nutrients, temperature, turbidity, pollutants, and salinity). Land within 100 feet of a salt pond is considered to be significant to the protection and maintenance of a salt pond and the land beneath it and therefore to the protection of the wetlands values of the pond.
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering, or building upon a salt pond, the Commission shall find that the salt pond is significant to the protection of the following interests: fisheries, shellfish, wildlife, recreation, and wetland scenic views. These findings may be overcome only upon a clear showing that the salt pond does not play a role in protecting any of the interests given above and only upon a specific written determination to that effect by the Commission.
B. 
Performance standards. A salt pond or land within 100 feet of a salt pond shall be presumed significant to the interests protected by the Bylaw as referenced in Subsection A; therefore, the following regulations shall apply:
(1) 
The work shall be done in accordance with procedures determined by the Commission to have no adverse effect on wildlife, fisheries, shellfish, existing water quality, recreation, or wetland scenic views and so as not to pollute the pond or alter the critical characteristics of salt ponds.
(2) 
Proposed projects which are not water-dependent shall maintain a 25-foot undisturbed buffer zone with no greater than 50% of the area between the 25-foot buffer zone and 50-foot setback disturbed. All structures which are not water-dependent shall be located at least 75 feet from a salt pond.
Exception: Structures shall be permitted down to the 50-foot setback provided that the undisturbed buffer zone is enhanced by 1.5X the structural area between the 50-foot setback and 75-foot setback in a manner contiguous with the undisturbed buffer zone. Any constructed bioswale shall count against this area so long as it is contiguous with the original undisturbed buffer zone. All structures in existence at the enactment of this performance standard will only be required to meet this requirement upon any expansion of the structure based on the area of expansion.
(3) 
The septic leach facility of a septic system shall be at least 100 feet from a salt pond.
(4) 
Projects designed to enhance a particular fishery or shellfish shall be designed in accordance with such procedures as the Commission determines will minimize adverse ecological effects on the salt pond, including adverse effects on plants and animals which are not the species targeted for management. If such management projects have adverse effects on any of the protected interests of the Bylaw, such projects shall be permitted only pursuant to a waiver, as set forth in § 390-3F of these regulations.
(5) 
Piers shall be constructed and maintained using procedures determined by the Commission to be the best available measures to minimize adverse effects on the interests protected by the Bylaw.
(6) 
Elevated walkways shall be designed not to affect vegetation or existing water circulation patterns. Elevated walkways shall be required to allow for pedestrian passage over the salt pond and fringing bordering vegetated wetlands.
(7) 
Fertilizers shall be used in accordance with the Best Management Practices for Landscape Fertilizer Use on Nantucket Island (a copy of which is attached to these regulations as Appendix A[1]).
[1]
Editor's Note: Appendix A is included as an attachment to this chapter.
(8) 
The Commission may impose such additional requirements as are necessary to protect the Interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that the regulations applicable to activities involving land containing shellfish are necessary for the following reasons: Shellfish are one of the interests protected by the Bylaw. Land containing shellfish is found within many of the areas protected by the Bylaw. In addition to the regulations for those resource areas as given above in these regulations, this section discusses additional protection for shellfish. Land containing shellfish and its habitat is important to the protection of marine fisheries in addition to the protection of shellfish. Shellfish on Nantucket are a very important recreational and commercial natural resource. Bay scallops, in particular, are an important economic resource on Nantucket. Shellfish used as a human food resource, as they are on Nantucket, need very clean, uncontaminated water, since they have the ability to concentrate very low levels of pollutants. Shellfish are a valuable renewable resource. The maintenance of productive shellfish beds not only assures the continuance of shellfish themselves but also plays a direct role in supporting fish stocks by providing a major food source. Characteristics of land containing shellfish which are critical to the protection of shellfish include, but are not limited to: wildlife habitat, water circulation patterns, rates of water flow, and amounts of water; the relief and elevation, distribution, grain size, and pollutant load of the sediments; and water quality (including turbidity, temperature, pollutants, nutrients, salinity, and dissolved oxygen).
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering, or building upon land containing shellfish or the water over land containing shellfish, the Commission shall find that the land containing shellfish is significant to the protection of the following interests: shellfish, fisheries, and recreation. These findings may be overcome only upon a clear and convincing showing that land containing shellfish does not play a role in protecting any of the interests given above and only upon a specific written determination to that effect by the Commission.
B. 
Performance standards. Land containing shellfish or land within 100 feet of land containing shellfish shall be presumed significant to the interests protected by the Bylaw as referenced in Subsection A; therefore, the following regulations shall apply:
(1) 
Projects shall not adversely affect water quality (including but not limited to changes in turbidity, temperature, salinity, dissolved oxygen, and additional nutrients and pollutants), water circulation, aquatic vegetation, or natural drainage from adjacent land.
