Download Appendix 1: Agricultural water wells in Canada

The Sustainable Water Well Initiative Business Case Report
April 2011
Appendix 1: Agricultural water wells in Canada
Across Canada the needs of agricultural well-owners, and how those needs may be met, are
influenced by differences in climate, geology, regulations and programs, demand for and uses of
water, well ownership structures and the physical stresses on groundwater supplies. Limited data
on the use of groundwater across Canada presents a challenge to identifying the number, location,
and needs of agricultural groundwater users. However, available information can provide some
insight. Figure 1 shows the location of water wells across Canada, which are concentrated in highly
populated and agricultural production areas. Figure 2 shows annual soil moisture deficit, which
indicates to an extent the dependence of producers upon irrigation, and may indicate higher
volumes of water use, and therefore greater use of groundwater resources where groundwater is
used. It also suggests potential groundwater recharge, and therefore aquifers in areas of high soil
moisture deficit may experience both greater than average groundwater demand and also lower
volumes of groundwater recharge. Average farm size is more than three orders of magnitude
greater in some parts of the prairies than much of the rest of the country (Figure 3). The trend in
Canada is for the number of farms to decrease while the total area of cropland is increasing[1],
which can be expected to influence water use and the financial resources available for managing
water supplies. Figure 4 shows the risk of coliform contamination in agricultural watersheds; hot
spots in southern Ontario and parts of the Prairie Provinces demonstrate that risks to groundwater
supplies differ across the country. The information provided here draws attention to the southern
prairies as a location where groundwater demand and pressures may be high. A more thorough
analysis is required to identify specific needs and priority areas for agricultural groundwater use
across the country.
Figure 1: Water wells across Canada (from Natural Resources Canada)
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The Sustainable Water Well Initiative Business Case Report
April 2011
Figure 2: Annual soil moisture deficit
(from the Agriculture and Agri-Food Canada report The Health of our Water)
Figure 3: 2006 Average farm area (from Agriculture and Agri-Food Canada)
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The Sustainable Water Well Initiative Business Case Report
April 2011
Figure 4: 2006 Risk of water contamination by coliforms in agricultural watersheds
(from Agriculture and Agri-Food Canada)
Dependence on groundwater
While data on groundwater use across Canada varies greatly in level of detail and accessibility, the
available information shows that dependence on groundwater differs dramatically between regions.
The population dependent upon groundwater for drinking water in 1996 ranged from 27.7% in
Quebec to 77.8% in PEI (Table 1). Information on the amount of groundwater that is allocated to or
used in agricultural is not readily available; water meters are not used in most irrigation systems
and only Alberta and Saskatchewan attempt to record volumes of groundwater used. Critical data
needed for groundwater management and targeting possible program recipients is missing on
groundwater allocation and use across all sectors[2]. In some jurisdictions it is not possible to
identify the number of farms using groundwater; some farmers use groundwater for agriculture in
the Yukon, but the number of farms using groundwater is not tracked, and British Columbia
currently does not require licenses for groundwater use, though that may change with the
modernization of the BC Water Act. Ontario and Manitoba are moving towards requiring reporting
of groundwater withdrawals[2]. Groundwater is not used for agriculture in the North West
Territories.
Nowlan (2005)[3] has compiled data that shows that, where information is available, groundwater
use allocated to agriculture ranges from as low as 3.1% in Saskatchewan to 44% in Manitoba
(Table 1). The amount of groundwater used for agricultural purposes varies regionally, as
evidenced by detailed studies in several Quebec watersheds where percentages of groundwater
use going towards agriculture varied from 23 – 42%[4]. Increased water demand is expected in the
agricultural sector as a result of increased demand for agricultural products and the impacts of
climate change[1].
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The Sustainable Water Well Initiative Business Case Report
April 2011
Table 1: Groundwater use across Canada (adapted from Nowlan, 2005[3])
Province / Territory
Percent of groundwater use
allocated to agriculture[3]
Population reliant on groundwater
[1996 data]
Number (%)[3]
British Columbia
20%*ii
1,105,803 (28.5%)
Alberta
16.9%iii
641,350 (23.1%)
Saskatchewan
3.1%iv
435,941 (42.8%)
Manitoba
44%v
342,601 (30.2%)
Ontario
27.3%
3,166,662 (28.5%)
Quebec
16%
2,013,340 (27.7%)
New Brunswick
No known allocations
501,075 (66.5%)
Nova Scotia
Not available
426,433 (45.8%)
Prince Edward Island
Not available
136,188 (77.8%)i
Newfoundland / Labrador
Not available
189,921 (33.9%)
Yukon
Not available vi
15,294 (47.9%)
North West Territories
Not available
18,971 (28.1%)
Notes:
* Estimate
i. Reporting for PEI is incomplete. Currently there are 13 municipal water systems in PEI, all of which are completely
reliant on groundwater.
