Brookline planning board presses for stronger protections on Mason/Onyx excavation plan — truck routes, MOU, water testing urged

Brookline Planning Board members spent substantial time on July 16 refining the town's response to a proposed excavation and aggregate project in Mason involving Onyx Corporation, urging stronger protections for Brookline roads and waterways and clearer enforcement mechanisms.

Board members and staff described recent public outreach and earlier joint meetings with select boards, and said the town has drafted a list of “asks” that it will send to Mason and to the district engineer at the New Hampshire Department of Transportation. Members emphasized that language in any memorandum of understanding should become a condition of site‑plan approval so obligations do not evaporate if the company reorganizes or rebrands in later years.

Two recurring concerns dominated discussion: truck routing and financial assurances for road impacts. Brookline asked that Russell Hill Road and Cleveland Hill Road be prohibited as alternate routes for heavy trucks; board members said a condition of approval (rather than only language in an MOU) would have stronger, enforceable effect. Members also questioned whether Onyx’s initial draft contribution (reported in the MOU as $50,000) would cover long‑term road rehabilitation should heavy truck traffic accelerate pavement deterioration.

The conservation commission and several board members asked for baseline and continuing water‑quality testing for nearby waterbodies (transcript reference: "Lake Botanba" in the meeting record) before, during and after Onyx work, to track impacts on dissolved oxygen and on freshwater mussels. Staff said NHDES permits and the state’s alteration of terrain/shoreland review processes provide some review, but recommended adding specific monitoring and an enforcement path as permit conditions.

Board members also urged practical measures to aid local oversight: identification for Onyx trucks (magnets or markings to distinguish company trucks and subcontractors), a named local enforcement officer (rather than ad hoc callbacks to the planning board), and clearer phasing limits to reduce the duration of heavy haul operations. The board said it wants third‑party engineering estimates of pavement and culvert repair costs to inform a stronger contribution figure in any MOU.

The planning board is preparing a formal letter with six prioritized asks to the Mason select board and the district DOT engineer; staff reported a third‑party engineer will review traffic and drainage materials and that Brookline will attend the Monday meeting in Mason to follow up. No formal town vote on conditions for the Mason project was recorded at the July 16 meeting; members agreed to continue pressing for conditions and to circulate draft language for review before the upcoming Mason meetings.