ABC Summary Position on Floodplain Overlay Zoning

A Better Cambridge takes the threat of climate change seriously, and we welcome efforts to combat the threat of increased flooding and heat over the next several decades. We believe that much of what is contained within the proposed climate overlay district zoning petition deserves serious consideration by the Planning Board and City Council. However, we worry that some of the petition’s recommendations will undermine the creation of much-needed affordable housing in the following ways:


Affordable housing will be less financially viable

In order to compete for public funding and leverage economies of scale, new affordable housing projects must contain at least 40 units. The high cost of land in Cambridge, combined with the proposed requirements for open space, permeable land, setbacks and tree cover, will make this difficult to achieve. Some market-rate developments may still be feasible, but they will likely be more expensive and less dense. What’s more, fewer units will be created under the city’s most recent affordable zoning ordinance, which mandates that at least 20 percent of a housing development be affordable.

It’s true that the petition allows for increased building height. The authors frame this as a way for developers to compensate for the land that will be set aside for other uses. There’s a catch, however: The petition prohibits adding density by raising the floor area ratio (FAR).

FAR is the ratio of a building’s total floor area to the size of the land on which it is built. For instance, a FAR of 2.0 allows a developer to build two floors over an entire lot (or four floors over half the lot).

Though they will be able to build taller, the cap on FAR will prevent developers from adding more usable floor space — thus depriving them of an important tool to offset their costs.


Buildable sites will be reduced

The Alewife district is a transit-rich location that contains some of the city’s last available large-scale land. If we are to meet our present and future housing needs, we must make the most of this resource.

This petition reduces buildable land in a number of ways. It establishes 25-foot yard setbacks for mature shade trees and mandates that at least 30 percent of lot area receives tree canopy coverage. It also sets aside 30 percent of each site for open space. The petitioners state a preferences for using “green infrastructure” — such as planting trees and creating landscapes — to capture stormwater, rather than underground storage tanks. But where storage tanks are allowed, they are required to be 50 percent larger than anticipated flood volume capacity.

Taken individually, these items may have environmental benefits, but added together they limit the areas where dense, transit-oriented development is feasible.


Housing will take longer to build — if it is built at all

The petition will subject almost all new construction in the Alewife District — as well as certain parts of Cambridgeport and East Cambridge — to the lengthy special permit process. This will make it much more costly and time-consuming to build new housing in those areas, particularly moderately-sized projects.

Though the petitioners deny that they are seeking a moratorium on housing development, the practical effects of some of their proposals are effectively the same. For instance, Alewife consists of a number of single roads that terminate, but the petition prevents new development on “dead-end roads”. This provision would effectively freeze construction until the city connects these streets into larger networks.


We must achieve both environmental protection and economic viability

We know how to build resilient housing on flood plains. This is already being done responsibly around the country and in our region. But many of the petition’s flood mitigation proposals far exceed the required remedies of our Commonwealth’s own environmental regulations, which are some of the most rigorous in the nation. In addition, the city already has many tools at its disposal to guarantee appropriate development, including EPA and DEP regulations that this petition ignores.

Overly-stringent flood plain protections and open space requirements may all but economically and physically stifle new construction, particularly affordable housing, due to higher costs and dimensional restrictions. This cannot be ignored, especially as our city faces a persistent affordable housing crisis. A more expensive Cambridge is not a more livable Cambridge.

ABC believes that the authors of this petition are sincere in their efforts to address climate change, and we recognize that the massive challenges we face require an active governmental response. However, we question the timing of this petition. The city is coming close to the end of the Envision Cambridge planning process, on which it has spent millions of dollars. We believe that the results will address many of the current petition’s problems.

We look forward to working with all concerned parties to craft a zoning plan that protects our most vulnerable neighborhoods from rising tides, without shutting out those who wish to live here.