Alewife Study Group > wetlands and flooding > Oct. 3 1999, Cambridge laws Search 

Cambridge's wetland protection laws
- ideas for improvement

(by Lew Weitzman, a member of the Alewife Study Group, updated Oct. 3 1999)

Cambridge is currently in the process of considering a conservation bylaw. 40% of Massachusetts' cities and towns already have conservation bylaws on the books. A good conservation bylaw can tremendously increase the ability of a municipality to protect its wildlife habitats and control flooding. Cambridge has the chance to once again show its leadership on environmental issues. A strong conservation bylaw should be enacted as soon as possible.

Background to the Massachusetts Wetlands Act
The commonwealth of Massachusetts now recognizes the importance of wetlands not only as a rich habitat for many forms of plants, birds and animals, but also as an important resource for citizens. Wetlands mitigate the dangers from toxic chemicals in the environment and act as buffer zone limiting the effects of flood damage during major storms.

The Massachusetts Wetlands Act (G.L. Ch.131 Section 41) was enacted in the late seventies. The Department of Environmental Protection (DEP) enforces the regulations that cover the Wetlands Act (CMR 10.50-10.60); However, it is up to each town's Conservation Commission to directly enforce these regulations and the DEP is generally only available for appeals.

The Wetlands regulations are very specific about which 'resource areas' fall within the jurisdiction of the Conservation Commissions. Resource areas are generally those that are near bodies of water such as rivers, pond or the ocean and/or contain wetlands habitats such as cattail marshes. The exact definitions are very technical and usually a biologist is required to make an exact determination of a wetland area.

100-year flood plains (and other lands subject to flooding) are also within the jurisdiction of the conservation commissions. FEMA publishes flood maps that are used to determine the boundaries of the 100-year flood plain.

Town Bylaws
The Wetlands Act regulations are generally considered a starting point for protecting wetlands and floodplains. 40% of the cities and towns in Massachusetts have passed their own bylaws clarifying and adding to the protections afforded by the Act. At the present time Cambridge does not have a conservation bylaw.

Bylaws can be passed as zoning or as non-zoning regulations. If they are passed as zoning they require a two third vote of the city council (six votes) and would be administered by the planning board. If they are passed as a non-zoning regulation they require a simple majority of the city council (five votes) and would be administered by the conservation commission.

Most towns have chosen to pass their bylaws as non-zoning regulations administered by their conservation commissions.

The Need for Conservation Bylaws in Cambridge
Only a few wetlands remain in the city of Cambridge. A strip lines the Charles River and surrounds Fresh Pond and a few other small bodies of water. The most significant wetland and flood plain is at Alewife along the Alewife Brook and the Little River. The 115 acre Alewife Reservation is part of this wetland area.

As a direct result of development on the Alewife flood plain and its low elevation, there is periodic and significant flood damage in the surrounding communities. A 1981 study by the MDC found property damage in the Alewife area to be the highest of any portion of the Mystic River watershed of which it is a part.

During flood events at Alewife, the Mystic River backs up into the Alewife Brook and Little River areas. Flood waters from Belmont also empty into this area during storm events. During the flood of October, 1996, the Alewife Brook flooded over the Alewife Brook Parkway and into North Cambridge neighborhoods. East Arlington neighborhoods adjacent to Alewife were also inundated with flood water. The Arthur D. Little parking lot was covered by several feet of flood water.

The flood event of 1996 was estimated to be a '30-40 year' event by the national weather service. The '100-year' event would be significantly worse and could even pose a threat to the city drinking supply at fresh pond.

Development pressures will continue to pose an immediate threat to Cambridge's remaining wetland and flood plain areas. For all of these reasons Cambridge is in desperate need of conservation bylaws.

Jurisdiction of the Conservation Commission
The first goal of a Cambridge conservation bylaw should be to expand the jurisdictional authority of the Cambridge Conservation Commission. Activities immediately adjacent to resource areas can have a significant impact and should be monitored. For example the construction of buildings immediately adjacent to a wildlife habitat can have significant effects on habitat. For this reason, many municipalities in Massachusetts have extended the jurisdiction of their conservation commissions to 100 feet outside of the 100-year flood plain.

