Swan River Major Contributions from the Buffalo Mission C5 West Prarie River Bay C1 C6 East and West Prairie Rivers

Technical Update: Examining the Health of the Lesser Slave Watershed

Plain Language Summary of: Technical Update for the Lesser Slave Watershed 2015 April 2015 Technical Update for the Lesser Slave Watershed Prepared for: Lesser Slave Watershed Council Prepared by: Hutchinson Environmental Sciences Ltd.: Christine Geiger, M.Sc. Dörte Köster, Ph.D. Hutchinson Tammy Karst-Riddoch, Ph.D. Andrea Smith, Ph.D. (reviewer) Environmental Sciences Ltd. www.environmentalsciences.ca With contributions from: Alyssa Tuininga - Alberta Environment and Sustainable Resource Development David Trew - North Saskatchewan Watershed Alliance North Saskatchewan Regional Kristy Wakeling and Miles Brown - Alberta Environment and Sustainable ResourcePlan: Development This plain-language summary was prepared by: Lake Paleolimnology Survey Shared Value Solutions

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Prepared for: Alberta Environment and Sustainable Resource Development ESRD Contract Number: 140201 HESL Job #: J130053

December, 2014

R10122014_J130053_Alberta_Paleo-Final_Draft.docx Table of Contents Introduction 4 River Health and Water Quality 5 Lake Nutrient Sources 6 Lake Health and Water Quality: Present and Past 8 Predicting Future Lake Water Quality 11 River and Lake Fish 12

3 Introduction Included in this summary: • an aquatic assessment of the lake and rivers, Gaining a better understanding of the health of the aquatic ecosystem in Lesser Slave Lake and its • a phosphorus budget for the lake, watershed is vital to designing watershed management • a BATHTUB model of lake phosphorus under activities to protect its waters into the future. For the current conditions and future hypothetical land Lesser Slave Watershed Council’s (LSWC) first State of the use scenarios, Watershed report (Jamison 2009), only limited data on lake and river water quality were available. Since then, • an interpretation of sediment (paleolimnological) data to assess historic trends in water quality, • water quality data have been collected from the lake and its tributaries - 2007-2013; • and an update on the state of fish populations in • lake sediment cores have been obtained - 2005, the lake and rivers. 2009; and • fisheries data amassed - 2003-2014 - to improve our understanding of the aquatic ecosystem. The purpose of the technical document on which this plain language summary is based is to summarize Main Questions: these data to assist water managers, stakeholders and the LSWC Integrated Watershed Management Plan What is currently known about Steering Committee in their ongoing watershed planning the health of the rivers and initiatives. There are many ways human activites in the watershed lakes? can potentially affect water quality in the watershed. Lesser Slave Lake is a popular destination for recreational How does aquatic health activities and serves as a water source for municipal and relate to watershed health and industrial purposes. The results of the data presented here show where watershed management activites human impacts? would be most beneficial.

The Lesser Slave Watershed Figure 1. Lesser Slave is located in the Foothills and Watersheds Boreal Natural Regions of Overview central Alberta, some 250 km Legend Population Centers

northwest of Edmonton. Rivers South Heart Selected Roads River Lakes The majority of the inflow to Sub-Watersheds McLennan Lesser Slave Lake enters the Driftpile River Winagami East Prarie River west basin by way of South Lake Salt Prarie Lesser Slave River Kathleen Heart River Heart River, which receives South Heart River Grouard Swan River major contributions from the Buffalo Mission C5 West Prarie River Bay C1 C6 East and West Prairie Rivers. Lesser Slave Lake C2 High Prarie West Basin Lesser Slave Lake Enilda East Basin C3 Joussard C3 C1 C4 Three main tributaries on Wagner Kinuso Lesser Slave C5 Faust the south shores of the lake C4 River C6 C2 drain the southern part of the Slave Lake watershed: Driftpile River, West Prarie Driftpile River Smith Swan River, and Assineau River Map Area

River. East Prarie Swan River Edmonton River

Calgary Lesser Slave River is the N outflow of the lake, and is Km 0 10 20 40 located at the eastern edge Swan Hills NAD 1983 2011 UTM Zone 12N Mapped by Fiera Biological Consulting on 13/02/2015 of the east basin. Basemap: ESRI light grey canvas 4 River Health and Water Quality

