Committee reviews "sustainable development" density bonus, green‑score and civic‑space proposals in recode presentation

Deputy Planning Manager Sam Durfee used the Planning & Economic Development Committee meeting on June 16 to revisit a recode case study and to outline a proposed "sustainable development" density factor that would sit between the base density and the inclusionary‑zoning (IZ) bonus.

Durfee said the sustainable development option is intended to reward higher‑order site design and performance — for example, enhanced landscaping, rainwater harvesting and vegetated roofs — by offering a modest density bonus to developers that meet a menu of green and performance standards. "We're trying to capture stuff on‑site ... which then also double as landscaping areas," Durfee said, describing rain gardens and bio‑retention that reduce reliance on large underground detention systems.

In the worked example Durfee presented — a hypothetical six‑story, ~140,000‑square‑foot building — he compared unit yields across the base, sustainable development and IZ options. Using the example table, total unit counts rose from roughly 163 under the base case to a higher total under sustainable development and up to about 213 under inclusionary zoning, with the IZ approach including an example 33 income‑restricted units. Durfee characterized sustainable development as "a way of incentivizing via density bonuses to provide affordable housing" in addition to a separate option that incentives site design.

Durfee explained the green‑score system that assigns credit for landscaping and stormwater practices (street trees, additional bio‑retention and rain gardens, green roofs, rainwater harvesting for irrigation and EV‑ready and bicycle parking). He said credits are aggregated and measured against site area to yield a green score that can unlock the sustainable‑development density factor. When asked whether rain gardens create standing water, Durfee replied they typically infiltrate and remain dry between storms; when asked what harvested rainwater would be used for, he said, simply, "Irrigation."

Committee members pressed on enforceability: Alderman Patricia Klee asked whether green roofs or planted features could be removed by later owners. Durfee said maintenance for the life of the development is a condition of site‑plan approval and that the city enforces approved site‑plan elements, including landscaping, if they are removed.

The presentation also addressed parking and mobility management. Durfee said the city is developing a mobility‑management manual that would let developers reduce parking by demonstrating measures such as subsidized transit passes, bicycle accommodations and other demand‑management strategies, replacing informal waiver requests with measurable programs.

Durfee discussed civic space as a required deliverable in large redevelopment overlays, noting a 20‑acre threshold as a working minimum to assemble a new neighborhood pattern. He said civic space can take varied forms — pocket parks, programmed plazas or pedestrian connections to larger parks — and that ownership and maintenance arrangements would be contextual. "If it is of that scale, city ownership and maintenance would make sense," Durfee said, while committee members warned that turning maintenance obligations to the city would increase DPW burdens. Chair Derek Thiebaud suggested a middle ground of roughly 15% civic space as a reasonable starting point, while other members emphasized that percentage should depend on context (adjacency to existing parks, neighborhood character and size).

Durfee also outlined the concept of neighborhood types and district groups used to calibrate the code: in areas with no existing neighborhood pattern (large commercial or industrial parcels) the code would require a mix of district types to create variety; in downtown contexts the code would rely on existing character rather than district groups and use smaller up‑zoning increments.

Near the end of the meeting Durfee reviewed proposed changes to accessory‑structure rules, carrying forward a prior cap (40% in some contexts) but proposing context‑based maximums — for rural districts allowing 50% of a house footprint or up to 600 square feet (whichever is greater) and smaller allowances in denser districts, with setbacks and lot‑coverage rules remaining in force. The committee discussed permitting and whether smaller accessory structures would still require building permits; Durfee said most such additions would still need a building permit but not necessarily planning‑board review.

Durfee said the city plans a pragmatic launch that could include a temporary blanket waiver (a 5%–20% tolerance) while staff gathers real‑world data on initial applications and refines standards. He told the committee the code will evolve after initial applications raise unanticipated issues.

The committee deferred further discussion of inclusionary zoning to a subsequent meeting and adjourned at 8:40 p.m.