2017-03-08 BOS Packet - Released

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,pus MopNr 1775 C+ A ' D Z_ w APRIL19' MEMORANDUM To: Board of Selectmen From: Conservation Commission Date: January 27, 2017 Re: Proposed traffic controls at Hartwell Avenue and Maguire Road intersection On December 19, 2016 and January 23, 2017, the Engineering Division made informal presentations to the Conservation Commission of its report on the designs of the five alternative traffic controls that might be proposed for the intersection of Hartwell Avenue and Maguire Road and their comparative costs (including wetland impacts) and benefits. The purpose of the presentations was to seek an informal opinion of the Conservation Commission as to whether the Commission would issue an Order of Conditions permitting any of the five alternatives, two involving roundabouts and three involving traffic signals. We explained that it would be extremely difficult for the Commission to issue an Order of Conditions for three of the alternatives, the two roundabouts and one of the traffic signals, because of the amount of wetland alteration involved, and that, between the remaining two alternatives, the Commission would strongly prefer the traffic signal with the retaining wall. Since the Board of Selectmen will be the authority that will direct the Engineering Division's further development of the plan that will be submitted for permitting, the Commission would like to explain to the board the reasons underlying our opinion. The Bordering Vegetated Wetland performance standards of the Massachusetts Wetland Protection Act(incorporated into the Lexington By-law for Wetland Protection) allow the Conservation Commission to permit a maximum of 5,000 square feet of wetland alteration. Any greater alteration requires a variance from the Department of Environmental Protection (DEP) Commissioner. The DEP Commissioner may issue a variance if he or she finds that there is no reasonable alternative that would allow the project to proceed in compliance with the performance standards. Both roundabouts and one of the signal options would alter more than 5,000 square feet of wetland (16,207 sf, 8,881 sf and 6,876 sf, respectively), while the remaining two signal options allow for compliance with the performance standards, and thus provide less adverse alternatives. In these circumstances, we doubt that the DEP Commissioner would grant a variance to alter more than 5,000 square feet of wetland. In addition, the Bordering Vegetated Wetlands performance standards require replication of wetland area that is lost through alteration. Lexington Wetland Protection Code regulations require a 2:1 ratio of replication area to lost area. Wetland replication has a fairly high failure rate and areas of replication are more likely to succeed as functioning wetlands and replace the functions of the lost wetland areas if they are constructed near the location of the lost wetland.