ii. Datum from 1981, and no updated data are available, though the ministry advises that the percentage use by various
sectors may not have changed significantly.
iii. Datum from 2001 and includes “agriculture” (16.5%) and irrigation (0.4%)
iv. Datum from 2004 and includes “irrigation-agriculture” (1.1%) and “industrial-intensive livestock” (2%)
v. Datum from 2005 and includes “agricultural” (7%) and “irrigation” (37%)
vi. It is expected that most greenhouse production in the Yukon is groundwater dependent, which included 22 of 148
farms in 2006, and for livestock watering, but groundwater use in agriculture is not tracked[5]
Groundwater Trends Relevant for Agricultural Well Owners
Agricultural practices depend upon a reliable source of safe water, and they also have the potential
to impact water quality and supply. The National Round Table on Environment and Economy cite
climate change adaptation and impacts on water quality and ecosystems as the key water issues
currently facing the agricultural sector in Canada[1]. Climate change scenarios predict increased
likelihood of extreme weather events, which may increase the incidence of floods. Changes to
precipitation patterns may also reduce recharge, and shallow aquifers may be especially
vulnerable during dry summer and fall months[6]. Some climate change scenarios predict an
increase in the frequency and length of droughts, and wells that are not properly monitored or
maintained are increasingly vulnerable to water shortages.
Avoiding contamination of groundwater is important due to the difficulty of remediating
contaminated groundwater which may leave aquifers in an unusable state for many years, the
large amounts of groundwater that can be impacted by contamination, the potential impacts on
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The Sustainable Water Well Initiative Business Case Report
April 2011
human and environmental health, and the difficulty of providing alternative water sources. Land
use decisions are critical for reducing the risk of groundwater contamination. Contamination can be
caused by local point source pollution such as livestock effluents, mining, other industries, and
waste disposal; it may also be caused regionally by diffuse sources such as agriculture. The
National Water Research Institute (NWRI) and the Geological Survey of Canada (GSC) are
collecting information to identify national trends in groundwater quality[2]. There have been many
cases of localized groundwater contamination in Canada, rendering groundwater unsuitable for
consumption or agricultural uses. The most frequent contaminants include nitrate, microbes,
metals, petroleum products and organic chemicals[2]. The impact of oil and gas wells is an
emerging issue with potential for cross contamination of upper aquifers by lower and poorer quality
aquifers due to deep wells acting as pathways between aquifers. The cumulative impact on
groundwater resources of approximately 1 million oil and gas wells over Northeast British
Columbia, Alberta and Saskatchewan is gaining attention but to the knowledge of the authors has
not been explored in detail.
There have been no cases of wide spread groundwater depletion in Canada, but there is an
increasing number of local examples. With many increasing stresses on both the quality and
quantity of groundwater resources, and the critical nature of these resources for human health,
economy, and ecology, they must be managed carefully in the future to avoid the types of
tragedies that have occurred in other parts of the world[2]. Groundwater “hot spots” are beginning
to emerge across Canada, including Manitoba where groundwater withdrawals have reversed
groundwater flow away from Lake Michigan, and central Alberta where new pipelines are now
transferring water between basins to supply water demands that can no longer be met by local
aquifers[3]. Localized groundwater depletion is an emerging issue of relevance in many parts of
Canada.
1.
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7.
8.
9.
Canada, N.R.T.o.t.E.a.t.E., Changing Currents: Water Sustainability and the Future of
Canada's Natural Resource Sectors. 2010, Canada. National Round Table on the
Environment and the Economy.: Ottawa, Ontario.
CCA, C.o.C.A., The Sustainable Management of Groundwater in Canada: Report of the
Expert Panel on Groundwater. 2009, Ottawa: Council of Canadian Academies. 254.
Nowlan, L., Buried Treasure: Groundwater Permitting and Pricing in Canada. 2005, The
Walter and Duncan Gordon Foundation.
Études stratégiques PAECQ. [cited 2011 21 February 2011]; Available from:
http://www.cdaq.qc.ca/ShowDoc.asp?Rubrique=365&Document=369&Contentid=479
.
Matthew Ball, E.M.a.R.Y., Personal Communication, K. Trajan, Editor. 2011.
Simpson, H., Promoting the management and protection of private water wells. Journal
of Toxicology and Environmental Health, Part A, 2004. 67: p. 1679-1704.
Sterrett, E.R.J., Groundwater & Wells Third Edition. 2008: Johnson Screens.
Mansuy, N., Water Well Rehabilitation: A Practical Guide to Understanding Well
Problems and Solutions 1999: Lewis Publishers.
Cullimore, R., Microbiology of Well Biofouling.
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