National Park Service U.S. Department of the Interior Natural Resource Stewardship and Science Determining the Historical Impact of Water-level Management on Lakes in Voyageurs National Park Natural Resource Technical Report NPS/VOYA/NRTR—2014/920 ON THE COVER Larry Kallemeyn steadies the ladder as Mark Edlund sections the long sediment core from Kabetogama Lake, Voyageurs National Park. Photograph by: Claire Serieyssol Bleser Determining the Historical Impact of Water-level Management on Lakes in Voyageurs National Park Natural Resource Technical Report NPS/VOYA/NRTR—2014/920 Mark B. Edlund1, Claire A. Serieyssol Bleser1, Larry W. Kallemeyn2, and Dan R. Engstrom1 1St. Croix Watershed Research Station Science Museum of Minnesota 16910 152nd St N Marine on St. Croix, Minnesota 55047 651-433-5953 Primary contact: mbedlund@ smm.org 2U.S. Geological Survey Columbia Environmental Research Center International Falls Biological Station 3131 Highway 53 International Falls, Minnesota 56449 October 2014 U.S. Department of the Interior National Park Service Natural Resource Stewardship and Science Fort Collins, Colorado The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado, publishes a range of reports that address natural resource topics. These reports are of interest and applicability to a broad audience in the National Park Service and others in natural resource management, including scientists, conservation and environmental constituencies, and the public. The Natural Resource Technical Report Series is used to disseminate results of scientific studies in the physical, biological, and social sciences for both the advancement of science and the achievement of the National Park Service mission. The series provides contributors with a forum for displaying comprehensive data that are often deleted from journals because of page limitations. All manuscripts in the series receive the appropriate level of peer review to ensure that the information is scientifically credible, technically accurate, appropriately written for the intended audience, and designed and published in a professional manner. This report received informal peer review by subject-matter experts who were not directly involved in the collection, analysis, or reporting of the data. Views, statements, findings, conclusions, recommendations, and data in this report do not necessarily reflect views and policies of the National Park Service, U.S. Department of the Interior. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the U.S. Government. This report is available in digital format from the Natural Resource Publications Management website (http://www.nature.nps.gov/publications/nrpm/). To receive this report in a format optimized for screen readers, please email [email protected]. Please cite this publication as: Edlund, M. B., C. A. Serieyssol Bleser, L. W. Kallemeyn, and D. R. Engstrom. 2014. Determining the historical impact of water-level management on lakes in Voyageurs National Park. Natural Resource Technical Report NPS/VOYA/NRTR—2014/920. National Park Service, Fort Collins, Colorado. NPS 172/127081, October 2014 ii Contents Page Figures.................................................................................................................................................. vii Tables .................................................................................................................................................... ix Project Summary ................................................................................................................................... xi List of Acronyms ................................................................................................................................xiii Project Rationale and Objectives ........................................................................................................... 1 Part I: Impacts Of Settlement, Damming, And Hydromanagement In Two Boreal Lakes: A Comparative Paleolimnological Study ............................................................................................... 5 Abstract .......................................................................................................................................... 5 Acknowledgements ........................................................................................................................ 5 I. Introduction ........................................................................................................................................ 7 Site Description and Background ................................................................................................... 8 Study site ................................................................................................................................... 8 History ....................................................................................................................................... 8 I. Material and Methods ....................................................................................................................... 11 Core Collection ............................................................................................................................. 11 Sediment Geochemistry and Dating ............................................................................................. 11 Hydrological and Climate Analysis .............................................................................................. 11 Diatom Analysis ........................................................................................................................... 11 Statistical Analysis ....................................................................................................................... 12 I. Results .............................................................................................................................................. 15 Sediment Dating and Geochemistry ............................................................................................. 15 Hydrograph ................................................................................................................................... 17 Diatoms ........................................................................................................................................ 17 Taxonomic richness and diversity ........................................................................................... 17 Community analysis ................................................................................................................ 19 Calibration set .......................................................................................................................... 21 Reconstructions ....................................................................................................................... 22 I. Discussion ......................................................................................................................................... 25 I. Conclusion ........................................................................................................................................ 29 iii Contents (continued) Page Part II: Interactive Effects of Hydromanagement, Land Use, and Climate Change on Water Quality of US–Canada Border Waters ...................................................................................... 31 Abstract ........................................................................................................................................ 31 Acknowledgements ...................................................................................................................... 31 II. Introduction ..................................................................................................................................... 33 II. Material and Methods ...................................................................................................................... 35 Study Sites .................................................................................................................................... 35 Historical Data .............................................................................................................................. 36 Field and Laboratory Methods ..................................................................................................... 38 Numerical Analysis ...................................................................................................................... 40 II. Results ............................................................................................................................................. 43 Historical Data .............................................................................................................................. 43 Sediment Dating and Geochemistry ............................................................................................. 45 Taxonomic Richness and Species Turnover ................................................................................. 45 Diatom Stratigraphies ................................................................................................................... 49 Variance Partitioning ...................................................................................................................