Restoring Water Quality in the Lake Memphremagog Basin: 2016 Water Quality Report Prepared for the NorthWoods Stewardship Center and Vermont Department of Environmental Conservation by Fritz Gerhardt, Ph.D. 10 March 2017 Memphremagog Watershed Association The Memphremagog Watershed Association (MWA), founded in 2007, is a nonprofit organization dedicated to the preservation of the environment and natural beauty of the Lake Memphremagog Basin. The Memphremagog Watershed Association achieves this mission by 1) promoting the ecological awareness of people who live in, work in, and visit the Lake Memphremagog Basin; 2) promoting efforts to preserve the environment and natural beauty of the basin; 3) working with area lake associations; local, state, and federal governments; and businesses to develop guidelines and policies that protect and improve the quality of life in and around the basin; and 4) participating in efforts to monitor water quality in the lake and its tributaries, clean-up and re-naturalize shorelines, and protect local plants and wildlife. Beck Pond LLC Beck Pond LLC, a limited liability company founded in 2009, partners with public and private organizations to conduct scientific research that not only increases our understanding of the natural environment but also informs and guides on-the-ground conservation and management. Among other projects, Beck Pond LLC has conducted scientific studies and participated in conservation projects that assess the impacts of historical land uses on forest plant communities; assess the impacts of invasive plants on grasslands and forests; identify, assess, and propose solutions to water quality problems in the Lake Memphremagog Basin and other watersheds in Vermont; protect and restore floodplain forests and wetlands in the Lake Memphremagog Basin and along the Connecticut River; and identify and protect critical wildlife habitats across northern New England and eastern Canada. Cover. Wetlands fill this old channel of the Barton River in Irasburg, Vermont on 21 August 2015. These wetlands formed when the Barton River was diverted and channelized to allow construction of the Connecticut & Passumpsic Rivers Railroad along the floodplain of the Barton River in 1863. These wetlands are currently managed by the Vermont Fish & Wildlife Department as part of the Willoughby Falls Wildlife Management Area and provide important habitat for fish and wildlife and improve water quality by filtering nutrients and sediment and absorbing floodwaters. Restoring Water Quality in the Lake Memphremagog Basin: 2016 Water Quality Report Prepared for the NorthWoods Stewardship Center and Vermont Department of Environmental Conservation by Fritz Gerhardt, Ph.D. Beck Pond LLC 394 Beck Pond Road Newark, VT 05871 [email protected] Fritz Gerhardt, Ph.D. 2016 Memphremagog Water Quality Report Acknowledgments This project would not have been possible without the support and assistance of many individuals and organizations. Meghan Carter (NorthWoods Stewardship Center) obtained funding for and administered this project. Ben Copans (Vermont Department of Environmental Conservation) helped develop and implement all aspects of this project, including obtaining funding and support from the Vermont Agriculture and Environmental Laboratory, designing and implementing the project, collecting water samples, compiling and analyzing the water quality data, and guiding and undertaking efforts to identify and implement phosphorus- reduction projects and practices. Neil Kamman (Vermont Department of Environmental Conservation) also provided valuable support for and helped develop and implement this project. Jim Kellogg (Vermont Department of Environmental Conservation) and Dan Needham (Vermont Agriculture and Environmental Laboratory) enabled establishment of the Analytical Services Partnership to analyze the water samples at the Vermont Agriculture and Environmental Laboratory. Alison Farnsworth (Vermont Agriculture and Environmental Laboratory) provided valuable administrative and logistical support for analyzing the water samples at the Vermont Agriculture and Environmental Laboratory. Don Hendrich and Chuck Goulding (Memphremagog Watershed Association) helped collect water samples. Numerous landowners graciously allowed us to sample water quality and discussed restoration and protection opportunities on their properties. The Vermont Agency of Natural Resources supported this project financially through an Ecosystem Restoration Program grant (2016-ERP- 2-18) and an Analytical Services Partnership with the Vermont Agriculture and Environmental Laboratory. The assistance and support of all of these individuals and organizations are greatly appreciated. ii Fritz Gerhardt, Ph.D. 2016 Memphremagog Water Quality Report Table of Contents Acknowledgments ................................................................................................................. ii Table of Contents ................................................................................................................. iii List of Tables ................................................................................................................. iv List of Figures ................................................................................................................. iv Executive Summary ................................................................................................................. vi Introduction ............................................................................................................................... 1 Study Goals ............................................................................................................................... 3 Study Area ............................................................................................................................... 4 Water Quality Sampling ................................................................................................... 6 Methods ................................................................................................................. 6 Results and Discussion ...................................................................................... 9 Individual Sites and Subwatersheds ...................................................................................... 20 Black River ................................................................................................................. 21 Barton River ................................................................................................................. 29 Clyde River ................................................................................................................. 31 Johns River ................................................................................................................. 32 Direct Tributaries ................................................................................................... 35 Stearns Brook ................................................................................................................. 37 Priority Subwatersheds ................................................................................................... 43 Methods ................................................................................................................. 43 Results and Discussion ...................................................................................... 43 Phosphorus Load Reductions ................................................................................................... 48 Methods ................................................................................................................. 48 Results and Discussion ...................................................................................... 51 Conclusions ................................................................................................................. 63 Recommendations ................................................................................................................. 65 Education and Outreach ................................................................................................... 67 Bibliography ............................................................................................................................... 69 Appendix A. Descriptions of 31 sites sampled along the Vermont tributaries .. 71 Appendix B. Water quality data collected at 31 sites .......................................................... 74 Appendix C. Quality assurance data collected at 31 sample sites ............................... 81 Appendix D. Glossary ................................................................................................... 85 iii Fritz Gerhardt, Ph.D. 2016 Memphremagog Water Quality Report List of Tables Table 1. Numbers of subwatersheds sampled, mapped, and assessed ............................... 44 Table 2. Priority subwatersheds, defined as those subwatersheds ............................... 47 Table 3. Best Management Practices applicable to each land use ............................... 50 Table 4. Area covered by each land use in six tributary watersheds ............................... 52 Table 5. Estimated annual phosphorus exports for each land use ............................... 53 Table 6. Phosphorus load reductions potentially achieved in Brighton Brook ................. 55 Table 7. Phosphorus load reductions potentially achieved in Shalney