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 www.sharedvaluesolutions.com 2 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,