Summary Report on the Initial Assessment of Ecological Health of Aquatic Ecosystems in : Water Quality, Sediment Quality and Non-Fish Biota

October 2007 ISBN: 978-0-7785-6744-8 (Printed Edition) ISBN: 978-0-7785-6745-5 (On-line Edition)

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SUMMARY REPORT ON THE INITIAL ASSESSMENT OF Ecological Health of Aquatic Ecosystems in Alberta: Water Quality, Sediment Quality and Non-Fish Biota

Prepared for:

Alberta Environment Water for Life – Healthy Aquatic Ecosystems Edmonton, Alberta

Prepared by: North/South Consultants Inc. , Alberta

October 2007

Aquatic Ecosystem Health in Alberta Alberta Environment

EXECUTIVE SUMMARY

Protection and maintenance of healthy aquatic ecosystems in Alberta is one of the overarching goals of the Water strategy. Implied in this goal is the need for a provincial-scale monitoring and evaluation system that includes regular reporting on the health of aquatic ecosystems.

This report focuses on three components of aquatic ecosystems throughout Alberta: water quality, sediment quality and non-fish biota. It provides a summary of current knowledge for major basins and key water bodies, and an initial assessment of aquatic ecosystem health based on interpreted data, published in readily available written reports or other formats. This information spans a period of approximately 20 years (1980’s to 2004).

Multiple gaps in data, knowledge, and assessment process are identified for water quality, and particularly for sediment quality and non-fish biota. Recommendations are made to help fill these gaps to allow more comprehensive reporting in the future. A conceptual framework for the design and implementation of a provincial monitoring, evaluation and reporting system on aquatic ecosystem health is provided.

This report is a summary of a substantial technical report entitled “Information Synthesis and Initial Assessment of the Status and Health of Aquatic Ecosystems in Alberta: Surface Water Quality and Non-fish Biota”, prepared for Alberta Environment and authored by North/South Consultants Inc. (2007).

The major findings of the initial assessment were:

Flowing waters:

• Surface water quality of the 11 major systems was evaluated. Of the 28 river reaches examined, most were rated as “Good”- 64% and “Fair” - 25%, and the remaining reaches were ranked as “Excellent” - 11%. • Water quality ratings for a selection of 14 major tributaries were “Excellent” - 7%, “Good”- 21%, “Fair” - 43%, and “Poor” - 7%; there was insufficient data for the remaining tributaries (21%). • In most cases, there was insufficient sediment quality and non-fish biota data to assess the ecosystem health of the and major tributaries.

Standing waters: • A selected evaluation of surface water quality data for Alberta lakes shows that many lakes are moderately to very highly productive (i.e., mesotrophic to hyper eutrophic). A more comprehensive assessment of ecosystem health of lakes is not possible at this time due to limited data for sediment quality and non-fish biota. • An assessment of ecosystem health of wetlands in Alberta could not be completed because of a general lack of data on surface water and sediment quality, and non-fish biota. • Another key limitation to the assessment of ecosystem health of lakes and wetlands is the need to develop appropriate ecological indicators of health for these diverse habitats.

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TABLE OF CONTENTS

EXECUTIVE SUMMARY ...... I LIST OF TABLES ...... IV LIST OF FIGURES...... IV AUTHORSHIP ...... V ACKNOWLEDGEMENTS...... V 1.0 INTRODUCTION ...... 1 2.0 INFLUENCES ON AQUATIC ECOSYSTEM HEALTH IN ALBERTA...... 9 2.1 Natural influences...... 9 2.1.1 Rivers and Streams ...... 9 2.1.2 Lakes...... 12 2.2 Human Activities ...... 13 3.0 RIVERS AND STREAMS IN ALBERTA ...... 16 3.1 Basin ...... 16 3.2 Peace and Basins ...... 16 3.2.1 Peace and Slave Rivers ...... 18 3.2.2 Wapiti- System ...... 19 3.3 Basin ...... 22 3.3.1 Athabasca River...... 22 3.3.2 Middle Reach Tributaries: McLeod and Lesser Slave rivers...... 27 3.3.3 Lower Reach Tributaries: Muskeg and Steepbank Rivers...... 28 3.4 Basin ...... 30 3.4.1 Beaver River ...... 30 3.4.2 Tributaries: and Marie Creek ...... 32 3.5 Basin...... 33 3.5.1 North Saskatchewan River...... 33 3.5.2 ...... 37 3.6 Basin...... 38 3.6.1 ...... 38 3.6.2 ...... 41 3.6.3 ...... 45 3.6.4 South Saskatchewan River...... 50 3.7 Milk River Basin...... 51 4.0 LAKES AND WETLANDS ...... 54 4.1 Lakes ...... 54 4.2 Wetlands ...... 59

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5.0 PROVINCIAL OVERVIEW: RIVERS AND STREAMS...... 60 6.0 CRITICAL INFORMATION GAPS AND RECOMMENDATIONS ...... 63 7.0 A FRAMEWORK FOR PROVINCIAL MONITORING AND REPORTING ON AQUATIC ECOSYSTEM HEALTH ...... 65 ABBREVIATIONS...... 67 GLOSSARY ...... 68

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LIST OF TABLES

Table 1 Summary of aquatic ecosystem health categories for the initial qualitative assessment ...... 7 Table 2 Descriptors of suitability ratings for water and sediment quality and non-fish biota...... 8 Table 3 Ranking of aquatic ecosystem health and data suitability for the evaluation of river reaches in Alberta...... 60 Table 4 Ranking of aquatic ecosystem health and data suitability for the evaluation of major tributaries...... 61 Table 5 Knowledge gaps and recommendations for future actions ...... 64

LIST OF FIGURES

Figure 1 Major river basins in Alberta ...... 3 Figure 2 When does the health of an aquatic ecosystem depart from the range of natural variability?...... 4 Figure 3 Ecoregions and sub-regions of Alberta...... 11 Figure 4 Human activities and land uses affecting AEH in Alberta ...... 15 Figure 5 Aquatic health assessments for the Hay, Peace and Slave Rivers ...... 17 Figure 6 Aquatic health assessment for the Athabasca River ...... 24 Figure 7 Aquatic health assessment for the Beaver River...... 31 Figure 8 Aquatic health assessment for the North Saskatchewan River...... 35 Figure 9 Aquatic health assessment for the Red Deer River...... 40 Figure 10 Aquatic health assessment for River ...... 43 Figure 11 Aquatic health assessments for the Oldman and South Saskatchewan rivers ...... 48 Figure 12 Aquatic health assessment for the Milk River ...... 53 Figure 13 Productivity of a selection of Alberta lakes based on phytoplankton biomass levels ...... 55 Figure 14 Rankings of aquatic ecosystem health in Alberta rivers...... 62 Figure 15 Development of a provincial monitoring and reporting system ...... 66

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AUTHORSHIP

Report by: Elaine Irving, Ph.D., P.Biol. – Senior Aquatic Ecotoxicologist

Karoliina Munter, M.Sc. – Aquatic Ecotoxicologist

David Klein, B.Sc. – GIS Specialist

Senior Review by: Karl Kroeker, B.Sc., P.Biol. – Principal

Editorial Review by: Anne-Marie Anderson and Richard Casey

ACKNOWLEDGEMENTS

We would like to take this opportunity thank the many people, who helped us along the way with the technical and summary reports.

Several Alberta Environment scientific and technical staff contributed significantly to the technical and the summary reports by providing relevant information, guidance and reviews. These include Anne-Marie Anderson, Colin Fraser, Leigh Noton, Richard Casey, Silvie Forest, David Trew, Doreen LeClair, Mary Raven, Al Sosiak, Wendell Koning, Chris Teichreb, Leanne Zrum, Craig Emmerson, Curtis Brock, Preston McEachern, Alina Wolanski, Theo Charette, Darcy McDonald, Ron Zurawell, Thorsten Hebben, Ed Bulger, and Luke Schoening.

Joanne Little from Alberta Agriculture Food and Rural Development, and Scott Millar and Allan Locke from Alberta Sustainable Resource Development also contributed to the review process.

Heather Proctor (), Rolf Vinebrook (University of Alberta), Gloria Wilkinson (Chair, Partnership), John Acorn (University of Alberta), Graham Griffits (Botanical Consultant, Athabasca), Roland Hall (University of Waterloo), Dörte Köster (University of Waterloo), and Andrea Kirkwood (University of Calgary) provided valuable insights on specific issues pertaining to aquatic ecosystem health in Alberta.

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1.0 INTRODUCTION

Albertans have recognized the need for a provincial water strategy because of growing concern about the current state (or health) and long-term sustainability of water supplies and aquatic ecosystems in the province. The provincial government has responded by developing Water for Life: Alberta’s Strategy for Sustainability1.

The strategy identifies three overarching goals:

• Safe, secure drinking water supply

• Healthy aquatic ecosystems (Text Box 1)

• Reliable, quality water supplies for a sustainable economy

In order to support the protection and maintenance of healthy aquatic ecosystems, an assessment of the current status was required. Key objectives of this assessment were to:

• Provide an overview of available knowledge on the status and health of aquatic ecosystems in Alberta. The aquatic ecosystems include rivers, streams, lakes and wetlands with diverse physical and chemical environments, and plant and animal communities.

• Provide general information on natural factors and major human activities that influence water quality, sediment quality and non-fish biota in the aquatic ecosystems.

• Identify gaps in current knowledge and provide recommendations to deal with any deficiencies.

The detailed findings of the assessment are in a technical report.2 This summary report is an overview of the initial assessment, the data gaps that were found, and the recommendations to fill the gaps to further enhance the monitoring and reporting system for Alberta.

The status and health of river, stream, lake and wetland ecosystems were evaluated for major river basins in Alberta (Figure 1). Specifically, the quality of water and bottom sediments, and non-fish biota (primarily aquatic invertebrates, algae, and in some cases aquatic plants) were evaluated. Other aquatic ecosystem components such as fish, riparian areas, and water quantity, are undergoing similar health assessments.

1 www.waterforlife.gov.ab.ca 2 North/South Consultants Inc., Clearwater Consultants Inc. and Patricia Mitchell Environmental Consulting. 2006. Information synthesis and initial assessment of the status and health of aquatic ecosystems in Alberta: Surface water quality, sediment quality and non-fish biota. Prepared for Alberta Environment, Edmonton, AB. North/South Consultants Inc. Page 1 Aquatic Ecosystem Health in Alberta Alberta Environment

2 TEXT BOX 1

What is Aquatic Ecosystem Health and how can it be measured effectively?

Based on a review of literature Stantec (2005)3 proposed the following definition of aquatic ecosystem health in Alberta:

“A healthy aquatic ecosystem is sustainable and resilient to stress. It maintains its ecological structure and function over time similar to the natural (undisturbed) ecosystems of the region, and provides an array of unimpaired ecological services that continue to meet social needs and expectations”.

Aquatic health can be measured using chemical, physical and biological indicators. In this report water quality, sediment quality and non-fish biota indicators were selected, and are defined by a set of measurable endpoints. For example, nutrients are indicators of water quality, and phosphorus concentration is a key measurement or endpoint. Other examples of indicator endpoints include the densities of benthic invertebrates and algal biomass. These indicator endpoints can be measured spatially at locations along a river and over time at a specific location. As illustrated in Figure 2, for each location there is a range of natural variability that is representative of a ‘healthy’ ecosystem. However, if measurements fall outside that natural range of variability, the ecosystem is likely under stress. If the ecosystem is unable to correct itself and rebound to the natural range of variability, then aquatic health is likely to be impaired and corrective action should be considered.

3 Stantec Consulting Ltd., 2005. Aquatic Ecosystems Review of issues and monitoring techniques. Prepared for Alberta Environment, Edmonton, AB. North/South Consultants Inc. Page 2 Aquatic Ecosystem Health in Alberta Alberta Environment

Figure 1 Major river basins in Alberta

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Approach followed in the Assessment

The assessment included the following phases:

• Existing, interpreted, and published information related to aquatic ecosystem health, or relevant to its assessment, was reviewed and synthesized. Information sources included provincial, federal, academic, non-governmental, and consultant reports, research papers and publications. The review focused on recent conditions, where possible, and did not involve the collection of new data, or the analysis of unpublished information.

• All major rivers and selected streams, lakes and wetlands within the river basins were selected for the assessment (Text Box 2).

• Indicators of ecosystem health (measurement endpoints) for water and sediment quality and non- fish biota were selected for rivers, streams, lakes and wetlands.

• Key stressors and issues that affect water and sediment quality and non-fish biota communities were identified for each river basin.

• When possible, aquatic ecosystem health and the suitability of available information were assessed as described in Text Box 3 and 4. The focus of the assessment was primarily on the rivers for which sufficient information was available to attempt an initial assessment of aquatic ecosystem health. For many water bodies such information was lacking and the outcome of the assessment was to provide a basis for identifying knowledge gaps that currently hinder our ability to maintain or improve the health of Alberta’s aquatic ecosystems.

“Water is the most critical resource issue of our lifetime and our children's lifetime. The health of our waters is the principal measure of how we live on the land.” Luna Leopold, Hydrologist

Figure 2 When does the health of an aquatic ecosystem depart from the range of natural variability? North/South Consultants Inc. Page 4 Aquatic Ecosystem Health in Alberta Alberta Environment

TEXT BOX 2 TEXT BOX 3 4 Selection of water bodies for Aquatic ecosystem health evaluation the assessment4 categories and criteria

Rivers, streams, lakes and wetlands The initial health assessment relied on the evaluation criteria were selected based on the following presented in Table 1. In addition, the suitability and criteria: relevance of the health status data and information was evaluated to indicate the confidence in the assessment • They represent the key areas of (Table 2). concern within major river basins. The water and sediment quality assessments relied on • They represent different natural established thresholds for indicator endpoints. These areas with unique physical, included Alberta4, Canadian and U.S.A. surface water chemical and biological quality guidelines and Canadian sediment quality guidelines characteristics within the basins, for the protection of aquatic life. Guidelines are generally such as ecoregions. applicable at broad spatial scales (i.e., national and • Recent published studies, provincial), but they may be over-, or under-protective, interpreted data, or other depending on site-specific conditions. Where available, appropriate information that was water quality objectives specifically derived for particular available. Sites with long term monitoring data were important rivers and ecoregions were used in the assessment. to the assessment. Examples include nutrient objectives derived for the Athabasca and Wapiti rivers. Except for , similar • For rivers and streams, objectives do not yet exist for lakes or wetlands in Alberta. upstream-downstream comparisons were conducted to assess changes in water quality, In addition, ratings from the provincial and federal water sediment quality and non-fish quality indices; specifically the Alberta River Water Quality biota. Key reaches were Index (ARWQI)5 and Canadian Water Quality Index (CWQI)6 identified along major rivers. were used. These indices summarize complex water quality • For lakes, the main focus was on data into easily understood information. Although valuable, measures of lake productivity, the indices have limitations, and can sometimes acidification, and salinity over misleadingly oversimplify the knowledge of the status of about the last 25 years. water quality conditions. Furthermore, the federal and • The health of wetland provincial indices are derived in different ways and index ecosystems was not evaluated values are not directly comparable. due to limited relevant information. Defined condition or effects thresholds (sometimes referred to as ‘biological criteria’) for non-fish biota are currently not established for Alberta. Due to this limitation, the assessments were restricted to site-specific descriptions of biological communities, comparisons to reference sites (e.g., upstream – downstream comparisons), and professional

4 Surface Water Quality Guidelines for Use in Alberta. 1999. Alberta Environment. http://environment.gov.ab.ca/info/library/5713.pdf 5 Alberta River Water Quality Index http://www3.gov.ab.ca/env/water/SWQ/resources01.cfm 6 Canadian Water Quality Index http://www.ccme.ca/sourcetotap/wqi.html North/South Consultants Inc. Page 5 Aquatic Ecosystem Health in Alberta Alberta Environment

a b TEXT BOX 4

Trophic status of lakes and rivers

Determination of lake and river trophic status relies on measurements of nutrients. These include phosphorus and nitrogen concentrations in surface waters and measures of the biomass of floating or bottom-dwelling algae. Chlorophyll a is a measure of the biomass of algae or plant material. River and lake productivity can be ranked into four trophic categories based on phosphorus, nitrogen and chlorophyll a concentrations in surface water:

• Hypereutrophic (very high productivity)(this category is used here for lakes only);

• Eutrophic (high productivity);

• Mesotrophic (moderate productivity); and

• Oligotrophic (low productivity).

