Rouge River State of the Watershed Report
Surface Water Quality
Goal: Surface waters of a quality, volume and naturally variable rate of flow to:
$ protect aquatic and terrestrial life and ecological functions; $ protect human life and property from risks due to flooding; $ contribute to the protection of Lake Ontario as a domestic drinking water source; $ support sustainable agricultural, industrial, and commercial water supply needs; $ support swimming, fishing and the opportunity to safely consume fish; and $ contribute to the removal of Toronto from the Great Lakes list of Areas of Concern.
Surface Water Quality
Key Findings:
• Overall, water quality in the Rouge River is relatively clean. The Main Rouge River shows greater signs of stress from the urbanized land uses in its catchment, relative to the less impacted, more rural Little Rouge River.
• Bacteria and chloride levels have generally been increasing in the River since the 1970s, in association with urbanization and road construction.
• Bacteria levels in the river pose risk to body contact recreation, but are only one of several factors contributing to postings at the Rouge beach on Lake Ontario.
• Chloride levels pose a threat to aquatic life in the Main Rouge and at certain times in the Little Rouge, especially downstream of major roads.
• Phosphorus levels have decreased since the 1970s due to restrictions on phosphates in laundry detergents and the decommissioning of sewage treatment plants in Markham, which previously discharged effluent to the Rouge River. Current phosphorus levels often fail to meet standards, largely due to organic and inorganic fertilizer applications on lawns, gardens and farm fields.
• Concentrations of PCBs, DDT, and Mercury were detected in juvenile fish above current standards at one or more monitoring stations in the Rouge River, indicating that these contaminants are bio-accumulating in the food chain. DDT levels have generally declined since the early 1990s.
• Consumption restrictions on sport fish appear to be limited to the Rouge Marsh, which is influenced by the Highway 401 upstream and Lake Ontario sources. Sport fish in Milne Reservoir are considered safe to eat.
• Water quality management in the Rouge should focus on stormwater management, stewardship practices, and enhancement of natural attenuation opportunities through natural heritage management.
Summary of Current CondCondiiiitionstions RatingsRatings:::: Objectives: Overall Rating
• Meet standards for body contact recreation at nearshore beaches and in Fair the river.
• Protect and restore surface water quality with respect to other pollutants, Good to ensure protection of aquatic life, ecological functions, human health and water supply needs.
• Protect and restore surface water quality with respect to toxic Good contaminants, to ensure protection of aquatic life, ecological functions, human health, and water supply needs.
TABLE OF CONTENTS
6.0 SURFACE WATER QUALITY ...... 6-1 6.1 Introduction...... 6-1 6.2 Understanding the Factors Affecting Surface Water Quality...... 6-1 6.3 Measuring Surface Water Quality...... 6-5 6.4 Existing Conditions...... 6-9 6.4.1 Bacteria: The Swimming and Body Contact Recreation Indicator...... 6-9 6.4.2 Conventional Contaminants: the Aquatic Health Indicator...... 6-10 6.4.3 Organic and Metal Contaminants: The Chronic Effects Indicator...... 6-15 6.4.4 Water Quality Trends in the Rouge River Watershed ...... 6-20 6.4.5 Other Issues: Spills, Landfills, Sanitary Servicing, Golf Courses ...... 6-23 6.5 Objectives for Surface Water Quality ...... 6-24 6.6 Summary and Management Considerations ...... 6-24 6.7 References ...... 6-26
List of Figures
Figure 6-1: Stream Water Quality Monitoring Stations and Fish Tissue Monitoring Stations.... 6-3 Figure 6-2: Percent of Samples that Meet Guidelines at Regional Monitoring Stations...... 6-8 Figure 6-3: Median chloride concentrations in the Rouge River from 1973 to 2003 ...... 6-22 Figure 6-4: Median phosphorus concentrations in the Rouge River from 1973 to 2003...... 6-22
List of Tables
Table 6-1: The environmental effects and sources for key water quality variables ...... 6-5 Table 6-2: Data Sources, locations and period of record...... 6-7 Table 6-3: Rouge River bacteria levels and Rouge Beach postings ...... 6-9 Table 6-4: The median and percent of samples that meet guidelines for conventional pollutants (1999-2003)...... 6-11 Table 6-5: Wet weather concentrations (2003/04)...... 6-14 Table 6-6: Levels of Canada Ontario Agreement 'Tier 1' Contaminants in the Main Rouge Rivers (1991/92 survey)...... 6-16 Table 6-7: Water quality summary table for metals (2002-2005)...... 6-17 Table 6-8: Young-of-the-year fish sampling locations where fish tissue guideline exceedances occurred (as indicated by an x) ...... 6-18 Table 6-9: Consumption restrictions for species tested (meals per month)...... 6-19 Table 6-10: Seasonal Kendall trend analysis results for selected water quality variables...... 6-21
Unique Rouge River Watershed Feature :::
The Rouge is the cleanest river system in Toronto ...
CHAPTER
SURFACE WATER QUALITY 666
6.06.06.0 SURFACE WATER QUALITQUALITYYYY
6.16.16.1 Introduction
Clean rivers and streams help sustain healthy aquatic communities, provide opportunities for recreation and aesthetic enjoyment, and contribute to the protection of drinking water sources. Preserving these beneficial uses, however, becomes increasingly challenging as new sources of pollutants are introduced into the watershed and land use change alters the natural features that help maintain good water quality. Farming practices, lawn care, vehicle use, construction works and removal of natural land cover are just a few of the many human activities that contribute to water pollution. While our ability to manage these activities has advanced, as indicated by some water quality improvements, signs of degradation in other indicators are becoming increasingly apparent as development continues to expand in the Rouge River watershed. This chapter documents trends in water quality over time, evaluates current conditions, examines the factors that influence these conditions and suggests priority issues for management of water quality in the watershed.
6.26.26.2 UnderstandiUnderstandingng the Factors Affecting Surface Water QuQualityality
Water quality is influenced by natural factors and human activities in the rural and urban landscape. Key factors in the Rouge River watershed are described in this section, as a context to the assessment of Rouge River water quality found in the following sections.
Natural Influences
Geology has a significant effect on water quality, primarily through its influence on groundwater recharge and discharge rates. High rates of groundwater discharge into streams translate into larger baseflows, cooler stream temperatures and typically cleaner surface water during dry weather. The cooler temperatures maintain higher oxygen levels and create a less favourable environment for deleterious bacteria to grow.
In the Rouge, the major recharge areas are associated with relatively permeable soils on the Oak Ridges Moraine and Iroquois Sand Plain. These features facilitate infiltration, resulting in
6-1 lower rates of overland runoff. As the infiltrated runoff moves through the soil, most pollutants are filtered or immobilized, providing a relatively clean source of water when it eventually re- emerges in a stream or lake. The quality of this groundwater input is important in the Rouge’s headwater tributaries as it represents 40-80% of the baseflow. By contrast, fine-grained clay and clay loam soils that characterize the Peel Plain have low infiltration capacity and are highly erodible. The low infiltration rates promote soil erosion by facilitating overland runoff. Areas with these types of soil often act as sources of sediment and associated contaminants, and therefore contribute to naturally higher levels of turbidity and sediment load.
Grass and forested riparian buffers play an important role in reducing the quality of overland runoff from erodible soils, steeply sloping land and poor land use practices on adjacent streams and wetlands. This result is achieved through filtration of sediment and associated contaminants, vegetative uptake of soluble nutrients, and infiltration of overland runoff from surrounding fields and hillslopes. Removal of over half the phosphorus, nitrogen and sediment inputs is typically achieved within the first 15 m of buffer width (Osborne and Kovacic, 1993; Castelle et al ., 1994). Woody riparian vegetation also helps to stabilize banks and moderate stream temperature by providing shade.
Wetlands, with their natural ability to store water and absorb nutrients during the growing season, have a significant effect on water quality as well. They help to reduce peak flows, maintain natural hydrological conditions and play an important role in regulating sediment and nutrient exchange within the river system (Mitsch and Gosselink, 1993). Like riparian buffers, wetlands filter the water and help attenuate floods, with considerable benefits to water quality (Mitsch, 1992).
