This Section 310 CMR 10.57 is incorporated subject to the changes
below.
A. Preamble.
(1) State regulations at 310 CMR 10.57(3)(b)(1) read "Isolated Land Subject
to Flooding is an isolated depression or a closed basin which serves
as a ponding area for runoff or high groundwater which has risen above
the ground surface." Section 10.57(2)(b) reads "Isolated Land Subject
to Flooding is an isolated depression or closed basin without an inlet
or an outlet. It is an area which at least once a year would confine
standing water to a volume of at least 1/4 acre-feet and to an average
depth of at least six (6) inches."
(2) Rationale for the change in size in these regulations (see below)
is the many small flooding areas which provide filtration and recharge
of runoff into the groundwater and the many kettle holes characteristic
of Orleans which at times intersect the water table but which are
often considerably smaller than the area protected by state regulations.
Many of these kettle holes as well as our small ponds, are, or may
be, connected hydrologically. With growing concerns about the quality
and quantity of our water supply and the quality of our surface waters,
the Commission believes a greater degree of protection for isolated
land subject to flooding is appropriate until further information
proves otherwise.
(3) Greater protection will also be provided for many small but significant
areas of wildlife habitat which provide seasonal wetland habitats
and essential breeding sites for certain amphibians requiring isolated
areas that generally flood in the spring and/or summer. Many birds,
reptiles and mammals also depend upon these wetlands as a source of
food, shelter and breeding habitat. Such wildlife and its habitat
also contribute to our recreational and aesthetic enjoyment.
B. Definition. "Isolated land subject to flooding (ILSF)" is a depression
or closed basin without an inlet or outlet, which serves as a ponding
area for runoff of fresh water or for high groundwater which, because
of an elevated water table, has risen above the ground surface. ILSF
is land which at least once a year, except during periods of drought,
confines standing water to a volume which would cover no less than
650 square feet at an average depth of two inches.
C. Boundary. The boundary of an area of land subject to flooding shall
be determined by one or more of the following, depending upon the
availability of information. Where more than one method is possible,
the method leading to the largest area shall be used. That boundary
shall be:
(1) The line enclosing that area having a vegetative cover of 50% or more of freshwater species as defined in §
196A-4 of these regulations; or
(2) The line enclosing the largest observed or recorded area of water
confined in said area; or
(3) The area calculated to be inundated by runoff from the one-hundred-year
storm. Such calculation shall be done in accordance with 310 CMR 10.57(2)(b)(3).
D. Presumption. Where a project involves removing, filling, dredging or altering of land subject to flooding (both bordering and isolated areas) the Commission shall presume that such an area is significant to the following interests specified both in §
196A-1B of these regulations and 310 CMR 10.57(1)(a)(b): public and private water supply and quality, groundwater supply and quality, flood control, prevention of pollution, wildlife habitat and to the interests of aesthetics and recreation.
E. Performance standards. A proposed project that may result in alteration
of an isolated wetland shall not result in the following:
(1) Flood damage due to filling which causes lateral displacement of
water that would otherwise be confined to such area.
(2) An adverse effect on public or private water supply or groundwater
supply, where such area is underlain by pervious material.
(3) An adverse effect on the capacity of said area to prevent pollution
of the groundwater, where the area is underlain by pervious material
which in turn is covered by a mat of organic peat, or muck or vegetation.
(4) An impairment of its capacity to provide for wildlife habitat, including seasonal wetlands (vernal pool) habitat as determined by §
196A-4 of these regulations.