Trophic classes for lakes7

Total Total Nitrogen Chlorophyll-a Secchi Depth Phosphorus (µg/L) (µg/L) (m) (µg/L) Oligotrophic < 10 < 350 < 2.5 > 4 Mesotrophic 10 - 35 350 - 650 2.5 - 8 4 - 2 Eutrophic 35 - 100 650 - 120 8 - 25 2 - 1 Hyper- eutrophic > 100 > 1200 > 25 < 1 Trophic Classes for Streams8

Maximum Mean Benthic Sestonic Total Benthic Total Nitrogen Chlorophyll Chlorophyll Phosphorus Chlorophyll (µg/L) (mg/m2) (µg/L) (µg/L) (mg/m2)

Oligotrophic < 20 < 60 < 10 < 700 < 25 Mesotrophic 20 - 70 60 -200 10 - 30 700 - 1500 25 - 75 Eutrophic > 70 > 200 > 30 >1500 >75

7 Vollenweider, R.A., and J. Kerekes. 1982. Eutrophication of waters: monitoring, assessment and control. Organization for Economic Co-Operation and Development (OECD), Paris, 156 pp and Nurnberg, G.K. 1996. Trophic state of clear and coloured, soft and hardwater lakes with special consideration of nutrients, anoxia, phytoplankton and fish. Lake and Reservoir Management 12(4): 432-447. 8 Dodds, W.K., J.R. Jones, and E.B. Welch. 1998. Suggested classification of stream trophic state: distributions of temperate stream types by chlorophyll, total nitrogen, and phosphorus. Water Research 32(5):1455-1462 and USEPA Agency (Environmental Protection). 2000. Nutrient criteria technical guidance manual: rivers and streams. United States Environmental Protection Agency Document 822-B-00-002, Office of Water. North/South Consultants Inc. Page 6 Aquatic Ecosystem Health in Alberta Alberta Environment

Proposed objectives for the Athabasca and Wapiti rivers9

Total Total dissolved Chlorophyll-a Total nitrogen (Nitrate+Nitrite)- Site Phosphorus phosphorus (µg/cm2) (µg/L) N (µg/L) (µg/L) (µg/L) Athabasca River Upper (headwaters to river 2.6 17 2 - 100 km 126) Middle (foothills region, 4.5 27 3 269 105 river km 126 to 293) Lower (mixedwood region, 4.6 51 15 553 137 river km 293 to confluence) 1.2 4 4 322 74

c

Table 1 Summary of aquatic ecosystem health categories for the initial qualitative assessment

Rating Water Quality Sediment Quality Non-Fish Biota Species composition, densities and No measurable impairment relative Contaminant concentrations are very biomass of the biological to reference or natural conditions; all similar to reference or natural communities (e.g., benthic or most data are compliant with Excellent conditions and compliant with invertebrates or phytoplankton) are water quality guidelines (WQG) or sediment quality guidelines (SQG) very similar to those of reference or reach-specific objectives natural conditions Species composition is similar to Minor impairment relative to Contaminant concentrations are that of reference or natural reference or natural conditions; data similar to reference or natural conditions, and population densities Good are usually compliant with WQG or conditions and usually compliant with or biomass show minor change due reach-specific objectives SQG to human influences Contaminant concentrations show Species composition shows slight Moderate impairment relative to moderate degradation relative to change relative to those of reference reference or natural conditions; data reference or natural conditions; data or natural conditions; and densities Fair are commonly not compliant with are not compliant with SQG and and/or biomass show moderate WQG or reach-specific objectives below probable effects thresholds change due to human influences (PET) High impairment relative to Contaminant concentrations show Species composition shows reference or natural conditions; data high degradation compared to moderate change relative to Marginal are more frequently not compliant reference or natural conditions; data reference or natural conditions; and with WQG or reach-specific are not compliant with SQG and densities and/or biomass show large objectives occasionally exceed PET changes due to human influences Contaminant concentrations show Very high impairment relative to very high degradation relative to Species composition, densities and reference or natural conditions; data reference or natural conditions; data biomass show very substantial Poor are generally not compliant with are not compliant with SQG and changes due to human influences WQG or reach-specific objectives regularly exceed PET Insufficient Data Insufficient data for an adequate assessment

9 Chambers, P.A., J.M. Culp, N.E. Glozier, K.J. Cash, F.J. Wrona and L. Noton. 2006. Northern Rivers Initiative: Nutrient and dissolved oxygen – issues and impacts. Environmental Monitoring and Assessment 113: 117-141. North/South Consultants Inc. Page 7 Aquatic Ecosystem Health in Alberta Alberta Environment

Table 2 Descriptors of data suitability ratings for water and sediment quality and non-fish biota

RATING DESCRIPTOR

Recent comprehensive study or studies including sound analysis and Good interpretation of relevant datasets are available

Available study or studies were limited in some aspects. For example, Fair relevant datasets or recent data may not be available, or the analysis of data is insufficient

Available data are few and/or of limited value for inclusion in an aquatic Marginal health assessment

Poor There are no, or few data, or previous studies

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2.0 INFLUENCES ON AQUATIC ECOSYSTEM HEALTH IN ALBERTA

Aquatic ecosystems are influenced by a wide variety of natural processes and human activities. It is important to consider natural and human influences separately when evaluating the ecological health of aquatic ecosystems. This will allow a better understanding of ecosystem processes, human influences and how to better manage human impacts. The following sections include background to illustrate the types and diversity of natural and human influences on aquatic ecosystems in Alberta.

2.1 NATURAL INFLUENCES

Aquatic ecosystems are extremely complex made up of physical, chemical and biological components that interact to support a large variety of ecological processes (e.g., nutrient cycling and assimilation of human wastes or toxins). Natural variation in these elements and processes are strongly influenced by broad differences in landscape features such as geology, soils, topography, elevation and climate that in turn define biological communities living in specific ecosystem types. Groupings of these characteristics are often used to define broad geographic ecoregion categories. There are six major ecoregions in Alberta: boreal forest, the Rocky Mountains, foothills, Canadian shield, parkland and grassland (Figure 3). Although the ecoregions have common characteristics, there is also variation of the characteristics within the regions and over time. For example, natural variability over time is strongly influenced by seasonal and year-to-year differences in weather, and by longer term changes in climate. In turn this temporal variation will influence the timing and degree of water movement over the landscape such as runoff and replenishment of surface and ground water supplies.

2.1.1 Rivers and Streams

Changes in elevation determine many physical attributes of rivers and streams, such as gradient (steepness), flow velocity and patterns of flow. River discharge (the volume of water) usually increases in a downstream direction due to cumulative contributions from tributaries, groundwater and surface runoff, factors which may be offset to some degree by loss to groundwater, evaporation and uses by humans.

Seasonally varying flows affect all natural river and stream ecosystems, whatever their size. Low, stable flows tend to occur during periods when runoff is low, usually in fall and winter. Snowmelt and rains in the spring and summer can result in rapid and substantial increases in flows. Glacial melt and groundwater inputs help to sustain flows in the headwaters of many large rivers during the dry summer months. Prairie rivers and streams that are fed by local runoff and ground water typically tend to have low flows in summer and fall. Seasonal and longer-term variations in river flows influence the overall water quality, sediment quality and biological communities in rivers and streams.

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River bottom substrates also tend to change from coarser cobble, or gravel substrates (erosional) in the headwaters, to increasingly sandy, silty, or muddy, substrates (depositional) in the middle and lower reaches. This coincides with a progressive increase in river discharge and depth, widening of the river channel, and often slowing of flows. Natural bank erosion, scouring, and re-suspension of river bottom sediments often result in cloudy, turbid water, high in suspended solids levels, particularly when river discharge is high. For many large rivers in Alberta, there is a natural increase in nutrient levels in a downstream direction that leads to a gradual increase in river trophic status, or biological productivity. This is evident in rivers originating in the Rocky Mountains where the headwaters are typically very low in nutrients and then become more eutrophic as they traverse the parkland and prairie ecoregions.

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Figure 3 Ecoregions and sub-regions of Alberta10

10 Natural Regions Committee. 2006. Natural Regions and Subregions of Alberta. Compiled by D.J. Downing and W.W. Pettapeice. Government of Alberta. Pub. No. T/852. North/South Consultants Inc. Page 11 Aquatic Ecosystem Health in Alberta Alberta Environment

Biological communities often respond in a predictable manner to longitudinal changes in the physical and chemical environments of rivers and streams:

• Benthic invertebrate communities characteristic of erosional habitats are more prevalent in headwater streams or upstream river reaches, while downstream communities are more typical of depositional habitats.

• Benthic algae tend to be more prevalent in the upper and middle reaches, than in lower reaches, where substrates tend to be less suitable and elevated suspended solids reduce light penetration. The composition of both benthic invertebrate and algal communities change with distance downstream in response to flow velocities and natural increases in nutrient levels.

Natural changes in water quality anticipated along large river systems include increasing levels of nutrients, dissolved and suspended solids, and other parameters such as some metals.

2.1.2 Lakes

There is a wide diversity of lake types in Alberta. Low nutrient lakes are common in the Rocky Mountains, while moderately or very highly productive lakes occur in much of central and northern Alberta. Although most lakes in the province have fresh water, saline lakes occur in much of southeastern Alberta. The natural variability in lakes is due to a large extent to the characteristics of the watershed (eg, geology, soils, area) and climate.

In the southern and southeastern part of the province (Grassland ecoregion; Figure 3 arid conditions prevail and surface water is scarce. Consequently, there are fewer natural lakes and more man-made reservoirs. Natural lakes tend to have high total dissolved solids or salinity levels. The Parkland ecoregion of Central Alberta represents a transition between the dry grasslands to the south and the wet boreal forest to the north. Lakes in this region are more numerous and become more nutrient rich, as the climate becomes wetter and the soils more fertile; they also vary substantially in size and characteristics. The Boreal Forest ecoregion, with its abundance of water, has many lakes, ranging from small lake-wetland complexes to extremely large lakes such as . In all probability many of these lakes were likely naturally nutrient rich, even before major watershed disturbance by European settlers. In contrast, lakes in the Rocky Mountain ecoregion tend to be naturally nutrient poor with low productivity.

The physical characteristics of lakes, such as lake depth, flushing rate, bottom type, surface area, volume, and watershed area and geology vary naturally among lakes. These characteristics influence concentrations and residence times of minerals, and nutrients.

Inflowing streams, groundwater, runoff from the watershed, and dust, gas or precipitation from the atmosphere represent ‘external loading’ sources of nutrients, minerals, and contaminants to lakes.

Processes within lakes also vary among lakes and over time. Lakes have different mixing patterns. Both thermal stratification and lake mixing depend on lake temperatures and depth, as well as wind patterns, internal currents, and physical characteristics of the lake. Mixing tends to be greater in lakes North/South Consultants Inc. Page 12 Aquatic Ecosystem Health in Alberta Alberta Environment

with large surface areas exposed to the wind, and shallow lakes stratify least because they are better mixed. Thermal stratification occurs when the heat absorbed from the lake surface remains within the warm upper layer above the denser cold-water layer. Thermal stratification can influence the movement of nutrients and dissolved oxygen between these layers. Turnover occurs when these layers are mixed again, usually by wind action.

Nutrients move within the water column and also between the bottom sediments and the lake water. The release of nutrients from sediments to the lake water is called ‘internal loading’; it can be an important source of phosphorus to Alberta Lakes.

TEXT BOX 5

Internal phosphorus loadings in Alberta

Nutrients not flushed out of a lake ultimately sink to the lake bottom where they are taken up by sediments. In many Alberta lakes, phosphorus accumulated in sediments may be released back into the overlying water under certain conditions in summer. This is referred to as the internal loading of phosphorus to a lake. Internal loading can result in more nutrient enrichment, with associated algal blooms and concerns with water quality. Monitoring by Alberta Environment indicates that, during summer, internal loading contributes 50–99% of the total phosphorus input to shallow lakes in central and northern Alberta. Internal loading is highest from phosphorus-saturated sediments, and occurs mostly during summer when water temperature is highest and dissolved oxygen levels near the bottom are very low. The external loading of phosphorus to a lake from its watershed is relatively easier to manage and reduce, than the internal loading. The aeration of to increase dissolved oxygen is an example of in-lake treatment to reduce internal loading. Pine Lake is a unique example in the province where withdrawal of phosphorus-rich water from the bottom was used to reduce lake nutrient concentrations. Concerted measures were also taken to reduce phosphorus contributions from the watershed by improving land management.

2.2 HUMAN ACTIVITIES

Numerous human activities in the province affect aquatic ecosystems. These activities generally fall into three broad categories: river flow regulation and water withdrawal or consumption; land use and landscape alterations; and release of contaminants into surface or ground waters. Sources of contaminants can be categorized as originating from point sources (discrete and identifiable), or non- point sources (diffuse). An effluent discharge is an example of a point source, while agricultural runoff is an example of a non-point source. The effects of point sources on aquatic ecosystems are relatively easy to measure and control, those of non-point sources are, more difficult to quantify and manage because of their very diffuse nature. (Figure 4). Point sources and non-point sources affect aquatic ecosystems in a cumulative fashion.

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Point sources include:

• treated municipal wastewater discharge; urban storm sewers outflows, combined sewer overflows

• industrial wastewater discharges from pulp mills, power plants, petrochemical plants, or food processing plants Non-point sources include atmospheric deposition of contaminants and overland runoff from:

• natural resource exploitation such as coal mining, oil and gas operations, forestry;

• agricultural field crops, rangeland and irrigation;

• urban and rural population centres

• recreational areas, roads and infrastructure

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a b a b

c d d a

Figure 4 Human activities and land uses affecting AEH in Alberta

Map Descriptions: i. Major municipalities shown as black shading, primary and secondary highways shown in red and grey respectively. ii. Major and minor dams are shown in black and blue respectively, whereas water control structures are shown as green dots. iii. Point source discharges shown are licensed discharges greater than 10,000m3 yr-1. iv. Water-short areas assessment criteria are: Water-short (red) considered either exceptionally dry or the area has been closed to most or all new water applications; Potentially Water-short (orange) considered either relatively dry or the area has a generally high level of water allocation compared to natural supply; Not Regionally Water-short (White). v. Green zone is shown in green, Irrigation Districts in dark grey, and federal and provincial parks and protected areas in red. vi. Map shows the Manure Production Index for the Agricultural Areas of Alberta where red denotes areas of highest production and dark green indicates areas of lowest production. vii. Brown indicates the Oil Sands areas, pink indicates natural gas fields, green the location of oil fields, grey the location of coal fields, and black squares and triangles the location of coal mines. viii. Sand, gravel and aggregate resources are shown in grey and major lakes and rivers are shown in blue. a Data courtesy of Resource Data Branch, Sustainable Resource Development, Government of Alberta. b Data provided by Environmental Monitoring and Evaluation Branch, Alberta Environment. c Alberta Agriculture, Food and Rural Development. 2005. Agricultural Land Resource Atlas of Alberta, 2nd Edition. Alberta Agriculture, Food and Rural Development, Resource Management and Irrigation Division, Conservation and Development Branch, Edmonton, AB. d Data courtesy of Alberta Energy and Utilities Board/Alberta Geological Survey, 2007. http://www.ags.gov.ab.ca/gis/gis_and_mapping.shtml

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3.0 RIVERS AND STREAMS IN ALBERTA

A brief description of the basin characteristics and stressors is provided for the major river basins, it is followed by the aquatic health assessment of the selected rivers, main tributaries and smaller streams (Figure 1). Aquatic health and the suitability of available information are either evaluated for each of the identified reaches, or for the entire river or stream.

