Assessing Alberta's Water Quality (CAESA Study 1995-1998)

Reports from Europe and other parts of North America have identified agriculture as a major cause of water quality degradation. To assess whether this was the case in Alberta, a five-year study monitored water quality in the province's streams, lakes and ground water resources. Conducted under the Canada-Alberta Environmentally Sustainable Agriculture (CAESA) Agreement, the study provides a broad spectrum of information about the current status of water quality in agricultural areas, and creates a valuable baseline with which to compare future water quality studies. The study results sound a warning signal, but researchers emphasize that the situation can be improved through the adoption of improved farm management practices. Changes already being initiated by the farm industry and the government will help protect Alberta's water resources and keep Alberta's agricultural industry growing through the 21st century.

What Did We Learn?

The study found significant evidence that agricultural practices are contributing to the degradation of in Alberta.

High concentrations of nutrients and bacteria were found in many streams and lakes (surface waters), and in shallow groundwater in agricultural areas. These concentrations often exceeded water quality guidelines. set by the federal and provincial governments. Pesticides were detected frequently, though concentrations were usually below water quality guidelines.

Deep groundwater was monitored in 448 farmstead wells across the province. Agricultural contaminants were rarely found. Where detections did occur, poor well design and improper well maintenance were suspected to be the major causes, rather than contamination from agricultural practices.

Nutrients and bacteria do occur naturally in the environment, but the study found a significant correlation between the agricultural intensity in the area - measured on the basis of livestock density, and fertilizer and herbicide inputs - and the number and concentration of the nutrient and bacteria detections.

Contaminant levels varied considerably in different parts of the province, but the risk of water quality degradation was most significant where intensive agriculture is practised. The risk is greatest in those areas where overall agricultural intensity based on all input factors combined is high. However, the potential for water quality degradation also exists where only livestock densities are high, or where individual chemical inputs are high.

Additional Study Findings

Overall compliance of surface and groundwater in Alberta's agricultural areas with water quality guidelines is presented in the chart on the opposite page. Some of the specific findings from the study are given below:

Nutrients

• In general, nutrient levels did not exceed the guidelines for human and livestock drinking water.

• Nitrogen and phosphorus concentrations often exceeded water quality guidelines for the protection of aquatic life in streams, especially in high and moderate intensity agricultural areas.

• Phosphorus concentrations often exceeded guidelines for the protection of aquatic life in small lakes located in high intensity agricultural areas, and in irrigation canals.

High levels of nitrogen and phosphorus in surface waters are a significant environmental problem because they cause excessive aquatic plant growth. When these plants decay, they cause oxygen levels in the water to drop. The lack of oxygen affects the ability of fish and other aquatic life forms to survive.

Runoff associated with livestock operations and crops was identified as a major source of phosphorus, but the study did not specifically evaluate which agricultural activities caused the buildup of other nutrients.

• Nitrate in shallow groundwater occasionally exceeded drinking water quality guidelines. High levels of nitrate-nitrogen were also found in shallow farmstead water wells, but the specific source was unclear.

• Groundwater research indicates that continuous, heavy applications of manure and fertilizer are likely to result in detections of nitrate in shallow groundwater. Shallow groundwater aquifers without a protective layer of impermeable material above them are at greatest risk.

• Approximately 90% of water samples from streams in low intensity areas, and 94% of samples from streams in high intensity agricultural areas, exceeded the bacterial guidelines for human drinking water. All samples from irrigation systems exceeded drinking water guidelines for bacteria.

  Agriculture is one of the causes of bacterial contamination, but wildlife and other human activities contribute to the problem.

• Exceedences of guidelines for bacteria in dugouts were generally high. Human drinking water guidelines were exceeded more often in southern Alberta, than in the Peace River area of northern Alberta.

• Fecal coliform bacteria levels met irrigation water quality guidelines more often for source water than in the return flows, where the irrigation water returns to the river.

• The CAESA Farmstead Water Quality project showed a significant number of rural families do not test or treat their water supplies.

