Contract Name: NSRP Lake Paleolimnology Survey Consultant Name: Hutchinson Environmental Sciences Ltd. This report was commissioned by Alberta Environment and Sustainable Resource Development (now Alberta Environment and Parks) to support both the implementation of the Land-Use Framework and the Cumulative Effects Management System. Recreational lakes within the North Saskatchewan Regional plan boundaries are of high ecological and recreational value. To better understand how to effectively manage cumulative impacts on the lakes, it is necessary to understand conditions in the lakes prior to development. Knowing these pre-development conditions will assist in setting reasonable and achievable goals for lake management. The paleolimnology study was undertaken by Hutchinson Environmental Sciences Ltd. The objective of the study was to provide a paleolimnological reconstruction of water quality conditions at Pigeon and Wabamun lakes. Sediment cores were collected, sectioned, and analyzed to assess temporal variability in paleolimnological indicators. Based on these results, an overview of anthropogenic impacts on lake water quality was to be provided. Both Wabamun and Pigeon lakes are productive, alkaline, and polymictic, and are situated within a carbonaceous geological setting. These characteristics are known to influence the interpretation of results and were not sufficiently considered in the report. Future work may be required to further describe the limitations and evaluate the data presented in report. This report has been completed in accordance with the contract issued by Alberta Environment and Parks (AEP). AEP has closed this project and considers this report final. AEP does not necessarily endorse all of the contents of this report, nor does the report necessarily represent the views or opinions of AEP or stakeholders. The conclusions and recommendation contained within this report are those of the consultant, and have neither been accepted nor rejected by AEP. Until such time as AEP issues correspondence confirming acceptance, rejection, or non- consensus regarding the conclusions and recommendation contained in this report, they should be regarded as information only. Oct 2016 © 2016 Government of Alberta 1 of 96 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 19, 2014 R24112015_J130053_Alberta_Paleo-Final.docx Hutchinson Environmental Sciences Ltd. 4482 97 St. NW. Edmonton AB, T6E 5R9 │587-773-4850 www.environmentalsciences.ca December 19, 2014 HESL Job #: J130053 Jason Kerr Limnologist - Red Deer - North Saskatchewan Region Suite 202, 4909 – 49 Street Red Deer, Alberta T4N 1V1 Dear Mr. Kerr: Re: ESRD Contract 140201: North Saskatchewan Regional Plan: Lake Paleolimnology Survey Final Report We are pleased to submit this final report to you, presenting the approach and results of the paleolimnological studies of Wabamun and Pigeon Lakes. The report contains detailed descriptions of the methodology, results and interpretation of the study. It closes with a summary section where the key results are presented and interpreted; first for each lake individually and then as a comparison of both. This report is intended for a technically instructed audience, but is the foundation for a public face document that will be submitted under separate cover. We have addressed the various comments received from ESRD and internal reviewers as well as comments on the second draft, and provided a comment disposition table under separate cover that outlines our approach to address comments. We thank you for the opportunity to assist with this very interesting project and hope that the report will help promote the further application of the paleolimnological approach to informing Alberta lake management. Sincerely, Hutchinson Environmental Sciences Ltd. Original signed by: Dörte Köster, Ph.D. Senior Aquatic Scientist [email protected] R24112015_J130053_Alberta_Paleo-Final.docx J130053, Alberta Environment and Sustainable Resource Development North Saskatchewan Regional Plan: Lake Paleolimnology Survey Signatures Report Prepared by: Original signed by: Dörte Köster, Ph.D. Senior Aquatic Scientist Original signed by: Tammy Karst-Riddoch, Ph.D. Senior Aquatic Scientist Original signed by: Kris Hadley, Ph.D. Industrial NSERC Fellow With contributions from Dr. Isabelle Larocque (The Lakes Institute), Dr. Peter Leavitt (University of Regina) and Dr. Yi Yi (Alberta Innovates and Technology Futures). Report Reviewed by: Original signed by: Neil Hutchinson, Ph.D. Principal Aquatic Scientist Hutchinson Environmental Sciences Ltd. R24112015_J130053_Alberta_Paleo-Final.docx ii J130053, Alberta Environment and Sustainable Resource