3.1 HAY RIVER BASIN

The Hay River Basin is one of the most northern river basins in Alberta. The majority of the basin lies within Alberta, with the remainder in BC and NWT. The Hay River originates in BC, flows through Alberta, and eventually drains into Great Slave Lake in the NWT. Wetlands, and especially peatlands, are common features in the basin’s landscape. The Hay River watershed has not been particularly affected by human activities. However, there is some oil and gas activity in the Hay-Zama lakes area. In addition, forestry, low intensity agriculture and periodic municipal wastewater effluent discharges from small urban developments occur in the basin.

Information on the health of aquatic ecosystems within the Hay River Basin is very limited. Nutrient levels indicate that the Hay River is quite productive, with particulate phosphorus and nitrogen levels regularly exceeding provincial guidelines. High levels of suspended sediments cause naturally elevated iron and aluminium levels during spring runoff. Cadmium and copper are occasionally present in high concentrations, but it is unclear whether the source of these metals is natural or human induced. Winter dissolved oxygen levels are low. Overall, water quality in the Hay River is ‘good’ according to the aquatic health assessment (Figure 5).

3.2 PEACE AND SLAVE RIVER BASINS

The Basin originates in the mountains of BC and ends at the Peace/Athabasca Delta in Alberta. The Slave River Basin extends from the delta into the NWT. These sparsely populated basins stretch out across the Boreal Forest, except for agricultural areas mainly located in the southern Peace River Basin (Figures 3 and 4).

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Figure 5 Aquatic health assessments for the Hay, Peace and Slave Rivers

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3.2.1 Peace and Slave Rivers

Much of the Peace River flow that crosses the border into Alberta originates from the Williston Reservoir which was created in 1967 when the WAC Bennett Dam was constructed on the British Columbia portion of the river. The dam has strongly influenced aquatic health in this river for decades, and for thousands of kilometres downstream. Flow regulation has dampened seasonal fluctuations in river discharge and compared to natural, pre-regulation conditions, winter flows are higher and summer flows lower. The river does not have the discharge extremes that historically helped flush sediment downstream. This is leading to the gradual filling of the riverbed with silt and sediment. In recent years, reduced precipitation and spring runoff volume have resulted in lower in-flows from major tributaries such as the Smoky River, although there has been no decline in average annual stream flows of the Peace River. The Peace and Slave rivers remain the largest in Alberta, with correspondingly large dilution capacities.

In Alberta, the Peace River receives effluent discharges from the Peace River Pulp Mill and the wastewater treatment plant (WWTP) from the Town of Peace River. The impact of these discharges on aquatic health is somewhat limited due to the sheer size of the river. Non-point source inputs also occur along the Peace River, but the extent of these and associated impacts are less well understood. These diffuse inputs are mainly associated with forestry and agricultural land use, and conventional oil and gas operations. However, point and non-point sources exert less influence on aquatic health indicators than natural downstream changes in river channel geomorphology. These changes include natural scouring processes, reduced flow rates, increased river discharge, a progressive change to finer river channel and bank substrates, and multiple tributary inputs.

Aquatic Health Assessment

TEXT BOX 6

Peace and Slave River reaches

Upper Reach: BC Border to Smoky River Confluence. Middle Reach: Smoky River Confluence to Fort Vermilion. Lower Reach: Fort Vermilion to the Delta.

Water Quality in the Upper Reach of the Peace River

For the most part, water quality in this reach is determined by river water quality at the provincial border, and is considered to be ‘good’ (Figure 5). River discharge patterns and the variation in suspended sediment transport are the main factors influencing river quality. Most sediments transported downstream originate from highly erodible soils associated with agriculture and forest land use in BC. Levels of suspended sediment, and levels of particulate nutrients and some trace metals, tend to rise during and other high discharge events. However, since such particulate forms are typically less

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available for uptake by river biota (e.g., plants, invertebrates, and fish) than dissolved forms, the impact due to eutrophication is limited.

Water Quality in the Middle and Lower Reaches of the Peace River and the Slave River

As the river flows towards Fort Vermilion, concentrations of most water quality indicators increase progressively. According to the ARWQI, water quality at Fort Vermilion is ‘good’ (Figure 5). Nutrient levels, and especially particulate phosphorus associated with suspended sediments are relatively high in this reach. Water quality can be considered ‘good’ until the lower reach, where it shifts to ‘fair’. This progressive decrease in water quality is attributed to consistently high levels of suspended sediment, and related increases in associated water quality parameters (nutrients, metals, biochemical oxygen demand, and turbidity). Water quality conditions in the lower Peace River and the Slave River are similar and have been given the same health ratings (Figure 5).

Sediment Quality and Non-Fish Biota in the Peace River

PCB contaminants have been reported at low levels in river sediments in the upper reach. Further downstream, organic contaminants11 also occur at low levels in middle reach sediments close to the Peace River Pulp Mill. Sediment quality is rated ‘good’ in the upper and middle Peace River (Figure 5).

Peace River benthic invertebrate communities reflect changes in channel geomorphology, river flows and discharge, water quality conditions, and river substrates. Bottom substrates change from mostly cobble and pebble in the upper reach to cobble, pebble and sand in the middle reach, and to sand and silt in the lower reach. Benthic communities are most abundant and diverse in the upper and middle reaches. Invertebrates in the lower reach are lower in abundance and diversity in response to the lower flows and sand/silt substrates. Within Alberta, tolerant invertebrates such as midge larvae and worms dominate the Peace River benthic communities. In parts of the upper and middle reaches, communities typical of erosional habitats, such as mayflies and stoneflies are most typical. Recent monitoring conducted for the Pulp and Paper Environmental Effects Monitoring Program, indicated that benthic invertebrate communities in this river do not show measurable responses to the pulp mill effluent. Consequently, aquatic health is rated ‘good’ (Figure 5).

Benthic algae are less abundant in the Peace River compared to other rivers. The highest algal biomass occurs in the upper reach, where substrates and flow conditions are more suitable.

3.2.2 Wapiti-Smoky River System

The Smoky River together with its largest tributary, the Wapiti River, forms the Smoky-Wapiti river system that drains about 20% of the Peace River Basin. These rivers are affected by discharges of pulp mill, municipal, and industrial effluents, in addition to inputs from coal mining, agricultural, and

11 Dioxins, furans, and chlorinated phenolics. North/South Consultants Inc. Page 19 Aquatic Ecosystem Health in Alberta Alberta Environment forestry activities. Both rivers are naturally nutrient poor and sensitive to nutrient enrichment from point sources and land-use changes.

Aquatic Health Assessment

Water Quality

Although water quality in the lower Smoky River is rated ‘good’ with the ARWQI, there is still an issue with elevated nutrient levels and nutrient quality has consistently been rated lower (Figure 5). Nutrient levels are consistently elevated during periods of high river discharge because particular phosphorus and sediments enter the river with surface runoff. Nutrient levels are lower than those recorded in the Peace River, but higher than in many other rivers in Alberta.

Water quality in the Wapiti River upstream and downstream of Grande Prairie is also ‘good’, although nutrient quality is often only ‘fair’. Nevertheless, additional integrated monitoring has confirmed that the lower Wapiti River is enriched by nutrient inputs from the Grande Prairie WWTP and the Weyerhaeuser Pulp Mill. Water quality in the Wapiti River is rated as ‘fair’ (Figure 5). Nutrient enrichment and subsequent impacts on biota are of most concern in this river, especially because recent lower flows exacerbate the situation.

The Wapiti River first becomes enriched with nutrients as it passes the Grande Prairie WTTP, an impact further amplified downstream by the pulp mill discharge. In fact, long-term monitoring data indicate that levels of phosphorus and nitrogen downstream of Grande Prairie exceed upstream levels several- fold. Furthermore, algal growth appears to be limited by both nitrogen and phosphorus upstream of Grande Prairie, but not downstream (Text Box 7). Municipal and pulp mill effluents have, in effect, changed the nutrient status of the lower Wapiti River. In an effort to provide more protection to the Wapiti River beyond provincial water quality guidelines, revised nutrient quality and algal biomass objectives have been proposed for this river. Long-term data collected at the mouth indicate that several forms of nitrogen and phosphorus, including dissolved forms, exceed these revised guidelines. This suggests that phosphorus and nitrogen forms readily available to river biota occur at levels of consequence for aquatic health.

Sediment Quality and Non-fish Biota in the Smoky and Wapiti rivers

Sediment quality in the Wapiti River is considered to be ‘fair’ based on monitoring conducted mainly in the lower river, below Grande Prairie. Levels of some organic contaminants, trace metals, and nutrients are higher in sediments downstream of the Grande Prairie WWTP and the pulp mill, while dissolved oxygen levels in sediment pore waters are comparatively lower in the lower reach.

Dioxins and furans are still present in fish tissue and sediments in the lower Wapiti River, but levels have recently declined due to the elimination of these chemicals from the pulp mill effluent. In contrast, levels of PCBs in sediments have not declined although they remain below guidelines. While the PCBs could originate from several sources, such as a historic spill at the pulp mill or historic sources in

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Grande Prairie, dioxins and furans present in the sediments are indicative of pesticide and pulp mill sources.

Benthic algal and invertebrate communities in the lower Smoky River, downstream of the Wapiti River, are impacted by nutrient inputs from this tributary. A typical response to nutrient enrichment has been observed, where invertebrate abundance and algal biomass are greater downstream, but the number of invertebrate types (taxon richness) does not change. Aquatic health in the Smoky River is ‘fair’, while in the Wapiti River itself, it is rated ‘marginal’, due the impact of man-induced nutrient enrichment on river biota downstream from Grande Prairie.

A riverside mesocosm12 experiment was used to separate the biological effects of the WWTP and pulp mill discharges. Both effluents represent significant nutrient sources and cause nutrient enrichment impacts, but the WWTP effluent was shown to represents a nitrogen source, while the pulp mill effluent represents a source of phosphorus and carbon. Since benthic algal biomass is more strongly related to nitrogen levels than to phosphorus or carbon levels, nitrogen is the main nutrient limiting algal biomass in the Wapiti River downstream of Grande Prairie.

TEXT BOX 7

Streams located in watersheds affected by agriculture and coal mining activities

Water quality of three agricultural streams from the Peace River Basin (i.e., Kleskun Drain, and Hines and Grande Prairie creeks) is monitored routinely. Overall water quality was ‘good’ in Hines Creek and ‘marginal’ in Grande Prairie Creek and Kleskun Drain. The following represent the main findings:

• Similar to other agricultural streams monitored in the province, these streams were nutrient- rich (eutrophic).

• Nutrients tend to be more bioavailable and present at higher concentrations in Kleskun Drain and Grande Prairie Creek (moderate agricultural intensity watersheds), compared to Hines Creek (low agricultural intensity watershed).

• Pesticides were more prevalent in Kleskun Drain, likely due to documented weed control efforts. Otherwise pesticide levels in these streams were related to the intensity of agriculture in the surrounding watersheds.

• Unlike other water quality parameters, levels of suspended sediment were related to discharge fluctuations rather than agricultural intensity, and were similar among streams.

Elevated selenium levels have been reported in Beaverdam and Sheep Creek water and sediments located downstream from coal mining activities.

12 Experimental apparatus or enclosure designed to approximate natural conditions, and in which environmental factors can be manipulated. North/South Consultants Inc. Page 21 Aquatic Ecosystem Health in Alberta Alberta Environment

3.3 ATHABASCA RIVER BASIN

The Athabasca River Basin extends northeast from the Rocky Mountains to the Athabasca River Delta and Lake Athabasca. This sparsely populated basin is mostly forested except for agricultural areas in the south, and large expanses of peatland in the north (Figures 3 and 4).

3.3.1 Athabasca River

The Athabasca River receives continuous discharges from five pulp mills13 and five municipal WWTPs14, and additional municipal discharges also occur to tributaries. These point sources contribute to nutrient enrichment in the upper and middle reaches, and they also contribute to declines in dissolved oxygen during late winter. The lower river flows through the extensive Athabasca oil sands deposit that is currently being developed. Oil sands wastewaters presently include treated refinery effluent, site drainage and runoff. The principal non-point source inputs to the river are from pipeline and road networks that support the oil and gas industry, forestry and agricultural land use practices.

The Athabasca River is unregulated and governed by climatic conditions, with peak summer and low winter discharges. In recent years, river discharge during winter has been low due to drier conditions and reduced snowmelt. Large extremes in seasonal discharge profoundly influence water quality and biota living in this river. During high discharge periods, nutrients and metals directly associated with suspended sediments can reach fairly high levels, although these may be mostly natural.

Levels of particulate nutrients tend to be highest during periods of high flows in summer. However, the actual impact of effluents during this time is often lower because of substantial dilution and high turbidity. As flows and suspended solids levels decline, light penetration increases thereby allowing benthic algae to utilize dissolved nutrients. Benthic algal biomass increases and algae take up sufficient nutrients from the water column to cause a downstream decline in some nutrients.

Aquatic Health Assessment

TEXT BOX 8

Athabasca River reaches

Upper Reach: Headwaters to upstream of Hinton. Middle Reach: Upstream of Hinton to Fort McMurray. Lower Reach: Fort McMurray to the Athabasca River Delta.

13 Two bleached kraft mills and three chemi-thermomechanical mills 14 Jasper, Hinton, Whitecourt, Athabasca, Fort McMurray North/South Consultants Inc. Page 22 Aquatic Ecosystem Health in Alberta Alberta Environment

Water Quality in the Upper Reach

The main issue affecting water quality in this reach is the localized impact of the Jasper WWTP discharge, but water quality in this reach is generally rated as ‘excellent’ (Figure 6). Nutrient levels are elevated, even several kilometres downstream of Jasper, and they cause the nutrient status of the river to change. The river is oligotrophic upstream of the WWTP, and benthic algal growth is limited by phosphorus. The Jasper WWTP discharges a moderate amount of phosphorus, but because the phosphorus is readily available for plant growth, the relatively small addition results in abundant algal growth for several kilometres. To protect aquatic life, ecoregion-specific guidelines were derived. They take into account all nutrient forms and aim at preventing excessive benthic algal biomass development. Furthermore, the Jasper WWTP has recently been upgraded; this has resulted in a reduction in phosphorus loading to the Athabasca River, and lower nutrient levels in the river.

Water Quality in the Middle Reach

Effluent and tributary inputs cause increases in nutrient levels over and above natural increases in the middle reach. Concentrations increase downstream of pulp mills and some WWTPs and eventually return to background levels further downstream. Although pulp mills discharge more nutrients to the river, nutrients derived from WWTP effluents appear more bio-available, and have a proportionally greater impact. In contrast, nutrient inputs from diffuse sources are less available for algal growth than either of these effluent inputs.

