AGENDA #9
MEMORANDUM
TO: Mayor and Town Council
FROM: Timothy Dempsey, Planning Board Chair
SUBJECT: Report on 2,000 vs. 5,000 square feet Thresholds for Stormwater Management and Tree Protection Controls for Single-Family/Two-Family Lots
DATE: October 11, 2004
This memorandum provides a unanimous report from the Planning Board regarding the 5,000 square foot threshold for stormwater management and tree protection controls for single-family/two-family lots.
BACKGROUND
The Town Council held a Budget Work Session on March 30, 2004. Among the items discussed was a Budget Working Paper on the following topic:
What would be the impacts of changing the threshold for requiring stormwater management and tree protection controls for single-family and two-family lots from the existing threshold of 5,000 square feet of land disturbance, to a new threshold of 2,000 square feet?
The staff report included data demonstrating that the 5,000 square foot threshold triggers requirements for stormwater management and tree protection for almost all new house construction, and allows most expansions of existing dwellings to take place without the requirements.
The question was referred to the Planning Board for discussion. On April 6, 2004, the Planning Board prepared a preliminary opinion that the current 5,000 square foot threshold of land disturbance for stormwater management and tree protection for single-family/two-family lots was too high. The Board voted 9-1 to recommend that stormwater controls and tree protection be decoupled for this type of development. On May 10, the Council heard this recommendation, along with comments that more information was needed. The Council then referred the item back to the Planning Board for further discussion. A copy of the May 10 Memorandum is attached.
On June 15, the Planning Board appointed Donna Bell, Rebecca Boyles, and Mitch Strobin to a committee to investigate the topic further. The Committee met with the Town’s Urban Forester and Stormwater Engineer to learn more about the current land disturbance threshold of 5,000 square feet that triggers both stormwater considerations and tree protection controls for development of homes. The Committee learned that the topic has many levels of complexity. For example, the Land Use Management Ordinance threshold of 5,000 square feet for land disturbance for stormwater controls/tree protection applies to all single-family/two-family lots in existence and that will be created. The threshold calculation of land disturbance applies to land disturbance that has occurred or will occur after January 27, 2003. Impervious surface limits for lots on the southern half of Town (in the State-mandated Watershed Protection District) began in 1993. Whereas, for the northern half of Town (outside the Watershed Protection District), impervious surface limits apply only to lots created after January 27, 2003.
RECOMMENDATIONS
The Planning Board received the recommendation of the Committee which concluded that there was no significant or measurable benefit associated with decoupling and/or reducing the 5,000 square foot threshold for land disturbance. The Planning Board’s recommendation to the Town Council is that the current land disturbance threshold for stormwater controls and tree protection devices remain at 5,000 square feet. The Board also found value in setting the same threshold for both types of requirements, to facilitate citizen understanding and administration of the regulations. The level of complexity of the interrelated regulations results in difficulty in explanation and implementation today. Various adjustments, discussed by the Committee and the Planning Board, would be difficult to justify because very little, if any, associated benefit could be found.
A change of a different type is desirable however, and the Planning Board recommends that attention be given to the matter of calculating cumulative land disturbance over time. Specifically, the Planning Board recommends that the cumulative approach to tracking land disturbance be adjusted to 5,000 square feet of disturbance within a 5 year period. (For example: if land is disturbed to construct a patio one year, and then the next year additional land is disturbed for an addition to the house, the requirements are triggered if the cumulative disturbance exceeds 5,000 square feet. If, however, planted areas grow back and remain undisturbed for 5 years, that original disturbance does not need to be counted in future calculations.)
In summary, the Planning Board recommends that the thresholds for land disturbance for stormwater controls and tree protection for home construction stay the same, at 5,000 square feet, and that regulations be adjusted to account for changes to a property over time.
RECOMMENDED AREA FOR FUTURE STUDY
In addition, the Planning Board expressed concern that single-family and two-family lots created before January 27, 2003, which are located outside the Watershed Protection District (located in the northern half of Town) are not subject to an impervious surface limit. And, although the 5,000 square foot threshold of land disturbance which triggers tree protection and stormwater controls forces homeowners to act responsibly with any new impervious surface proposed, the regulations do not explicitly restrict the amount of impervious surface for these lots. Recognizing that the Town Council purposely grandfathered existing lots from many of the Land Use Management Ordinance stipulations, the Planning Board nevertheless believes that this exemption from impervious surface limits for existing lots located outside the Watershed Protection District is a matter which could be important and should be brought to the Council’s attention.
ATTACHMENTS