Purpose: The purpose of this section is to preserve and enhance the landscape by encouraging the maximum retention of natural topographic features, such as drainage swales, streams, slopes, ridgelines, rock outcroppings, vistas, natural plant formations and trees; to minimize water runoff and soil-erosion problems incurred in grading of steep slopes; to encourage innovative architectural, landscaping, circulation and site design. For the purposes of this subsection, the term "natural" shall be defined as the condition of the ground surface as it exists at the time a subdivision or development is proposed including any man-made alterations such as grading, excavation or filling which may have occurred prior to the time such subdivision or development is submitted. No land intended for subdivision or development may be regraded or filled in such manner as to circumvent this section.

Provisions not applicable: The provisions of this section shall not apply to building lots in a definitive subdivision plan submitted before the effective date of this section in accordance with MGL Chapter 41 in order to obtain the protections afforded by MGL c. 40A, § 6.

Slope defined: The slope of land at any point, stated as a percentage, shall be defined as the change in elevation over a horizontal distance measured perpendicular to the contours divided by the distance over which the change occurs multiplied by 100. The slope of land at any point, may be stated as a ratio (2:1, 3:1, 4:1, etc.). The first number of the ratio indicates the horizontal distance and the second number indicates the vertical rise.

Protected slopes: All natural slopes exceeding 33% (3:1) over a horizontal distance of 30 feet as measured perpendicular to the contour on a tract or parcel of land intended or proposed for subdivision or on a building lot first shown on a plan recorded or endorsed after the effective date of this section are protected and shall remain undisturbed.

Slopes excluded from minimum lot area calculation: All areas with natural slopes exceeding 33% (3:1) over a horizontal distance of 30 feet as measured perpendicular to the contour on a tract or parcel of land intended or proposed for subdivision or development, or on a lot intended for building purposes shall be excluded from the calculation of the minimum lot area required for the applicable zoning district.

Special permit for exemption. The Community Planning Commission may grant a special permit for exemption from the provisions of this section if, in the Commission's opinion, the proposal satisfies the purposes of § 200-127A above.