Development North Saskatchewan Regional Plan: Lake Paleolimnology Survey Acknowledgments We would like to thank Chris Teichreb, at that time AESRD limnologist, for leading this project, helping with field work, core sectioning, water quality data acquisition and report review. We thank Bradley Peter and Elynne Murray from the Alberta Lake Management Society for their assistance with sediment coring and sectioning in the lab and Chris Ware with additional field assistance. The report benefited from detailed reviews of a number of ESRD limnologists. Hutchinson Environmental Sciences Ltd. R24112015_J130053_Alberta_Paleo-Final.docx iii J130053, Alberta Environment and Sustainable Resource Development North Saskatchewan Regional Plan: Lake Paleolimnology Survey Executive Summary Background Lakes in the North Saskatchewan Region, including Pigeon and Wabamun Lakes, are among the most heavily used recreational lakes in Alberta, in part due to their proximity to urban centres such as Edmonton. These lakes hold significant value as habitat for aquatic life, water sources for municipalities, industries, and farmers and for their aesthetic and recreational value for homeowners and visitors. Recently, apparent increases in algal blooms and fish kills have threatened the ecological integrity of these systems and may negatively affect their value to users. Pigeon Lake and Wabamun Lake both have an extensive history of regional development, but limnological studies are limited to the past ca. 35 years, leading to uncertainty about the degree to which water quality has changed due to human activities. Alberta Environment and Sustainable Resource Development initiated this paleolimnological study to fill this information gap from historical limnological data preserved in lake sediments. Objectives The objectives of the study were to 1. Establish predevelopment baseline limnological conditions in Pigeon Lake and Wabamun Lake, 2. Provide insight into the individual and cumulative effects of different factors on lake water quality, 3. Distinguish between natural and anthropogenic nutrient sources, 4. Distinguish between human impacts that can be actively managed through local land use planning (e.g., nutrient inputs from the watershed) and regional or global impacts (e.g., climate change) that require different management strategies, and 5. Understand how physical, chemical and biological processes in the lakes affect their sensitivity to external factors and therefore their responsiveness to potential management actions. Methods Sediment cores were collected from the central deep basin in Pigeon Lake and in the western basin of Wabamun Lake. The sectioned cores were sub-sampled and analyzed for radioisotopes (lead-210, cesium- 137), carbon and nitrogen elemental and stable isotopes, algal pigments, diatom algae and chironomid (midge) communities. Surface water total phosphorus (TP) and conductivity were reconstructed using a diatom-based inference model developed for Alberta lakes. The nature and timing of notable changes in paleolimnological data were compared to known land use histories, measured water quality and climate records to assess any potential causes of changes in lake health. Results The 40-cm long core from Pigeon Lake represented approximately the past 120 years and the 41 cm-long Wabamun Lake core covered about 270 years, based on the CRS dating model applied to lead-210 data and confirmed by the cesium-137 peak. Both cores therefore captured the period of major land disturbances Hutchinson Environmental Sciences Ltd. R24112015_J130053_Alberta_Paleo-Final.docx iv J130053, Alberta Environment and Sustainable Resource Development North Saskatchewan Regional Plan: Lake Paleolimnology Survey with early agriculture in the 1900s and extensive residential development after 1950, while only the Wabamun Lake core covered the time before the arrival of non-native settlers. Pigeon Lake Biotic assemblages and sediment chemistry were relatively stable in the sediment core from Pigeon Lake and indicated only minor changes in lake productivity that were coincident with watershed development in the mid-20th Century. More recent changes in the paleolimnological record are most consistent with physical and chemical changes in the lake resulting from declining lake levels and climate change.. In the 1950s, a few paleolimnological indicators suggested an ecosystem change to slightly more productive conditions, represented by a minor increase in colonial and N-fixing blue-green algal pigments, a subtle increase in eutrophic chironomid and diatom taxa and a slight increase in diatom-inferred TP. These changes were in contrast to a decrease in