The Rouge River marsh, located at the mouth of the watershed, is the recipient of water flowing through the river system. Some of the material transported downstream is likely deposited here, trapped by the barrier beach and road that separate this coastal wetland from Lake Ontario. The marsh helps to purify Rouge River water before it enters Lake Ontario. Other wetlands remaining in the Rouge River system are at the headwaters of the Berczy Creek, Bruce Creek, Robinson Creek and the Upper Rouge subwatersheds (see Figure 6-1). Unfortunately, most of the wetlands in the watershed were drained, cleared and filled for farming and other uses and those that remain are under stress as a result of urban expansion, agricultural practices and other human activities.
Influences in the Rural and Urban Landscape
Farms can be a significant non-point source of sediment, nutrients, bacteria and pesticides to rivers, if appropriate management practices are not followed. Decisions on cropping methods, manure storage and animal fencing for example, all have profound implications to the water quality of adjacent river systems. Septic systems, can also contribute pollution to streams if they are not appropriately maintained (Schueler, 1999). Groundwater can also be contaminated by failing septic systems, which is of particular significance in rural areas where residents are often dependent on wells for their drinking water.
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Figure 666-6---1111:::: Stream Water QQualityuality Monitoring Stations and Fish Tissue MonitoringMonitoring Stations
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Pollution levels vary substantially with stream flow rates and volumes. These variations reflect differences in sources between dry and wet weather. Dry weather flows originate primarily from groundwater, which has been filtered by the soil and is typically less contaminated than surface runoff. In urban areas, the groundwater component of dry weather flow may be augmented by lawn watering, vehicle washing, and swimming pool discharge to storm sewers, illegal sanitary connection discharges and accidental or deliberate spills to roadside catchbasins (Snodgrass and D'Andrea, 1993). Rural area sources of dry weather flow may include excess crop irrigation, septic system drainage, or barnyard run off, although these would normally influence surface water levels only indirectly by increasing groundwater recharge.
The majority of wet weather runoff in urban areas cannot infiltrate due to the prevalence of impervious surfaces. Instead, the wide variety of contaminants that accumulate on impervious surfaces during dry weather are washed off and transported through roadside ditches and sewer networks to watercourses. This fast-flowing water picks up bacteria from wildlife and domestic pet feces, nutrients and pesticides from lawn and garden maintenance, toxic chemicals from industrial sites and a wide range of contaminants associated with transportation land uses, including heavy metals, oil, grease, road salts and hydrocarbons. Atmospheric sources of pollutants, such as, particulate matter and polycyclic aromatic hydrocarbons (PAHs) can be relatively more significant in urban areas than rural, due to nearby sources and the large area of impervious surface available to capture these pollutants. The ‘flashy’ stream flows associated with urban surfaces increase channel erosion, which adds to the levels of suspended solids and turbidity in the river system .
Currently, 35% of the Rouge River watershed is classified as urban. Since the early 1990s, new developments have been required to implement stormwater quantity and quality controls and, where applicable, drain roof runoff to grassed areas surrounding the house. As a result, approximately 60% of the urban area has stormwater controls with quantity and quality functions. The remaining 40% consists of older developments in Toronto, Markham, Richmond Hill and Stouffville, of which 55% have no controls and 45% have quantity control only (see Figure 13-6 in chapter 13 (Land and Resource Use). TRCA, in partnership with municipalities, have identified stormwater retrofit opportunities in older areas to help improve water quality. The City of Toronto’s recently completed Wet Weather Flow Management Master Plan (WWFMMP) exemplifies this new and evolving approach to stormwater management in recognizing rainwater and snowmelt as a resource and adopting a treatment train approach that emphasizes source control measures first, followed by conveyance and end-of-pipe controls (City of Toronto, 2003).
Despite these advances in stormwater management, there remain several challenges to managing wet weather flow impacts in urban areas. While the incorporation of stormwater ponds in urban developments has become an accepted practice, studies across North America report that structural end-of-pipe controls such as ponds and engineered wetlands are not sufficient to protect receiving waters and safeguard the health of downstream aquatic communities (e.g. Aquafor Beech Ltd., 2006; Stribling et al ., 2001; Maxted, 1999), although they contribute to improved water quality (Metropolitan Washington Council of Governments, 1995). The aquatic impacts appear to be related to post development changes in flow regime, increases in stream temperature and inadequate sediment control during the construction period. Further, end-of-pipe controls are not designed to remove road salts, which can present
6-4 serious threats to the health of aquatic life (Environment Canada and Health Canada, 2001). Consideration of the effects of urban development and the associated stormwater management practices was an important part of the water quality assessment in the Rouge River.
6.36.36.3 Measuring Surface Water Quality
Surface water quality contaminants are typically grouped according to their management implications into bacteria, nutrients (N and P), metals, conventional pollutants (e.g. suspended solids, chloride) and organic compounds. Elevated levels of bacteria can impact human health and the recreational uses of a water body. Conventional pollutants and nutrients are assessed with regard to the protection of aquatic life and other issues such as aesthetics. The environmental effects and sources of these pollutants are presented in Table 6-1.
Table 666-6---1111:: The environmental effects and sources for key wawaterter quality variables
Variable Effect Source
Total Elevated concentrations reduce water clarity, which can TSS originates from Suspended inhibit the ability of aquatic organisms to find food. areas of soil Solids Suspended particles may also cause abrasion on fish disturbance, including gills. As solids settle, coarse rock and gravel spawning construction sites and and nursery areas become coated with fine particles, farm fields, lawns, limiting the ecological function of these important areas. gardens, eroding Many pollutants are readily adsorbed by suspended stream channels, and solids, and may become available to benthic fauna when grit accumulated on deposited. Build-up of sediments influences the roads. frequency of method of dredging activities in harbours and reservoirs.
Phosphorus Phosphorus is essential to the growth and survival of Sources include lawn organisms. However, oversupply of this nutrient and garden fertilizers, promotes eutrophication of surface waters by stimulating eroded soil particles, nuisance algal and aquatic plant growth, which deplete sanitary sewage, animal oxygen levels as they decompose resulting in adverse wastes and decaying impacts to aquatic fauna and restrictions on recreational plant material. use of waterways.
Nitrate Excessive nitrate (NO 3-N) can encourage nuisance algae Nitrate originates from growth and lead to eutrophication in aquatic agricultural and environments (and the degradation of aesthetics). Nitrate residential application of has also been shown to exert chronic toxic effects in fertilizer, animal wastes, amphibian species at relatively low concentrations. sewage and decaying plant material.
UnUnUn-Un ---ionizedionized Un-ionized ammonia is a form of nitrogen that is toxic to Ammonia is a natural Ammonia aquatic life at low concentrations. It is influenced by constituent of human temperature and pH. and animal sewage, and also forms from the microbial decomposition of organic tissue.
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Variable Effect Source
Chloride Chloride levels influence the quality of irrigation water, The largest source of and the aesthetics and taste of drinking water. Elevated chloride is from road levels may also harm aquatic life. Background salt application during concentrations in natural surface waters are typically the winter months. below 10 mg/L.
Dissolved Dissolved oxygen levels fluctuate naturally in response to Oxygen levels are Oxygen physical mixing, salinity, temperature, and biological depleted by bacterial activity (e.g. plant photosynthesis). Low dissolved respiration during the oxygen levels lead to stress responses in aquatic decomposition of organisms, and increase the toxicity of some metals and organic matter at the organic compounds (e.g. lead, copper, cyanide). sediment-water interface.
E. coli The presence of Escherichia coli in surface water is Bacterial sources indicative of loadings of faecal matter of either animal or include illegal sewer human origin. Elevated levels can result in restrictions on connections and inputs the recreational use of water bodies. from wildlife and domestic animals.
Heavy metals and organic pollutants are detrimental to aquatic life, but also affect human health through consumption of sport fish and bio-accumulation in the food chain. Synthetic organic chemicals, such as are found in pharmaceutical products, can also find their way into the environment through, for example, septic and sewage treatment plant effluent. They can even enter our drinking water, if they are not among the suite of chemicals tested and targeted for treatment in drinking water treatment plants. Evidence is beginning to show the effects of these contaminants on endocrine disruption and hormone levels in animals and humans. Metals and organic pollutants are discussed as a separate category in this report because they can have adverse effects even at very low concentrations in surface waters.
