A communication transmitted from Louis A. DePasquale, City Manager, relative to a recommendation from the Planning Board to not adopt the Stormwater Separation from Flat Roofs Zoning Petition

CITY OF CAMBRIDGE, MASSACHUSETTS PLANNING BOARD AB CITY HALL ANNEX, 344 BROADWAY, CAMBRIDGE, MA 02139 NATA Date: February 26, 2019 Subject: Stormwater Separation from Flat Roofs Zoning Petition Recommendation: The Planning Board does NOT RECOMMEND adoption. To the Honorable, the City Council, On January 22, 2019, the Planning Board held a public hearing on this City Council zoning petition to amend Article 5.000 of the Zoning Ordinance to allow, by Board of Zoning Appeal (BZA) special permit, increased height and floor area limitations for certain modifications to existing buildings with flat or concave roofs and central roof drains connecting to the City's stormwater infrastructure. City Councillor Craig Kelley presented the petition and addressed questions from Board members. No members of the public made comments. Following deliberation, the Board voted to communicate an unfavorable recommendation. The Board supports the goals stated in the petition, and is in general agreement that zoning incentives for incremental improvements to existing buildings may be an appropriate tool to advance the City's climate change mitigation objectives. However, the Board questions whether this particular proposal is the right approach to adopt at this time. The Board has reviewed this petition, in some form, multiple times in the past and continues to have concerns, which are summarized below and are similar to concerns expressed in prior recommendations. Moreover, if this petition were to move forward, the Board would suggest that the drafting of the petition be clarified with assistance from staff to make its implementation more practical. The Board agrees with the goal of separating stormwater from central storm drains where possible to reduce sewer system intake and promote groundwater recharge by keeping water on- site in a way that does not impact neighboring properties. However, zoning incentives should be considered more broadly rather than only for one particular building type and one particular type of improvement. The City should look to the recent Envision Cambridge process and other planning efforts to consider and prioritize a range of desired improvements, and zoning incentives should be evaluated based on the public benefit of the improvement and not only as a measure to recoup the costs to the property owner. Tradeoffs with other public policy objectives also need to be better understood. Board members also noted several issues specific to this proposal. Closing a storm drain and adding pitch to a roof is a relatively simple improvement that may not justify a significant increase in height and floor area, but may be addressed by more modest incentives such as allowing skylights or roof access without penalty. It was noted that adding a rooftop structure Page 1 of 2

City of Cambridge, MA • Planning Board Recommendation Stormwater Separation from Flat Roofs Zoning Petition with a pitched roof that is set back from the walls of the building may be structurally impractical on typical flat-roofed buildings, such as three-deckers, and may be better achieved in other ways. Some Board members raised concerns about the iconic character of neighborhoods predominated by three-deckers and how they would be impacted by adding new structures above the existing roofs on scattered sites, and suggested that the Historical Commission may need to be consulted. Finally, since many flat-roofed buildings contain multiple units and may have multiple condominium owners, it was unclear how such buildings would be able to realize a benefit from this proposal, and it was suggested that approaches outside of zoning might be needed to incentivize these types of improvements. Respectfully submitted for the Planning Board, Cohering ate Conully Catherine Preston Connolly, Chair. Page 2 of 2 February 26, 2019