Evaluating the health of the major rivers of the Lesser Slave Watershed allows us to better understand their River Quality Highlights natural states and the relative impact of human activities on different areas within the watershed. • Rivers were elevated in nutrients, typical for River water quality can be altered by soil erosion, Alberta boreal streams. river bed erosion due to channelization and diking, • River water quality varied among subwatersheds, logging, agriculture, fire disturbance, beaver dams, but the largest differences were seasonal and industrial activities and municipal inputs such as treated were associated with varying flows and water wastewater as the water moves from the headwaters to sources. the river mouth. • The most suspended sediments, and the largest Because these rivers flow into the lake, their health has a phosphorus and metal concentrations occurred direct impact on lake water quality. Determining which rivers are the most and least healthy allows us to focus during spring/summer peak flows due to watershed management activities appropriately. watershed and riverbed erosion. Factors affecting river health are interrelated: • The largest spring peaks in sediments were observed in East Prairie River, whose flow patterns • Flow - faster flows cause more erosion, increasing have been severely altered by channelization suspended sediments and diking. • Sediment loads - the amount of suspended sediment depends on the soils through which the river flows • Driftpile and Swan Rivers had the lowest phosphorus concentrations, possibly due to the • Nutrient loads - the more suspended sediments, the lower extent of agriculture in these watersheds. higher the nutrient loads • Seasonal differences were less pronounced in • Metals - metals in suspended river sediments can be transformed into bioactive forms that can have toxic South Heart River, due to its slower flow near effects on aquatic life. When metals arrive in Lesser the mouth. However, it showed the highest Slave Lake during the higher spring flows, they have phosphorus concentrations, possibly due to larger the potential to affect lake fish. watershed inputs from agricultural lands or its slower flow. Natural vs. Human Influences • Composed of Lesser Slave Lake outflow water, • Increased spring flows are natural for rivers in Lesser Slave River showed substantially different this region. However, flows can be affected by water quality patterns than the other rivers, channelization. with much lower suspended sediments and • The fact that many metal concentrations in these phosphorus. rivers exceeded federal water quality guidelines can be attributed to the naturally rich soils in this region.0.16 River Trophic Status Based on Median Phosphorus However, any human activities that affect the soils0.14 such as agriculture can raise these levels yet higher. Concentrations* 2007-2013 0.12 • Similarly, many Alberta lakes are naturally high in 0.1 0.16 nutrients (more productive) because of the soil 0.14 characteristics of the boreal region; however, 0.08 0.12 activities on the land such as logging can increase0.06 0.1 soil erosion and runoff into the rivers, raising nutrient0.04 Total Phosphorus (mg/L) (mg/L) Phosphorus Total 0.08 concentrations. 0.02 0.06 0.04 0 (mg/L) Phosphorus Total West 0.02 Prairie East Prairie South Heart Dri8pile Swan LSR (Lake 0 OuBlow) West Prairie East Prairie South Heart Dri8pile Swan LSR (Lake Rivers OuBlow) *Note: This trophic status classification describes potential for algae Rivers and plant growth based on phosphorus concentrations in Canadian Ultra-‐oligotrophic Oligotrophic Mesotrophic Meso-‐eutrophic waters (CCME 2004). The scale ranges from very low (ultra-oligotrophic) Ultra-‐oligotrophic Oligotrophic Mesotrophic Meso-‐eutrophic to very high potential for algae and plant growth (hyper-eutrophic). Eutrophic Hyper-‐eutrophic Median TP Eutrophic Hyper-‐eutrophic Median TP 5 Lake Nutrient Sources

Calculating the Lake’s Nutrient Source Highlights Phosphorus Budget • Internal load was the largest contributor to the The nutrient status of Lesser Slave Lake and the resulting Lesser Slave Lake Phosporus budget at about 65% algal blooms are major concerns for many stakeholders. of the total - typical of Alberta lakes. There are three main nutrients required for algal growth • The watershed, including rivers and direct runoff in aquatic systems: phosphorus, nitrogen and carbon. Most freshwater systems are limited by phosphorus, areas, contributed about 25%. which means that phosphorus concentrations control • Atmospheric deposition contributed less than how many algae grow in the lake. An excess of 10% and wastewater loads were negligible in phosphorus can cause plant (including algal) growth comparison with the other sources. to become a nuisance, which is why phosphorus is the nutrient most studies focus on. • Tributary loads were the main external sources of phosporus at more than 75%. A phosphorus budget for the lake is calculated by quantifying all known sources of phosphorus to the • The South Heart and Swan Rivers contributed

lake. This budget helps us gain a greater understanding the largest phosphorus loads,J140058, East Lesser Prairie Slave WatershedRiver Council of how watershed management could influence contributedTechnical intermediate Update loads, for the andLesser West Slave Prairie Watershed lake phosphorus levels and future algal blooms. The and Driftpile Rivers contributed the smallest load. phosphorus sources included in this Tributaryphosphorus loads budgetwere the main external sources of P, representing more than three quarters of external P were rivers, runoff from the landscape,(Figure point 42). sources, The relative contribution of individual rivers to the external budget was consistent between atmospheric deposition and internalthe loads methods, from with lake the South Heart and Swan Rivers contributing the largest P loads, East Prairie River contributing intermediate loads and West Prairie and Driftpile Rivers the smallestJ140058, loadLesser (SlaveFigure Watershed 42). CouncilThis sediments. Comparison of River Phosphorus Loads consistency provides assurance that all applied P budget methodsTechnical representUpdate for edthe Lesserwell the Slave differences Watershed