(2) 
Land containing shellfish shall not be compacted by vehicular traffic or other means. The land's elevation and sediment grain size shall also not be altered.
(3) 
Projects shall not obstruct the ability of the public to gather shellfish recreationally or the ability of commercial fishermen to harvest shellfish.
(4) 
Any project which may release pollutants shall utilize the best available measures to remove pollutants or prevent risk of pollution.
(5) 
All septic leach facilities shall be at least 100 feet from land containing shellfish.
(6) 
Fertilizers shall be used in accordance with the Best Management Practices for Landscape Fertilizer Use on Nantucket Island (a copy of which is attached to these regulations as Appendix A[1]).
[1]
Editor's Note: Appendix A is included as an attachment to this chapter.
(7) 
No project detrimental to scallops shall be permitted, except activity allowed pursuant to a waiver from these regulations, as set forth in § 390-3F.
(8) 
Piers shall be constructed and maintained using the best available measures to minimize adverse effects on the interests protected by the Bylaw.
(9) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to activities involving fish runs are necessary and proper for the following reasons: Fisheries are one of the protected interests under the Bylaw, Chapter 136, § 136-2, of the Code of the Town of Nantucket. Anadromous and catadromous fish are renewable protein resources that provide recreational and commercial benefits. In addition, throughout their life cycle such fish are important components of freshwater, estuarine, and marine environments and are food sources for other organisms. Fish runs provide habitats for other fish and shellfish. Characteristics of fish runs which are critical to the protection of anadromous/catadromous fish include: accessibility and location of spawning and nursing grounds, volume and rate of water flow in both migratory and spawning areas, water quality (including turbidity, temperature, pollutants, nutrients, salinity, and dissolved oxygen) and sediment and erosion control. Fish runs are important for wildlife habitat, recreation, and wetland scenic views.
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering or building upon a fish run, the Commission shall find that the fish run is significant to the protection of the following interests: fisheries, wildlife, sediment and erosion control, water quality, wetland scenic views, and recreation. These findings may be overcome only upon a clear showing that the fish run and the land under a fish run does not play a role in protecting any of the interests given above and only upon a specific written determination to that effect by the Commission.
B. 
Performance standards. Fish runs or land within 100 feet of a fish run shall be presumed significant to the interests protected by the Bylaw as referenced in Subsection A; therefore, the following regulations shall apply:
(1) 
Proposed projects shall not be permitted to fill a fish run, impede the migration of fish, or change the volume, rate, or quality of water flow in a fish run.
(2) 
Proposed projects shall not use procedures which the Commission determines are detrimental to spawning or nursery habitats necessary to sustain the various life stages of the fish.
(3) 
Proposed projects which are not water-dependent shall maintain a 25-foot undisturbed buffer zone with no greater than 50% of the area between the 25-foot buffer zone and 50-foot setback disturbed. All structures which are not water-dependent shall be located at least 75 feet from a vegetated wetland.
Exception: Structures shall be permitted down to the 50-foot setback provided that the undisturbed buffer zone is enhanced by 1.5X the structural area between the 50-foot setback and 75-foot setback in a manner contiguous with the undisturbed buffer zone. Any constructed bioswale shall count against this area so long as it is contiguous with the original undisturbed buffer zone. All structures in existence at the enactment of this performance standard will only be required to meet this requirement upon any expansion of the structure based on the area of expansion.
(4) 
The septic leach facility of a septic system shall be at least 100 feet from the fish run.
(5) 
All work in a fish run shall be prohibited between March 15 and June 15 in any year.
(6) 
All projects, including road maintenance, shall use procedures the Commission determines will minimize the siltation of a fish run.
(7) 
Elevated walkways designed not to affect water quality, sunlight penetration, water volume, or wetland scenic views shall be required for pedestrian passage over a fish run.
(8) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to activities involving land subject to coastal storm flowage are necessary and proper for the following reasons: Land subject to coastal storm flowage (the coastal floodplain) buffers and protects upland areas from severe storm conditions. Since the floodplain contains areas where the water table is close to the surface (as well as other wetland resource areas), pollutants in a floodplain, including contents of septic systems and fuel tanks, may affect private water supply, groundwater quality, wildlife, fisheries, resiliency and shellfish during a storm. Direct and collateral damage to man-made structures in the floodplain are caused by wave impacts and inundation by floodwaters and storm-driven debris. Desires of property owners to protect themselves from the effects of storms can lead to pressure on the Town and its regulatory bodies to erect engineering structures in wetlands which can have a detrimental effect on wetland values and public health and safety.