Table 6-2 describes the sources of data used in this assessment. The majority of water quality data characterizing current conditions in the Rouge River watershed was collected under TRCA’s Regional Watershed Monitoring Network (Chapter 3) ambient water sampling program (1999 to 2003) and the Ontario Ministry of the Environment’s (OMOE) tributary toxics dry/wet weather sampling program (1991/92). The OMOE program focuses primarily on metals and organic compounds identified as priority pollutants under the Canada-Ontario Agreement on Great Lakes Water Quality. Historical trends in water quality are based on sampling data collected from the late 1960s to 1996 under the OMOE’s Provincial Water Quality Monitoring Network. The location of monitoring stations are shown in Figure 6-1.
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Table 666-6---2222:: Data Sources, locations and period of record
Data Sources Monitoring Period of Water Quality Comments Station(s) Record Groups
Regional Water 3 stations on 1999 - 2002 conventional, Routine monthly Quality Monitoring the Main Rouge nutrients, metals grab samples - Network and 2 on the bacteria biased towards dry Little Rouge weather
Provincial Water 3 stations on Historical data conventional, Routine grab Quality Monitoring the Main Rouge prior to 1996 nutrients, metals samples 2 times per Network and 1 on the bacteria month - biased Little Rouge towards dry weather
City of Toronto Rouge Beach swimming Beach postings Postings based on Beach Sampling on the season geometric mean of E. Program waterfront 1997 - 2003 coli in 5 samples
Lake Ontario 1 stns on the 1991-1992 Conventional, 24 hour time- Tributary Toxics Main Rouge metals, organic integrated composite Monitoring Program upstream of compounds samples -wet and dry (Boyd et al ., 1999) confluence with weather Little Rouge
MOE Guide to Eating Rouge Marsh; 2002 Mercury, PCBs, Adult fish tissue Ontario Sport Fish Milne Reservoir; mirex and analysis Spawning Runs pesticides
MOE Young-of-the- Below Milne 2002 organic Juvenile fish tissue Year Fish Monitoring Res.; Hwy 48 - compounds analysis L. Rouge; Warden & Hwy 7; Hwy 401
Tissue analyses of juvenile fish and sport fish from the Ministry of the Environment’s Young-of- the-Year and sport fish contaminant programs (2002) were used as an indication of the presence of organic contaminants or metals in biologically available forms. The locations of current and historical monitoring stations are shown in Figure 6-2....
The water quality implications of oil and chemical spills, landfills, septic systems and golf courses require further study. A qualitative assessment of these issues follows the quantitative discussion of water quality in the Rouge River.
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Figure 666-6---2222:: Percent of Samples that Meet Guidelines at RegionRegionalal Monitoring Stations
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6.46.46.4 EEExistingExisting Conditions
6.4.1 Bacteria: The SwimmSwimminging and Body Contact Recreation IIndicatorndicator
Escherichia Col (E.coli ) is used in Ontario to indicate the presence of harmful bacteria in swimming areas and drinking water. The provincial guideline for E.coli is 100 coliforms/100 mL for recreational areas. The Toronto Stage 2 Remedial Action Plan goal is for lake water to contain less than 100 coliforms/100 mL for 95% of the swimming season (Waterfront Regeneration Trust, 2002).
The Rouge Beach on Lake Ontario is the only location that is monitored and posted when bacteria exceed safe levels for swimming. Bacteria levels at three monitoring stations along with posting frequencies at the Rouge Beach are presented in Table 6-3. Eighty percent or more of samples collected met the provincial guideline at the two stations near the confluence of the Little Rouge and Main branches. The third station at Major Mackenzie Drive on the Little Rouge River met the PWQO only 64% of the time. The geometric mean and median concentrations of E.coli for the May to October monitoring period were less than 75 coliforms/100 mL at all three stations.
By contrast, the Rouge Beach, near the mouth of the river, was only safe for swimming between 5 and 38% of the June to September period from 1999 to 2003 (Table 6-3). E.coli densities at this location were greater than observed elsewhere in the Rouge River, which suggests that the river is not the only source of bacteria to the beach. The slow residence time of water in the Rouge marsh may be allowing bacteria to incubate resulting in elevated levels within the marsh.
The benefits of stormwater management in reducing bacteria levels at the Rouge beach were modelled in Toronto’s WWFMMP. Results indicated that even with aggressive controls in the City, the Rouge beach would remain closed for most of the swimming season unless upstream municipalities commit to a similarly aggressive approach to stormwater control. Over 80% of the Rouge River watershed is outside of the City of Toronto (City of Toronto, 2003a).
Table 666-6---3333:: R: RougeR ouge River bacteria levels and Rouge Beach postingspostings
Rouge River stations % of samples that meet Waterfront --- Rouge Beach the PWQO (1999(1999---- % of swimming season safe for swimming (1999(1999---- 2003)* 2003)**
Sheppard East, 97011 80% 1999- 5%
Major Mac., 97009 64% 2000- 5 % 17% Twyn Rivers, 97013 83% 2001- 20% (5 year average) 2002 -38%
2003 - 18% Sources: Regional Watershed Monitoring Network and City of Toronto. *percent of samples equal to or above 100 coliforms/100 ml in samples collected from May to October. **Year-to-year variations in beach postings are influenced by variations in the intensity and frequency of rainfall.
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The most recent wet weather sampling data for bacteria are from a sampling program conducted by the Ministry of the Environment in 1991/1992 on the main branch, immediately upstream of the confluence with the Little Rouge River (Boyd et al ., 1999) (Figure 6-1). The wet weather data are based on time-integrated composite samples collected over the first 24 hours of 17 precipitation events, and focus on high flow conditions during the spring and summer.
In the MOE study, mean E.coli densities during wet and dry weather were 1060 (n=10) and 314 (n=9) coliforms/100 ml, respectively. By comparison, a 1986 monitoring study in the headwaters of Bruce Creek reported mean wet and dry E. coli densities (n=22) of 2347 and 62 coliforms/100 ml (Hubbard et al. , 1987). Wet weather runoff from rural areas like upper Bruce Creek, conveys pollutants to streams from manure storage facilities, barnyards, field application of manure, and suburban storm sewers.
Targets and Rating for the Bacterial Indicator
The targets selected for meeting the surface water quality objective of managing the Rouge River watershed for body contact recreation are provided below, along with a rating for existing conditions in the watershed. The two targets relate to conditions in the Rouge River and conditions at the Rouge River waterfront beach, respectively. The target for the river assumes that wet weather flows occur 25% of the time, when bacteria counts would generally exceed swimming guidelines. Bacteria levels would typically be lower during the remaining 75% of the time, when low flow conditions prevail. The Rouge beach indicator is based on the Toronto Remedial Action Plan and WWFMMP goal for lake water to meet the E.coli guideline during 95% of the swimming season.
Objective: Meet standards for body contact Overall Rating recreation at nearshore beaches and in the riverriver.... Fair
Indicator Measure Target
Swimming Escherichia Greater than 75% of surface water samples meet the and body Coliform densities in PWQO of 100 coliforms/100 mL. contact water samples recreation Rouge Beach is open for an average of at least 95% of the swimming season
An overall rating of ‘fair' for the body contact recreation indicator was assigned based on reasonably low E. coli levels in the Rouge River ( i.e. the target was met on average) and a waterfront beach that is unsafe for swimming during most of the summer.
6.4.2 Conventional ContaContaminants:minants: the Aquatic Health IndicatorIndicator
Conventional pollutants discussed in this section were selected for their importance to common water use concerns. Their effects and sources were summarized in Table 6-1 earlier in the chapter.
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Data for existing conditions were collected under the Regional Watershed Monitoring Network at 5 stations (Figure 6-2). Grab samples were collected once a month, year round. The median concentration and frequency of samples that meet existing guidelines for selected conventional pollutants are presented in Table 6-4. The median concentrations represent predominantly dry weather or low flow conditions in the Rouge River. In-situ measurements of dissolved oxygen are not included because concentrations consistently met provincial guidelines throughout the watershed. The impact of water temperature on aquatic life is assessed in relation to historical fish communities and thermal river reach designations in Chapter 8 (Aquatic System).
Table 666-6---4444:: The median and percent of samples that meet guideliguidelinenesne sss for conventional pollutants (1999(1999----2003).2003).