among the subwatersheds.Tributary Interestingly, loadsPhosphorus were the themain Swan external River sources contribution of P, representing was verymore thanclose three to quartersthat of ofthe external South P Mean Annual Phosphorus Load RiversHeart River despite the(Figure fact 42thConcentration).at Thethe relativeSwan contributionR. watershed of individual is about rivers half to the the sizeexternal of thebudget SHR was watershed. consistent between This demonstrates that boththe methodsmethods, withtook the into South account Heart and the SwanFlow much Rivers (m3/s)larger contributing runoff producedthe largest (Kg/yr)Pby loads, the foothillsEast Prairie areas River contributing intermediate(mg/L) loads and West Prairie and Driftpile Rivers the smallest load (Figure 42). This in the Swan River subwatershed compared to the Dry and Central Mixedwood natural areas in the South consistency provides assurance that all applied P budget methods represented well the differences Calculating River WestHeart Prairie River. among the subwatersheds.0.05 Interestingly, the Swan2.85 River contribution was very 6,282close to that of the South Phosphorus Loads: Heart River despite the fact that the Swan R. watershed is about half the size of the SHR watershed. This EastFor Prairie lake and watersheddemonstrates management that0.069 both these methods results took into imply account 3.88that the nutrientmuch larger reduction runoff produced in11,872 watersheds by the foothills of areasthe largest contributors, Swanin the SwanR. and River SHR, subwatershed show the compared largest topotential the Dry and to improveCentral Mixedwood lake water natu quality.ral areas in the South Flow x Concentration Heart River. South Heart 0.114 9.79 49,452 = Load For lake and watershed management these results imply that nutrient reduction in watersheds of the Driftpile River largest contributors,0.039 Swan R. and SHR, show the2.29 largest potential to improve lake4,014 water quality. Figure 42. Lesser Slave Lake External Phosphorus Loads for 2012.

Swan River 0.054 11.25 26,916 Figure 42. LesserRiver Slave TP Lake-based External External Phosphorus P LoadsLoad for 2012.

River-based ExternalRiver TP Phosphorus-based External Load P Load 144 320 Septic 144 320 Septic For lake and watershed Lagoon 23,109 Lagoon 23,109 management, these results31,862 31,862 AtmosphericAtmospheric imply that nutrient reduction DepositionDeposition DirectDirect Runoff Runoff

in watersheds of the largest Swan River Swan River contributors, Swan River and 19,009 Driftpile River 6,281 19,009 Driftpile River South Heart River, show6,281 the East Prairie River East Prairie River largest potential to improve 11,872 West Prairie River 11,872 West SouthPrairie Heart River River lake water quality. 26,916 4,014 South Heart River 6 26,916 4,014

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J140058, Lesser Slave Watershed Council Technical Update for the Lesser Slave Watershed

6.6 Internal Loading

Internal load from sediment release represented 69.3% of the P budget for LSL (Figure 41). This is similar to the earlier estimates for 1992-93 calculated by Noton (1998), where internal loading represented 65% of the P budget. It is a common occurrence for lakes in Alberta that internal P load exceeds the external P load (Mitchell and Prepas 1990). Large internal loads have a strong effect of lake productivity, i.e., algal growth, because phosphorus loads from internal release occur in dissolved form and are therefore more biologically available than other sources of P (Sosiak and Trew 1996).

6.7 Lesser Slave Lake as a Phosphorus Sink

While the previous sections have dealt with sources of P to the lake, it has to be stressed that Lesser Slave Lake, just as most other lakes, acts as a sink for P in the landscape. Based on cumulative external P inputs (124 t/yr) and P exports through the Lesser Slave River (26,652 kg/yr), we estimated that the lake retained over 81% of the external P load (Figure 40). This is a quite large retention factor despite the large internal load in summer.