The effluent discharge from Hinton Pulp has the greatest impact on the Athabasca River, because it has a larger nutrient loading than other pulp mills and discharge occurs in an area of the river where dilution capacity is lower. Nutrient concentrations increase directly downstream from the pulp mill, but decrease to background levels within 50-100 km. The cumulative impact of nutrient discharges to the middle reach becomes apparent when nutrient levels above Hinton (reference section) are compared to those above Whitecourt (exposed section). Nutrient levels above Whitecourt are double those reported above Hinton. Further downstream, as the river flows into the Boreal ecoregion, it becomes more nutrient rich for natural reasons. Therefore, even though the river receives additional effluent discharges, there is little difference between nutrient levels in reference and exposed sections. On balance, water quality for the entire middle reach is deemed to be ‘good’ according to the aquatic health assessment (Figure 6).

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Figure 6 Aquatic health assessment for the Athabasca River

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Water Quality in the Lower Reach

River nutrient status, in terms of phosphorus, shifts from oligotrophic to mesotrophic, and phosphorus levels have exceeded the proposed nutrient ecoregion guideline several times. This is a result of the cumulative nutrient enrichment from upstream effluent inputs, as well as non-point source inputs from agriculture, forestry, and natural sources.

Due to large-scale oil sands extraction activities in the lower river basin, several organic compounds are of potential concern, including naphthenic acids and polycyclic aromatic hydrocarbons (PAHs). Currently, levels of these compounds appear to be low, but further water quality guideline or site- specific objective development are required.

TEXT BOX 9

Dissolved oxygen in the Athabasca River

Northern rivers often experience low dissolved oxygen conditions, particularly in late winter. In the Athabasca River, the decline in dissolved oxygen levels along the river is exacerbated by low winter flows and the input of nutrients and oxygen demanding substances from a variety of natural, municipal and industrial sources. Oxygen demand from the river bed also plays a role and tends to increase downstream of nutrient inputs from pulp mill and municipal effluents The middle reach, from Hinton to Fort McMurray, has been most affected, such that low winter dissolved oxygen levels represent the water quality issue of most concern. There is a cumulative decline in dissolved oxygen levels from Hinton to Grand Rapids. Downstream from the rapids, levels return to near saturation, but then gradually decrease again as the river flows north to the Athabasca Delta. These spatial and periodic declines in dissolved oxygen have negatively affected benthic invertebrate communities upstream of Grand Rapids.

Sediment Quality in the Athabasca River

Sediment quality in the middle and lower reaches is most affected by the accumulation of organic contaminants from natural sources, and industrial or other human activity. A basin-wide survey reported no widespread contamination of sediments by contaminants such as dioxins and furans, PCBs, resin acids, and PAHs. Although locally higher levels, linked to pulp mill effluent discharges, were recorded in sediments downstream of Hinton. Although sediments downstream of Hinton continue to be enriched with some organic compounds, levels of dioxins and furans have declined to very low levels after the virtual elimination from the mill effluent. Recent monitoring of PCBs in the upper and middle reaches revealed higher than expected levels upstream of Hinton, possibly due to atmospheric inputs via glacier melt. Downstream of Hinton levels increased slightly, but remained below guidelines. Overall, sediment quality in the middle Athabasca River was considered to be ‘fair’ (Figure 6).

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In lower Athabasca river sediments, PAHs are mostly derived from diffuse natural sources such as exposed bitumen. Within this reach the river changes to a more depositional, shifting sand environment. This makes the detection of changes over time based on annual monitoring very difficult. For this reason, the Regional Aquatics Monitoring Program (RAMP) monitors sediment quality just prior to entering the delta, and in truly depositional channels within the delta, instead of the mainstem Athabasca River. Contaminant levels within and close to the delta are within the baseline condition established by RAMP and below available guidelines.

Non-Fish Biota in the Athabasca River

Nutrient enrichment downstream of Jasper results in greater benthic algal biomass and invertebrate abundance, with more midge larvae and fewer mayflies. This impact appears to be less pronounced following a reduction in nutrient loading due to the upgrading of the Jasper WWTP in 2003. Elevated nutrient levels leading to increases in benthic algal biomass have been reported consistently downstream of Hinton, Whitecourt and Fort McMurray (Text Box 10). Benthic algal and invertebrate communities tend to be most impacted downstream of Hinton Pulp mill. Elevated benthic algal biomass and invertebrate abundance, and altered invertebrate communities persist up to 100 km downstream. The river is naturally nutrient poor in this stretch, as indicated by the proposed Foothills ecoregion algal biomass objective, but biomass downstream of Hinton exceeds this guideline several times. Further downstream, as the river flows through the Boreal ecoregion, it becomes naturally more nutrient rich and has been assigned a higher ecoregion algal biomass objective. The river is less sensitive to nutrient inputs in this area and the objective is exceeded only marginally downstream of the three pulp mills. In the case of the most downstream pulp mill (Al-Pac), both upstream and downstream biomass levels exceed this guideline.

In its lower reach the Athabasca River becomes wider; its flows are slower, but its discharge is larger. The shifting sand habitat is harsh and supports limited algal communities. Benthic invertebrate communities in this reach consist of low to moderate densities of few tolerant species. RAMP monitors biota in tributaries and the truly depositional Athabasca Delta, instead of the Athabasca River itself.

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TEXT BOX 10

Athabasca River nutrient status and biological responses to effluent inputs

Over the last decade, the Northern River Basins Study (NRBS) and Northern River Ecosystem Initiative (NREI) set out to gain a better understanding of the impact of nutrient inputs on the Athabasca River. Emphasis was placed on evaluating the river’s nutrient status and the response of biota to nutrient inputs, as well as on understanding the driving mechanisms. To this end, an integrated monitoring approach was adopted that involved river monitoring and field-experimentation. The main findings are given below:

• Upstream of most point source discharges, benthic algal biomass is limited by nitrogen, phosphorus or both nutrients.

• Algal growth in reference river sections within the Foothills ecoregion is only limited by phosphorus, but further downstream as the river flows through the Boreal ecoregion, algal growth is limited by both nitrogen and phosphorus.

• Below Hinton discharges, algal biomass is not limited by either phosphorus or nitrogen. River nutrient status remains altered as far as 120 km downstream of these discharges, and algal biomass is many times greater than upstream.

• Exposure to dilute effluents causes an enrichment effect on the river food web: nutrient inputs induce changes in algal communities and increases in algal biomass; in turn invertebrates and higher trophic biota, such as fish, respond to the greater availability of food.

• The combined Hinton Pulp Mill effluent causes changes in benthic algal and invertebrate communities consistent with moderate nutrient enrichment15. Benthic communities downstream of the other four mills respond in a similar way.

15

3.3.2 Middle Reach Tributaries: McLeod and Lesser Slave rivers

As two of the largest tributaries, the McLeod and Lesser Slave rivers have a substantial effect on the Athabasca River and their water quality is rated as ‘fair’. The McLeod River discharges the largest volume of water to the middle Athabasca River, and contributes the largest suspended sediment and associated nutrients loads. Sediment and nutrient sources include forestry activities, mining, and agriculture (Text Box 12) forest fires, peatlands, wetlands and other natural sources. However, it is the mobilization of selenium by coal mining activity that is of most concern (Text Box 11).

The receives effluent discharge from the Slave Lake Pulp mill as well as municipal discharges, and non-point source inputs from forestry and agriculture. The impact of point sources on

15 In that respect, invertebrate abundance increases and community composition changes, but the number of invertebrate types (taxa richness) does not change to any extent North/South Consultants Inc. Page 27 Aquatic Ecosystem Health in Alberta Alberta Environment

river health indicators has been exacerbated in recent years by low river discharge. Recent monitoring indicates that the pulp mill discharge is responsible for mild nutrient enrichment downstream, as indicated by a localized increase in algal biomass. Although, downstream benthic invertebrate communities differ somewhat from those upstream, the change is not attributed to adverse effects from the pulp mill discharge. Natural downstream changes in substrate, flow, channel gradient and other physical characteristics that are typical of a shift from depositional to erosional habitat account for much of the observed change in benthic invertebrate community.

TEXT BOX 11

Impacts of coal mining in the McLeod River basin

Several headwater streams in the upper McLeod River are influenced by coal mines in the front range of the Rocky Mountains. Selenium concentrations in surface waters are often one or two orders of magnitude higher at sites downstream of mine disturbances compared to upstream reference sites on the same streams. Available long-term selenium data at the McLeod River mouth showed a general but small concentration increase in the late 1990s, compared to earlier data back to the early 1980s. The increase appears to be due to inputs from the mines. The water quality of Luscar Creek and is considered ‘marginal’ due to influences of the mines.

Additional studies have been conducted to determine the fate of selenium in stream food webs including sediments and aquatic biota, as well as laboratory studies on detrimental effects on fish. In general, there were small increases of selenium concentrations in sediment and aquatic invertebrates at exposed sites compared to similar samples from reference sites; although some results showed a lot of overlap at these lower trophic levels in the food web. Selenium bioaccumulation and biomagnification16 was most pronounced in specific fish tissues, with some of the highest concentrations found in the mature ovaries of rainbow trout from Luscar Creek. Elevated selenium in mature fish eggs is of concern because of maternal transfer to the offspring. The toxicity studies on offspring from fish taken from the streams near the mines showed developmental deformities occurred more frequently in rainbow trout fry from adults taken at exposed sites compared to reference sites. This pattern was not as strong for brook trout. Studies on selenium mobilization and effects on stream ecosystems near mountain coalmines of west central Alberta are ongoing.

16

3.3.3 Lower Reach Tributaries: Muskeg and Steepbank Rivers

Monitoring data for the Muskeg and Steepbank rivers suggest that these rivers have not yet been substantially affected by oil sands development in their basins (Text Box 12). While water quality in the

16 Selenium increases with each trophic level (for example, higher concentrations in fish compared to invertebrates). North/South Consultants Inc. Page 28 Aquatic Ecosystem Health in Alberta Alberta Environment

Steepbank River is considered to be ‘good’, water quality in the Muskeg River is only ‘fair’ due to natural factors. Compared to other tributaries, the Muskeg River has a lower river gradient, less erodible banks and riverbed, and greater reliance on shallow groundwater inputs from its peatland watershed than on surface water inputs. These natural factors often compromise water quality in this river at certain times of the year.

Peatlands play a key role in defining water quality in the Muskeg River, by transporting shallow groundwater and controlling the export of nutrients to the river. In the upper reaches, the Muskeg River is slower flowing, with numerous beaver ponds, and more influence from the surrounding watershed. The upper river is more nutrient rich than the lower river. The lower river exhibits low dissolved oxygen and even anoxic conditions during winter because of natural factors. These include a low discharge, oxygen demand that exceeds supply, oxygen deficient peatland drainage water; oxygen depletion in beaver ponds; and groundwater inputs. In contrast, the Steepbank River is well oxygenated, with faster flows and coarser substrates. The lower Steepbank River is oligotrophic based on phosphorus levels, but similarly to the Muskeg River, the upper reaches are more nutrient rich. Both tributaries are naturally high in iron and aluminium, mainly due to peatland drainage.

Sediments in both tributaries are predominantly sand with varying levels of organic carbon. Naturally elevated levels of hydrocarbons, such as PAHs, are common as a result of exposure to oil-seeps or exposed bitumen, but levels remain within the regional baseline established by RAMP. On balance, sediment quality in these two rivers is considered to be ‘fair’. It should be noted, however, that oil sands development does not appear to have affected sediment quality in these rivers to date. Similarly, benthic invertebrate communities in these rivers have not been adversely affected by oil sands development, but longitudinal differences exist. These are primarily due to downstream changes in substrate, flow, channel gradient and other physical characteristics associated with a change from depositional to erosional habitat. Furthermore, exposure to naturally occurring bitumen may also be a factor, particularly in the Steepbank River.

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TEXT BOX 12

Stream aquatic health

Agricultural Streams: and Wabash Creek are located in low and high agricultural intensity watersheds, respectively. Water quality is poorer in Wabash Creek, mainly because of elevated nutrient levels. However, the higher discharge of the Paddle River results in greater transport of suspended solids down this stream. Water quality was therefore considered ‘fair’ in Paddle River and ‘marginal’ in Wabash Creek

Streams within the Oil Sands Region: Jackpine Creek, a tributary of the Muskeg River, is a low gradient stream that drains surrounding peatlands. High organic carbon levels, low levels of suspended solids and nutrients, and periodic low dissolved oxygen, or anoxia, characterize water quality during winter. Sediments are predominantly sand and are low in carbon, with midge larvae dominating invertebrate communities. Monitoring data suggest that the aquatic health of this stream is ‘good’.

Boreal Streams: These streams drain phosphorus rich soils and thus tend to export phosphorus. Nutrient export increases following major forest fires and in-stream phosphorus levels can remain elevated for a number of years. It is likely that benthic algal biomass in at least some streams is nitrogen limited, and that grazing invertebrates such as mayflies may exert further control. There is currently insufficient information on these streams to assess aquatic health.

3.4 BEAVER RIVER BASIN

The Beaver River Basin, located on the eastern edge of the province, extends from Alberta into Saskatchewan and is one of the smallest basins in Alberta (Figure 1). The Beaver River originates from Beaver Lake and flows generally southeast before crossing the provincial border. Land cover in the basin is dominated by boreal forest, but the southern part of the basin has some cropland and communities such as Bonnyville, and Grand Centre (Figures 3 and 4). Numerous oil sands projects are ongoing or being planned in the northern part of the basin. The issue of increasing water demand and decreasing water supply has been identified as a problem since the 1980s.

3.4.1 Beaver River

The Beaver River receives non-point source inputs from land use activities mainly associated with agriculture and oil sands development. Several communities release effluents to the river, including Cold Lake and the Canadian Forces Base at Cold Lake.

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Aquatic Health Assessment

TEXT BOX 13

Beaver River reaches

Upper Reach: Headwaters to upstream of the River confluence. Lower Reach: Moose Lake River confluence to Beaver Crossing.

The upper reach of the Beaver River has very nutrient rich water, and nutrient levels have increased since the mid-1980s. These increases reflect naturally elevated levels of particulate nutrients, but also the effects of land use changes in the basin, including change from forested land to developed areas. Low winter dissolved oxygen levels occur along the upper reach (Text Box 14). Iron concentrations are high, especially during winter months, possibly because of local geology, groundwater inputs, or sediment release under low oxygen conditions. Levels of suspended sediments are typically low in the river. Overall, based on rather limited information, water quality within the upper reach is ‘fair’ (Figure 7).

Figure 7 Aquatic health assessment for the Beaver River

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Likely as a result of inflows of less nutrient rich water from the Sand River, nutrient levels in the lower Beaver River are somewhat lower than in the upper reach. Dissolved nutrient levels have decreased in the recent decades, possibly due to improvements in the water quality of Marie Creek, a tributary that receives municipal effluent from the Canadian Forces Base WWTP. Similar to the upper reach, winter dissolved oxygen levels are low in this reach (Text Box 14). Several metals are elevated along this reach, and high copper and chromium levels are attributed to municipal effluent discharges. Water quality remains ‘fair’ along the lower reach (Figure 7). However, this assessment of the lower reach does not incorporate the impact of effluent from Cold Lake and Grand Centre regional WWTP because it is released downstream of the PPWB monitoring site.

TEXT BOX 14

Dissolved oxygen in the Beaver River

Dissolved oxygen levels regularly fall below provincial and federal guidelines during the winter months in this river. Previous research has shown that dissolved oxygen levels drop quickly after ice forms. This rapid decrease results from limited re-aeration under ice cover, oxygen-poor groundwater inflow, or the consumption of dissolved oxygen by decaying organic matter. Treated municipal effluents released to the Beaver River include organic materials that consume oxygen. However, the release of these effluents is restricted to the open water season to avoid further oxygen depletion under ice cover.

