Civil Engineering Reference
In-Depth Information
low-value crops (Bjornlund 2010). As a consequence, the extraction of surface
water and hydrologically connected groundwater for all forms of consumptive
use was capped.
Even eastern Canada, which has traditionally been seen as having a
plentiful water supply, has had increased problems. Recent mid-summer base
flows in the Grand River, Ontario, which supplies several mid-sized cities,
were primarily comprised of treated sewage. Pollution of a municipal ground-
water source from diffused agricultural sources caused death and illness in
the town of Walkerton in 2000 and prompted a considerable response from
policy-makers (Ferreyra
et al.
2009).
Box 1.4: Managing urban water supply and pollution in
southern Ontario, Canada
Grand River, Ontario
The Grand River is characterised by seasonal flow of heavy spring
runoff with a low end-of-summer flow primarily maintained by treated
sewage discharged by the many small towns and cities in southern
Ontario that it runs through on its way to Lake St Clair, the smallest
of the Great Lakes. It is Canada's only designated 'Heritage River' in
a built-up area, designated partly due to historic mills, a canal, and
other man-made waterway features. The management body, the Grand
River Conservation Authority (GRCA), is trying to restore original
flow patterns to some extent, which have implications for water use
restrictions and historic mill races. The GRCA deals with multiple
well-informed stakeholders and relies on provincial government
agencies and local community groups to implement many of its actions,
although it is unique in having its own source of funding from small
hydropower projects and camping fees.
Walkerton, Ontario
The case of Walkerton is an example of a government policy and legis-
lative response to an environmental disaster that killed 7 people and
made 2300 seriously ill in southern Ontario in May of 2000. One of the
wells supplying the town of Walkerton (pop. 5000) became contami-
nated with
E.coli
as a result of a nearby feedlot effluent draining into the
aquifer recharge area, known for years as a potential source of contami-
nation. An inquiry, known as the Walkerton Commission, found
the Walkerton Public Utilities Commission operators to be grossly
negligent. The preliminary direct economic impact was estimated at
$65M. Recommendations focused on source water protection and a
comprehensive multi-barrier approach, among other things.