Figure 40. Lesser Slave Lake Phosphorus Retention for 2012. J140058, Lesser Slave Watershed Council Technical Update for the Lesser Slave Watershed P Load Comparison Between Inputs Lesser Slave Lake as a Phosphorus Load Comparisonand Exports Between Inputs and Exports 6.8 Lesser Slave Lake P Budget Summary Phosphorus Sink 140 J140058, Lesser Slave Watershed Council Technical Update for the Lesser Slave Watershed The total annual phosphorus120 load to Lesser Slave Lake in 2012 was estimated at 352 t/yr by the river-TP While the previous sections have dealt with sourcesmethod . Internal load was the largest contributor to the LSL P budget with 229 t/yr, representing about of phosphorus to the lake, it has to be stressed65 that% of the P load, while100 the watershed, including rivers and direct runoff areas, contributed about 25% 6.8 Lesser Slave Lake P Budget ExternalSummary Inputs: Storage in Lesser Slave Lake, like most other lakes, acts as(123 a sink t) (Figure 41). This large importance of internalWatershed, load lakeis typical- for Alberta lakes (Mitchell and Prepas 80 Aquatic Life for phosphorus in the landscape: we estimated1990). that Atmospheric theThe total annual deposition phosphorus contributed load to Lesser less Slave thanside Lake 10% in 2012and waswastewater estimated atloads 352 t /yrwere by the negligible river-TP in comparisonm withethod the. Internal other loadsources. was the largest contributor to the LSL P budget withand 229 Sediments t/yr, representing about lake retained over 81% of the phosphorus that entered it. 60 development, 65% of the P load, while the watershed, includingprecipitation rivers and direct runoff areas, contributed about 25% (123 t) (Figure 41). This large importance of internal load is typical for Alberta lakes (Mitchell and Prepas The retention mainly happens through settling of 1990). Atmospheric40 deposition contributed less than 10% and wastewater loads were negligible in

particles to the lake bottom, where they form lake comparisonCummulative P Load (t/yr) with the other sources. Figure 41. Lesser Slave20 Lake Complete Phosphorus Budget for 2012. sediment. Such particles include river-transported Export: through Lesser Slave River sediments, particles from the atmosphere, algae 0 Figure 41. Lesser Slave Lake Complete Phosphorus Budget for 2012. and other organisms that grow in the lake and their Lesser Slave Lake P Budget (kg/yr) excretions. Lesser Slave144 Lake320 Phosphorus Budget (kg/yr) The retention mainlyLesser happens throughSlave settlingLake ofP particlesBudget to the(kg/yr) lake bottom, where they form lake 23,109 This percentage is quite large despite the large internalsediment. Such particles include river-transported sediments, particles from the atmosphere, algae and 144 320 Septic load from sediments in summer. other organisms that grow in the lake and 19,009their excretions. This sediment record forms over the years and 23,109 can be used to reconstruct how the lake ecosystem evolved overSepticLagoon time, as previously shown in the 19,009 paleolimnology section (section 5.1). While this loss of P to the sediments appears large, some of this P Internal Phosphorus Loads 26,916 LagoonAtmospheric Deposition is regularly recycled to the water column through internal4,014 loading processes and “reused” to stimulate The internal load is the amount of phosphorus that is 26,916 Atmospheric Deposition algae growth and thereby continuously contributes to the relatively4,014 highDirect algal Runoff production in Lesser Slave released from sediments into the water column. DuringLake. Direct Runoff 11,872 Swan River the open water season, some of the phosphorus that has 11,872 6,281 Swan River accumulated in the sediments is regularly recycled to 6,281 Driftpile River Driftpile River the water column through internal chemical processes Hutchinson Environmental Sciences Ltd. 31,86231,862 East Prairie River and “reused” to stimulate algae growth, continuously East Prairie River R270315_J140058_LSL_Draft.docx228,892 228,892 30 WestWest Prairie Prairie River River contributing to the relatively high algal production in Lesser Slave Lake. SouthSouth Heart Heart River River Internal Internal

Lake Phosphorus Loading

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Rivers In River Out

In From Sediments

7 Lake Health and Water Quality: Present and Past

Aquatic mammals, plants, birds, invertebrates and fish Present Water Quality Highlights rely on the water quality and aquatic habitat of Lesser • Lesser Slave Lake is an alkaline, moderately Slave Lake. For many Lesser Slave Lake enthusiasts, productive mesotrophic to eutrophic lake. understanding present lake water quality and trends over time is of concern, particularly as it relates to algal • Thermal stratification is weak and occurs only blooms. temporarily and close to the lake bottom. • Phosphorus concentrations in the lake increase Present Conditions substantially from internal loading during the East vs. West Basins course of summer, and fuel the development of algal blooms. The review of lake water quality data shows distinct differences between the east and west basins. Because • Compared to the east basin, the west basin is the majority of rivers flow into the west basin, it is more more elevated in turbidity, metals and nutrients. turbid (cloudy) with sediments, particularly during peak • This discrepancy is likely due to the larger spring flows, with higher metal and nutrient content than influence of rivers and possibly a larger influence the east basin. of internal loading, given the west basin is Other factors affecting algal blooms include the fact shallower than the east basin. that the lake doesn’t strongly separate into colder and warmer layers (stratification), allowing the phosphorus released from the sediments to be readily available for algae to feed on. Trophic State Study - 2005-2006 Past Conditions: Using a A primary water quality concern for Lesser Slave Lake is eutrophication. Because monitoring data Paleolimnologic Approach related to trophic conditions (nutrient and algal concentrations), is sparse and only extends back Paleolimnology is the science that uses information to the 1980s, Alberta Environment undertook contained in lake sediments to reconstruct a paleolimnological study to assess long-term past water quality and related environmental changes in trophic state of the lake in 2005/2006, conditions. It is a proven, powerful tool that encompassing the long history of land use in the can provide high resolution, long-term records watershed beginning in the mid-1800s. of lake water quality. As sediments accumulate at the bottom of a lake basin, so do a myriad Persistent Organic Pollutants Study - 2009 of physical, chemical and biological indicators of environmental conditions that exist at the In 2009, Alberta Environment collected an time of deposition. Assuming that the sediments additional sediment core from the east basin of containing these indicators are deposited in an the lake to assess potential increases in persistent orderly fashion, indicators can be isolated from the organic pollutants (POPs, including PCBs, dioxins sediment at increasing depths to provide a record and furans) due to concern over the accidental of environmental conditions going back in time, release of POPs from the Swan Hills hazardous from years to millennia, and the sediments can be waste treatment facility in 1995 and their potential accurately dated using radioisotopes. mobilization following forest fires in the watershed. A formal report has not been completed to describe the results of this study. The following sections provide an overview of the methods and results of the trophic status and POP paleolimnological studies. 8 Obtaining Sediment Cores Sediment Cores for Trophic State Study 2006 The study team sampled sediments from deep locations in the west and east basins of Lesser Slave Lake in 2005/2006. Researchers lowered the sediment corer - a long, hollow tube - slowly into the sediments and then carefully raised it so that the interface between 1900 the sediment and the water was undisturbed. In the laboratory, the cores were sectioned off at 0.5-cm increments for the first 40 cm of the core. The sediment cores encompassed more than 200 years of deposition for the west basin (44 cm long core) and