3.4.2 Tributaries: Sand River and Marie Creek

As the largest tributary, the Sand River contributes approximately half of the Beaver River flow and greatly influences mainstem water quality. The Sand River watershed is in relatively pristine condition with only one significant development, the EnCana Foster Creek oil sands project. Water quality in the Sand River is similar to that of the Beaver River, although its nutrient levels are lower. Dissolved oxygen levels are low in winter, and iron levels are high throughout the year.

Marie Creek has nutrient rich water, but the levels of most nutrients, except ammonia, have generally decreased since the 1980s. These relatively high nutrient levels are due to discharges of treated municipal effluent from the Canadian Forces Base WWTP. Unlike in the Beaver and Sand rivers, dissolved oxygen levels in Marie Creek typically remain high throughout the year and iron levels tend to be low.

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3.5 NORTH SASKATCHEWAN RIVER BASIN

The North Saskatchewan River extends from the Rocky Mountains to Saskatchewan, where it joins the South Saskatchewan River to form the Saskatchewan River that continues to Lake Winnipeg. The upper basin is dominated by forestry and agriculture, with some industrial and municipal discharges (Figure 3). Industrial developments related to oil and gas abstraction, coal mining and power generation are distributed throughout the basin. The greatest concentration of industrial development is located in the middle basin, in the Edmonton and Fort Saskatchewan area, which is also the most populated. Although agriculture is common basin-wide, it is the dominant land-use downstream of Fort Saskatchewan in the lower basin.

3.5.1 North Saskatchewan River

The North Saskatchewan River is regulated by two dams located in the upper basin, and receives in- flows from six major tributaries within Alberta17. Water quality close to Edmonton has been an issue since the 1950s as a consequence of the combined impact of municipal and industrial discharges, and urban and rural runoff. Impacts on river water quality have been monitored at two provincial long-term monitoring sites located upstream and downstream of Edmonton and Fort Saskatchewan (i.e., at Devon and Pakan (Figure 8). Downstream of Pakan the river flows through sparsely populated land and receives inputs from tributaries and non-point sources mainly related to agricultural land use practices. Even so, nutrient enrichment due to urban point sources extends to the Alberta/Saskatchewan border.

Aquatic Health Assessment

TEXT BOX 15

North Saskatchewan River reaches

Headwaters and Upper Reach: Headwaters to Devon. Middle Reach: Devon to Pakan (upstream to downstream of Edmonton). Lower Reach: Pakan to the Provincial Border.

Headwaters and Upper Reach

Water quality in the headwaters and the upper reach is rated as ‘good’ (Figure 8). No long-term changes or trends have been recorded, except for increasing concentrations of dissolved solids. Similar increases have been noted in all reaches and are possibly related to relatively low river discharge in recent years. The headwaters and the upper reach are oligotrophic, although particulate phosphorus levels are elevated at high flow. In general, particulate phosphorus is not as bioavailable as dissolved phosphorus and hence is of lesser concern for eutrophication and impacts on river biota. Cobble,

17 Brazeau, Nordegg, Ram, Clearwater, Sturgeon and Vermilion rivers North/South Consultants Inc. Page 33 Aquatic Ecosystem Health in Alberta Alberta Environment pebble and gravel, typical of erosional substrates, are most common and are mainly colonized by benthic invertebrates, such as mayflies, caddisflies and stoneflies, which prefer clean substrates, well- oxygenated water and swift current.

Middle Reach

Long-term monitoring at Devon and Pakan has consistently demonstrated deterioration in river health between these two sites (Figure 8). The magnitude of changes exceeds that of natural changes expected in a large river system. The overriding impact is one of nutrient enrichment which is due to a progressive longitudinal increase in nutrient levels resulting from the cumulative effects of point sources and non-point sources. Compliance with nutrient guidelines decreases in downstream direction and there is a shift in trophic status between Devon (oligotrophic in terms of phosphorus and nitrogen) and Pakan (eutrophic in terms of phosphorus, but mesotrophic in terms of nitrogen). Nutrient levels are highest during and following rainstorms as a result of inputs from bank erosion, re-suspension of sediments from the riverbed, and contributions of sediments and nutrients from runoff . Despite elevated nutrient levels, dissolved oxygen measurements taken at these sites generally comply with provincial guidelines.

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Figure 8 Aquatic health assessment for the North Saskatchewan River

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In the vicinity of Edmonton, levels of suspended solids in the river show localized peaks, particularly during high rainfall events. These do not entirely correspond to point source discharges, and may also reflect tributary and non-point source inputs18. Storm water runoff and combined sewers, in particular, are recognized sources of contaminants. A greater number of pesticides are detected more frequently, with lower guideline compliance, at Pakan compared to Devon. In contrast, trace metal levels at Devon and Pakan are rather similar, and levels at both sites are elevated during periods of high flows and high suspended loads.

Sediment quality information was limited and dated for this reach and for the North Saskatchewan River, in general. It suggests that sediments downstream from Edmonton tend to be higher in organic carbon and some trace metals, compared to those upstream and that industrial discharges and runoff/seepage may affect sediment and pore (interstitial) water quality.

From Devon to Pakan, benthic algae and invertebrates exhibit changes in community composition that are typically associated with nutrient enrichment (Text Box 3). Three distinct zones comprising communities characteristic of unimpacted, impacted, and recovering conditions were described between Devon and Pakan19

The enrichment effect is primarily due to continuous discharges of treated municipal wastewater from Gold Bar and Capital Region WWTP, and to intermittent discharges from combined sewers and storm water sewers. Further downstream, industrial point sources and urban, industrial, agricultural and natural non-point sources are also contributors. Recent and ongoing upgrades to WWTPs and the Edmonton sewer system have reduced nutrient loading to the river, but increases in the urban population serviced by the WWTPs, urban sprawl and industrial growth could counteract these reductions unless adaptive management is implemented. The persistent enrichment that extends many kilometres downstream from the urban and industrial area makes it more difficult to evaluate the individual impacts of industrial discharges, but local effects have been demonstrated in the vicinity of some industries.

Based on available information, river health in the middle reach is rated ‘fair’ for water quality, but only ‘marginal’ for non-fish biota (Figure 8).

Lower Reach

Although nutrient levels in this lower reach remain higher than those recorded at Devon, levels tend to decrease with distance downstream from Pakan. The river shifts from eutrophic to mesotrophic in terms of phosphorus, but remains mesotrophic in terms of nitrogen. This indicates that moderately enriched conditions persist until the Alberta/Saskatchewan border. Historical information suggests that benthic algal and invertebrate communities in this reach continue to recover from the nutrient enrichment in the Edmonton area.

18 Such as sediment inputs from erodable river banks during wet periods. 19 Based on total abundance, taxa richness, abundance per major taxon, and diversity. North/South Consultants Inc. Page 36 Aquatic Ecosystem Health in Alberta Alberta Environment

Based on available information, river health in the lower reach is rated ‘fair’ (Figure 8).

3.5.2 Battle River

The Battle River flows eastward into Saskatchewan where it joins the North Saskatchewan River. This river differs from other large provincial rivers because it doesn’t receive glacial melt, and its flows depend solely on surface and ground water inputs. Climatic factors strongly influence river discharge, which is typically low, although peaks occur occasionally20. Water allocations to municipal, industrial, and agricultural sectors place further pressure on river levels, a situation that is likely to intensify with further development. This has prompted the undertaking of an instream flow needs assessment and basin-wide management plan for this river.

In all probability, the Battle River would be nutrient-rich even in the absence of human activities, since it is a low gradient, slow flowing river in a nutrient-rich watershed. Municipal point sources and agricultural non-point sources combined with low river flows and limited dilution capacity contribute substantially to the already high nutrient levels. Municipal discharges are of particular concern in the more populated middle and lower reaches, where substantial population growth is anticipated. These reaches are dominated by cropland, and moderate or low livestock densities. The highest livestock densities occur in the upper section of the middle reach, near Ponoka.

Battle River water quality is considered ‘fair’. The river is either mesotrophic or eutrophic, with elevated levels of particulate phosphorus and nitrogen, and low winter dissolved oxygen levels. Conditions are worst in the middle reach, between Ponoka and , where most of the largest municipal point sources enter. Phosphorus and nitrogen exceed guidelines frequently, and winter dissolved oxygen levels often are below the guidelines in this reach. Guideline compliance improves close to the border, possibly because of reduced nutrient loading and some dilution by groundwater inputs.

Concentrations of suspended and dissolved solids increase substantially with distance downstream, likely because of municipal inputs, groundwater inputs, and natural runoff from soils relatively high in natural salts. Pesticides are an issue in the basin as a whole, but are of most concern in the middle reach.

Relevant information on sediment quality and biota is very limited. Trace metal concentrations are highest from the headwaters to Driedmeat Lake mainly because of the prevalence of fine-grained, organic sediments. Further downstream there are areas of localized enrichment of some metals. Mid- channel benthic invertebrate communities are adapted to depositional environments typical of rivers with a low gradient and slow flows. Littoral communities associated with aquatic plants are more diverse.

20 Higher flows during snowmelt and seasonal rains. North/South Consultants Inc. Page 37 Aquatic Ecosystem Health in Alberta Alberta Environment

TEXT BOX 16

Aquatic health of agricultural stream

Unlike urban and industrial runoff, the impact of agricultural non-point sources on stream water quality has been well documented in the North Saskatchewan River Basin where five streams are routinely monitored21. Streams flowing through watersheds of high or moderate agricultural intensity (Tomahawk and Strawberry creeks) have ‘marginal’ water quality. Water quality in the three remaining streams is rated ‘fair’. All streams are considered to be eutrophic, with ‘poor’ nutrient water quality, except for the low intensity stream, Rose Creek, which receives a ‘marginal’ rating. High or moderate agricultural intensity streams typically have nutrient levels that are less compliant with guidelines, and present in forms more bioavailable to stream biota. Pesticides are also more prevalent in streams flowing through high or moderate agricultural intensity watersheds. Unlike other water quality parameters, levels of suspended solids are better correlated to runoff potential and annual stream flow volumes than to agricultural intensity.

21

3.6 SOUTH SASKATCHEWAN RIVER BASIN

The South Saskatchewan River Basin includes four large rivers: the Red Deer, Bow, Oldman and South Saskatchewan rivers. The Red Deer, Bow and Oldman, originate in the Rocky Mountains and flow eastward through the Grassland ecoregion (Figure 4). The South Saskatchewan River is formed from the confluence of the Bow and Oldman rivers, and it joins the Red Deer River east of the Alberta/Saskatchewan border. Five of Alberta’s six ecoregions occur in this river basin, which accounts for the diversity of its landscapes. Land use ranges from relatively pristine areas, mainly in the Rocky Mountains, to managed lands that retain some natural structure and function; and finally to lands that have been significantly altered (Figure 3). Urban wastewater and storm water effluents are among the largest single point sources of contaminants within the basin. Agriculture is particularly intensive in the middle and lower reaches of the four rivers, while forestry, mining and ranching are more typical of the upper reaches. Oil and gas exploitation occurs throughout the basin.

3.6.1 Red Deer River

The Red Deer River originates in Banff National Park. It flows northeast through the Foothills and Parkland ecoregions toward Red Deer, then it flows southeast through the Grassland ecoregion and Dinosaur Provincial Park to the provincial border. The river is regulated by the Dickson Dam, which created Glennifer Lake upstream of Red Deer.

21 Rose, Tomahawk, Stretton, Buffalo and Strawberry creeks North/South Consultants Inc. Page 38 Aquatic Ecosystem Health in Alberta Alberta Environment

The Red Deer River is nutrient poor in its headwaters, but becomes gradually more nutrient-rich in downstream direction, in part for natural reasons, but also because of man’s activities. The largest point sources of nutrients are the municipal WWTPs at Red Deer and Drumheller. Petrochemical plants at Prentiss and Joffre contribute to the nutrient load, but to a lesser extent. In wet years most of the loading comes from tributaries22; it is mainly a result of agriculture and forestry practices.

Aquatic Health Assessment

TEXT BOX 17

Red Deer River reaches

Headwaters: Headwaters to Glennifer Lake. Upper Reach: Glennifer Lake to Red Deer. Middle Reach: Red Deer to Drumheller. Lower Reach: Drumheller to the Provincial Border.

Water Quality in the Headwaters and Upper Reach

The headwater reach has a natural flow regime23, minimal disturbance, and limited development, and is the least impacted reach in the watershed. Water within this reach is typically high in dissolved oxygen and low in nutrients (oligotrophic) although particulate phosphorus occasionally reaches high levels. The overall water quality of the headwaters is therefore ‘good’ (Figure 9).

Water quality along the upper reach downstream of Glennifer Lake reflects the impact of increasing point and non-point source inputs. In addition, the Dickson Dam alters the natural flow pattern by increasing downstream winter flows. The river generally remains well oxygenated along the upper reach, although non-compliance with the provincial guideline may occur occasionally. Relative to headwaters there is an increase in nutrients and metals levels. Despite this slight deterioration water quality is rated as ‘good’ along the upper reach (Figure 9).

Water Quality in the Middle and Lower Reaches

Water quality in the Red Deer River downstream of Red Deer reflects increasing municipal and agricultural impacts. Particulate phosphorus, nitrogen and metal levels increase in the middle reach, and the river becomes moderately nutrient rich (mesotrophic) based on phosphorus levels. Recent measurements indicate that oxygen levels rarely drop below the guideline. Water quality fluctuates between ‘good’ and ‘fair’ ratings, and there are considerable year-to-year variations in nutrient, pesticide and metal levels (Figure 9).

22 Especially Little Red Deer, Medicine and Blindman rivers. 23 No dams or other flow regulation structures. North/South Consultants Inc. Page 39 Aquatic Ecosystem Health in Alberta Alberta Environment

Figure 9 Aquatic health assessment for the Red Deer River

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Nutrient and metal levels also increase along the lower reach. There is an increase in trophic status from the middle to the lower reach: from mesotrophic to eutrophic, based on phosphorus, and from oligotrophic to mesotrophic, based on nitrogen. Nutrients are mostly associated with particulate matter and increase in a downstream direction. Dissolved oxygen levels are generally high, but drop occasionally to low levels during winter months. Flow regulation from the Dickson Dam has resulted in higher winter dissolved oxygen levels, but if nutrient loading continues to increase, low dissolved oxygen levels, typical of pre-impoundment conditions, may recur.

Water quality decreases to ‘fair’ along the lower reach (Figure 9).

Sediment Quality and Non-fish Biota in the Red Deer River

The existing knowledge on sediment quality was mainly gathered in the early 1980s. Recent benthic algal biomass information both upstream of Red Deer and in the lower reach indicates eutrophic conditions with no significant upstream to downstream change. Historically, benthic algal biomass peaked downstream of Red Deer due to nutrient enrichment caused mainly by the city’s municipal effluent discharge. Significant upgrades took place in the city’s WWTP in the late 1990s, and the nutrient load from the plant has since decreased. There are no current data to show whether the biomass increase is still as pronounced directly downstream of Red Deer as it used to be. Based on these limited nutrient enrichment data, the health of benthic algal communities is ‘fair’ in the upper, middle and lower reaches of the river (Figure 9).

3.6.2 Bow River

The Bow River originates at in the Rocky Mountains. From there, it flows through the foothills onto the prairies, passing through Calgary toward its confluence with the Oldman River. The river is the most regulated in Alberta, with eleven hydroelectric facilities within its watershed. Water use is divided among industry, municipal and recreational users, but by far the greatest water user is irrigation. The hydroelectric facilities, withdrawals, and irrigation diversions all contribute to the alteration of natural river flows. River flows, especially low summer flows in the lower reaches, greatly influence water quality, as do the eleven reservoirs, which retain sediment and contaminants. The headwaters of the Bow River receive effluent discharges from , Banff, and Canmore WWTPs. Further downstream, Calgary discharges treated wastewater and storm water to the river. Non-point sources within the sub-basin include agriculture and industry.