Main Rouge Little Rouge MMMainMain Rouge Little Rouge Bruce Ck. Sheppard Ave Twyn Rivers Warden Ave Major Mac. Major Mac.
Water # 97011 # 97013 # 97777* # 97009 # 97018* GuideGuide---- Quality line Variable
median median median median median median median median median median %meet %meet %meet %meet %meet %meet %meet %meet %meet %meet median median median median median median median median median median %meet %meet %meet %meet %meet %meet %meet %meet %meet %meet guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline
Suspended 26.7 74 7.5 72 8 100 5 88 6.5 100 30 1,5 Solids (mg/L)
Phosphorus 0.03 52 0.02 56 0.05 31 0.03 51 0.03 45 0.03 2 (mg/L)
Nitrate 0.89 50/94 1.0 48/86 0.71 77/ 1.0 48/94 0.76 73/ 1.0 3/2.5 4 (mg/L) 100 100
UnUnUn-Un ---ionizedionized 0.002 96 0.001 90 0.000 100 0.000 87 0.001 100 0.022 Ammonia (mg/L
Chloride 134 80 63 91 269 46 56 88 55 100 250 6 (mg/L) Bold underlined values represent concentrations above guidelines. Data Source: Regional Watershed Monitoring Network. Guideline References (see text): 1. EIFAC, 1965; CCME, 1999; 2. Provincial Water Quality Objectives (MOE, 1999b); 3. CAST, 1992 4. Rouse et al ., 1999; 5. Canadian Water Quality Guidelines (CCME, 1999); 6. Environment Canada and Health Canada, 2001 *At station 97777 and 97018, data were collected from June 2001 to August 2003 and June 2002 to August 2003, respectively.
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Total Suspended Solids
Median total suspended solids (TSS) concentrations in samples collected from 1999 - 2003 at all five stations in the Rouge River were below the guideline of 30 mg/L (CCME, 1999). The maximum observed from 1999 to 2003 was 182 mg/L, which occurred on the Main Rouge River branch at Sheppard Ave near the end of a storm event. Higher TSS concentrations would be expected during the early storm period as grit and dirt accumulated during dry weather are washed off of impervious surfaces. Short term exposures of high suspended sediment concentrations during rain storms or the spring freshet have been reported to exert severe effects on biota (Waters, 1995).
Nutrients
Phosphorus is the limiting nutrient for plant growth in most inland waters and, as such, is often regarded as the principle cause of eutrophication in receiving waters. Median concentrations of phosphorus range from 0.02 mg/L at Twyn Rivers Drive in the Little Rouge River to 0.05 mg/L at Warden Avenue in the Main Rouge, south of Highway 7. The provincial guideline of 0.03 mg/L was exceeded between 69 and 44% of the time, with the greatest number of exceedances occurring at Warden Avenue.
Nitrate (NO 3 - N) contributes to excessive plant growth at concentrations above approximately 1.0 mg/L (CAST, 1992). Nitrate has also been shown to have chronic toxic effects in amphibian species at concentrations as low as 2.5 mg/L (Rouse et al ., 1999). At all Rouge River stations monitored, median nitrate concentrations were less than 1 mg/L. Maximum concentrations were above 3 mg/L at some locations, but only for short periods associated with wet weather runoff.
Un-ionized ammonia is a form of nitrogen that is toxic to aquatic organisms at concentrations above 0.02 mg/L. Elevated concentrations are often associated with sewage treatment plants, of which there are none discharging to the Rouge River. Most water samples collected met provincial standards for un-ionized ammonia (0.02 mg/L). The Little Rouge River had slightly higher concentrations than the Main branch of the Rouge River, possibly reflecting greater inputs from failed septic systems, farm runoff or areas with livestock access to streams. Since 1995, these issues have been addressed in part through a number of rural pollution clean-up initiatives in the Rouge River watershed undertaken through TRCA’s Rural Clean Water Program (TRCA, 2003b) .
Chloride
Road salt has come under increased scrutiny since it was deemed to be a toxic substance as defined by the Canadian Environmental Protection Act (Environment Canada and Health Canada, 2001). The five year scientific risk assessment leading to the designation of chloride as a toxic substance suggests a limit for chloride (a major constituent of road salt) of approximately 250 mg/L for the protection of aquatic life. The suggested irrigation water limit for agricultural crops ranges from 100 mg/L for sensitive plants to 700 mg/L for more tolerant ones (Canadian Council Ministers of the Environment, 1999). Chloride is highly soluble and does not readily adsorb to mineral surfaces. Hence, it is not effectively treated by stormwater technologies such as ponds that rely on settling for pollutant removal (e.g. Stormwater Assessment Monitoring and Performance (SWAMP, 2003a).
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Chloride concentrations in the Rouge River varied considerably among stations. The highest median values were recorded at Warden Avenue on the Main branch (97777), which receives runoff from built-up areas in Markham and Richmond Hill. At this station, less than half of samples collected were below the 250 mg/L limit. Further downstream, at Sheppard Avenue (97011), 80% of samples collected met the guideline and in the predominantly agricultural areas of the Little Rouge River (97011) and Bruce Creeks (97018), over 85 % of samples met the guideline. Although most water samples collected from the Little Rouge River were relatively low in chloride, maximum concentrations in the Creek were 3,620 and 4,937 mg/L at the Sheppard Avenue and Major Mackenzie Drive stations, respectively. Both of these values were associated with snow melt events. Inspection of winter chloride data suggests a snow dump site or other significant source upstream of Major Mackenzie Drive .
Road salts from major highways are a significant contributor to stream chloride levels during the winter. A monitoring study of a highway stormwater quality retention pond discharging to the Rouge River south of Highway 401 (SWAMP, 2003a) showed a mean cold season (December to April) chloride concentration entering the pond (1,689 mg/L) over twice that recorded in stormwater entering ponds from residential catchments (approx. 700 mg/L) (SWAMP, 2003b, 2002a, 2002b). As mentioned earlier, stormwater ponds do not remove chloride, but they do prolong its release over a longer time period than would be the case if the stormwater were discharged directly into the river. This effect is a result of densimetric stratification in the pond. The salty stratified layer dissipates only after chloride is flushed from the pond by large spring and summer rain events. While this process prolongs the release of chloride to receiving waters, it also has the positive effect of reducing potential chronic impacts to receiving water biota associated with very concentrated plugs of chloride over short durations.
Wet weather data
Wet weather sampling data for conventional contaminants were available from an ongoing sampling program conducted by the Ministry of the Environment in 2003/04 on the main branch near Highway 7 and Ninth Line, and on the Little Rouge River near Dicksons Hill (see Figure 6-2). The wet weather data are based on single grab samples collected at different points along the hydrograph (e.g. rise, peak, run) with automated samplers during storm events in the spring, summer and fall.
Wet weather results for selected conventional pollutants from the MOE sampling program are presented in Table 6-5. As expected, sample concentrations for most constituents during wet weather were higher than during dry weather (see Table 6.4). The wide range of concentrations reflects the highly variable nature of wet weather flows.
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Table 666-6---5555:: Wet weather concentrations (2003/04)
Little Rouge @ Dicksons Hill Main Rouge, near Markham 150263 150264 Variable Guideline % meet % meet min max median min max median guideline guideline
TSS 1.1 478 9.7 87 1.4 96.8 20.8 75 30 mg/L
TP 0.01 0.69 0.04 27 0.02 0.17 0.07 10 0.03 mg/L
Nitrate 0.34 4 1 47/80 0.2 2.6 0.73 60/95 1.0/2.5 mg/L
Chloride 46.6 80.1 72.1 100 54.8 334 94.6 95 250 mg/L n=17 and 22 at the Little Rouge and Markham stations respectively
Rating for the Conventional Contaminants Indicator
The measures and targets selected for meeting the surface water quality objective of managing the Rouge River watershed with respect to conventional contaminants are provided below, along with a rating for existing conditions in the watershed. These targets are consistent with the Toronto Remedial Action Plan and Toronto Wet Weather Flow Management Master Plan objectives for conventional pollutants.