continuous record 1800 more than 400 years of deposition for the east basin (40 cm long core), providing a long-term record of natural baseline conditions prior to human influences in theAnalyzing Indicators of Environmental Dating a Core watershed of the lake and a high resolution record of Dating a Core Sample changes since settlement in the mid-1800s to 2005.Change in the Sediments In the lab, the age of sediments in a core is determined Sample The study team analyzed the sediments to reconstruct what lake by the analysis of natural radioisotopes - Lead-210 and In the lab, the age of Sediment Core for Persistent Organic conditions were like before non-indigenous settlement to Radium-226, in particular. Peaks of artificial isotopes - sediments in a core is Pollutants Study understand changes in the lakes over time. Cesium-137 and often Americium-241 - in sediment cores determined by the analysis A 48-cm long sediment core was collected in October, from the period of maxium nuclear weapons testing fallout of natural radioisotopes — 2009 from a deep, central location in the east basinThe and team chosein 1963-64 a number provide of an indicators independent to measure age marker and to confirm Lead-210 and Radium-226, in sectioned at 1-cm intervals. analyze throughoutand refine the the core chronology sample . of the core. particular. Peaks of artificial This core dated back to ~1760. The bottom-most sample isotopes — Cesium-137 analyzed for POPs corresponds to ~1810 (30-31 cm),Each so indicator contributed a piece to the overall picture of the and often Americium-241— the analysis of POPs extends to early settlement timeslakes’ histories over time, including connections to human impacts in sediment cores from in the early1800s and before the production and usesuch of as eutrophication, land-use practices and climate change. the period of maximum PCBs in North America, which began in ~1929. nuclear weapons testing fallout in 1963-4 provide an independent age marker to confirm and refine the chronology of the core. Analyzing Indicators of Environmental Change Indicator Analyzed Information Obtained For the trophic state study, the team Carbon and Nitrogen content • Nutrient sources chose a number of indicators of changes and isotopes • Algal abundance in trophic status (see table to the right) to measure and analyze throughout the core Pigments • Abundance of algal samples from the east and west basins. groups, such as blue Pigments from algae, bacteria green algae The cores for the persistent organic and plants often preserve in lake pollutants study were analyzed for POPs sediments long after the structures of • Total algal abundance using High Resolution Gas Chromatography the organisms have disappeared. Mass Spectometry. A mass spectrometer produces charged particles (ions) from the chemical substances that are to Fossil Diatom Algae • Nutrient status be aanalyzed. The mass spectrometer Diatoms are microscopic, single • Conductivity Midge then uses electric and magnetic fields to celled algae, the fossils of which are • Habitat larve measure the mass (weight) of the charged well preserved in lake sediments. (right) particles. Diatoms Fossil Chiromonmid (Midge) • Oxygen conditions 9 (below) Larvae • Nutrient status The fossils of these insect larvae are • Habitat well preserved in lake sediments.

