Water Report

Executive Summary

The Region of Peel State of the Environment: Water Report is the second in a series of three state of the environment reports being prepared by the Region of Peel. The objective of this report is to establish baseline conditions for groundwater, surface water and drinking water resources in Peel Region and determine if conditions are improving or deteriorating.

The organization of Peel's State of the Environment: Water Report reflects the movement of water through the hydrologic cycle from groundwater to surface water to Lake Ontario. Beginning with groundwater, this section provides a description of groundwater resources in Peel Region and addresses its availability and quality as the primary source of drinking water in the Town of Caledon. The following section, on surface water, provides indicators of water quality and water quantity for the three main watersheds in Peel Region, the Credit River, the Etobicoke Creek and the Humber River. The final section, Lake Ontario, assesses the quality of the water along the Mississauga waterfront as a natural resource and as a source of drinking water for residents in Mississauga, Brampton and parts of Caledon.

Groundwater

Groundwater is an important component of stream baseflow and a significant determinant of surface water quantity and quality. This in turn influences the suitability of surface water as habitat for plants and animals. Groundwater is also a valuable natural resource which permits development in areas where surface water based municipal piped water is not available. Since most areas of Mississauga and Brampton are now serviced by municipal water from the South Peel Water Supply System, groundwater availability is of greatest interest in the Town of Caledon. In this section of the State of the Environment (SOE): Water Report, groundwater is assessed in terms of its availability and its quality as a source of drinking water in the Town of Caledon.

Overburden aquifers are important sources of water for municipal wells in Alton, Caledon Village, Caledon East, Palgrave and Bolton. A large number of private wells in central Caledon between Sandhill and Campbell's Cross and north east Caledon also draw water from overburden aquifers.

The settlements of McLeodville, Skywood and Mono Mills are supplied with water from bedrock aquifers located in north west Caledon. The well yields in this area are generally good, however shallow bedrock wells may fluctuate due to seasonal and annual variations in precipitation recharge to the aquifer. South central Caledon and east Caledon from Palgrave to Wildfield are also supplied with water from bedrock aquifers. Bedrock formations in these two areas of Caledon are comprised of dense shales which do not transmit water well and constitute poor aquifers. Although they are poor water bearing zones, many private wells sufficient for domestic purposes have been developed in these areas of Caledon.

As water requirements of modern households continue to increase, the availability of groundwater may be a limiting factor to growth and development in areas serviced by private wells or municipal communal wells. The yield from Regional production wells is critical if higher density development in areas not serviced by the South Peel Water Supply System is to be supported. If the quantity of groundwater available is insufficient to service the projected population growth, then either ground or surface water must be piped in from other localities, often at considerable expense, or the desired growth cannot occur.

The Region of Peel currently operates several separate communal well systems in the Town of Caledon. It is the legislative responsibility of the Region of Peel to ensure that the water provided for human consumption is fit to drink and that water samples be analyzed for specified bacteriological and chemical parameters at a specified frequency. The results of selected parameters tested in communal well water samples collected in 1993 are examined in the SOE: Water Report. All health related parameters tested, including chloride, nitrate, sodium, and fluoride, were within Ontario Drinking Water Objective Maximum Acceptable Concentrations.

Samples collected from individual wells in Alton, Caledon East, and to a lesser extent Caledon Village and Mono Mills displayed increasing trends of nitrate concentrations. A correlation of increasing nitrates and population growth is evident in these centres.

Several communal wells in Caledon yield water with a sodium concentration above 20 mg/l. Although not considered toxic to humans, sodium in drinking water in excess of 20 mg/l may be of significance to individuals with hypertension, certain renal conditions, or cardiovascular diseases. The Medical Officer of Health is notified when the sodium concentration in a communal water supply exceeds 20 mg/l so that the information may be disseminated to local physicians.

When municipal water is not available the burden of developing a safe water supply rests upon individual property owners. Several studies have demonstrated that private wells, specifically shallow wells, commonly produce water that does not meet the Ontario Drinking Water Objectives without treatment. The Ontario Drinking Water Objectives do not apply directly to private wells, but may be used as guidelines for assessing water quality. Homeowners may submit private well water samples for testing through the Peel Health department.

