The Commission finds that regulations applicable to activities involving
inland water bodies are necessary and proper for the following reasons:
Where land under water bodies is composed of pervious material, such
land represents a point of exchange between surface water and groundwater.
Depending upon the hydrological conditions and water levels at a given
point in time, these areas may serve as exchange or discharge points,
or both, with groundwater. An area may serve as recharge area at one
season and a discharge point at another time. This allows pollutants
and nutrients easy access into private wells or the general groundwater
supply. The physical nature of land under water bodies is highly variable,
ranging from deep organic and fine sedimentary deposits to gravel
and large rocks. The organic soils and sediments play an important
role in the process of detaining and removing dissolved and particulate
nutrients from surface water above. These also serve as traps for
toxic substances (such as heavy metal compounds). Land under water
bodies, in conjunction with banks, serves to confine floodwater within
a definite channel during the most frequent storms. Filling within
this channel blocks flows which in turn causes backwater and overbank
flooding during such storms. An alteration of land under water bodies
that causes water to frequently spread out over a large area at lower
depth increases the amount of property that is routinely flooded.
Additionally, it results in an elevation of water temperature and
decrease in wildlife habitat in the main channel, both of which are
detrimental to fisheries, particularly during periods of warm weather
and low flows. It may also flood waterfowl nesting sites which otherwise
would not be disturbed. Land under ponds and lakes is vital to a large
assortment of warm water fish during spawning periods. Species such
as large-mouth bass (Micropterus salomoides), small-mouth bass (Micropterus
dolomieui), blue gills (Lepomis macrochirus), pumpkinseeds (Lepomis
gibbous), black crappie (Pomoxis nigromaculatus), and rock bass (Ambloplites
rupestris) build nests on the lake and bottom substrates within which
they shed and fertilize their eggs. Land within 100 feet of any bank
abutting land under a water body is significant to the protection
of the interests which these water bodies serve to protect. Characteristics
of water bodies which are critical to wildlife, wildlife habitat,
and fisheries include water circulation and flushing rates, distribution
of sediment grain size, and water quality (including amounts of dissolved
oxygen, nutrients, and pollutants). Leaving ponds and the land bordering
ponds in an unobstructed state may be important to recreational swimming,
fishing, and boating. Water bodies and the area around them also provide
other recreational opportunities such as hunting and wildlife observation.
Cattail borders or other vegetated borders of large ponds are important
in reducing shoreline erosion and storm damage by dissipating the
high energy of storm waves and by anchoring the sediments. Water bodies
provide important feeding and/or drinking areas for many types of
aquatic wildlife, birds, and animals. Ponds and other water bodies
produce insects that hatch and are used as food by several species
of birds, particularly swallows. Ducks, geese, swans, and herons all
use water bodies and surrounding borders for feeding, shelter, and/or
nesting areas. Many other birds, animals, reptiles, and amphibians
use land under water bodies, water bodies, and the borders of water
bodies for various parts of their life cycles. Changes in sediments,
water quality, water level, or species composition of food sources
or ground cover may be detrimental to any of the above wildlife and
wildlife habitat. Ponds and the land surrounding them often form important
wetland scenic views. The enclosed area and the limited size of most
freshwater bodies on Nantucket make them particularly sensitive to
pollution or nutrient inputs. These inputs can change the plant and
animal species composition of the water body and thus can be detrimental
to fish and wildlife. Bioaccumulation of pollutants through food webs
can also create dangerous levels of pollutants or toxins for wildlife
and humans.