Radioisotopes (lead, radium, cesium) • Sediment age

7 Lessons Learned from the Past Past Lake Water Quality Trends: The paleolimnological studies provide evidence of the effect human activities in the watershed have What the Sediments Reveal on the lake. Trophic State Study - main changes For example, over time, increased sedimentation observed: from the rivers has had a direct impact on aquatic • Lesser Slave Lake has always been an alkaline, communities in the lake. Although the core samples moderately productive eutrophic lake, but that from the east and west basins are comparable human impacts have modified the lake, mostly in length - 40 cm and 44 cm respectively - the since the 20th century. east basin’s core contained sediments from two hundred years prior to what was in the west basin • During the 20th century, the west basin showed (1600 vs.1800). This difference is in part J140058,due to Lesser the Slave Watershed Councilmore turbid (cloudy) waters, likely caused by Technical Update for the Lesser Slave Watershed naturally larger river influence in the west basin, but increased suspended sediment load from the Overall,also the fluxpointses of total to PCBs increased and dioxins oversedimentation time broadly reflect emissionin the patternswest in North America.watershed, making the water more cloudy with PCBs were present in pre-production sediments and increased greatly in the mid-1900s with the basin from the rivers. less light available to support algal growth. production and use of these chemicals for manufacturing of electrical equipment, heat exchangers, and hydraulicSupporting systems reaching that a peak evidence flux in 1978 ( Figureis the 27 ).collapse These chemicals of the reached Lesser Slave• LakeAfter 1960s, all algal groups increased in likely by atmospheric deposition of PCBs subject to long-range transport. After 1978, fluxes declined to the topphytoplankton of the core with the exception (floating of a minor algae) peak in 1991.community The large decline in the in PCBs is consistentabundance in the east basin, indicating higher with a1960s reduction when in PCBs thefollowing East the banPrairie of their Rivermanufacturing, was extensivelyimport and use in Canada in 1977 andphosphorus concentrations in the lake. implementation of strict regulatory controls and measures to remove PCBs from the environment. channelized for flood control. When the banks of • The same change was observed in the west basin, The secondarythose channelspeak of PCBs werein 1991 modifiedis close in timing in tothe the accidental1990s, therelease of POPs from thebut only after ca. 1990, indicating that favourable transformercommunity malfunction atmade the Swan a Hills comeback. facility in 1996 and subsequent fire activity in 1998 (section 2.2). Other factors, however, may have contributed to this peak including increased inputs from runofflight conditions for algae to use the increased and riverLesson flows or learned forest fire activity from that the can sediment enhance mobilization record: and transportwhen of PCBs to the lake.nutrient concentrations for growth became Sediment concentrations remained lower than those caused by the long-range atmospheric deposition peak inconsidering 1978, however, and the remained health well belowof the guidelines watershed,, not causing aleave concern for aquatic life. available. room for the rivers to be rivers. Allow them to Figure 27. Total PCB Fluxes in Lesser Slave Lake Sediments (East Basin) Total PCB Fluxes in Lesser Slave Lake Sediments (East Basin) Persistent Organic Pollutants Study - 80.0 two main trends over time: 70.0 • A long-term increase in PCBs, dioxins 60.0 and furans since the 1960s, when world- 50.0 /yr) 2 wide production began, which is likely 40.0 attributable to long-range transport of 30.0 Flux (g/m these pollutants, and then decreasing 20.0 levels since control measures have been 10.0 implemented. 0.0 1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000 • A short-term peak in the late 1990s in Year PCBs, dioxins and furans, possibly due to

Total PCBs PCB Production Onset the accidental release from the Swan Hills PCB Production and Import Ban Swan Hills Release hazardous waste facility and local fires. Fire Event The levels remained below the peak of the long-range transport, and continue to decrease with reduced use of these ThereThe are no knownpaleolimnological natural sources of PCBs, yet these are studiespresent in the sediments pre-dating production of PCBs in North America, most likely due to downward migration of PCBs in the sediment substances overall. core. Downward mobility of PCBs has been observed in other studies (e.g., Gevao et al., 1997) and is supportedhave by a) the provided larger contribution of lessimportant chlorinated PCB homologs (mono(mo)-, di- tri- and • POP levels remained considerably below tetra(te)information-CB) to the total PCB flux in preabout-production relative the to post history production times, of and b) the increase levels that could affect organisms living on of the least chlorinated forms (moCB and diCB) with depth in pre-production times (Figure 28). Lower the sediments. human impact on the lake and

will Hutchinson be Environmental useful Sciences Ltd. in informing lake R270315_J140058_LSL_Draft.docx 9 and watershed management objectives. 10 Predicting Future Lake Health and Water Quality