Objective: Protect and restore surface water quality with resprespectect to other Overall Rating pollutants, to ensensureure protection of aquaquaticatic life, ecological functions,functions, human health and water supply needs. Good
Indicator Measure Target
conventional Concentrations of Concentrations of conventional pollutants meet available pollutants conventional variables guidelines, as follows: (suspended solids, $ suspended solids: 30 mg/L 1 phosphorus, nitrate, $ phosphorus: 0.03 mg/L 2 ammonia, dissolved $ nitrate: 1.0 mg/L (eutrophication) 3 oxygen and chloride) $ 2.5 mg/L (amphibians) 4 $ un-ionized ammonia: 0.02 mg/L 2 $ DO: 5.0 mg/L warm water biota 6.0 mg/L cold water biota 5 chloride: 250 mg/L 6 Sources: 1. (CCME, 1999); 2. Provincial Water Quality Objectives (MOE, 1999b); 3. CAST, 1992; 4. (Rouse et al ., 1999; 5. PWQO at 10 to 15 degrees Celsius; 6. EC & HC, 2001
An overall rating of good was assigned to the conventional contaminants indicator based on high marks for dissolved oxygen, suspended solids and un-ionized ammonia, but poor results for nitrate and total phosphorus, especially during wet weather, and for chloride during dry weather.
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6.4.3 Organic and Metal Contaminants: The Chronic Effects Indicator
Organic Compounds
Organic contaminants such as pesticides, PCBs and PAHs have been linked to chronic health effects in aquatic organisms, terrestrial wildlife species and humans. Aquatic impacts of organic pollutants can include physical deformities, tumours and lesions, some leading to population declines through increased embryo mortality and damage to reproductive systems. Many of these compounds either have been demonstrated, or are believed to be carcinogenic to humans
Forty-one harmful pollutants were identified under the Canada-Ontario Agreement (COA) for priority management in the Great Lakes Basin ecosystem. Fourteen of these, called ‘Tier 1' contaminants, are known to persist and biomagnify in the environment, and have been targeted for virtual elimination (Table 6-6). Significant progress has been made over the past 15 years in reducing production and release of these chemicals, and some, such as DDT, Chlordane, Mirex, Alkyl-lead and Toxaphene are no longer being released in Ontario.
The second group, called Tier 2 contaminants are believed to be persistent and have the potential for biomagnification and toxicity. However, there is not sufficient agreement among scientists in both the U.S. and Canada to warrant setting joint targets and goals with regard to these substances. The pollutants in the Tier 2 category include 17 Poly Aromatic Hydrocarbons (PAHs) and various other organic compounds.
The only data on organic contaminants in the Rouge River available at the time of writing were from the 1991/1992 study by the Ministry of the Environment, described in the previous section (Boyd et al., 1999). At that time, some chemicals that were phased out in the early 1970s, such as PCBs and DDT, were still being detected in the Rouge River (Table 6-6); as elsewhere in the Toronto Region. However, PCBs were the only Tier 1 contaminant found to be occasionally in exceedance of guideline levels. The presence of these chemicals in surface water does not necessarily indicate current use of these chemicals in the watershed, as these compounds are subject to atmospheric transport and deposition, and can reside for long periods of time in stream sediments and animal tissues.
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Table 666-6---6666:: Levels of Canada Ontario Agreement ''TierTier 1' Contaminants in the Main Rouge Rivers (1991/92 survey)
Dry Weather Wet Weather TTTieTieieierr 1 Contaminants* PWQO % > MDL ### % meet PWQO % > MDL % meet PWQO
Aldlrin/Dieldrin 73 100 81 100 1.0 ng/L
B(a)P -- -- 60 100 210 ng/L**
Chlordane -- 100 41 100 60 ng/L
DDT+ 64 100 42 100 3 ng/L
HCB 27 ------6.5 ng/L
PCBs 7++ 919191 7++ 949494 1 ng/L
Mirex 0 100 0 100 1 ng/L Source: Boyd et al ., 1999 # MDL: Method Detection Limit + Samples were collected during 16 wet weather events and 11 dry weather periods. ++ Average of wet and dry * Other ‘Tier 1 Contaminants’, such as octachlorostyrene, dioxins and furans, are usually sampled in fish tissues, not water, since they occur at very low concentrations. Toxaphene and alkyl-lead are not tested because they were not expected to be present. Mercury is discussed in the next section. ** This was the value used in the MOE report. The Canadian Water Quality Guideline is 15 ng/L .
Among Tier 2 contaminants, only PAHs were analyzed in the 1991/92 study. Unlike other organic compounds, PAHs are not manufactured directly by humans, but enter the environment indirectly as by-products of combustion processes. Residential heating, vehicular exhaust, power generation and wood burning are all sources of PAHs. Emissions from these sources are deposited on surfaces and wash off with stormwater runoff into rivers and creeks (Sharma et al ., 1997). In the Rouge River, sample concentrations of most PAHs exceeded Provincial guidelines, but exceedance frequencies were among the lowest of all other five Toronto watersheds sampled in the study.
There were no pesticide data for the Rouge River, but a detailed study of “in-use” pesticide concentrations in the Don and Humber rivers was conducted in 1998 and 1999 (Struger et al ., 2002). Urban and agricultural pesticide use in the Humber would be expected to be broadly consistent with that of the Rouge River watershed. In the Don and Humber study, 159 pesticides were analyzed in 133 samples collected during wet and dry weather, including common pesticides used in urban lawn care and agriculture such as diazinon, 2,4-D, MCPP and dicamba. The most frequently detected chemicals were MCCP (30% of samples collected), diazinon (29%), 2-4-D (7%) and atrazine (4%). Among the pesticides detected, most were below available water quality guidelines, except diazinon and carbofuran, which exceeded their respective PWQOs in 20 and 1% of samples collected, respectively. Diazinon is currently being phased out for urban lawn insect control.
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Trace Metals
Metals are found naturally in the environment, but are toxic at elevated levels. Copper, lead and zinc originate from urban land use and a wide range of industrial activities. They are the most common heavy metals found in stormwater runoff (Marselek and Shroeter, 1988). Mercury and cadmium are designated under the Canada Ontario Agreement as Tier1 and Tier 2 contaminants, respectively.
Samples collected under the Regional Watershed Monitoring Network were analyzed for 16 metals at five stations on the Main and Little Rouge Rivers. Only those metals reported in Table 6-7 were observed above guideline levels. The percentage of samples meeting guidelines was typically above 80%. The only exceptions were aluminum on the main branch (67%) and (surprisingly) cadmium on Bruce Creek (75%). The earlier study in 1991/1992 (Boyd et al ., 1999) reported that samples met guidelines for lead, copper and cadmium only 36%, 82% and 64%, respectively. The lower exceedance frequencies observed in the 1999 to 2003 sampling program suggest that conditions may have improved for these metals in the Rouge River since 1991/92.
Table 666-6---7777:: Water quality summary table for metals (2002(2002----2005)2005)
Main Rouge Little Rouge Main Rouge Little RoRougeuge Bruce Ck. Sheppard Twyn Rivers Warden Ave Major Mac. Major Mac. Ave Water # 97011 # 97013 # 97777* # 97009 # 97018* GuideGuide---- Quality
line
Variable medianmedian medianmedian medianmedian medianmedian medianmedian % % meet % meet % meet % meet % meet % meet % meet % meet % meet % meet median median median median median median median median median median % % meet % meet % meet % meet % meet % meet % meet % meet % meet % meet guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline guideline
Aluminum 48.9 67 7.7 89 0.5 100 0.5 94 38.1 93 100 1 (ug/L)
Lead ((ug/L)ug/L) 0.3 94 0.3 89 0.3 100 0.3 94 0.3 97 52
Copper 1.74 92 2.66 78 2.65 100 1.92 100 0.8 100 5 (ug/L)
Zinc (ug/L) 2.6 95 8.6 83 10 84 4 88 0.9 100 20 2
Iron (ug/L) 171 83 137 89 234 80 140 82 168 96 300
Cadmium 0.3 88 0.05 95 0.12 100 0.05 100 0.3 75 0.5 2 (ug/L) Source: Regional Watershed Monitoring Network. 1. Canadian Water Quality Guideline. The Provincial Water Quality Objective applies to clay free samples only. 2. Interim PWQOs.