Surface Water

Water Temperature
The temperature of surface water is controlled by a number of physical factors including groundwater discharge, baseflow, stream depth and velocity, riparian cover and seasonal fluctuations. Together these factors produce a pattern of seasonal water temperatures which the aquatic community is dependent upon for survival. An increase in water temperature above the normal range will negatively impact the aquatic community. The disruption of the natural factors controlling in-stream temperatures and waste discharges from water pollution control plants and storm sewers are increasing surface water temperatures in parts of Peel.

Water temperatures in Peel generally increased southward from the headwater areas in north Caledon to the urban centres of Brampton and Mississauga. The average summer water temperatures in Peel's cold water fisheries remained below 20° C in 1992. The highest average summer water temperatures in 1992 were recorded in Mississauga along the Etobicoke Creek and the Credit River. Average summer temperatures in this area were approximately 20° C.

Trend: Only two water monitoring stations in Peel displayed an increasing trend in water temperatures between 1982 and 1992. These stations are located at Lakeshore Road in Mississauga along the Etobicoke Creek and the West Credit River located above Belfountain in Caledon.

Suspended Solids
Total suspended solids are a measure of the total particulate matter that is suspended in water. Unnaturally high levels of suspended solids in surface waters will reduce the amount of sunlight available for aquatic plants and animals, clog fish gills, cover spawning areas and disrupt feeding habits. Often the suspended solids contain significant quantities of trace organic and inorganic contaminants such as pesticides, phosphorous and heavy metals which may further degrade water quality and possibly impact human health.

Typical of urban areas, concentrations of suspended solids in Peel were approximately two to three times higher in Mississauga than the rural areas of Caledon. This was due in part to the higher volumes of runoff that occur in urban areas during storm events. The exceptions to the urban rural trend were station 76-006 located immediately south of the Orangeville Water Pollution Control Plant on the Credit River and station 80-004 located north of Mayfield Road in Caledon along the Etobicoke Creek. Concentrations at station 76-006 were similar to the levels found in Brampton and Mississauga reflecting the urban character of the Town of Orangeville and the Water Pollution Control Plant's (WPCP) occasional discharge of suspended solids into the Credit River. Station 80-004 registered the highest average annual concentration of suspended solids in all of Peel in 1992. Average concentrations at this station were 175% greater than the next highest level in Peel which was also recorded in the Etobicoke Creek.

Trend: Since 1982, concentrations of suspended solids increased in all reaches of the Credit River and the Etobicoke Creek. The only decreasing trend since 1982 occurred at station 83-018 along the Humber River in the Town of Caledon.
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Phosphorous
High levels of nutrients in a surface water body will result in excessive growth of vegetation, including algae, and will consequently cause eutrophication. Eutrophication occurs when heavy algae growth results in continuously or seasonally low oxygen concentrations impacting the number and type of fish and plant species existing in a water body. Phosphorous, and to a lesser extent nitrogen, are recognized as the two nutrients that most frequently limit algal production in surface water.

In 1992 average phosphorous concentrations in Peel exceeded the Provincial Water Quality Objective (PWQO) in samples collected at 15 of the total 18 water monitoring stations in the Region. The highest concentrations occurred in the Town of Caledon at station 76-023 near Melville and at station 80-004 two kilometres northwest of Snelgrove. Sources of phosphorous near Melville include a golf course, farms and the Orangeville WPCP which is upstream from the water monitoring station. High concentrations near Snelgrove are believed to be associated with local farm practices.

Trend: Although phosphorous levels in Peel were predominately above the PWQO for phosphorous, there is evidence of a decreasing trend at all surface water monitoring stations.
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Fecal Coliform
A common indicator of bacterial pollution in surface water is fecal coliform counts. Diseases, such as those found in the gastro-intestinal tract, eye, ear, nose, throat or in the skin, may occur when surface water containing high fecal coliform concentrations is used for swimming, bathing, or other recreational activities.

