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Ground water levels

Ground water levels are of critical importance to every person on Earth – and get more important every day. Here’s a Canadian statistic that may be surprising. According to Water Security, a Primer (a document produced by the Canadian Water Network (CWN)), one quarter of all Canadian communities experienced water shortages during the latter half of the 1990s. Stats like this one make us understand how important it is to measure, monitor and protect our ground water levels. The good news is that steady progress is being made with these tasks across the country.

Ground water levels are of critical importance to every person on Earth – and get more important every day. Here’s a Canadian statistic that may be surprising. According to Water Security, a Primer (a document produced by the Canadian Water Network (CWN)), one quarter of all Canadian communities experienced water shortages during the latter half of the 1990s. Stats like this one make us understand how important it is to measure, monitor and protect our ground water levels. The good news is that steady progress is being made with these tasks across the country.

The term to describe having adequate quantities of good-quality water on an ongoing basis, for human use and the environment as well, is water security. The World Economic Forum has called it “the gossamer that links together the web of food, energy, climate, economic growth and human security challenges that the world economy faces over the next two decades.” According to the CWN and its associated Canadian Watershed Research Consortium, no widely accepted, standardized index of water security yet exists in Canada (or elsewhere for that matter), but extensive efforts to establish one are underway.

Several water security indices have already been developed, but they have generally been limited in focus – for example, relating only to drinking water. They therefore don’t allow decision-makers to do things like effectively assess and handle conflicting demands for water use. Developing a useful and comprehensive index is a tough task, with key challenges that include defining exactly what needs to be measured and at what scale.

People like Gemma Dunn are forging ahead. “For our recent research project [www.watersecurity.ca], we developed the Water Security Status Indicator assessment method,” notes the research associate in the Program on Water Governance at University of British Columbia. “It is not a new indicator, but rather a method that allows for the simultaneous analysis of multiple indicators.” It adopts a localized “place-based” approach and examines both surface water and ground water. “One other point to mention is that water security implies a long-term view,” Dunn adds, “yet indicators can only assess its current state. A comprehensive assessment of water security should [therefore] also include the assessment and management of future risk to water quality and/or quantity.”

Read on for a look at ground water levels across Canada compared to average and historic levels, the factors affecting them, details on monitoring programs and more.

British Columbia
The B.C. Ministry of the Environment operates the Provincial Observation Well Network in order to monitor long-term fluctuations and trends in ground water levels. These 189 wells are generally established in areas of human settlement, and collect data automatically to provide an understanding of how specific aquifers are replenished and how ongoing use is affecting water availability. From 2000 to 2005, 35 per cent of the wells experienced lowering water levels, up significantly from 21 per cent during the period from 1995 to 2000. These decreasing levels don’t appear to be related to natural variations in precipitation, but could be a result of increased monitoring in the most heavily developed aquifers, reports Ministry of the Environment spokesperson David Karn.

He adds, “It is difficult to summarize the ground water level conditions of the province as a whole, due to the province’s varied topography and hydrogeology.”

The current focus for the Provincial Observation Well Network is to equip the observation wells with data loggers that are compatible with satellite telemetry to enable public access to near real-time ground water level data, to improve data verification methods, and to develop user-friendly online reporting.

Professor Diana Allen of the Department of Earth Sciences at Simon Fraser University and her colleagues have been studying ground water levels in B.C. wells not affected by human use. Results of Allen’s recent studies, conducted with Paul Whitfield and Dan Moore, are about to be submitted to the Canadian Water Resources Journal. “Overall, summer ground water levels seem to have lowered across the province,” Allen notes, “despite an increase in winter precipitation and recharge during the same time period.”

Alberta
As in B.C., most of Alberta’s Groundwater Observation Well Network (GOWN) wells are also equipped with technology that automatically measures and records water levels, with select wells already equipped with telemetry for near real-time readings. GOWN was initiated in 1957 and continues to expand beyond its current 280 wells. “Data acquired from the GOWN helps Alberta Environment and Sustainable Resources Development develop environmental indicators,” says spokesperson Renée Hackey. “Existing preliminary studies have looked at local responses of ground water systems to climatic conditions (primarily precipitation rates) and observed a positive correlation.” In terms of annual levels, ground water levels in Alberta are similar to those across Canada – typically rising during spring and early summer, following snowmelt and spring rains, then declining slowly over late summer and through winter when frozen ground inhibits recharge. Hackey says, “GOWN observations show a delayed response of ground water level in the Rockies and foothill areas, whereas Prairies regions tend to respond faster, with water level rising very fast following heavy rainfalls.”

Obviously, the magnitude of ground water level fluctuations can vary greatly from season to season and from year to year, but it’s heartening to know that a high-level assessment of Alberta’s ground water level records indicates no significant changes compared to historical levels.

“Currently, there is a provincial groundwater mapping and inventory program underway to help assess and quantify the state of our ground water resources,” says Hackey. “This initiative will support the establishment of baselines against which to assess the magnitude, and, cause and effects of ground water level fluctuations, and the sustainability of the ground water resource in the province.”

