pervious zoning ordinance (ordinance) 1-27-11 — File 190780

CITY OF SOMERVILLE ORDINANCE NO. _________ IN THE BOARD OF ALDERMEN: ______ AN ORDINANCE AMENDING THE SOMERVILLE ZONING ORDINANCE TO ADD A DEFINITION OF PERVIOUS AREA AND AMEND THE TABLE OF DIMENSIONAL REQUIREMENTS AND FOOTNOTES TO REQUIRE A MINIMUM PERVIOUS AREA ON LOTS IN CERTAIN ZONING DISTRICTS WHEREAS, impervious surfaces can contribute to runoff that overburdens drainage facilities; and, WHEREAS, the creation of additional impervious surfaces changes the nature of stormwater runoff and can create flooding on adjacent properties; and, WHEREAS, the addition of significant asphalt on existing lots creates a ‘heat island’ effect that raises air temperatures on hot days; and, WHEREAS, the addition of asphalt driveways and parking areas can be detrimental to character of Somerville’s neighborhoods; and, WHEREAS, it is necessary to ensure that lots in Somerville continue to provide open spaces for the benefit of the community; and, WHEREAS, it is desirous to promulgate regulations to oversee the impervious coverage of surfaces in Somerville to reduce potential adverse impacts; THEREFORE, be it adopted by the Board of Aldermen, in session assembled, that the below listed sections of the Somerville Zoning Ordinance are hereby amended as identified. 1. Article 2: Definitions are hereby added to as follows (additions are underlined): 2.1.122a Pervious Area: The area of a lot covered by surfaces or materials that allows for the movement or passage of water into soils below. Pervious areas include, but are not limited to, areas of a lot covered by soil/mulch, vegetative matter, permeable pavers, green roofs, or other materials that allow for the passage of water. Compacted gravel, artificial turf, and structures without green roofs shall not be considered as pervious area. 2. Article 8: Section 8.5, Table of Dimensional Requirements is hereby added to as follows (additions are underlined):   TABLE OF DIMENSIONAL REQUIREMENTS Districts RA RB RC - 1 -

- 2 - C. Maximum ground coverage (%) 50 50 70 D. Landscaped area, minimum percent of lot 25 25 25 K. Pervious Area, minimum percentage of lot(24) 35 35 30 3. Article 8: Section 8.6, Footnotes to the Dimensional Table is hereby added to as follows (additions are underlined): 24. A waiver to the Pervious Area requirement may be issued by a Special Permit by the SPGA, per Section 5.1 of the SZO if the proposed plan meets the findings of Section 5.1.4 and addresses adverse environmental impacts per Section 5.1.4.e.