§ 196A-9. Land subject to flooding or inundation by groundwater or surface water

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 ¼ 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 § 196-4 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 100 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-1A 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
4. 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.
5. An impairment of its capacity to provide for wildlife habitat, including seasonal wetlands (vernal pool) habitat as determined by § 196A-4 of these regulations.