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Aquatic Health Assessment

TEXT BOX 18

Bow River reaches

Upper Reach: Lake Louise to upstream of Calgary. Middle Reach: Calgary to the Carseland Dam. Lower Reach: Carseland Dam to the confluence with the Oldman River.

Water Quality in the Upper Reach

Water quality is ‘excellent’ along the upper reach as the river flows from the relatively pristine Rocky Mountains, through the foothills, to the prairies (Figure 10). This reach is naturally low in nutrients and it is classified as oligotrophic. Particulate nutrient levels are often elevated during peak runoff in spring, but these nutrient forms are generally not readily available for plant growth. Nutrients gradually increase in a downstream direction, and levels just upstream of Calgary are higher than in the headwaters. To some extent, the progressive downstream enrichment of the river occurs naturally, but it is also a consequence of municipal effluent discharges from Lake Louise, Banff and Canmore. Dissolved solids increase markedly along the reach, possibly because of road salting, as well as contributions from natural sources. The Bow River is well-oxygenated along this reach, and levels of trace metals and pesticides are low.

Water Quality in the Middle Reach

Aquatic health in the middle reach of the Bow River reflects impacts from urban runoff, municipal discharges from Calgary, and tributary inputs. Calgary’s two WWTPs, Bonnybrook and Fish Creek, represent the largest effluent loading to the Bow River. Despite the upgrading with nutrient removal and disinfection technologies in recent decades, a marked peak in nutrient levels is still evident immediately downstream of Calgary. This nutrient enrichment causes a trophic shift from naturally oligotrophic to mesotrophic conditions. Nutrient enrichment, diurnal fluctuations in photosynthesis and respiration, and the discharge of substances with high biochemical oxygen demand (BOD) occasionally cause dissolved oxygen levels to drop below the provincial guideline. Suspended solid levels in this reach can increase substantially during periods of high flows, and with contributions of urban runoff from Calgary, particularly from storm water outfalls. Pesticide levels and the number of pesticides detected are higher downstream of Calgary, mainly as a result of residential use. Occasionally, levels guidelines for the protection of aquatic life are exceeded.

According to the provincial water quality index and the aquatic health assessment, water quality in this reach remains ‘good’ (Figure 10).

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Water Quality in the Lower Reach

The lower reach of the Bow River begins below the Carseland Weir, some distance downstream from Calgary. Water quality in this reach is most influenced by agriculture, irrigation, and natural processes like river channel erosion. Nutrient levels decrease somewhat from the peak levels downstream of Calgary due to dilution, aquatic plant uptake, and other processes. Dissolved oxygen levels tend to be higher in this lower reach. Improved water quality indicates that the river has, or is in the process of recovering from the impacts of upstream discharges. In contrast, trace metal and pesticide levels progressively increase in the lower reach, which may reflect agricultural inputs.

According to the provincial water quality index and the aquatic health assessment, water quality in this reach also remains ‘good’ (Figure 10).

Figure 10 Aquatic health assessment for the Bow River

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Sediment Quality and Non-fish Biota in the Bow River

The Bow River does not support a true phytoplankton community, and the majority of algae in the water column originate from scoured benthic algae. Benthic algae and certain aquatic plants, especially pondweeds, can be very abundant downstream of Calgary due to nutrient enrichment from the city’s WWTPs. However, according to a recent long-term study, aquatic plant biomass greatly decreased following nutrient removal at the WWTPs. Even so, plant biomass still shows a marked increase downstream of these facilities compared to upstream. In addition to nutrient loading, aquatic plant growth is also affected by river flows, and plants are less abundant during high runoff years when they are scoured from the riverbed by swift currents.

Despite WWTP upgrades, and unlike larger aquatic plants, benthic algal biomass remains at nuisance levels downstream of Calgary. This biomass is indicative of eutrophic conditions. Algal biomass in the upper and lower reaches of the Bow River is moderate compared to the middle reach. Overall, aquatic ecosystem health based on plant communities changes from ‘good’ in the headwaters to ‘marginal’ along the middle reach because the higher than natural abundance of plants is an indication of eutrophication. The ecosystem health rating recovers to ‘fair’ along the lower reach (Figure 10). Recent information on benthic invertebrate communities is scarce, but shows increases in invertebrate abundance downstream of Calgary because of nutrient enrichment, followed by recovery along the lower reach.

3.6.2.1 Headwater Tributary:

The Ghost River originates in the Rocky Mountains, and flows through the Foothills Parkland sub- region before draining into the Ghost Reservoir upstream of Cochrane. The drainage basin is used heavily for ranching, grazing, recreation, logging, and oil and gas exploration and production. River flows are affected in Banff National Park, where the river is partially diverted to , and by the Ghost Dam near the Bow River confluence. In addition, natural factors such as spring snowmelt and the resulting high flows influence the river’s water quality. For example, suspended sediment and particulate phosphorus levels peak during high flow. Nutrient levels are typically within recommended limits and suspended solid levels remain generally low. However, erosion caused by off- road vehicle use is known to result in high suspended solid levels. Dissolved oxygen concentrations are generally high, although occasionally declines occur during periods of high summer temperatures.

The water quality of the river is regarded as ‘excellent’ despite the relatively intensive use of the basin.

3.6.2.2 Middle Reach Tributary: Elbow River

The Elbow River begins at in the Rocky Mountains, before flowing northeast to join the Bow River in Calgary. The Elbow River has been dammed just upstream of the confluence with the Bow River to form the , which supplies half of Calgary’s drinking water. Recreational use is prominent in the Kananaskis region, whereas agricultural, industrial and urban development intensifies closer to the confluence. River water quality has deteriorated in recent years

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upstream of the Glenmore Dam, due mainly to increases in nutrients and suspended sediment. Nevertheless, nutrient levels are still indicative of oligotrophic conditions, and dissolved oxygen levels remain high. The Glenmore Reservoir acts as a sink for particulate matter and improves water quality downstream by decreasing suspended solids levels and especially, particulate phosphorus levels. However, benthic algal biomass is high near the mouth of the river, immediately below the reservoir and is indicative of eutrophic conditions. A number of pesticides have been detected, but at concentrations below guidelines. Overall, water quality is ‘good’ in the Elbow River based on the ARQWI rating.

3.6.2.3 Lower Reach Tributary: Nose Creek

Nose Creek is a prairie stream that flows south through Airdrie before joining the Bow River in Calgary. Much native vegetation (Grassland ecoregion) in the drainage basin has been replaced with cropland, pasture and urban development. Stream flows and water quality are influenced by channelization and land use practices in the watershed. Nutrients and fine suspended sediments are elevated because of urban and agricultural runoff. Low dissolved oxygen levels occur periodically downstream of Airdrie. Metals, especially aluminum and iron, are occasionally high mostly during winter months (low flows) and during rainstorms (high runoff). Pesticide concentrations are highest at the mouth, and in some instances guidelines for the protection of aquatic life are exceeded. Water quality is considered ‘poor’ in the creek, mostly as a result of urban and agricultural impacts.

3.6.3 Oldman River

The Oldman River originates in the Rocky Mountains and flows east through the foothills’ rangelands, and through Lethbridge before merging with the Bow River to form the South Saskatchewan River. Climate can influence water quality both in times of droughts and floods (Text Box 19). Water supply is a concern in this semi-arid region because of the perennial potential for droughts and water shortages. These concerns have prompted an instream flow needs assessment, and basin-wide management plan for the river. The Oldman River drainage basin supports an extensive network of storage reservoirs, canals and pipelines as part of an important irrigation infrastructure. River flow is regulated by a number of structures, with the Oldman River Dam (constructed in 1992) as the largest. Non-point sources to the river include urban, agricultural and industrial inputs, point sources include eight WWTPs. Prior to upgrades in 1999, the Lethbridge WWTP was the largest point source in the Oldman River basin. Presently, the impact of the effluent is smaller, and it is comparable to other urban and agricultural sources. Overall, water quality in the Oldman River has improved during the past ten years, and higher summer flows due to the Oldman River Dam have improved dissolved oxygen levels downstream of Lethbridge.

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TEXT BOX 19

Climate’s impact on water quality in the Oldman River

Climate can have a large influence on the water quality of southern Alberta rivers and streams. In the Oldman River basin, climate affects surface water flows through precipitation, evaporation and snowmelt. Nutrient concentrations, among other constituents, are strongly linked to flow in the Oldman River, and concentrations peak during the high flows that occur during spring runoff, or heavy rainfall events. For example, river water quality declined clearly in 2002, following unusually heavy rainfalls, and the entry of substantial loads of soluble constituents and sediments in the river. Conversely, water quality was higher during drought conditions in 2000 (Figure 11).

Aquatic Health Assessment

TEXT BOX 20

Oldman River reaches

Upper Reach: From the headwaters to Brocket. Middle Reach: Brocket to upstream of Lethbridge. Lower Reach: Lethbridge to the Bow River confluence.

Nutrient levels are naturally low along the upper reach, and dissolved oxygen levels remain high. Particulate metals are occasionally elevated, although these are unlikely to result in any impacts on the growth or survival of aquatic organisms. Suspended sediments settle in the Oldman Reservoir and levels below the dam are lower than above. Overall, water quality is ‘good’ in the upper reach, with low nutrient and pesticide levels and occasionally high metal levels (Figure 11).

Most nutrient levels increase along the middle reach along with increasing agricultural intensity. Nevertheless, the river remains oligotrophic based on nutrient concentrations. Levels of suspended and dissolved solids also increase, and erosion, surface runoff and irrigation return flows are the most significant sources. Irrigation return flows convey excess supply water, and surface and subsurface runoff and carry nutrients, sediment and pesticides to the Oldman River. Consequently, pesticide detections, concentrations and variety increases along the middle reach. Water quality remains ‘good’ in the middle reach, despite progressively increasing nutrient and pesticide levels (Figure 11).

The lower reach begins downstream of Lethbridge, the major urban centre in the Oldman River drainage, and drains very intensively farmed land. Despite upgrades to the city’s WWTP, levels of

North/South Consultants Inc. Page 46 Aquatic Ecosystem Health in Alberta Alberta Environment nutrients and turbidity in the Oldman river remain higher downstream of Lethbridge than upstream. Turbidity and pesticide levels increase in a downstream direction, mainly because of agricultural and urban runoff. Despite the increasing contaminant load, the overall water quality remains ‘good’ along the lower reach of the Oldman River (Figure 11).

Non-fish Biota in the Oldman River

Benthic algae are more prevalent along the middle reach of the Oldman River in response to nutrient enrichment. Benthic algal biomass is indicative of eutrophic conditions in the headwaters and the middle reach, but of mesotrophic conditions near the mouth. Relatively high benthic algal biomass along the upper reach is an artefact of the location of the Brocket sampling site. This site is located below the Oldman River Dam. Because the dam operation reduces spring flows, algae are not scoured out and continue to grow more than would be expected under unregulated flows. Aquatic plant growth is densest downstream of Lethbridge to the mouth, a section of the river where slow stream velocities allow aquatic plants to grow well. Aquatic ecosystem health based on primary producer communities, changes from ‘fair’ in the headwaters to ‘marginal’ along the middle reach but recovers to ‘good’ along the lower reach. Interpreted benthic invertebrate information dates largely back to the late 1980s. However, changes in the benthic fauna along the river’s course are currently being investigated by University of Calgary researchers.

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Figure 11 Aquatic health assessments for the Oldman and South Saskatchewan rivers

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3.6.3.1 Middle Reach Tributary:

The Belly River originates in Montana’s Glacier National Park and enters Alberta in the southeast corner of Waterton National Park. From there it flows northeast to join the Oldman River upstream of Lethbridge. The upstream Alberta portion flows through the foothills and is generally swift and turbulent. In contrast, the downstream section flows through prairie and is slower, wider and winding. The Belly River is an important source of irrigation water and is regulated by three diversions that reduce downstream flows. There are no major urban centres or industries that discharge to this river. In general, nutrients and dissolved solids levels are low close to the mouth, and the water is well oxygenated. Irrigation water withdrawals reduce the river’s capacity to flush away accumulating silt, nutrients and contaminants and the resulting degradation, or loss of aquatic habitat, affects the productivity of aquatic organisms. Water quality information is limited, and no information describing sediment quality and non-fish biota was found for the Belly River, so ecosystem health could not be assessed.

3.6.3.2 Lower Reach Tributaries: St. Mary and Little Bow Rivers

The St. Mary River flows from the Rocky Mountains in Glacier National Park, Montana over the prairies and meets the Oldman River at Lethbridge. Only two small urban centres, Magrath and Cardston, release effluents to the river, and their impact on the water quality is minimal. Water quality and quantity are influenced by the St. Mary Reservoir, located half way down the river. The reservoir supplies water to four irrigation districts in the region and little flow is left in lower sections of the St. Mary, especially under dry conditions. The St. Mary River has low nutrient levels indicative of oligotrophic conditions, and the river is well oxygenated.

The flows through the Grassland ecoregion and agricultural lands on the prairies, before joining the Oldman River downstream of Lethbridge. Agricultural intensity increases in the lower reach, downstream of the . Flow is regulated both upstream and downstream of the reservoir during the irrigation season. Water quality is highly dependent on climatic factors. High nutrient levels tend to occur in the river following runoff events due to rains or snowmelt. Although groundwater is a potential nutrient source, agricultural drains and irrigation returns contribute the largest nutrient load to the river. Dissolved oxygen levels fall occasionally below the guideline at night upstream of the Travers Reservoir, likely because of respiration of aquatic plants and attached benthic algae. Dissolved oxygen levels increase again, closer to the Oldman River confluence. A number of pesticides have been recorded in the river, but levels were below guidelines for the protection of aquatic life.

Information describing water quality, sediment quality and non-fish biota in the Belly, St. Mary and Little Bow rivers was insufficient for conducting a health assessment.

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3.6.4 South Saskatchewan River

From the confluence of the Bow and Oldman rivers, the South Saskatchewan River flows northeast, through Medicine Hat into Saskatchewan. The river flows through a wide, deep valley, and much of the drainage basin is used for agricultural production. Other human activities in the basin include oil and gas development, industries, mixed farming and military activities at the Suffield Canadian Forces Base. Water quality is mainly influenced by the Bow and Oldman rivers, and there are no dams or major tributaries to the South Saskatchewan River in Alberta. Municipal effluent from Medicine Hat has a minimal impact on the river’s water quality.

Aquatic Health Assessment

The South Saskatchewan River is oligotrophic based on phosphorus levels and mesotrophic based on nitrogen levels. Nutrients occur mostly in particulate form and can occasionally reach high levels. The river is well oxygenated and has variable levels of suspended sediments. Aluminum and iron concentrations are occasionally elevated, while most other metals remain low. Pesticides occur at low levels and do not exceed guidelines for the protection of aquatic life. Water quality in the South Saskatchewan River is ‘good’, thanks to its dilution capacity and its recovery from upstream impacts (Figure 11). Benthic algal biomass upstream of Medicine Hat indicates slight mesotrophic conditions, but it is lower than peak levels found in the Bow and Oldman rivers.

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TEXT BOX 21

Streams located in watersheds affected by agriculture

Thirteen agricultural streams24 are routinely monitored in the four South Saskatchewan River sub- basins. They represent the entire scale of agricultural intensities (high, moderate, low) and include streams receiving nutrient and pesticide-rich irrigation return flows.