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering, or building upon land subject to coastal storm flowage, the Commission shall find that the land is significant to the protection of the following interests: flood control, erosion control, and storm damage prevention, water quality, erosion and sediment control, resiliency and wildlife habitat. These findings may be overcome only upon a clear showing that land subject to coastal storm flowage does not play a role in protecting any of the interests given above and only upon a specific written determination to that effect by the Commission.
B. 
Performance standards. Land subject to coastal storm flowage or land within 100 feet of land subject to coastal storm flowage shall be presumed significant to the interests protected by the Bylaw as referenced in Subsection A; therefore, the following regulations shall apply (Specific resource areas that lie within the area of land subject to coastal storm flowage, and the wetland values they protect, are otherwise addressed elsewhere in these regulations. The regulations concerning those areas are in addition to the regulations set forth in this section.):
(1) 
The work shall not reduce the ability of the land to absorb and contain floodwaters, or to buffer inland areas from flooding and wave damage.
(2) 
Projects shall not cause groundwater, surface water, or saltwater pollution triggered by coastal storm flowage. All septic tanks and leach facilities shall be located outside the one-hundred-year floodplain.
(3) 
All private underground fuel tanks shall be outside the one-hundred-year floodplain. Commercial tanks shall be outside the one-hundred-year floodplain, or if the Commission determines this is not practicable, the commercial tanks shall be secured so that they cannot float loose.
(4) 
Building upon areas subject to coastal storm flowage and sea-level rise in locations where such structure would be subject to storm damage or high-tide flooding may not be permitted. When permitting new projects, risk determination shall utilize the latest available data from Nantucket’s NOAA tide gauge and the latest sea-level rise projections available from the Massachusetts Coastal Flood Risk Model (MC-FRM). If permitted, all construction must be in compliance with state and local building code regulations for flood hazard areas. All construction within this area shall also demonstrate consistency with the Town of Nantucket Coastal Resiliency Plan.
(5) 
All swimming pools are required to be designed to have no ability to interact with floodwaters.
(6) 
Fertilizers shall be used in accordance with the Best Management Practices for Landscape Fertilizer Use on Nantucket Island (a copy of which is attached to these regulations as Appendix A[1]).
[1]
Editor's Note: Appendix A is included as an attachment to this chapter.
(7) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.
A. 
Characteristics and protected interests.
(1) 
The Commission finds that regulations applicable to activities involving estimated habitat for rare/significant wildlife and rare/significant flora and fauna for coastal wetlands are necessary and proper for the following reasons: Any coastal resource area identified in Chapter 136, Wetlands, § 136-3, of the Code of the Town of Nantucket within which is found any state rare species (plant or animal) officially listed by the Massachusetts Division of Fisheries and Wildlife, or in which is found any species (plant or animal) the Commission has recognized as significant under the Bylaw, or any coastal resource area falling within any of the most recent Estimated Habitat Maps of the Massachusetts Natural Heritage and Endangered Species Program, shall be considered rare/significant species habitat, as defined in § 390-2 of these regulations. Rare/Significant species habitat preservation is important in order to maintain healthy ecosystems, wetland resources and biodiversity, and is important for protecting recreational interests, and in protecting wetland scenic views.
(2) 
In view of the foregoing, whenever a proposed project involves removing, filling, dredging, altering or building within areas of estimated habitat for rare/significant wildlife and rare/significant fauna for coastal wetlands, the Commission shall find that such land is significant to the protection of the following interests: fisheries, shellfish, wildlife, biodiversity, recreation, and wetland scenic views. These findings may be overcome only upon a clear showing that these estimated habitat areas do not play a role in protecting any of the interests given above and only upon a specific determination to that effect by the Commission.
B. 
Performance standards. Estimated habitat areas shall be presumed significant to the interests protected by the Bylaw as referenced in Subsection A; therefore, the following regulations shall apply:
(1) 
No activity shall be permitted that alters existing vegetation within 25 feet of verified rare/significant species habitat.
(2) 
No activity shall be permitted that results in the construction or enlargement of a structure within 50 feet of verified rare/significant species habitat.
(3) 
No alteration of topography (filling or cutting) and/or drainage characteristics shall be permitted within 50 feet of verified rare/significant species habitat.
(4) 
No new construction or enlargement of drainage facilities within 25 feet of verified rare/significant species habitat shall be permitted.
(5) 
No part of any septic system shall be placed within 50 feet and no leaching facility shall be placed within 100 feet of a verified rare/significant species habitat.
(6) 
The Commission may impose such additional requirements as are necessary to protect the interests protected by the Bylaw.