Mashpee MA passes nitrogen and phosphorous low impact articles at Town Warrant
Updated: Nov 18, 2022
From the Mashpee Enterprise, on a Town Warrant vote on October 17, 2022:
Article 7, 8, 9 and 12 passed, directly addressing stormwater management. Article 7 makes stormwater low-impact design strategies mandatory while Articles 8 and 9 specify specific low-impact design requirements for the removal of nitrogen and phosphorous from stormwater.
Article 8 addressed the nutrient removal from single- and two-family dwellings, while Article 9 specified requirements for all other lots such as subdivision roadways, commercial and industrial buildings, and multifamily residences.
From the Town of Mashpee Warrant, October 17, 2022:
Article 8 To see if the Town will vote to amend §174-27.2 (B) (2) of the Mashpee Zoning Bylaw, Stormwater Management, by adding new subsections (d) and (e) after §174-27.2 (B) (2) (c) as follows: (d) Incorporates filter media and/or an internal water storage zone to optimize nitrogen and phosphorous removal for projects which employ bio retention or similar filtering best management practices (e.g., rain gardens, tree filters, sand/organic filters, and dry water quality swales) for treatment prior to infiltration. (e) evaluates and designs new stormwater quantity control BMPs and other drainage system components in accordance with the Resilient Massachusetts Action Team (RMAT) Climate Resilience Design Standards and Guidelines, as may be amended from time to time, to account for projected increases in precipitation intensity and frequency over the duration of the useful life of the systems. , or take any other action relating thereto.
Submitted by the Board of Selectmen
Explanation: This article specifies specific low impact design requirements for removal of nitrogen and phosphorous from stormwater at single and two family dwellings.
The Board of Selectmen recommends approval of Article 8 by a vote of 4-0 The Finance Committee recommends approval of Article 8 by a vote of 4-0
Article 9 To see if the Town will vote to reformat and amend §174-27.2 (B) (3) of the Mashpee Zoning Bylaw, Stormwater Management, by adding new subsections ‘vi’ and ‘vii’ under current §174-27.2 (B) (3) (v) and indenting appropriately as follows: 3) For new subdivision roadways or for lots occupied or proposed to be occupied by uses other than single or two-family homes, a stormwater management plan which (a) utilizes site planning and building techniques including LID planning and development strategies, such as minimizing impervious surfaces and disturbance of existing natural areas, pervious reserve or overflow parking areas, multi-level buildings, parking structures, “green roofs” and storage and re-use of roof runoff, to minimize runoff volumes and the level treatment required to reduce contaminants
(b) minimizes erosion and runoff from disturbed areas during construction and,
(c) provides for the following:
Artificial recharge or precipitation to groundwater through site design that incorporates natural drainage patterns and vegetation and through the use of constructed (stormwater) wetlands, bio retention facilities, vegetated filter strips, rain gardens, wet (retention) ponds, water quality swales, organic filters or similar-site-appropriate current best management practices capable of removing significant amounts of nitrogen and other contaminants from stormwater. Said stormwater treatment facilities shall be designed and sized to retain up to the first inch of rainfall from their catchment area within the area designed for nitrogen 51 treatment, before any overflow to subsurface leaching facilities and otherwise meet the Stormwater Management Standards and technical guidance contained in the Massachusetts Department of Environmental Protection’s Stormwater Management Handbook, as amended, or State-approved BMP guidance, whichever is stricter Volumes 1 and 2, dated March 1997, for the type of use proposed and the soil types present on the site. Such runoff shall not be discharged directly to rivers, streams, other surface water bodies, wetlands or vernal pools. Except for overflow from stormwater treatment facilities as described above and when there are no other feasible alternatives, dry wells shall be prohibited.
Except when used for roof runoff from non-galvanized roofs and for runoff from minor residential streets, all such wetlands, ponds, swales or other infiltration facilities shall be preceded by oil, grease and sediment traps or fore bays or other best management practices to facilitate control of hazardous materials spills and removal of contamination and to avoid sedimentation of treatment and leaching facilities.
All such artificial recharge systems shall be maintained in full working order by the owner(s) under the provisions of an operations and maintenance plan approved by the permitting authority to assure that systems function as designed.
Infiltration systems shall be located so that no part of any leaching system is located less than one hundred (100) feet from drinking water wells. Any infiltration basins or trenches shall be constructed with a three (3’) footminimum separation between the bottom of the leaching system and maximum groundwater elevation
Roadway widening or improvements that increase the amount of impervious area on the redevelopment site by greater than or equal to a single lane width shall meet the requirements of MS4GP part 2.3.6.a.ii.4(a) – (c) fully.
For projects which employ bio retention or similar filtering best management practices (e.g., rain gardens, tree filters, sand/organic filters, and dry water quality swales) filter media and/or an internal water storage zone to optimize nitrogen and phosphorous removal shall be incorporated into the design for treatment prior to infiltration.
Design of new stormwater quantity control BMPs and other drainage system components shall be designed in accordance with Resilient Massachusetts Action Team (RMAT) Climate Resilience Design Standards and Guidelines, as amended, to account for projected increases in precipitation intensity and frequency over the duration of the useful life of the systems. , or take any other action relating thereto.
Submitted by the Board of Selectmen
Explanation: This article specifies specific low impact design requirements for removal of nitrogen and phosphorous from stormwater at all lots that are not single and two family dwellings such as new subdivision roadways, commercial and industrial uses/buildings, and multifamily residential. Further this article proposes a minor reformatting of text by indenting subsections appropriately where they currently are not.
The Board of Selectmen recommends approval of Article 9 by a vote of 4-0
The Finance Committee recommends approval of Article 9 by a vote of 4-0