  Because bacterial contamination of surface water is widespread and derives from a variety of sources, public health officials strongly recommend all water be tested and treated before human use.

• Based on water quality guidelines for human and livestock consumption, and for the protection of aquatic life, pesticide residues from agricultural sources were not a significant problem.

• Very low level herbicide detections were frequently found in many surface waters and some ground water. Most detections were well below water quality guidelines. In surface waters, most detections were related to spring snowmelt events.

  Researchers believe the herbicides are left from previous seasons.

• Samples from irrigation canals showed residues of two of the herbicides tested, MCPA and dicamba, frequently exceeded water quality guidelines for irrigation.

• Levels of MCPA and dicamba exceeded irrigation guidelines in streams and lakes in high intensity agriculture areas. In general, herbicide levels were higher in irrigation canals than in other water sources in the province.

  Since canal water is used to irrigate a variety of crops, herbicides in irrigation water may have negative impacts on some crop yields.

• Herbicide levels in canals increased from upstream to downstream. The highest levels were found in irrigation return flows.

• A few low-level pesticide detections were found in farmstead wells. However, research studies conducted in central and southern Alberta indicate that over a long period, herbicides can leach into shallow ground water.

Three major monitoring projects were used to develop the baseline information for this study. In addition, a number of specific research projects augmented the monitoring work.

Monitoring of farmstead wells and dugouts
As part of this study, 824 wells and 126 dugouts were monitored, on farmsteads selected at random from rural municipalities across the province. Ground water from the wells was tested on a one-time basis. To get a more accurate picture of potential seasonal variations, 14 dugouts in northwestern Alberta were tested bimonthly.

Monitoring of surface waters
Using an innovative, scientific selection method, based on a large number of statistical databases, a total of 27 streams and 25 lakes in runoff-prone landscapes were monitored. The water bodies tested were chosen to represent areas of high, moderate and low agricultural intensity. The water bodies monitored were in non-industrial areas and were not located immediately downstream of a municipality.

The watersheds of Haynes Creek, near Lacombe, and of Crowfoot Creek, east of Calgary, were also studied on a more concentrated basis.

Monitoring of irrigation canals
Results from a number of monitoring projects, conducted between 1992 to 1996, were summarized. The samples compared water quality at locations where water entered the irrigation system, and in return flows, where water came back to the rivers. In all, water was monitored in six of Alberta's 13 Irrigation Districts. All are located in southern Alberta.

Research projects
A variety of research projects, based on field trials, computer modeling, and other approaches, explored the processes by which agricultural contaminants might affect water quality. The projects included research on the water quality impacts of different manure and nutrient management systems, and different crop rotation programs. Studies on the herbicide and nutrient leaching potential of different soils and groundwater geology were also conducted.

Water Quality Guidelines

Water quality guidelines are set by the federal and provincial governments for five categories of water use: human drinking water, recreation, livestock drinking water, irrigation, and the protection of aquatic life. The guidelines typically provide a protection factor of 10 to 100 times the identified safe limits.

Drinking water guidelines apply to all water used for domestic purposes, including cooking, laundry and personal hygiene. They are based on current scientific knowledge regarding human health and assume life-long use of the water being tested.

Recreation guidelines are based largely on the bacteria content of water used for swimming. Guidelines for livestock drinking water are based on current knowledge of the effects of regular use of the water for animals, and on human health concerns related to the consumption of the animals.

Irrigation guidelines are based on crop reactions to regular use of the water, and on human health concerns related to use of the irrigated crops.

Guidelines for the protection of aquatic life are set to ensure the survival of plants and animals that live in or near water bodies.

More Information

Assessing Alberta's Water Quality is one of a series of special information bulletins on agriculture and resource management produced by Alberta Agriculture, Food and Rural Development.

For copies of the CAESA Water Quality Study technical reports, or for more information on sustainable agriculture, contact your regional conservation co-ordinator or your district office of Alberta Agriculture, Food and Rural Development. Or telephone the Alberta Government RiteLine, toll free, at 310-0000.