Saskatchewan
Ground water levels have currently been relatively constant in the monitoring network operated by Saskatchewan’s Water Security Agency (WSA). However, since the high precipitation events of 2010, 45 of the 70 wells reached record high levels,” notes WSA communications manager Patrick Boyle. For example, three monitoring wells in the Saskatoon area increased by 4.33 m, 3.17 m and 0.96 m. Dr. Cherie Westbrook confirms that the province’s ground water levels in the southern half of the province are at historic highs.

“Many southern Saskatchewan streams flowed continuously through the summer and into the fall in the last couple of years, whereas they normally only flow during snowmelt and heavy rains,” notes the associate professor at the Centre for Hydrology in the Department of Geography & Planning at the University of Saskatchewan. “These baseflows are normally ground water-flow supported.”

Westbrook has been looking at records going back to the 1960s, and says that current levels are similar to those observed in both 1975 and 1985, although they were only transiently high (for a year or two, not several years in a row). “I focus mostly on unconfined aquifers,” she says. “I have looked at a few records for confined aquifers, and they too show higher water levels over the past few years, as compared to the record. It’s been super wet around here, since about 2006.” Besides land use changes, human use and climate variations, Westbrook notes that a local factor that can affect unconfined aquifer ground water levels is beaver damming, which she researches in the mountains of Saskatchewan.

Looking back, Boyle adds, “There were also seasonal fluctuations and declines in water levels due to droughts in 2002 and 2003. The one exception was in observation well “Verlo” located in the Great Sand Hills.” The long-term level there has been in slow decline, and the WSA is not yet sure why. The well is not affected by pumping.

Prairies
Cesar Perez-Valdivia, who is completing a PhD in environmental engineering and is also a senior hydrological engineer with the WSA, has been studying Prairie ground water levels with Drs. Jessica Vanstone and Dave Sauchyn of the Prairie Adaptation Research Collaborative at the University of Regina. Not surprisingly, the team found that shallow aquifers are strongly affected by precipitation and temperature. Ground water level trends seem to move in two-to-seven-year and seven-to-10-year oscillation modes, but an 18-to-22-year ground water level trend was also evident. The team believes it’s worth investigating how atmospheric pressure patterns might affect long-term ground water levels in shallow unconfined aquifers. They also note that because moisture-sensitive tree ring chronologies have proven to be useful in southern Alberta to reconstruct historical records of ground water levels in shallow aquifers, they may prove useful in southern Saskatchewan as well. In a separate study, Perez-Valdivia and Sauchyn looked at 33 wells across the Prairies. These wells, mostly located in sand and sandstone area aquifers and not affected by human use, were found to be highly sensitive to climatic variations.

Manitoba
Manitoba has been monitoring water levels in major aquifers since the mid 1960s, so in some areas, there is up to a 50-year record. “Ground water conditions are generally quite good throughout the province,” says Graham Phipps, manager of the ground water management section at Manitoba Conservation and Water Stewardship. “Most monitoring wells show that levels are returning to near long-term averages or remain above average after major recharge events in the 2000s and especially after the spring of 2011. Over the past decade, water levels have tended to fluctuate around or above long-term averages.”

Drought in the 1980s affected long-term water levels throughout most of the province, but they recovered during the decade after. Most areas with a long enough record show that the lowest water levels occurred between 1989 and 1994. Phipps says the only current concern related to drought is for very shallow wells completed into thin superficial aquifers, where water levels may drop to a point with insufficient drawdown remaining in the well. “In areas where this occurred during the summer of 2012, the wells can usually be deepened to provide a more reliable supply,” explains Phipps. “In recent years, high ground water levels have been a greater concern than drought in some areas of the province where the water table has risen enough to affect basements.”

Indeed, some areas of Manitoba have recently set new maximum water levels. “Winter precipitation this year was near normal for the south-central and south-eastern regions and above average for the western and north-western areas of agro-Manitoba,” Phipps notes. “The slow spring melt should lead to good recharge throughout all areas and possibly above average in the west.”

Ontario
In response to the 1998-99 drought, the Ontario Ministry of the Environment (MOE) established the Provincial Groundwater Monitoring Network, with various conservation authorities and municipalities serving as partners. “The wells monitor ambient ground water levels and quality in major aquifers,” says MOE communications officer Kate Jordan. “Ground water levels are collected hourly from 471 monitoring wells and water samples are taken annually.”

The water level data is also being analyzed. For example, MOE staff has been working with the Ontario Ministry of Natural Resources and hydrogeologists from various conservation authorities to determine the best statistical methods to apply. “The lowest ground water levels occurred during years 2001, 2002, 2007 and 2012, when low water conditions were experienced in Ontario,” Jordan explains. “However, in 2008 a cool and wet summer occurred and ground water levels were higher than normal.” The MOE has also worked with Environment Canada to look at how ground water levels could potentially be different in the future using the projections from 26 different climate models. “It was found that by the year 2100, ground water levels could increase by up to 10 cm or decrease by up to 50 cm,” Jordan says.