Expanding Habitat Protections
The wetlands regulations as written provide almost no protection for wildlife habitats outside of actual wetlands. For example wildlife habitats within the 100-year flood plain are virtually unprotected. The Bedford conservation bylaw has corrected this by requiring that construction in their 100-year flood plain not "alter the ability of the land to provide breeding habitat, escape cover, or food for wildlife." Duxbury's conservation bylaw emphasizes the significance of their flood plain to their adjacent wetlands. Dunstable's conservation bylaw adds new protections to their 100-year flood plain and protects its 'aesthetic character'.

The existing wetlands regulations provide no protection to wildlife, only their habitats. This strange distinction needs to be clarified in any conservation bylaw. In one Massachusetts town a fence was erected that blocked animals from getting into a wildlife area but the town was unable to do anything about it as the DEP appeals court ruled that the Act only protected the habitat and not the animals that lived in it!

Construction in the Flood Plain
The Wetlands Act does not prohibit construction in flood plains. It does require compensatory storage be provided for any lost volume of flood storage. This new flood storage must be in an area that is not already in the flood plain and at similar elevations as that which was lost.

Even with the best of compensatory storage schemes it is clear that flooding continues to increase where construction occurs. Therefore, it is the recommendation of FEMA that no construction occur in the 100-year flood plain and this is also the policy of the Cambridge emergency response plan. The state Zoning Act (G.L. Ch. 40A) also encourages municipalities to prohibit or regulate development on flood plains.

The town of Brewster conservation bylaw does not permit construction of any kind in their flood plain. Cambridge may want to consider a similar policy given the extent of construction that has already occurred on their few remaining flood plain areas and the threat to property and water supply that exists. At the very least loopholes in compensatory storage ought to be closed.

Compensatory Storage
In the past developers have been able to create large parking lots without having to compensate for its effect on the volume and velocity of floodwater. Meadows and wetland areas absorb floodwater and slow down its speed during a major storm. Paved parking lots do not do this.

Bedford has recognized this phenomenon by requiring no more than 25% impervious surfaces in the 100-foot buffer zone to wetlands. Bedford also requires that construction in their flood plain "neither decrease the flood storage capacity nor decrease the groundwater infiltration rate".

The weight of built structures has a significant effect on flood capacity and ought to be a factor in calculating compensatory storage. The weight of a building will compress soil so that it can no longer hold as much water.

A loophole has allowed developers to excavate compensatory storage from ground areas that already contain groundwater. Clearly these types of flood storage areas would add nothing to total flood storage capacity and should not be accepted as meeting the intent of the law. The Danvers conservation bylaw has closed this loophole by requiring that "storage capacities shall be based on the volume of active storage above maximum seasonal groundwater levels".

And, finally, there has been no consideration given to area-wide flooding conditions. Until now a developer has been allowed to focus exclusively on their own contribution to flooding without an analysis of the general conditions in their area. The Danvers conservation bylaw has corrected this oversight by requiring that "hydrologic analysis shall be based on a reasonable estimate of developed conditions within the entire watershed".

Wetlands Replication
The Wetlands Act allows the destruction of up to 5,000 square feet of wetlands so long as they are replicated elsewhere in the watershed. This policy is now being reconsidered by many municipalities.

The Dover conservation bylaw concludes that "wetlands replication is generally unsuccessful". The Chicopee conservation bylaw goes further and states that "the quality and quantity of Chilcock's (a significant wetlands in the town) wetlands shall be increased and restoration and replacement shall undo past damage."

A policy of increasing wetlands similar to that adopted by Chicopee is in line with Governor Cellucci's goal of creating 3,000 new acres of wetlands by the year 2010.



Contact the Alewife Study Group, North Cambridge Massachusetts, by email at information@alewife.org