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As the consultant to the Bridge Design Review
Committee on the question of the feasibility and
cost of a tunnel, I would like to correct
misunderstandings about the tunnel option for the
crossing.
Tunnels, to carry all or some of the roadways
across the Charles River, are technically feasible
and pose none of the environmental hazards
suggested by Hughes.
Borings from the river bottom showed that the
soil contained a normal level of pollution -- it is
not a severely toxic mess.
The soil would not present any special problems
for disposal or to aquatic life during
construction. The material excavated in building a
tunnel could have been disposed of as are other
excavated material from the Central Artery (they
have different disposal/treatment procedures
depending on the level of contamination). While
dredging for the tunnel would have stirred up the
river bottom, there are methods for constructing
tunnels, which minimize soil disturbance and/or can
contain the stirred up material.
The BDRC did not consider in detail the variety
of tunnel construction options, although many
members favored a tunnel.
Tunneling does have potential problems -- such
as river constriction during construction -- but
these can be accommodated by proper design and
construction of the project.
Thus, it is not correct to say that
environmental issues disqualified a tunnel as an
option for taking the highway across the Charles
River, or that a tunnel was unbuildable.
Also, the effect of the Central Artery North
(Charlestown) project literally casting boundary
conditions in concrete is not mentioned in Hughes
article.
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