Prince Edward Island
The province has 16 ground water monitoring wells with the data – including some real-time data – already available on the Internet. “These long-term records show that ground water levels are essentially flat, with typical seasonal variations,” says Ron Ryder, communications officer at PEI’s Department of Environment, Labour and Justice.

Data from Bloomfield, New Dominion and Caledonia can be used as examples, he says, with each well providing data going back over 30 years. “Average annual levels in since 2005 are higher than long-term averages, but this is simply a reflection of recent annual precipitation,” Ryder notes. “It would be premature to attribute this to climate change or indicate a change in long-term levels. The lowest levels occurred in the second half of 2001 due to an unusually dry summer.” There has been some recent research on possible climate change impact for Prince Edward Island. Ryder says it focused on sea level rise effects on sea water intrusion to ground water, and these were shown to be negligible.

Nova Scotia
Nova Scotia has 38 observation wells. Results from 2012 show that only 13 of them exhibited statistically significant ground water level trends last year, with five having small upward trends and eight having small downward trends. “The downward trends tend to be larger than the upward trends,” says Jason Dauphinee-Muise, manager of water resources at Nova Scotia Environment. Most of the trends indicate ground water level changes of less than 1 m. “In the eight wells that are showing small downward trends, the reason has not been confirmed; however, three of these observation wells are located in municipal well-fields where water level declines are expected to be associated with well-field pumping (for the town’s water supply). The province does not have data comparing currently levels with historical data.

New Brunswick
Ground water levels in New Brunswick were monitored from the early 1970s to 1993 using a Stevens F-type recorder coupled with manual observations. “During that time, it appeared that the province-wide trend indicated a general increase in water well levels,” says Darryl Pupek, director of environmental evaluation and reporting at New Brunswick’s Ministry of Environment and Local Government. Between 1993 and early 2000s, the ground water monitoring network was disbanded. However, the network was subsequently re-established and currently has one,third of the original number of monitoring locations. “Trends at existing sites,” says Pupek, “although very preliminary, appear to suggest stable levels across the province. It’s expected that ground water levels should remain relatively stable for the foreseeable future.”

Pupek also points to an analysis by researchers Barret Kurylyk and Kerry MacQuarrie (from a study which is currently being published) of average annual ground water level recharge from snowmelt over the period from 1961 to 2000. They found that over the years, there were increases of as much as 50 per cent to a decrease of six per cent, in comparison to the average. “The snow pack in the Saint John River Basin, both in the north and south regions of the basin,” Pupek notes, “has been trending slightly downward.”

Newfoundland and Labrador
While Newfoundland and Labrador does not have long-term historical data or a current ground water monitoring well network with which to compare current groundwater levels, this past year the Department of Environment and Conservation received a number of inquiries, both from municipalities and private well owners, regarding wells drying up or losing capacity. However, “a number of the private wells which dried up were dug wells,” notes Tina Coffey, communications officer at the department.

“It is likely that water losses reported to us last year were due in part to less precipitation in the summer,” she adds. “We have no data to link ground water levels to snow amounts. Additionally, the areas where wells have been affected are in the populated areas that rely on groundwater for drinking water supplies.” They have no data thus far indicating if the reported water level declines are province-wide.

Northern Canada
No ground water or surface water monitoring occurs in Nunavut. In the Northwest Territories, surface water levels are monitored in 14 rivers and Great Slave Lake. In general, using decade averages, river “winter flow” shows increasing trends across all eco-zones, and for large and small basins alike. There was a temporary drop in river levels associated with an earthquake in 2002. From 1968 to 2010, the Slave River’s total annual flows are trending downward slightly. From 1968 to 1971, Slave River flow was reduced while the Williston Reservoir on the Peace River in British Columbia. was filled. Since related hydroelectric operations began in 1972, the lowest total
annual flow was experienced in 2010, after several years of extremely dry conditions in the northern regions of British Columbia, Alberta and Saskatchewan. Comparable extreme lows occurred previously in 1980, 1981 and 1995.

Water levels in Great Slave Lake are influenced by the Slave River as it contributes about 77 per cent of the inflows. With regulation of the flow of the Peace River since 1968, the total volume of the Slave River has not changed, but the flow regime change has reduced the average high level of Great Slave Lake by 9 cm.

As in the Northwest Territories, the earthquake in 2002 also temporarily reduced water levels in the Yukon. However, they have stayed steady otherwise. “Our longest ground water monitoring record goes back to 2001 (six monitoring wells, mostly around Whitehorse) and while there has been some annual fluctuation, there are no evident trend patterns in this record,” says J. Richard Janowicz, manager of the Hydrology Water Resources Branch at the Yukon Department of Environment.

Treena Hein is a science writer based in Ontario.