Smith Mountain Lake Water Quality Monitoring Program 2020 Report Prepared by Dr. Clay Britton, Dr. Delia R. Heck, Dr. David M. Johnson, Ms. Carol C. Love, Dr. Bob R. Pohlad, School of Arts and Sciences Ferrum College Sponsored by The Smith Mountain Lake Association Funded by American Electric Power Bedford County Regional Water Authority Smith Mountain Lake Association Virginia Department of Environmental Quality Western Virginia Water Authority (WVWA) January 12, 2021 SMLA WATER QUALITY MONITORING PROGRAM 2020 TABLE OF CONTENTS Table of CONTENTS ...................................................................................................... i FIGURES ...................................................................................................................... iii TABLES ........................................................................................................................ v 2020 Officers ................................................................................................................. vi 2020 Directors ............................................................................................................... vi 2020 Smith Mountain Lake Volunteer Monitors ........................................................... vii 1. EXECUTIVE SUMMARY ....................................................................................... 1 1.1 Conclusions – Trophic Status ................................................................................................. 1 1.2 Conclusions – DO, Temperature, pH and Conductivity Lake Depth Profiles .......................... 2 1.3 Escherichia coli Measurements .............................................................................................. 2 1.4 Algae in Smith Mountain Lake ............................................................................................... 2 2. INTRODUCTION .................................................................................................... 4 3. METHODS ............................................................................................................... 7 4. TROPHIC STATUS MONITORING...................................................................... 10 4.1 Introduction ......................................................................................................................... 10 4.2 Methods ............................................................................................................................... 10 4.3 Results ................................................................................................................................. 12 4.4 Discussion ............................................................................................................................ 14 4.5 Conclusions ......................................................................................................................... 18 5. WATER QUALITY TRENDS BY ZONE .............................................................. 19 5.1 Introduction ......................................................................................................................... 19 5.2 Methods ............................................................................................................................... 19 5.3 Results ................................................................................................................................. 21 5.4 Discussion ............................................................................................................................ 25 5.5 Conclusions ......................................................................................................................... 28 6. VERTICAL PROFILES OF WATER QUALITY PARAMETERS......................... 30 6.1 Introduction ......................................................................................................................... 30 CONTENTS i SMLA WATER QUALITY MONITORING PROGRAM 2020 6.2 Methods ............................................................................................................................... 31 6.3 Results ................................................................................................................................. 31 6.4 Discussion ............................................................................................................................ 36 6.5 Conclusions ......................................................................................................................... 37 7. BACTERIA IN SMITH MOUNTAIN LAKE ......................................................... 38 7.1 Introduction ......................................................................................................................... 38 7.2 E. coli Methods .................................................................................................................... 38 7.3 E. coli Results and Discussion .............................................................................................. 39 7.4 E. coli Conclusions .............................................................................................................. 43 8. ALGAE IN SMITH MOUNTAIN LAKE ............................................................... 44 8.1 Introduction ......................................................................................................................... 44 8.2 Methods ............................................................................................................................... 44 8.3 Results ................................................................................................................................. 45 8.4 Discussion ............................................................................................................................ 52 8.5 Conclusions ......................................................................................................................... 54 9. QUALITY ASSURANCE/QUALITY CONTROL ................................................. 55 9.1 Introduction ......................................................................................................................... 55 9.2 Calibration Data for Total Phosphorus Method and Results .................................................. 55 9.3 Calibration Data Discussion and Conclusions ....................................................................... 55 9.4 Comparison of Standards Method and Results ...................................................................... 56 9.5 Comparison of Standards Discussion and Conclusions ......................................................... 56 9.6 Blank and Spiked Blank Method and Results ....................................................................... 57 9.7 Blank and Spiked Blank Discussion and Conclusions ........................................................... 57 9.8 Duplicate and Spiked Sample Analysis Method and Results ................................................. 57 9.9 Duplicate and Spiked Sample Analysis Discussion and Conclusions .................................... 58 9.10 Analysis of Certified Standard Method and Results .............................................................. 58 CONTENTS ii SMLA WATER QUALITY MONITORING PROGRAM 2020 9.11 Analysis of Certified Standard Discussion and Conclusions ................................................. 58 9.12 QA/QC for Chlorophyll-a .................................................................................................... 59 9.13 QA/QC for Secchi Disk Depth ............................................................................................. 59 9.14 QA/QC for E. coli Methods and Results ............................................................................... 59 9.15 QA/QC for E. coli Discussion and Conclusions .................................................................... 61 10. SAMPLING EFFICIENCY .................................................................................... 62 11. CONCLUSIONS .................................................................................................... 63 12. ACKNOWLEDGEMENTS .................................................................................... 67 REFERENCES ............................................................................................................. 68 APPENDIX .................................................................................................................. 70 FIGURES Figure 4.1. Trophic status parameters (total nitrogen, total phosphorus, chlorophyll-a, and Secchi depth) for Smith Mountain Lake for each sampling period ....................................... 13 Figure 4.2. Variation of trophic status parameters with distance to the dam for Smith Mountain Lake in 2020 ............................................................................................................ 14 Figure 4.3. Maps showing variation in trophic status parameters for 2020 ................................. 17 Figure 5.1. Average annual total phosphorus concentration by year and zone ............................ 22 Figure 5.2. Average annual chlorophyll-a concentration by year and zone ................................. 23 Figure 5.3. Average annual Secchi depth by year and zone ........................................................ 24 Figure 5.4. Average parameter value by zone for 1987-2020 Carlson’s Trophic State Index Components