Using the BATHTUB Model Future Water Quality Forecast The BATHTUB model allows us to predict future lake phosphorus concentrations based on the current The development scenario predicted a 10% increase established phosphorus budget. in phosphorus and the restoration scenario predicted As its name implies, the model considers all of the a 10% decrease. possible phosphorus inputs into the lake basin, including contributions from • These modest changes are mainly due to the large influence of internal loading from the • the watershed via rivers and direct run-off, sediments, which is assumed constant in these • the atmosphere through precipitation, and two scenarios. • internal loading from the sediments, • The change in phosphorus concentrations from and modifies those inputs to produce various possible pre-settlement times to current times estimated future concentration scenarios. in the paleolimnology study was about double Two future scenarios: of what the BATHTUB model restoration scenario predicted. Researchers used the BATHTUB model to run two future scenarios: • This difference may be explained by uncertainties • full development of the watershed, and in the internal load estimate, which may decrease with reduced phosphorus availability in sediments • restoration to minimal impact (reforestation and reduction of human impacts to those resembling under a restoration scenario and uncertainties presettlement conditions). associated with the sediment study approach. In both scenarios, the only variable modified was the • Somewhat larger decreases in lake phosphorus phosphorus input from rivers; internal loading and could be possible as a result of reduced precipitation were kept at current levels. The effect of phosphorus inputs from the watershed. climate change, which would release more phosphorus • On the other hand, changes in climate may from the sediments, was not included in the model. counteract the effect of nutrient load reductions For the full development scenario, researchers took from the watersheds by enhancing internal the highest current phosphorus concentration - seen loading and algae growth (higher temperatures in the South Heart River - and raised the levels in the increase internal loading from the sediments). other tributaries to meet it. However, it is possible that this subwatershed could be further developed, raising phosphorus levels yet higher. The BATHTUB model predictions For the restoration scenario, researchers took the lowest current phosphorus concentration - seen in the Driftpile indicate that, although high River - and lowered the levels in the other tributaries to internal phosphorus loading meet it. However, it is possible that this level is higher than presettlement levels would have been. from the sediments moderates As with all models, the results can only be as precise as the effect of efforts to reduce the inputs; there is always uncertainty in predicting the future. watershed phosphorus inputs to the lake, those efforts remain important and worthwhile to protect future lake water quality.

11 River and Lake Fish

Fish are indicators of the health, stability and sustainability of aquatic ecosystems and can be used to Fish Population Highlights evaluate and monitor environmental change. Lake fish populations in the Lesser Slave Watershed face direct • Fourteen fish species are currently present in Lesser preseure from fishing. River fish in the watershed face Slave Lake; the historical lake trout population is additional pressures from habitat loss and fragmentation, considered extirpated (wiped out). water allocation and use and environmental change • Walleye populations were assessed as vulnerable, resulting from landscape alterations and change and associated with industrial development, agricultural use • Northern pike populations as collapsed, as and urbanization. indicated by Fall Walleye Index Netting. Lesser Slave Lake, Winagami Lake and Fawcett Lake • In Winagami Lake, Walleye populations were are the primary lake environments within the watershed assessed as vulnerable and northern pike supporting fishing activities. populations as stable. Contributing sub-watersheds include the Swan River and • In Fawcett Lake, both Walleye and northern pike the South Heart River, while the outflowing subwatershed populations were assessed as vulnerable. includes Lesser Slave River. • In addition to the native fisheries, there are a For the purpose of this summary, four native fish species number of stocked lakes with non-native fisheries from the larger Athabasca watershed and Lesser Slave of rainbow and brook trout. Lake sub-watershed were selected as indicators for lentic (lake) and lotic (river) fisheries to describe general • River populations of key indicator species goldeye stock status, abundance, distribution and associated and arctic grayling were considered low density risks: across the watershed. • Lake fish indicators: walleye and northern pike • Anthrophogenic risk factors and limitations in terms of land use impacts on habitat ranged from • River fish indicators: goldeye and arctic grayling low to very high among the watersheds and likely vary also among smaller subwatersheds. Fish Sustainability Index (FSI) • These limitations did not appear to correlate in an The Fish Sustainability Index (FSI) is the primary means obvious way with fish population indicators on a of reporting on the historical and current status and larger watershed scale and therefore likely need abundance of fish populations in Alberta. It provides to be assessed on a smaller subwatershed scale. a ranking and associated colour coding for each of the metrics used to assess a fish species. These rankings correspond to biological thresholds and categories derived from the data collected during standardized field assessments to compare the status, abundance and structure of species across the entire province and report on the natural and human activity-related risk factors influencing these fisheries. Summary of Fish Sustainability Index metrics for walleye and northern pike from three main lakes in the Lesser Slave Lake watershed. Natural AnthropogenicNatural Anthropogenic Historical Adult CurrentHistorical Adult Adult CUE CurrentCurrent AdultImmature CUE Current Immature Risk Catagories RiskLake Catagories SpeciesLake Species Limitations to LimitationsLimitations to to Limitations to Density (fish/netDensity night) CUE(fish/net (fish/net night) night) CUE (fish/net night) Productivity ProductivityProductivity Productivity 5 -Low Risk 5 -Low Risk WALL 5WALL 25 22 52 35 3 Lesser Slave Lake Lesser Slave Lake 4 - Low Risk 4 - Low Risk NRPK 5NRPK 15 Not Ranked1 Not Ranked5 35 3 3 - Moderate Risk 3 - Moderate RiskWALL StockedWALL Stocked2 23 33 23 2 Winagami Lake Winagami Lake 2 - High Risk 2 - High Risk NRPK 5NRPK 45 Not Ranked4 Not Ranked3 23 2 1 - Very High Risk 1 - Very High RiskWALL 4WALL 24 22 52 45 4 Fawcett Lake Fawcett Lake NRPK 5NRPK 25 Not Ranked2 Not Ranked5 45 4

