| The Summer Street Bridge:
A Behind The Scenes Look At How KKWWD Dealt With The Closure Of The Summer Street Bridge in Kennebunk
Don Gobeil, Technical Services Director
In the normal everyday operation of our utility, we function just like most organizations and
businesses. We follow a detailed and comprehensive budgeting process that establishes priorities
for the upcoming year based upon identified needs and available resources. At the same
time, we are cognizant of the realities of operating a far flung multi-town utility. One such reality
is, stuff happens. We must also react to situations that occur that are beyond anyone's control.
Water main breaks are one example of an unanticipated event that must be dealt with, regardless
of its budget implications. Another example is the recent episode involving the Summer
Street Bridge in Kennebunk. Because of the unique, high profile nature of this project, it
provides us an opportunity to offer others a behind the scenes glimpse of how a utility reacts
and responds to a serious, unanticipated emergency.
In 1987, the Water District, as part of its long term system improvement program, installed a
new 16-inch water main along Summer Street. The main utilized the bridge as a way of crossing
the railroad tracks. A 16-inch water main, for us, is a large diameter main. It is designed to
carry a significant percentage of the water necessary to supply the Lower Village of Kennebunk,
Kennebunkport and coastal Biddeford.
When the call came in on Tuesday, July 27, 2004 that construction work being done on the railroad
tracks had de-stabilized the bridge footing, we understood immediately the potential implications
this event could have for us. Any disruption in our capability to deliver water to Kennebunkport
and beyond during the height of the summer season could become a major issue. We
were now thrust into being a key player in a blossoming emergency and had to act quickly. The
following day, at a tense meeting held among all the involved parties at the Water District office,
a strategy for immediate action was developed. The bridge had to be removed and a temporary
bridge installed as quickly as possible, and a new bridge had to be designed and built.
The District immediately identified several issues that had to be acted upon quickly. Among
them were: 1) Was the existing water main in immediate danger of failure as a result of the
bridge settlement? 2) How could we deliver an adequate supply of water to Kennebunkport in
the event we lost the main, and how will we deal with not having the main available when it
had to be removed to facilitate the construction of the new bridge? And 3) We needed to immediately
design and plan for the new permanent main. All this activity was happening while we
were busy trying to implement all the worked we had already planned and budgeted for.
Figure 1 - Part of the main hanging after the bridge removal. | In evaluating the integrity of the existing main, we undertook a thorough and detailed engineering
review of the construction methods and materials used during the original 1987 installation
of the main. We determined that while the bridge 'carried' the
main from one side to the other, it was not actually
supporting it. This evaluation allowed us to decide
to keep the main active
while the bridge was dismantled and removed. The
actual bridge demolition induced serious vibration
stress on the main, but when demolition was complete,
the main literally hung in thin air from one side
to the other (see
figure 1).
At this point we had a functioning main with as yet no disruption of service. But we knew that the main
would need to be removed to accommodate the building of the new bridge. The only other water
main serving Kennebunkport is a smaller 10-inch main coming from Wells along Route 9 (Western
Avenue). We had to analyze the hydraulic capacity of the main to determine if it could meet
the demand load. We found that in order to safely meet the demand, we had to design and build
a temporary booster station along Western Avenue. With the unconditional cooperation of the
Kennebunk Sewer District, we were able to use part of their lift station site on Western Avenue
to place our temporary booster facility. To design and build a booster station is a very technical
process. The fact that we could accomplish this task in-house in a condensed time frame is a
testament to our talented staff and is something we are very proud of.
Figure 2 - A look at the new piping showing the changed geometry. | While this process was ongoing, we had to design the new permanent water main. The new bridge
design was vertically and horizontally different than the original bridge. This proved to be a challenge
in geometry to ensure that the main installed on the new bridge could be connected successfully
to the existing mains on either side (see figure 2). Along with that, all the construction
activity had to be choreographed around the work being done by the bridge contractor, all within a
very tight timeline. Our part of the overall project had to go smoothly or serious delay and disruption
of the overall project would result. In the end, on November 16, 2004, the bridge was
complete, a new water main was in service and traffic flow was restored.
The significance of this event is the reality that providing an uninterrupted supply of water to
our customers relies not only on good planning and anticipation, but also on the ability to react
and adjust to situations that arise that are beyond anyone's control. Over the course of three
months and hundreds of hours of staff time, we were able to successfully meet the challenge
that this event represented, with no compromise of service to our customers.
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