Final Environmental Impact Report - Whittier Bridge/I-95 ...

Whittier Bridge/I-95 Improvement Project FEIR
Chapter 2.0: Response to Comments on the Environmental Assessment/Draft Environmental Impact Report
Response: It was mistakenly stated in the EA/DEIR that existing culverts under I-95 would be
enlarged as a result of construction activities. It has been determined that no existing culverts will be
enlarged for the project; highway widening activities north of the Route 110 interchange will be
restricted to the median and will not require modification of existing culverts. One culvert, located
between the Merrimack River and Route 110 in Amesbury, will be lengthened to accommodate the
relocation of I-95 northbound.
There are no impacts to wildlife habitat by the project, so no mitigation is required. Wildlife habitat
enhancement includes widening the existing wildlife passage under the Whittier Bridge by relocating
bridge abutments farther back from the Merrimack River shoreline, providing an enlarged corridor
within the RFA along the river banks, and consequently promoting wildlife connectivity between
areas east and west of I-95, an important wildlife corridor.
DEP-9: The last recorded major floods in the Merrimack River occurred in April 2007 and April 2010, so flooding
during the 42-month in-water work period is a likely possibility that needs to be anticipated and planned for in
advance of proposed work. As part of its ongoing technical assistance meetings, MassDEP will discuss with
MassDOT whether there are contingency measures that could be implemented to reduce impacts to resource areas
as a result of flooding during the construction period. If reasonable measures are available, MassDEP would
recommend that MassDOT propose them in the FEIR. A protocol for daily dewatering discharges to the Merrimack
River from the coffer dams also needs to be developed in advance, to limit turbidity impact from dewater to fishery
and avoid discharge of lead or asbestos in the dewater.
Response: Section 1.4.8 includes information on procedures to be included in the design/build
contract to be followed in the event of flooding events during construction. Section 1.4.9 includes a
draft protocol for dewatering discharges from the cofferdams to limit turbidity impacts and avoid
discharge of lead or asbestos in the dewatering discharges.
DEP-10: Standard 1: no new untreated discharges or erosion to waters/wetlands (310 CMR 10.05(6)(k)(1) and 314
CMR 9.06(6)(a)(1): The DEIR indicated 50 separate outfalls plus an unspecified number of bridge scuppers are
proposed to discharge stormwater runoff from redevelopment and new development sections of the roadway and
bridges. [MassDEP has concurred with MassDOT that it is infeasible for the Whittier Bridge to incorporate stormwater
treatment for the discharges from the bridges' scuppers into the Merrimack River. Therefore, references in [the DEP
comments] to stormwater treatment do not include this stormwater source.] The DEIR did not identify whether
stormwater treatment is to be provided at each outfall location. As the conservation commissions will hold public
hearings and may issue decisions in advance of completion of the MEPA process, MassDOT needs to provide a
table to each commission for each new outfall (including relocated outfall) and existing outfall to be retained, that
describes the TSS treatment to be provided at each new outfall and level of treatment to the maximum extent
practicable for each outfall to be retained.
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