Fecal coliform counts were consistently higher in the urban areas of Peel in 1992. All water monitoring stations south of Caledon recorded average fecal coliform counts above the PWQO. The highest average counts in Peel occurred along Fletchers Creek in Brampton and along the Etobicoke Creek at Lakeshore Road in Mississauga. Average annual concentrations at these two stations were approximately ten times greater than the Provincial objective level of 100 counts. One specific source of this bacterial pollution can not be identified; however, higher levels in this area are probably attributed to stormwater runoff and sewer outfalls.

Trend: Fecal contamination in Peel increased between 1982 and 1992 at all water monitoring stations south of Caledon. The most significant increase in Peel during this time period occurred in Fletchers Creek. Average fecal coliform counts increased from 188 in 1982 to 1,568 in 1992; a 734 percent (%) increase. Decreasing counts were observed along the West Credit River above Belfountain and in the Upper Humber River.
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Copper
As an indicator of trace metal concentrations and toxicity in the surface waters of Peel, copper concentrations are presented for the Credit River, the Humber River and the Etobicoke Creek Watersheds. Excessive levels of copper in surface water may result in the disturbance of fish reproduction and feeding habits, deformities, growth reduction and potentially lethal to entire fish communities. Low levels of copper in surface water are not considered to be as hazardous to human health as it is to the aquatic community.

Average concentrations of copper in the Credit River and the Humber River in 1992 were below the PWQO level established for copper in surface water. The highest concentrations of copper in Peel during 1992 occurred in the Etobicoke Creek. Average concentrations exceeded the PWQO level at two of the four monitoring stations situated along the Creek. Industrial activity in the vicinity of these monitoring stations is believed to be the source of the copper loading. In comparison to the average copper levels in the Credit River and Humber River, concentrations in the Etobicoke Creek in Mississauga were approximately 71 percent (%) greater.

Trend: Copper concentrations decreased at all water monitoring stations in Peel between 1982 and 1992. Although concentrations are declining, copper levels in the Etobicoke Creek in Mississauga remain equal to or above the PWQO level.
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Streamflow in the Credit River is highest during March, April and May, decreases steadily over the period June to October, and begins to recover during November and December. As a component of streamflow in the Credit River, groundwater baseflow is much higher in the rural areas in the upper Credit River than in the urbanized reaches. At Orangeville, Alton, Erin, Cataract, and Boston Mills, groundwater baseflow is estimated to be 73 to 76 per cent of streamflow. At Norval and Erindale, groundwater baseflow falls to 48 to 52 per cent of streamflow. Due to the increased volumes of surface water runoff in the urban areas, total stream flow is significantly greater in the lower reaches of the Credit River compared to the headwater area near Orangeville.

Studies suggest that surface runoff to the Credit River will increase, and groundwater baseflow will decrease with increasing urbanization. However, measures to offset the impact of changing land use such as the construction of stormwater management ponds or the infiltration of stormwater runoff should compensate for the changes in natural infiltration and baseflow.

Less detailed information is available on the Etobicoke Creek and Humber River watersheds. The average annual streamflow in the Etobicoke Creek increased between 1970 and 1990. The urbanization of Brampton and Mississauga over this time period resulted in an increase in surface water runoff and consequently streamflow.

Between 1970 and 1981 the Humber River's mean annual flow near Cedar Mills demonstrated an increasing trend. In 1982 the Humber River monitoring station was relocated to Palgrave. Between 1982 and 1990 that station demonstrated a decreasing trend. These trends are unexplained.
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Conclusion
Surface water quality in Peel frequently exceeded Provincial Water Quality Objectives and Guidelines in the urban centres of Brampton and Mississauga. The only parameter measured in this section that was higher in Caledon than in Brampton and Mississauga was phosphorous.