Not reflected in the studies cited earlier are the contributions of heavy metals to the surface waters of the Rouge River watershed through recent aquifer dewatering along 16 th Avenue in Markham to facilitate infrastructure construction. Pumping groundwater directly from deep
6-17 aquifers into the river system by-passes natural filtration processes and brings unusually high levels of certain chemicals to the surface. Iron and manganese are the main contaminants, in this case, although phosphorus concentrations were also elevated in one well. While manganese in the receiving waters lies within acceptable levels, iron was twice the provincial guideline, potentially affecting reproduction and growth of some aquatic organisms. Dewatering activities ceased in 2006.
Contaminants in Fish Tissues
Tissue analysis of juvenile fish (young-of-the-year) and sport fish can be used to demonstrate the degree of threat presented by pollutants to aquatic species and also to humans through fish consumption. The detection of organic contaminants or metals in fish flesh is an indication that these pollutants are present in river water or sediments in forms that are biologically available, and depending on the nature of the contaminant, may be bio-accumulated through the food chain. Restrictions on the consumption of sport fish are set if these contaminants exceed established levels in order to protect humans against potential adverse health effects.
In 2002, young-of-the-year fish tissues were sampled at four stations in the Rouge River at Warden Avenue near Highway 7, below the Milne Reservoir near Markham Road, at Highway 401 on the Main Rouge and at Highway 48 on the Little Rouge River (Figure 6-2). Table 6-8 shows the results of the analysis. Organic contaminant levels in tissues of juvenile forage fish were similar to those observed in other Toronto watersheds. Mean concentration exceedances were noted for PCBs at one station, DDT at two stations, and mercury at one station. Since the early 1990s, concentrations of DDT have generally declined, whereas PCBs and mercury do not show a discernable trend (Petro, 2004).
Table 666-6---8888:: YoungYoung----ofofofof----thethethethe----yearyear fish sampling locations where fish tissue guidguidelineeline exceedances occurred (as indicated by an x)
Below Milne Warden and Location HHHwyHwy 48 Hwy 401 Rating Reservoir Hwy 7
PCBs (100 ng/g) Good X √ √ √
DDT (14 ng/g) Poor √ X X √
Mercury (0.033 ug/g) Good √ X √ √ Source: (Petro, 2004)
Tissue analysis of sport fish sampled in the Milne Reservoir in 2002 showed that all species of bass and carp tested were considered safe to eat (Table 6-9), reflecting an improvement over 1997, when rock bass at this location had consumption restrictions. In the Rouge River marsh, certain size classes of small and largemouth bass had consumption restrictions, but bullhead, carp and pumpkinseed were safe to consume up to the maximum limit of 8 meals per month (rock bass were not tested at this site). Four fish species that spawn in the Rouge River - coho
6-18 salmon, chinook salmon, brown trout and rainbow trout - also had consumption restrictions. Since these fish spend most of their lives in Lake Ontario, consumption restrictions on these fish are not indicative of poor water quality in the Rouge River. Restrictions at all locations have remained the same since 1999.
Table 666-6---9999:: Consumption restrictions for species tested (mea(mealsls per month)
Fish Species Milne Reservoir Rouge Marsh
Largemouth bass Safe 4 meals
Smallmouth bass Not tested 2-4 meals
Rock bass Safe Not tested
Carp Safe Safe
Black Crappie Safe Not tested
Pumpkinseed Not tested Safe
Brown bullhead Not tested Safe
Rating Excellent Fair The term ‘Safe’ is based on the theoretical determination that no more than 8 meals per month of sport fish are consumed (4 meals for children under 15 and women of child bearing age). Tissue samples are analyzed for mercury, mirex, PCBs and pesticides. Source: OMOE, 2002
Rating for the Organics and Metals Indicator
The targets selected for meeting the surface water quality objective of managing the Rouge River watershed with respect to metals and organic contaminants are provided below, along with a rating for existing conditions in the watershed. These targets are generally consistent with the Toronto Remedial Action Plan and Toronto Wet Weather Flow Management Master Plan objectives for toxic contaminants.
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Objective: Protect and restore surface water quality with resprespectect to toxic Overall Rating contaminantscontaminants,, to ensure protection of aquatic life, ecological functions, human health, and water supply needsneeds.... Good
Indicator Measure Target
Heavy metals Concentrations of Concentrations of metals and organics meet PWQOs. and organic persistent organic contaminants contaminants, Banned priority toxics are not detected in surface waters. pesticides and heavy metals in surface Organic contaminant levels in young-of-the year fish meet waters, and in fish IJC and CCME guidelines. (young-of-the year and adult sport fish) Restrictions on sport fish consumption have not increased from 1999 levels.
An overall rating of good was assigned to the chronic effects indicator. On the positive side, this rating reflects relatively low levels of metals and organics in water samples, and few consumption restrictions on sport fish, especially upstream of the Lake Ontario zone of influence. On the negative side, concentrations of PCBs, DDT and mercury in young-of-the- year fish tissues were above CCME and IJC guidelines at some monitoring stations. PAHs also frequently exceeded provincial objectives in Rouge River surface waters.
6.4.4 Water Quality Trends in the Rouge River Watershed
Trends in water quality over time were assessed for suspended sediment, phosphorus, chloride and bacteria using Seasonal Kendall Trend Analysis. Results of this analysis at provincial monitoring stations for which historical data were available are shown in Table 6-10. These tests were performed with data for the entire period of record for each station, as indicated in the table.
Faecal coliform levels have been increasing over the past 30 years in the upper and lower reaches, as measured at the Box Grove and Highway 2 stations (Table 6-10). This increasing trend reflects the impacts of urban growth in these portions of the watershed, in the form of new bacterial sources from domestic animals and increased stormwater runoff. No trend was observed on the mostly rural Little Rouge River of the river and at Sheppard Avenue on the Main Rouge.
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Table 666-6---10101010:: Seasonal Kendall trend analysis results for seleselectedcted water quality variables
Main Rouge @ Main Rouge @ Main Rouge @ Little Rouge @ Twyn Water Box Grove, Sheppard Ave. E., Hwy #2, Rivers Drive, Toronto, Quality Markham Toronto; Toronto; Station #97013 Variable Station #97003 Station #97011 Station #97005 (1973(1973----1995)1995) (1971(1971----1995)1995) (1973(1973----1995)1995) (1972(1972----1995)1995)
Suspended n/a n/a Decreasing n/a Solids z = -2.3
Phosphorus Decreasing Decreasing Decreasing Decreasing z = -11.7 z = -10.1 z = -9.3 z = -2.6
Chloride Increasing Increasing Increasing Increasing z = 7.1 z = 4.9 z = 7.1 z = 6.9
Faecal Increasing No statistical trend Increasing No statistical trend Coliform z = 2.5 z = 1.0 z = 4.2 z = -0.9 Note: Seasonal Kendall trend analysis results are statistically significant at the 95% level of confidence. Source: Provincial Water Quality Monitoring Network. These stations were decommissioned by the province in 1995
The absence of total suspended solids (TSS) monitoring at most stations between 1981 to 1994 limited the assessment of trends for this contaminant. The only station for which there was continuous monitoring was on the Main Rouge at Hwy 2, which showed a slight decreasing trend over the 23 years of record (Table 6-10). A period of higher TSS occurred in the late 1980's to early 1990's, corresponding to the housing boom at that time. This was followed by a slow decline in TSS as construction activities slowed, until monitoring was discontinued in 1995 .
Increasing levels of chloride have been observed over the last three decades at all stations in the watershed. These trends can be attributed to an expanding number of roads and paved surfaces that receive salt applications during the winter months. Increases in the Little Rouge River, where there has been less urbanization, have been slower than on the Main branch (Figure 6-3).
Phosphorus levels have decreased significantly over the last 30 years, due to the success of management programs, such as those introduced in the early 1970s to reduce phosphorus use in detergents, as well as programs promoting reductions in fertilizer use. The most dramatic decreases in the Main Rouge occurred before the mid 1980s in association with the decommissioning of sewage treatment plants which discharged effluent to the river in Markham (Figure 6-4).