• Stream water quality is generally correlated to the agricultural intensity in the surrounding drainage area. In this respect, water quality is ‘good’ in low intensity streams and ‘marginal’ or ‘fair’ in high and moderate intensity streams.

• Levels of suspended solids reflect stream discharge and/or the runoff potential within the watershed rather than the intensity of agriculture.

• Nutrients occur at high levels in almost all of the streams, but the relationship with agricultural intensity is inconsistent as some streams with low agricultural intensity have higher nutrient levels than streams with moderate intensity.

• Pesticide levels are generally moderate in the agricultural streams in the South Saskatchewan River Basin.

• Irrigation return flows have higher nutrient and pesticide levels than streams with dry-land farming.

24

3.7 MILK RIVER BASIN

The Milk River Basin, the smallest of Alberta’s major river basins, is located in the southernmost part of the province. The Milk River originates in the foothills of the Rocky Mountains in Montana, before crossing the international boundary and joining the North Milk River. The Milk River flows eastward through the southern portion of the province before crossing the border back into Montana. Much of the basin is used for agriculture, either for irrigated or dry-land crops, or livestock production (Figure 3). Much of the cultivated land is in the central portion of the basin; the eastern part of the watershed is mainly rangeland.

In addition to agricultural non-point sources, Coutts and Milk River, the two major towns in the basin, discharge treated municipal wastewater to the river. Historically, the Milk River Basin has experienced a number of water supply shortages, such as during periods of drought when part of the river actually ran dry. Milk River flows have been augmented since 1917 by diverting water for irrigation in Montana and Alberta from the St Mary’s River via the St. Mary Canal, into the North Milk River in Montana.

24 Prairie Blood Coulee, Willow Creek, , Meadow Creek, Trout Creek, Haynes Creek, Ray Creek, Renwick Creek, Threehills Creek, Battersea Drain, Crowfoot Creek, Drain S-6 and New West Coulee. North/South Consultants Inc. Page 51 Aquatic Ecosystem Health in Alberta Alberta Environment

The diverted water, increases flows in the Milk River to about 20 times natural flows. However, the diversions are seasonal and Milk River flows can still be very low at times. A general shift from lower to higher nutrient levels is apparent along the Milk River, and this is the main factor accounting for the declining water quality from the upper to the lower reaches.

Aquatic Health Assessment

TEXT BOX 22

North Milk and Milk River Reaches

North Milk River. Upper Reach: The international border to the Town of Milk River. Middle Reach: Town of Milk River to Highway 880. Lower Reach: Highway 880 to the international border.

North Milk River

Water quality in the North Milk River is considered to be ‘excellent’ (Figure 12). Dissolved oxygen levels remain high and nutrient levels low throughout the year.

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Figure 12 Aquatic health assessment for the Milk River

Milk River

Nutrient levels are slightly higher in the upper reach of the Milk River compared to the North Milk River, but still low enough for the river to be classified as oligotrophic. Some metals are higher in this reach compared to the North Milk River, but it is likely that these metals are associated with sediment particles and they are not a major concern to aquatic health. The upper reach of the Milk River has ‘good’ water quality based on the available information (Figure 12). Water quality of the middle reach reflects the increasing impact of agriculture, but is also considered ‘good’. Nutrient levels peak in the lower Milk River and highest values in spring coincide with high suspended sediment levels. Occasionally nutrient levels are high at low flow under ice. Dissolved oxygen levels are sometimes low in the lower reach and may stress fish and invertebrates. High summer water temperatures may further stress benthic invertebrates and other organisms adapted to cool water. Pesticide levels tend to be low in both North Milk and Milk rivers, although somewhat higher in the lower reach. The lower reach of the latter receives only a ‘fair’ rating.

Limited information from the 1980s suggests that benthic algal biomass increases markedly from the upper reaches to the lower reach and that benthic invertebrate communities are typical of a warm, slow river with high levels of suspended sediments and sediment deposition rates. Species that are well adapted to silt-covered substrates thrive, especially in the lower reaches. Mayflies, caddisflies and stoneflies, which prefer swifter water and clean substrate, occur in all reaches, but in low numbers.

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4.0 LAKES AND WETLANDS

4.1 LAKES

Maintaining healthy lakes and reservoirs in Alberta is important to:

• Safeguard water supplies, recreational and fishing opportunities, and ecological services or benefits for humans;

• Conserve plant and animal communities in lakes and their watersheds; and

• Maintain the health of watersheds and connected watercourses and wetlands

Alberta’s lakes and watersheds are subject to many pressures, including agriculture, industrial and urban and rural population growth, increasing recreational activities, and the effects of industrial air emissions, climate change, and drought.

There are currently several active lake monitoring programs in Alberta (Text Box 23), but they focus mainly on water quality and seldom include monitoring of plant and animal communities, or lake bottom sediments25. This limits the ability to complete meaningful assessments of lake ecosystem health.26

TEXT BOX 23

Current and recent lake monitoring in Alberta

• Over 150 recreational lakes have been, or continue to be monitored by Alberta Environment and partners (Figure 13). With few exceptions, monitoring focuses on the assessment of trophic state and basic ion chemistry.

• One partner in this monitoring, the Alberta Lake Management Society’s volunteer lake monitoring program LakeWatch, monitors a selection of recreational lakes on a rotational basis to assess productivity during the open water period.

• More than 400 lakes are monitored in north-eastern Alberta for indicators of acid sensitivity by Alberta Environment, the Cumulative Environmental Management Association (CEMA) and the Regional Aquatics Monitoring Program (RAMP). Information generated by this program is particularly important given the increased loads of acidifying emissions from the oil sands development in this region.

• A number of boreal lakes and lake-wetland complexes in the Peace and Athabasca River basins have been, or continue to be monitored as part of multidisciplinary research initiatives26. This work is directed towards investigating the effects of logging, forest management practices, and fire on lake nutrient dynamics, ecology and hydrology.

• As additional watershed and lake management associations are formed, other smaller individual lake monitoring studies are being initiated.

25 Most of biological and sediment quality information dates back 20-40 years and is summarized in Mitchell, P. and E. Prepas (eds.). 1990. Atlas of Alberta. University of Alberta Press. Edmonton. Atlas of Alberta Lakes website available at http://sunsite.ualberta.ca/Projects/Alberta-Lakes/. 26 These initiatives include: the Terrestrial, Riparian Organisms, Lakes and Stream Project (TROLS) and the Forest Watershed and Riparian Disturbance Project (FORWARD). North/South Consultants Inc. Page 54 Aquatic Ecosystem Health in Alberta Alberta Environment

Figure 13 Productivity of a selection of Alberta lakes based on phytoplankton biomass levels

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Aquatic Health Assessment

Aquatic ecosystem health assessments for individual lakes were not possible in this initial assessment for two main reasons: the lack of suitable data, as discussed previously, and the lack of indicator thresholds. There is a general lack of knowledge on the ‘natural state’ of lakes, including the range of natural variability for the main types of lakes in Alberta. This is required to describe reference conditions for the different lake types and to derive thresholds for ecosystem health indicators. An important consideration is that landuse in many lake watersheds has changed dramatically since the arrival of Europeans. In some areas this may influence the development of thresholds for health indicators. Despite facing similar challenges, some agencies in North America and Europe have successfully developed indicator thresholds for nutrients in lakes.

For this initial assessment, the health evaluation is limited to a more general discussion on three important stressors affecting lake health in Alberta: 1) productivity; 2) acidification; and 3) salinity.

Lake Productivity

Increases in lake productivity, or changes in trophic status due to nutrient enrichment are of concern in Alberta. Accordingly, most lake monitoring efforts have focused on this (Text Box 23). Eutrophication is a natural process that occurs slowly (over hundreds or thousands of years). However, human activities can increase the rate at which it occurs. Lake eutrophication generally causes corresponding increases in overall phytoplankton biomass, and can lead to more frequent and intense algal blooms, particularly in the summer. These blooms can be dominated by cyanobacteria (often referred to as blue- green algae) that produce toxins. The mass death and decomposition of these blooms can cause the depletion of dissolved oxygen, create unpleasant odours, and cause the rapid release of toxins. Algal toxins represent a real risk to animals and humans, and algal blooms can negatively affect lake aquatic health. Very high productivity can also decrease the recreational use of a lake. However, many lakes in northern and central Alberta are naturally productive, with naturally high populations of algae and cyanobacteria, and these negative conditions may, to some extent, be natural and not necessarily reflective of deteriorating aquatic health.

Although, lake productivity of Alberta spans all four trophic categories, most lakes monitored by Alberta Environment are mesotrophic or eutrophic (Figure 13).

• Close to half of the lakes monitored in the Peace, Athabasca and North Saskatchewan River basins are hypereutrophic, while the remainder are eutrophic or mesotrophic.

• Lakes monitored in the Beaver River Basin in Central Alberta are mostly eutrophic or mesotrophic; while further south, lakes in the South Saskatchewan River basin span all trophic categories. Many lakes in the latter basin are irrigation impoundments or reservoirs that contain river water with low nutrient levels.

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• Lakes in the western Montane or Foothill ecoregions are typically oligotrophic. Further east and at lower elevations in Boreal or Parkland ecoregions, lakes tend to be naturally more nutrient rich.

The classification of Alberta lakes according to trophic status has some notable limitations (Text Box 24).

TEXT BOX 24

Limitations to generalizing about lake productivity across Alberta

• Monitoring efforts have focused mainly on recreational lakes or reservoirs in central and southern Alberta. Thus the overall dataset does not necessarily represent lakes across all ecoregions.

• The trophic classification of a lake is dependent on the scope of the data. For example the sampling frequency over years and timing within an open water season may have varied. Alberta Environment and partners are taking steps to standardise sampling designs to reduce the influence of such factors.

• Few lakes in Alberta have undergone long-term monitoring.

Sensitivity of Lakes to Acidification

Sulphur and nitrogen compounds from industrial emissions can result in acid deposition and potential acidification of lakes or wetlands. This is a particular concern in north-eastern Alberta where sources or loads of these pollutants to the atmosphere are high (from oil sands mines and processing operations) and the watersheds and lakes or wetlands are particularly susceptible to acidification. Acidification of lakes can lead to detrimental effects including changes in the aquatic communities and ecological processes in lakes.

Aside from the volume and composition of the acid deposition, the sensitivity of a lake will be primarily influenced by the buffering capacity of the watershed soils and lake water to neutralise the acids. The most acid sensitive lakes are typically those with low alkalinity and pH. In Alberta these are often located in upland peatland areas or on the Canadian Shield.

Acidification can affect the bioavailability of many compounds, such as trace metals, to plants and animals. As a result, acidification can negatively affect biological diversity in a lake, with tolerant species becoming dominant. However, the majority of lakes in Alberta reside in carbonate-rich basins and are highly buffered (able to neutralize acids). Lakes considered to be sensitive and located fairly close to the oil sands region, are currently being monitored by CEMA and RAMP (Text Box 23).

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Research is also being conducted to map sensitive lakes and soils, and calculate the level of deposition lakes can tolerate before they reach a ‘critical’ load that may affect aquatic health (Text Box 25).

TEXT BOX 25

How is acid sensitivity measured and why?

Acid sensitivity is measured as a critical load of acid input. ‘Critical load’ can be defined as the highest load of acid deposition that will not cause chemical changes leading to long-term harmful effects on the most sensitive ecological systems. The critical load approach has been used in lake sensitivity and environmental impact assessments, where critical load is compared to the Potential Acid Input (PAI) to determine impact. These have shown that in 3.8% of the 450 lakes and ponds studied by CEMA in the Athabasca oils sands area, critical loads have already been exceeded in the absence of any industrial emissions. When emissions from all oil sands industries currently operating and approved for development are included, predictions are that critical loads will be exceeded in 6.0% of the studied lakes.

Lake Salinity

Salts mainly enter aquatic systems via weathering of rocks or from groundwater inputs, but they can also be transported by wind and rain. Salinity, a measure of dissolved salt concentration, is important in determining the distribution of plants and animals in aquatic ecosystems.

While the majority of lakes monitored by Alberta Environment are freshwater lakes, some are slightly saline, moderately saline or saline. In recent years there has been concern that lower rainfall in some parts of Alberta has resulted in increased lake salinity. Declines in lake levels due to periods of drought are typically associated with increased salinity. Lakes particularly sensitive to increased salinity are those with little or no surface outflow for long periods at a time. Such lakes are described as having poor flushing rates, or long residence times.

Saline water bodies tend to have a lower diversity of plants and invertebrates than freshwater lakes, and plant and animal communities in saline lakes are generally quite distinct from those of freshwater lakes. In freshwater lakes, there is a direct positive relationship between phosphorus levels and phytoplankton biomass (i.e., algal biomass increases in response to increased phosphorus levels). In saline lakes, such as , this relationship is weak and lakes remain relatively unproductive despite high phosphorus levels.

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4.2 WETLANDS

Alberta contains 117,400 km2 of wetlands, approximately 18% of the total land area of the province. Wetlands are presently the least sampled aquatic ecosystems in Alberta. A meaningful health assessment could not be conducted because there is a lack of information with which to assess wetland health, and no established monitoring network through which to collect that information.

Nevertheless, a substantial amount of work has been undertaken and is ongoing. Maintaining the aquatic health of wetlands is important because they provide habitat for plants and animals, including rare and endangered species. They also provide a multitude of ecological services, such as control and water purification and storage. The term wetland usually refers to both peatlands and non- peat wetlands, but it is important to distinguish between the two.

• Peatlands, or organic wetlands, are formed under wet anaerobic conditions and cover large areas and accumulate large amounts of organic matter or peat. An estimated 93% of Alberta’s wetlands are peatlands (bogs and fens) and are found predominantly in Alberta’s boreal forest.

• Non-peat wetlands, or mineral wetlands, wetlands include sloughs (marshes), areas of shallow open water, either permanent or non-permanent, and swamps. They occur all over the province, but the prairie pothole region in southern Alberta may have the highest density of sloughs and shallow open water wetlands.

Wetland loss has been identified as a concern in Alberta, and wetland mapping efforts are being intensified to identify wetland resources and facilitate resource management. While the majority of the wetlands in the prairie and aspen regions are already disturbed by human activities, other relatively pristine wetlands and peatlands exist in Alberta.

TEXT BOX 26

Peace Athabasca Delta

The Peace-Athabasca Delta is the largest boreal freshwater delta in the world and it is listed as a wetland of international importance by the Ramsar Wetland Convention. The delta is formed by the Peace, Athabasca and Birch rivers at the western end of Lake Athabasca. Fluctuating water levels affect the structure of the delta, which is a dynamic and highly productive ecosystem. These fluctuations are caused by changes in flows and ice conditions in the Peace and Athabasca rivers, with the highest water levels occurring during ice jams in the spring. During the past 50 years, winter precipitation in the upper portion of the Peace River Basin has decreased. This decrease has resulted in reduced spring runoff and the likelihood of floods caused by ice jams. Perched (elevated) basins of the delta depend on these floods to replenish their water supply. Following the construction of the WAC Bennett dam in the Peace River Canyon, British Columbia, the delta experienced a prolonged period of drying due to lack of seasonal flooding (1975 to 1996). The perched basins were replenished in 1996 and 1997, but have been drying again since. Studies indicate that riparian habitat and ecosystem function within the delta has been greatly affected by these dryer conditions.

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5.0 PROVINCIAL OVERVIEW: RIVERS AND STREAMS

An assessment of aquatic ecosystem health of flowing water systems was determined for the following:

• All 11 major river systems in Alberta, with one to four reaches in each river system.

• Fourteen major tributaries of the rivers.

• The results for other streams (including those influenced by agriculture and in the forested green zone) are in Section 3.0.