12 Fall Walleye Index Netting protocol (FWIN) Lake fish populations were assessed in the fall of 2014 using the Fall Walleye Index Netting protocol, a standardized sampling methodology. While this technique has been designed to assess walleye, the index netting is also useful in understanding the relative density of other fish species. The index netting standard is a series of multi-mesh J140058, Lesser Slave Watershed Council nets that are placed in a lake or reservoir using Technical Update for the Lesser Slave Watershed a stratified, random approach. This means that the total number of nets needed (based onFigure lake 47. Fall Walleye Index Netting Catch Rates for Walleye in Lesser Slave Lake from 2005 – 2014 surveys compared to the status criteria outlined in Sullivan, 2003 for categorizing Alberta size) are placed in proportion to depth zones, and Walleye populations. randomly spaced within each particular zone. In a FWIN, one standard net is set for a Lesser Slave Lake Walleye Catch per Unit Effort over time 24-hour period, and the catch is counted. That unit of time is measured as a “catch per unit effort” (CUE). Typically, the FWIN catch rate will be reported as the average for the survey program at a lake. So, a FWIN CUE of 10 walleye per net means that an average of 10 fish was captured per net per 24 hours.

Status of River Fish: Arctic Grayling The arctic grayling FSI showed that this species has seen significant EB: East Basin WB: West Basin J140058, Lesser Slave Watershed Council declines in abundance and Technical Update for the Lesser Slave Watershed population structure across its native range in Alberta. As a result, FigureArctic 53. Grayling Arctic Grayling historic historic and andcurrent current adult adult densities densities in in subsub watersheds within within the the Environment and Sustainable Lesser Slave Lake Watershed Lesser Slave Lake Watershed Resource Developmnet (ESRD) Fisheries Management recognized the need to increase the harvest and overharvest protection for arctic grayling provincially; the fisheries management objective for arctic grayling has been set as conservation, recovery and restoration corresponding to a province wide catch and release regulation introduced as of April 1, 2015. In addition to reducing the risk to artic grayling populations by eliminating harvest, ESRD has recognized the necessity to focus on habitat protection and sustainable land management practices as being of parallel importance to meeting the Hutchinson Environmental Sciences Ltd. objectives of population recovery. R270315_J140058_LSL_Draft.docx 59

Table 30. Species composition within the South Heart River sub watershed.

Common Name Scientific Name Status2010

Arctic Grayling Thymallus arcticus Sensitive

Brook Stickleback Culaea inconstans Secure

Longnose Sucker Catostomus catostomus Secure

Northern Pike Esox lucius Secure

Pearl Dace Margariscus margarita Undetermined

Walleye Stizostedion vitreum Secure

White Sucker Catostomus commersoni Secure

Yellow Perch Perca flavescens Secure

Note: Tributaries include: East Prairie River, West Prairie River and unnamed tributaries to these systems.

Hutchinson Environmental Sciences Ltd.

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References Canadian Council of Ministers of the Environment (CCME). 2004. Canadian water quality guidelines for the protection of aquatic life: Phosphorus guidance framework for the management of freshwater systems. For a complete list of references, please refer to the main scientific document for which this is the plain language summary: Hutchinson Environmental Sciences Ltd. 2015: Technical Update for the Lesser Salve Watershed. Prepared for: Lesser Slave Watershed Council.

Image Credits Carbon isotopes: www.umces.edu/al/central-appalachians-stable-isotope-facility Chirolarv01.jpg: www.aquatax.ca/aquatax.html CRYPTOCH.jpg: www.paleolab.ca/wwwguide/chironomini/concave.htm Diatomeen.jpg: www.bgbm.org/de/node/1305 Process images: Hutchinson Environmental Sciences Ltd. Scenic images: Lesser Slave Watershed Council Fall Walleye Index Netting protocol graphic: Alberta Environment and Sustainable Resource Development Phosphorus Budget Graphic adapted from U.S. Geological Survey: http://pubs.usgs.gov/sir/2005/5071/images

14 15 Hutchinson Environmental Sciences Ltd.

North Saskatchewan Regional Plan: Lake Paleolimnology Survey

Prepared for: Alberta Environment and Sustainable Resource Development ESRD Contract Number: 140201 HESL Job #: J130053

December, 2014

R10122014_J130053_Alberta_Paleo-Final_Draft.docx