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Figure 666-6---3333:: Median chloride concentrations in the Rouge RiveRiverr from 1973 to 2003
180 160 Main Rouge - 97011 140 Little Rouge - 97013 120 100 80 60 40 20 MedianChlorideConc.(mg/L) 0 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003
Figure 666-6---4444:: Median phosphorus concentrations in the Rouge RiRiverver from 1973 to 2003
0.6 Main Rouge - 97011 0.5 Little Rouge - 97013 0.4 0.3 0.2 0.1 0 Median Phosphorus Conc. (mg/L) Conc. Median Phosphorus 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003
Data are insufficient to assess trends in organic contaminant levels in surface water, other than to say that they have generally declined, reflecting a phase out of the use of many of these chemicals (OMOE, 1999). The 2002 Progress Report of the ‘Great Lakes Bi-national Toxics Strategy’ attributes significant decreases in Ontario emissions of toxic pollutants (Tier 1) since the late 1980s due to stronger regulations and voluntary actions (United States Environmental Protection Agency and Environment Canada, 2002).
As noted earlier in this chapter the concentration of heavy metals during dry weather in the Rouge River appear to have declined somewhat since the early 1990s. The reduction in lead has been especially significant and corresponds with the phase out of lead in the early 1970s as an anti-knock additive in gasoline, in paints and as solder in food cans.
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6.4.5 Other Issues: Spills, LandfillsLandfills,, Sanitary Servicing,Servicing, Golf Courses
Spills
The effect of spills on aquatic life or water quality has not been well documented. Many of the substances spilled into the environment accumulate in stream sediments, which reduce the quality of habitat for benthic invertebrates and other bottom feeding organisms. Oil also clings to vegetation and grasses on the banks of rivers, posing a threat to animals that feed on these plants. The toxicity of a spill will depend on the spill duration, the type of spill, the amount, rate and time of release and other spill characteristics. Compounds with rapid bio-concentration kinetics, such as naphthalene, phenanthrene and benzene, are more likely to be acutely toxic (Davis et al ., 1984).
Studies summarizing spills data were recently conducted for three municipalities in the Rouge River watershed: the City of Markham, the City of Toronto and the Town of Richmond Hill (Li, 2002a, 2002b, 2002c). These studies showed that between 1988 and 2000, there were approximately 300 oil spills and 90 chemical spills in the Rouge River watershed, of which roughly 200 oil spills and 70 chemical spills drained to the River or one of its tributaries. The majority of oil spills occurred on major roads, whereas chemical spills were mostly associated with commercial plants, storage facilities and tanker trucks. In terms of volume, the petroleum sector contributed the most to chemical spills, often as a result of container or fuel tank leaks. One recent spill in the Little Rouge River resulted in fish kills extending 4 km downstream of the spill.
Landfills
There are six closed and/or abandoned landfill sites in the Rouge River watershed. Three are located in the Lower Rouge subwatershed, one near Beaver Creek and one west of Exhibition Creek (OMOE, 1991). All of these landfills were active prior to the establishment of Ministry of the Environment regulations on the design of landfills to protect surface and groundwater resources. Hence, liners or leachate collection systems were probably not installed, thereby increasing the risk of leachate leaking through the bottom and sides of the landfills. The former City of Scarborough initiated a remediation program for old landfills in 1992. Most sites have been studied to assess methane gas and groundwater conditions. Unfortunately, data from this program were not available when this chapter was being prepared.
Sanitary Servicing
Currently, there are no sewage treatment plants discharging to the Rouge River. Construction of the York-Durham Water Pollution Control Plant near the Duffins Creek on Lake Ontario resulted in the decommissioning of two plants on the Rouge River in 1980. Many of the rural area residents in the Rouge River watershed rely on septic systems to meet their wastewater disposal needs. On the Humber River, a tracer study of septic system effluents in a rural community found that septic system contributions to stream flow were a negligible fraction of total flow in the river (Gartner Lee, 2002). A similar result was reported in a modelling study of bacteria transport in Bruce Creek during wet weather, but during dry weather, wildlife and septic system failures were predicted to be the primary sources of bacteria delivered to the Bruce's Mill Conservation Area (TRCA, 1991).
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Golf Courses
There are 24 golf courses located across the Rouge River watershed. This land use activity can be a source of pesticides and nutrients if appropriate best management practices are not applied. There are few local data assessing nutrient and pesticide contributions to rivers or streams from golf courses. Humber River data from a recent monitoring study of in-use pesticides and nutrients in the Toronto area rivers suggested that the Scarlett Woods Golf Course was probably not a significant source of nutrients or pesticides to the river (Struger et al ., 2002).
Water use can be a serious concern if the golf course is relying on the river as its source of irrigation water. Golf course turf requires significant water inputs that are often drawn out of the adjacent watercourse. On small tributaries in particular, these water takings can pose significant threats to stream health. Loss of vegetation, creation of ponds, and pesticide and fertilizer use may also be significant depending on golf course design. Aware of the growing public concern over water and chemical use, many golf course managers have taken proactive measures to retrofit courses to meet industry environmental standards (Webb, 2002).
6.56.56.5 Objectives for Surface Water Quality
Three objectives have been adapted for surface water quality in the Rouge River watershed:
1. Meet standards for body contact recreation at nearshore beaches and in the river 2. Protect and restore surface water quality with respect to conventional pollutants, to ensure protection of aquatic life, ecological functions and water supply needs. 3. Protect and restore surface water quality with respect to toxic contaminants, to ensure protection of aquatic life, ecological functions, human health, and water supply needs.
For the purposes of this chapter, these objectives and ratings of current conditions are presented in Section 6.4.
6.66.66.6 Summary and Management Considerations
This assessment of ambient water quality conditions showed that, overall, water quality in the Rouge River remains relatively clean. Concentrations of only a few pollutants have increased since the 1970s ( e.g. chloride, bacteria) and several have shown significant declines (notably lead and phosphorus). These trends combined with current water quality conditions translated into generally favourable ratings for all three indicators evaluated.
Priority contaminants of concern identified by assessments include chloride, phosphorus, nitrate, E. coli and some trace organic pollutants. Chloride concentrations are increasing rapidly as urban development expands on the main branch of the Rouge River. Current chloride levels during the winter pose a threat to aquatic life in many parts of the watershed, especially downstream of transportation corridors. Observed nutrient levels were often above receiving water standards, and showed little spatial variation across the watershed. Bacteria levels in the river pose a risk for body contact recreation, but appear to be only one of several factors contributing to frequent postings at the Rouge beach. Reducing the number of postings at the beach will require addressing bacteria sources both in the river, in the nearby marsh and along the waterfront.
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Concentrations of PCBs, DDT, and mercury were detected in young-of-the-year (YOY) fish above current standards at one or more monitoring stations in the Rouge River, indicating that these contaminants are bio-accumulating in the food chain. DDT levels in YOY fish have generally declined since the early 1990s. Consumption restrictions on sport fish appear to be limited to the Rouge marsh, which is influenced by the Highway 401 upstream and Lake Ontario sources. Sport fish in Milne Reservoir are considered safe to eat.
Unfortunately, there were few data upon which to assess current and historical water quality conditions during wet weather. Guideline exceedances are common during high flow for a wide range of water quality variables, even in relatively undeveloped watersheds. The Rouge River watershed is not an exception in this regard, as indicated by the OMOE wet weather sampling results discussed earlier. Additional targeted wet weather sampling would help to better characterize water quality issues of concern and provide a useful baseline for future assessments.
A variety of stormwater treatment technologies have been applied in the Rouge River watershed to help address quantity, quality and downstream erosion concerns associated with wet weather flow. However, in roughly 40% of the urban area, stormwater runoff is discharged through dry quantity ponds or directly into the watercourse without treatment. In newer urban areas with quantity and quality controls, stormwater technologies are mostly limited to end-of- pipe controls such as ponds and pond retrofits. In the future, greater emphasis needs to be placed on controlling pollution at source through pollution prevention programs and lot-level controls, coupled with innovative ‘low impact’ site designs for new development.
Management of water quality in the Rouge River should also ensure protection and enhancement of natural attenuation processes in the watershed. Among the many natural mechanisms influencing water quality, groundwater discharge and woody riparian cover are perhaps the most important. Protection of discharge zones, associated recharge zones, and establishment or enhancement of riparian benefits will provide multiple benefits in terms of water quality, aquatic habitat, aesthetics and recreation.
