Groundwater in the Great Lakes Basin

(U.S. EPA, 2006). The majority of the basin’s drinking
water supply systems were constructed before World
War II (Tate, 1990). In the 1960s, water utilities were
expanded to accommodate increasing urbanization. Since
then, few upgrades have been implemented (Renzetti,
2003). As a result of capacity problems and the associated
costs of maintenance and repair (Brooks, 2005), the
drinking water conveyance infrastructure is leaky and
water loss high. Inadequate infrastructure and capital
limitations have resulted in water quantity and quality
problems for cities in the Great Lakes - St. Lawrence
River Basin (Maas, 2003). A leak of only one drop per
second represents a water loss of 10,000 litres per year
(Environment Canada, 2000). It’s noteworthy that it is
at least three times more expensive to repair a water line
after it fails compared to the costs associated with regular
inspection and maintenance (Liquid Assets, 2008).
Toronto, for example, experiences about 1,600 watermain
breaks per year (Gray, 2008). Officials report
that aging pipes, including a batch installed in the
1950s that have corroded faster than expected, are to
blame for the increasing number of breaks. Breaks can
be sudden and catastrophic, such as one in 2006 that
resulted in a 10-metre-wide sinkhole that closed a major
road for several months. In another case, a prior watermain
break washed away soil beneath another heavily
travelled artery (Gray, 2008). Ultimately, in February
2008, freezing and thawing temperatures, coupled with
the continuous pounding of traffic, weakened the road,
leading to a cave-in 30 metres deep.
To ascertain the efficiency of the urban water infrastructure
in the basin, data and information collected
from interviews were combined with materials
published by Environment Canada and the U.S. EPA to
estimate the percent of water loss due to conveyance
for 16 cities in the basin. Only the residential sector was
considered.
The consequences of deteriorated urban water infrastructure
can be expressed as the volume of water
lost due to conveyance leakage (Figure 3) and as the
monetary cost to the city based on the charge for water
(Figure 4).
• Detroit has one of the largest, most inadequate
infrastructure systems in the basin. Conveyance
losses of approximately 17.2% equal 122,966,261 m 3
per year at a cost of approximately $ 55,088,884.
• Montreal is losing approximately 40% of its total
output, which equals 119,858,800 m 3 per year at a
cost of approximately $ 44,347,756.
• Toronto, which displays a more adequate infrastructure
system, is losing approximately 10% of
its total output to conveyance losses, which equals
24,531,156 m 3 per year at a cost of approximately $
31,277,233.
• Smaller cities such as Rochester, Duluth, Thunder
Bay and Sarnia have less urban water infrastructure,
leading to much lower losses from leakage in
the conveyance system.
Figure 3.
Amount of water lost per year due to
conveyance
To correct its water infrastructure deficits, Toronto
plans to hike water rates 62% by 2012 to fund a
ten-year plan to upgrade and repair the city’s 16,000
kilometres of aging water and sewer lines. If funding
were continued with the current price structure,
approximately 200 years would be required to replace
water and sewer lines (Gillespie, 2004).
In addition to monetary costs to the municipality
and, ultimately, the user, leaking municipal drinking
water conveyance systems allow a sizable quantity of
potable water to infiltrate the groundwater. Based on
this information, one can infer significant groundwater
infiltration of untreated water from leaking sewage
and stormwater conveyance systems. The relative and
absolute impact on groundwater quality and quantity
should be investigated.
Figure 4.
Amount of money lost per year due to
conveyance
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