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Capital
Campaign - Drainage Project
For many
years, St. Andrews Church has sustained water damage in the
basement classrooms causing mildew, rot and damage to
furnishings. During
the summer of 2008, a number of contractors were contacted to
develop a permanent solution to recurrent water in the
basement of the church. These
solutions were for inside work to address the problem – some
of the estimates were as high as $250,000.
Obviously the church could not afford this amount of
money and more importantly, the problem of water coming into
the basement would not be eliminated.
The
Properties Ministry decided to look into other solutions.
Measurements and rough calculations indicated that the
probable cause was inability to carry surface water from rain
storms away from the building at a rapid enough rate, thereby
causing the water to back up into the basement. During a thunderstorm, the water levels were observed and
recorded in pictures to document what happened. Observations confirmed that this was the primary cause of
water coming into the basement.
The photos and analysis were shown to the parish in the
Presentation of 12-14-2008 along with plans of the work
necessary to correct the problem.
As an
explanation, the original design of the church drainage
provided a single dry well with about 20% of the capacity
needed to drain the water from a typical thunderstorm.
The design life of dry wells is about 50 years allowing
for silt buildup and roots blocking the water flow – both
silt and roots were extreme in our dry well before correction.
This means the capacity had been greatly reduced from
the design capacity to perhaps 10% of that needed to keep the
basement dry. Clearly
this problem had to be corrected.
The church
hired Schofield Brothers to perform a complete analysis and
develop a design to handle the surface water runoff.
Using computer software to predict the 100 year storm,
a design was developed for a complete church remediation plan.
To confirm the adequacy of the plan, a perk test was
conducted at two points in the planned drainage area.
The perk test confirmed that the soil was sandy
(providing good drainage capability) and that the water table
was well below the level of the church basement floor and was
not the cause of the water in the basement.
The plan was broken into 5 separate manageable parts.
Since the major problem was associated with the runoff
on the north-east area of the church roof/driveway, etc, it
was decided to focus on Phase A and its associated downspout
connections (Phase C).
Bids were
solicited from four (4) contractors to perform the necessary
work. The lowest
bidder was D. J. Morris of Sudbury with whom a contract was
signed to install the Phase A work.
The work was performed in the spring of 2009.
This resulted in a new water quality unit and a
recharger field of about 50 feet by thirty feet, about 8 feet
deep. Water
outflow from the existing drywell was routed to the new water
quality unit. The
steps installing this are shown in photos A-01 through A-13.
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