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6.76.76.7 References
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Boyd, D. 1999. Assessment of Six Tributary Discharges to the Toronto Area Waterfront. Volume 1: Project Synopsis and Selected Results . Ontario Ministry of the Environment. Prepared for the Toronto and Region Remedial Action Plan.
Boyd, D., M. D’Andrea and R. Anderton. 1999. Assessment of Six Tributary Discharges to the Toronto Area Waterfront. Volume 2: Technical Appendix and Data Summary . Ontario Ministry of the Environment. Prepared for the Toronto and Region Remedial Action Plan.
Canadian Council of Ministers of the Environment (CCME). 1999. Canadian Environmental Quality Guidelines (CWQG). Canadian Council of Ministers of the Environment. Winnipeg.
Castelle, A. J., A. W., Johnson and C. Connoly. 1994. Wetland and Stream Buffer Size Requirements - A Review, Journal of Environmental Quality. Vol. 23, pp. 878-882.
City of Toronto. 2003a. Wet Weather Flow Management Master Plan: Final Summary Report . Toronto.
City of Toronto. 2003b. Wet Weather Flow Management Master Plan: Waterfront Response. Final Report. Toronto.
Cohen, S., S. Nickerson, R. Maxey, A. Dupuy and J. Senita. 1990. A groundwater monitoring study for pesticides and nitrates associated with golf courses on Cape Cod. Groundwater Monitoring Review . Winter 1990, pp. 160-173.
Council for Agricultural Science and Technology (CAST). December 1992. Water Quality: Agriculture’s Role . pp. 29-30.
Davis, W. P., D. E. Hoss, G. I. Scott, and P. F. Sheridan. 1984. Fisheries Resource Impacts from Spills of Oil or Hazardous Substances, In: Cairns, J.J. jr. and A. L. Buikema jr. (eds) Restoration of Habitats Impacted by Oil Spills . Boston, Butterworh Publishers. pp 157-173.
Environment Canada and Health Canada. 2001. Road Salts: Priority Substances List Assessment Report . Prepared for the Canadian Environmental Protection Act, 1999 Priority Substances List. Internet Publication.
European Inland Fisheries Advisory Commission (EIFAC). 1965. Water quality criteria for European freshwater fish. Report on finely divided solids and inland fisheries. International Journal of Air and Water Pollution . Vol. 9, pp. 151-168.
Fleming, R. and H. Fraser. 1999. Nitrate and Phosphorus Levels in Selected Surface Water Sites in Southern Ontario - 1964-1994 . Unpublished report. University of Guelph.
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Gartner Lee Limited. 2002. Nobleton Sewage Servicing Follow-Up Studies: 2000-2001 . Prepared for Totten Sims Hubicki Associates and the Regional Municipality of York, Toronto.
Hubbard, R., B. Hindley, P. Mar, H. Power,T. Ryan. 1987. Metropolitan Toronto and Region Rural Beaches Impact Study. Annual Report , Toronto and Region Conservation Authority.
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Li, J. 2002b. Spill Management for the Toronto AOC, the City of Markham Study , Ryerson Polytechnic University. Toronto.
Li, J. 2002c. Spill Management for the Toronto AOC, the City of Richmond Hill Study , Ryerson Polytechnic University. Toronto.
Marselek and Shroeter. 1988. Annual Loadings of toxic contaminants in urban runoff from the Canadian Great Lakes Basin. Water Pollution Research Journal of Canada . Vol. 23, pp. 360-78.
Maxted, J. 1999. The Use of Retention Basins to Mitigate Stormwater Impacts on Aquatic Life. In Roesner, L.A. (Ed.) Effects of Watershed Development and Management on Aquatic Ecosystems . Proceedings of the ASCE Conference. Snowbird, Utah.
Metropolitan Washington Council of Governments. 1995. Chapter 2: The Importance of Imperviousness, In Site Planning for Urban Stream Protection , Maryland, pp.19-33.
Mitsch, W. J. and J. G. Gosselink. 1993. Wetlands , 2 nd edition, Von Nostrand Reinhold, New York.
Mitsch, W. J. 1992. Landscape design and the role of created, restored and natural riparian wetlands in controlling nonpoint source pollution. Ecological Engineering. Vol. 1, pp. 27- 47.
Osborne, L. and D. Kovacic. 1993. Riparian vegetated buffer strips in water-quality restoration and stream management. Freshwater Biology . Vol. 29, pp. 243-258.
Ontario Ministry of the Environment. 2003. Guide to Eating Ontario Sport Fish . Twenty-second edition revised. Queen’s Printer for Ontario. Toronto.
Ontario Ministry of the Environment. 1999. Surface Water Monitoring and Assessment: 1997 Lake Ontario Report. Queen’s Printer for Ontario, Toronto.
Ontario Ministry of the Environment. 1999b. Water Management, Policies, Guidelines: Provincial Water Quality Objectives, Ontario . Queen’s Printer, Toronto.
Ontario Ministry of the Environment, 1991. Waste Disposal Site Inventory . Queen’s Printer for Ontario. 6-27
Petro, S. 2004. Young-of-the-Year Fish Database Update for the Rouge Watershed . Ontario Ministry of the Environment
Rouse, J. D., C. A. Bishop, J. Struger. 1999. Nitrogen Pollution: An assessment of the impact on amphibians. Environmental Health Perspectives , Vol. 107(10), pp. 1-6.
Schueller, T. 1999. Microbes and urban watersheds: concentrations, sources and pathways. Watershed Protection Techniques , Volume 3(1).
Sharma, M., E. A. Mc Bean, J. Marsalek. 1997. Source Characterization of Polycyclic Aromatic Hydrocarbons in Street and Creek Sediments. Water Quality Research Journal of Canada. Vol. 32:1, pp23-35.
Snodgrass, W. and M. D’Andrea. 1993. Dry Weather Discharges to the Metropolitan Toronto Waterfront , a report prepared for the Toronto Remedial Action Plan, Queen’s Printer of Ontario, Toronto.
Stormwater Assessment Monitoring and Performance (SWAMP) Program. 2003a. Performance Assessment of a Highway Stormwater Quality Retention Pond - Rouge River, Toronto, Ontario . Toronto.
Stormwater Assessment Monitoring and Performance (SWAMP) Program. 2003b. Performance Assessment of an Open and Covered Stormwater Wetland System – Aurora, Ontario .
Stormwater Assessment Monitoring and Performance (SWAMP) Program. 2002a. Performance Assessment of a Stormwater Retrofit Pond – Harding Park, Richmond Hill, Ontario .
Stormwater Assessment Monitoring and Performance (SWAMP) Program. 2002b. Performance Assessment of a Pond – Wetland Stormwater Management Facility – Markham, Ontario
Stribling, J., E. Leppo, J. Cummins, J. Galli, S. Meigs, L. Coffman, and M. Cheng. 2001. Relating instream biological conditions to BMP activities in streams and watersheds. In: Linking Stormwater BMP Designs and Performance to Receiving Water Impacts Mitigation . United Engineering Foundation. Snowmass, Colorado, 2001.
Struger, J., T. Fletcher, P. Martos, B. Ripley, G. Gris. 2002. Pesticide Concentrations in the Don and Humber River Watersheds (1998-2000) , Environment Canada and Ontario Ministry of the Environment, City of Toronto.
TRCA. 1991. Rural Beaches Project: Clean Up Rural Beaches (CURB) Report . Prepared for the Ministry of the Environment, Toronto.
TRCA. 2003a A Summary of Water Quality Conditions in the Toronto Region from 1996 to 2002 . Toronto, Ontario.
TRCA. 2003b. Rural Clean Water Program , http://www.trca.on.ca/water_protection/rural_water/ 6-28
United States Environmental Protection Agency and Environment Canada, 2002. Great Lakes Binational Toxics Strategy: Progress Report , http://www.binational.net/bns/2002.
Waterfront Regeneration Trust. 2002. Clean Waters, Healthy Habitats, Progress Report 2001, Technical Edition , Toronto and Region Remedial Action Plan, Ontario.
Waters, T. F. 1995. Sediment in Streams: biological effects and control. American Fisheries Society.
Webb, M. 2002. The Green Goes Green , in R.O.B Magazine.
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