The highest levels of water pollution commonly occurred in the Etobicoke Creek. As an indicator of trace metals in surface water, copper levels in the Etobicoke Creek frequently exceeded provincial objective levels and were approximately 71 percent (%) higher than levels found in the Credit River and the Humber River in 1992. Since 1982, average concentrations of phosphorous and copper decreased at most water monitoring stations in the Region. Water temperature, one of the most significant parameters regulating the existence and distribution of fisheries in Peel, decreased at most monitoring stations between 1982 and 1992. During the same time period, suspended solids and bacterial contamination displayed an increasing trend.

Streamflow in the Credit River varied considerably on an annual basis; however, the average flow over the past 30 years did not demonstrate any significant trend. Streamflow in the Humber River and the Etobicoke Creek increased between 1970 and 1990.

Lake Ontario

In this section of the report, Lake Ontario water is assessed in terms of its quality along the Peel shoreline and as a source of drinking water for residents in Mississauga, Brampton and parts of Caledon.

As part of the Drinking Water Surveillance Program, water in the South Peel Water Supply System is sampled and analyzed at both the Lakeview and Lorne Park Water Treatment Plants (WTPs) and throughout the distribution system. Samples are collected from both raw water and treated water in the WTPs. The samples collected of the raw Lake Ontario water provide data that can be compared with the Provincial Water Quality Objectives established for surface water to determine the quality prior to treatment.

Phosphorous
Phosphorous concentrations at the Lakeview WTP constantly exceeded levels recorded at the Lorne Park WTP between 1987 and 1992. Average annual concentrations at the Lakeview WTP exceeded the PWQO for phosphorous three out of the six years it was measured. During the same time period average concentrations at the Lorne Park WTP remained well below the PWQO. The highest levels of phosphorous at the Lakeview WTP occurred during the months of March and April thereby suggesting a correlation to the high levels of spring runoff that is typical for this time of year.

Fecal Coliform
Average concentrations at both the Lakeview and Lorne Park WTPs were well below the PWQO for fecal contamination in surface waters.

Copper
In 1992 average annual copper concentrations were approximately four times higher at the Lorne Park WTP than the Lakeview WTP and more than three times greater than the PWQO level of 5 µg/l. Potential sources of copper in this area include the Clarkson Water Treatment Plant, urban runoff and storm sewer outfalls. From 1987 to 1991, 100 percent (%) and 95 percent (%) of the samples analyzed for copper at the Lakeview and Lorne Park WTPs exceeded the PWQO respectively. Since 1987, copper concentrations show a decreasing trend at the Lakeview WTP and a increasing trend at the Lorne Park WTP.
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Drinking Water
The raw water that is drawn from Lake Ontario by the Lakeview WTP and the Lorne Park WTP provides water for over 700,000 residents in Peel Region. The raw water is treated to ensure that it does not contain disease-causing organisms or hazardous concentrations of toxic chemicals, and that the water tastes and smells acceptable. The Drinking Water Surveillance Program (DWSP) is a provincial monitoring program used to provide immediate and reliable information on the quality of municipal drinking water. Samples collected in this program are tested and compared to Ontario Drinking Water Objectives (ODWOs) to ensure compliance.

The two WTPs in Peel Region produced good quality water in 1991 and 1992. No known health related guidelines including ODWOs were exceeded in these years. Any health concerns with the water provided by the South Peel system may be related to the addition of chemicals that are required in the treatment process. Chemicals remaining in the treated water that are potentially a health concern include trihalomethanes and aluminium. However, both of these parameters were well below ODWO levels in 1991 and 1992.
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Conclusion
Copper concentrations in the nearshore waters of Lake Ontario frequently exceeded the provincial objective levels for copper between 1987 and 1992. Bacterial and nutrient levels during this time were well within provincial standards for surface water. After treatment in the Lakeview and Lorne Park Water Treatment Plants, water distributed through the South Peel System to residents in Mississauga, most of Brampton, and parts of Caledon was of good quality in 1991 and 1992. Samples obtained from various parts of the distribution system in 1991 and 1992 were within all health related guidelines including the Ontario Drinking Water Objectives (ODWOs).
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Revised: Thursday July 26 2007

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