The main findings for the river reaches and major tributaries are in Tables 3 and 4, and Figure 14. Aquatic ecosystem health and suitability of data used for the assessment are ranked from excellent to poor quality.

Table 3 Ranking of aquatic ecosystem health and data suitability for the evaluation of river reaches in Alberta.

The horizontal bars show the percentage of reaches in each category.

Note: 1A total of 11 Alberta rivers were included in the assessment with 1-4 reaches for each: Hay (1), Peace (3), Slave (1), Athabasca (3), Beaver (1), North Sask. (4), Red Deer (4), Bow (3), Oldman (3), South Sask. (1), and Milk (4) rivers.

The main findings of the health assessment (Tables 3 and 4; Figure 14):

• Most of the 28 river reaches evaluated had ‘good’ or ‘fair’ water quality (64% and 25%, respectively). The remaining reaches (11%) had excellent water quality. Data suitability was mostly good or fair for the assessment (32% and 57%, respectively).

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• Water quality of the key tributaries in the main river systems of Alberta27 was generally ‘good’ or ‘fair’ (21% and 43%, respectively). About 7% of the tributaries had ‘excellent’ or ‘poor’ water quality. There was insufficient data for an assessment of the remaining tributaries (21%). Data suitability was mostly good or fair (43% and 29%, respectively).

• In comparison to the results for surface water quality, there were very limited data for sediment quality and non-fish biota for the river reaches and tributaries. However, the available data for these ecosystem components showed that the river reaches and major tributaries were mostly ranked as good or fair.

Key needs to support the ability to conduct this assessment and future reviews of aquatic ecosystem health include the value and integrity of longer-term federal and provincial surface water quality monitoring programs, and a planned effort for more extensive and frequent sampling of sediment quality and non-fish biota. Adequate information on the quality of aquatic sediments and biological communities, in combination with surface water quality, is currently lacking. This is required to produce an accurate and defensible assessment of the ecological health of aquatic ecosystems in Alberta.

Table 4 Ranking of aquatic ecosystem health and data suitability for the evaluation of major tributaries.

The horizontal bars show the percentage of tributaries in each category.

Note: 1 Tributaries from Peace and Slave (Smoky and Wapiti rivers), Athabasca (McLeod, Lesser Slave, Steepbank, and Muskeg rivers), North Saskatchewan (Battle and Sturgeon rivers) and South Saskatchewan (Ghost, Elbow, St. Mary, Belly, and Little Bow rivers and Nose Creek) River basins are included.

27 North Saskatchewan, Athabasca, Peace and South Saskatchewan River systems. North/South Consultants Inc. Page 61 Aquatic Ecosystem Health in Alberta Alberta Environment

Figure 14 Rankings of aquatic ecosystem health in Alberta rivers

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6.0 CRITICAL INFORMATION GAPS AND RECOMMENDATIONS

The Water for Life strategy goal of ‘healthy aquatic ecosystems’ requires a comprehensive monitoring and reporting system to allow ongoing evaluations of aquatic ecosystem health in Alberta. This initial assessment focused on an evaluation of three key components of aquatic ecosystems (quality of surface waters, sediment and non-fish biota communities). This assessment will need to be integrated with other reviews of key ecosystem components that are currently underway: surface water quantity, fisheries and riparian areas. Together, they will provide a more complete assessment of the current condition of aquatic ecosystems in Alberta. In turn this will provide a reference point for future evaluations, and thus allow for a performance measurement of environmental management policies and practices.

The findings of this assessment (and others noted above) can be used to develop the monitoring and reporting system for Alberta. In this study, limitations of the existing data and knowledge often impeded the ability to assess the health of the main ecosystem types in a consistent and comprehensive manner. Where assessments were possible, the level of confidence associated with health ratings varied substantially due to the scope and suitability of the data and information sources.

Key information gaps that impeded the assessment and recommended solutions are outlined in Table 5 under the following categories:

• Monitoring program design and data collection

• Data management, accessibility, and reporting

• Availability of reference conditions and ecological thresholds that define ‘healthy’ conditions

It is important to note that development of the overall monitoring and reporting system to assess aquatic ecosystem health is complex and multidisciplinary and will need to consider the main ecosystem types in Alberta (rivers, streams, lakes and wetlands) and the wide variation in the characteristics of natural ecoregions (eg, alpine, boreal, parkland, prairie).

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Table 5 Knowledge gaps and recommendations for future actions

Category Knowledge Gaps Where To From Here?

Aquatic health should be defined by an integration of physical, chemical Monitoring Program In general, emphasis has been placed on the monitoring of chemical and biological information. An integrated provincial monitoring and Design and Data and physical conditions in water; monitoring of sediment and biological reporting system should be developed to provide a more accurate and Collection conditions is lacking. comprehensive health assessment. This could be made up of a variety of programs integrated into an overarching framework.

Accessibility of information varies substantially. In particular, industrial Accessibility of monitoring reports should be improved. Reports and data Data Management, compliance monitoring reports and Environmental Impact Assessment should be produced in a timely fashion and in electronic formats amenable Accessibility, and reports are not always accessible. to further analysis and integration. Reporting Data interpretation and reporting are limited for a substantial portion of All monitoring data need to undergo routine analysis and interpretation, and routine monitoring data collected from aquatic ecosystems in Alberta. be reported on a timely and regular basis.

With the exception of major rivers, water quality information is too Long-term monitoring should be conducted at reference (not, or least limited to characterize ‘natural’ or reference conditions, while sediment disturbed) sites to determine the range of natural variability in water and quality and non-fish biota information is insufficient for all ecosystem sediment quality and non-fish biota indicators. types.

Currently, aquatic health assessments are heavily dependent on Description of ‘Healthy’ provincial and national water quality guidelines; these may not offer Appropriate chemical, physical and biological indicators of aquatic conditions the appropriate level of protection on a site-,or ecoregion-specific ecosystem health need to be identified for various water body types. basis Thresholds need to be developed for meaningful spatial and temporal Little progress has been made in the development of aquatic health scales (e.g., site- or ecoregion-specific; recognizing seasonally-induced indicators for non-fish biota. Thresholds are lacking for non-fish biota variability), and taking into account site- or region-specific stressors. indicators that recognize the characteristics of local biological communities and the stressors they are exposed to.

Long-term water quality monitoring in major rivers provides a good Water quality monitoring networks should be expanded with the addition of knowledge base for an initial health assessment. new sites and/or more frequent monitoring at some existing sites. Major Rivers Information on sediment quality and non-fish biota is limited or lacking Sediment quality and non-fish biota should be monitored at medium and at long-term monitoring sites. long-term monitoring sites.

Information on water quality is often sparse and dated for major An integrated monitoring approach should be applied to major tributaries tributaries. Information on sediment quality and non-fish biota with monitoring of all aquatic health components. information is even more limited.

The AESA program should be expanded to include a broader range of Other Rivers and The AESA program on agricultural streams was specifically designed aquatic ecosystem health indicators. Additional streams would likely have Streams to track effects of agriculture on water quality. to be added to the current program.

The nature and extent of monitoring on non-agricultural streams varies A monitoring network should be established for non-agricultural streams substantially, and to date, a coordinated monitoring approach has that covers a cross-section of stream types and stressors within Alberta. been lacking.

To date, routine monitoring has focused on recreational lakes and In order to identify representative lakes, a provincial lake classification that does not adequately represent a cross-section of lakes in Alberta. considers inherent limnological and watershed features needs to be completed first.

A representative cross-section of lakes, including recreational lakes, should Lakes There is a lack of sediment quality and non-fish biota information for most lakes. This limits our ability to determine if water quality undergo integrated long-term monitoring of water and sediment quality and conditions are affecting the plants and animals living in our lakes. non-fish biota.

Without an understanding of the ‘natural’ range of variability in lakes, it Integrated monitoring will allow for the identification of meaningful health is difficult to develop appropriate thresholds for indicators of aquatic indicators and the development of appropriate thresholds. ecosystem health.

Wetland loss is a major concern in the province. Although wetland A complete assessment of wetland loss across the province should be mapping and inventory is proceeding, wetland loss has not yet been conducted. quantified. Wetlands Wetlands are the least sampled of all aquatic ecosystems in Alberta. An integrated monitoring program should be implemented for selected Existing information from research and monitoring initiatives rarely wetlands across the province to establish baseline conditions, identify supports a health assessment. aquatic ecosystem health indicators and thresholds.

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7.0 A FRAMEWORK FOR PROVINCIAL MONITORING AND REPORTING ON AQUATIC ECOSYSTEM HEALTH

As noted in the list of gaps and recommendations, there is a need to develop and implement an integrated monitoring system to collect, analyse and report on the aquatic ecosystem health in Alberta. This is a large and complex undertaking that, whenever possible should be based on existing monitoring programs and support elements (e.g., scientific expertise in program designs, data collection, management and analysis, consistent and scientifically sound protocols, and quality assurance procedures)28. This will allow agencies and partners to build on collective strengths and allow for the more timely development of the system.

A conceptual framework for the monitoring and reporting system is presented in Figure 15. Steps in development of the system are outlined (in clockwise direction) beginning with the initial task to define aquatic ecosystem health and then to develop the knowledge and tools needed to complete development and implementation of the monitoring and reporting system. Success of the overall system will require broad support including multiple partnerships and ecological research and pilot studies to address gaps in knowledge. Many of these gaps are identified in Section 6.0. Effective sharing of knowledge from the monitoring and reporting system will be key to the development and performance measurement of existing or new environmental policy. This is consistent with adaptive management principles that are integral to the Water for Life strategy.

The development and implementation of the monitoring and reporting system will likely take several years, and will be an iterative process, and it will also need to maintain continuity in component objectives, methods and analysis. Given that defensible and meaningful reporting on aquatic health in the province will be a challenge and ongoing, a sustained long-term commitment of resources and effort will be required by all agencies involved.

28 For example, Alberta Environment: provincial river and lake monitoring programs; federal monitoring at PPWB and national park sites; and other government, industry and volunteer monitoring initiatives such as RAMP, AESA, EEM and ALMS-Lakewatch.

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Figure 15 Development of a provincial monitoring and reporting framework

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ABBREVIATIONS

AENV Alberta Environment

AESA Alberta Environmentally Sustainable Agriculture

ARWQI Alberta River Water Quality Index

BI benthic invertebrates

BOD Biochemical oxygen demand

CCME Canadian Council of Ministers of the Environment

CEMA Cumulative Environmental Management Association

CWQI Canadian Water Quality Index

EC Environment Canada

EEM Environmental Effects Monitoring

LTRN Long-Term Monitoring Network

MTRN Medium-Term Monitoring Network

PAH polycyclic aromatic hydrocarbon

PCB polychlorinated biphenyl

PP primary producers

PPWB Prairie Provinces Water Board

RAMP Regional Aquatic Monitoring Program

WWTP wastewater treatment plant

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GLOSSARY

Aquatic Ecosystem Any aqueous environment in which plants and animals interact with each other and the chemical and physical features of the environment. Aquatic Ecosystem The ability of the physical, chemical and biological components of an ecosystem to support Health and maintain a balanced, adaptive community of organisms having a species composition, diversity and functional organization comparable to that of natural ecosystems within a region.

Aquatic Environment Areas that are permanently under water or that are under water for a sufficient period to support organisms that remain for their entire lives, or a significant portion of their lives, totally immersed in water. Aquatic Ecosystem A measure (e.g., physical, chemical, biological, sociological, etc.) that provides evidence as to Health Indicator the state of the ecosystem. Benthic Invertebrates Invertebrate organisms, such as insects, worms, snails and clams, living on or within the bottom materials of streams, lakes or ponds. Benthic algae Algae growing on bottom sediments; including mud, sand, gravel and rocks. Dissolved Dissolved Matter: That portion of matter or solids, exclusive of gases, which is dispersed in water to produce a homogenous liquid. Dissolved Solids The total mass of dissolved mineral constituents or chemical compounds in water; they form the residue that remains after evaporation and drying. Often referred to as the total dissolved salts (TDS) concentration or dissolved ion concentration. In seawater or brackish water this is approximated by the salinity of the water.

Ecoregion A part of an ecozone characterized by distinctive regional ecological factors, including climate, physiography, vegetation, soil, water and fauna. Ecosystem A community of interdependent organisms together with the environment that they inhabit and with which they interact. Ecosystem Service The benefits people obtain from ecosystems. These include provisioning services such as food and water; regulating services such as flood and disease control; cultural services such as spiritual, recreational, and cultural benefits; and supporting services such as nutrient cycling that maintain the conditions for life on Earth. Endpoint An endpoint, or indicator, is a characteristic of an ecosystem that may be affected by exposure to stress. A measurement endpoint is a measurable environmental characteristic, usually related to a valued environmental component. Eutrophic Waterbodies which are rich in nutrients and very productive in terms of aquatic animal and plant life. Eutrophication A process where water bodies receive excess nutrients, usually from erosion and runoff from surrounding lands, that stimulate excessive plant growth and may cause seasonal deficiency in dissolved oxygen. The process can be both natural and enhanced by human activity. Guidelines The science-based levels above which an environmental effect may occur. Littoral The shallow zone of a lake or river in which light penetrates to the bottom, permitting plant growth. Mesotrophic Waterbodies which contain moderate quantities of nutrients and are moderately productive in terms of aquatic animal and plant life. Monitoring Any ongoing activities that measure the state of the environment or components within it, usually compared to a reference value. Non-Fish Biota Aquatic biota not including fish species, e.g., phytoplankton, periphyton (benthic algae), macrophytes (aquatic plants), zooplankton and benthic invertebrates. Non-Point Source A contaminant source by which contaminants are discharged over a widespread area or from a number of small inputs rather than from distinct, identifiable sources. Oligotrophic Waterbodies which are nutrient poor and contain little aquatic plant or animal life.

Particulate A very small solid suspended in water which can vary widely in size, shape, density, and

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electrical charge.

Point-Source Any discernible, confined and discrete conveyance, such as a pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, landfill leachate collection system or vessel from which pollutants are discharged. Pore water Water occurring in the pores of sediment, soils and rocks. Primary Producers Organisms that occupy the first trophic level in the grazing food chain. These organisms are photosynthetic autotrophs, such as plants and algae. Riparian Habitat along stream banks, or lake or wetland shores. River Reach A relatively uniform section of a river. Sediment Loose particles of sand, clay, silt, and other substances that settle at the bottom of a body of water. Sediment can come from the erosion of soil or from the decomposition of plants and animals. Wind, water, and ice often carry these particles great distances. Sediment Quality A measure of the condition of sediment relative to the requirements of one or more species and/or any human need or purpose. Based on chemical composition or on the results of bioassays. Stressor Physical, chemical and biological factors that are either unnatural events or activities, or natural to the system but applied at an excessive or deficient level, which adversely affect the ecosystem. Stressors cause significant changes in the ecological components, patterns and processes in natural systems. Examples include water withdrawal, pesticide use, timber harvesting, acidification, and land-use change. Surface Water Water that remains at, or close to the land surface (e.g., a river). Suspended Very small particles which remain distributed throughout the water column due to turbulent Solids/Sediment mixing exceeding gravitational sinking. Trophic Status A measure of biological productivity for rivers, streams, lakes and wetlands. Turnover The mixing of upper and lower layers of lake water that have different temperatures. Mixing causes the temperature to become uniform throughout the water column. Water Quality A measure of the condition of water relative to the requirements of one or more species and/or any human need or purpose. Water quality encompasses the physical, chemical, and biotic characteristics of water. This includes such things as temperature, colour, turbidity, salts, nutrients, metals, organic compounds, bacteria, and algal content.

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