2019 Water Quality Report And Historical Analysis Long Lake Mickey Lake Ruth Lake Monitoring Years 1993-2019 Submitted to: Long Lake Association Long Lake Foundation Oleson Foundation Long Lake Township Prepared with the assistance of: Great Lakes Environmental Center 739 Hastings St. Traverse City, MI 49686 Northwestern Michigan College Great Lakes Water Studies Institute 1701 E. Front St. Traverse City, MI 49686 Cooperative Lakes Monitoring Program Michigan Lake Stewardship Association Interns: Abbey Hull, Michelle Preston, and Kathryn DePauw Long Lake Mentors: Barry Lishawa, Len Klein, Phyllis Laine, and Richard Roeper. Table of Contents Reference Information 2 Executive Summary of Results 4 Section I - Yearly Data 2019 Long Lake, Mickey Lake, and Ruth Lake Water Quality Assessment 6 Chemical Data Long Lake Water Chemistry Data 11 Mickey Lake Water Chemistry Data 12 Ruth Lake Water Chemistry Data 13 Water Chemistry Graphs 14 Physical Data May 10, 2019 20 May 15, 2019 21 May 29, 2019 23 June 12, 2019 23 June 26, 2019 24 July 10, 2019 25 July 22, 2019 25 August 7, 2019 26 August 21, 2019 27 September 4, 2019 27 September 18, 2019 28 Dissolved Oxygen/Temperature Depth Profiles 31 Plankton of Long Lake 33 Section II - Historical Data Historic Data Trends 40 Long Lake 41 Mickey Lake 48 Ruth Lake 51 Page Lake 54 Fern Lake 55 Bibliography 56 Appendix A Indigenous Unionid Clam Refugia from Zebra Mussels in Michigan Inland Lakes 57 1 Reference Information Figure 1. Water quality sampling sites on Long Lake, 1997-2019 LAKE SAMPLE SITE LATITUDE LONGITUDE Long Lake #1 #2 44.72473° -85.75612° #3 Mickey Lake #1 44.73257° -85.7664° #2 44.73217° -85.76867° Ruth Lake #1 44.69483° -85.76255° ______________________________________________________________________________ Table 1. Trophic State Classification (Chapra, 1997) Variable Oligotrophic Mesotrophic Eutrophic Total Phosphorus (μg/L) <10 10-20 >20 ​ Chlorophyll a (μg/L) <4 4-10 >10 Secchi depth (m) >4 2-4 <2 Hypolimnion Oxygen (% sat) >80 10-80 <10 2 Table 2. Phosphorus Data for Area Lakes and Sediments (GLEC, 2006, p. 12) ​ ​ Water Total Sediment Phosphorus ​ Lake Phosphorus (μg/L) (mg TP/kg DW) ​ ​ ​ ​ Torch 1.7 86 Burt 2.2 119 Lime 4.4 200 Crystal 4.8 332 North Leelanau 4.8 489 South Leelanau 4.9 398 Glen 5.1 326 Little Traverse 5.1 401 Cedar 5.3 396 Platte 7.7 620 For a comparison of lake quality in Michigan, see: Water-Quality Characteristics of ​ Michigan’s Inland Lakes, 2001–10 https://pubs.usgs.gov/sir/2011/5233/pdf/sir2011-5233_web.pdf _____________________________________________________________________________________ Trophic Status: A measure of lake productivity ​ ​ Oligotrophic Lakes: Display lower aquatic plant production and nutrient levels (typically referring to ​ ​ phosphorus levels). Usually deep and clear water. Cool, oxygen-rich bottom waters are home to cold-water fish, including whitefish and trout. Eutrophic Lakes: Display high aquatic plant production and nutrient levels. Typically shallow and ​ ​ murky, turbid water. Oxygen-depleted bottom are home to warm water fish, including pike and bass. Mesotrophic Lakes: Lakes that display characteristics between oligotrophic and eutrophic status. These ​ ​ lakes may be undergoing eutrophication. Eutrophication: Lakes naturally move from an oligotrophic lake to a eutrophic lake throughout their ​ ​ lifetimes. Most lakes start very large and clear and slowly warm up and fill in with sediment over time. This is a natural process that takes thousands of years. Cultural Eutrophication: Humans can speed up the eutrophication process by adding excess nutrients ​ ​ and sediments to the lake. It is important to monitor lakes to establish historical trends that will help show if cultural eutrophication is occurring there. 3 Executive Summary of Results 2019 Summary: The 2019 analysis of data from Long, Mickey, and Ruth lakes showed very little change compared to previous years. Parameters that were tested and compared included various chemical and physical parameters. CLMP standards were used for the first time in 2018 so new tables comparing 2018 and 2019 nitrate/nitrite levels have been added. A plankton analysis was completed for Long and Mickey Lakes this year. A plankton analysis was not done in Ruth Lake. Long Lake parameters mostly fell within oligotrophic levels. Phosphorus levels show a slight downward ​ trend, remaining in the oligotrophic range. Chlorophyll a, Calcium and secchi depth were all steady compared to previous years. Gloeotrichia, which is a nutrient pollution indicator species, was very ​ ​ prevalent in Long Lake. Mickey Lake parameters mostly fell within oligotrophic levels as well, however they all have reached ​ nearly mesotrophic levels. Surface phosphorus and chlorophyll a levels have decreased since 2018. There were no plankton found that raised concerns with the experts. Ruth Lake is currently a eutrophic lake, and the tested parameter levels did not change significantly ​ compared to 2018. Phosphorus levels could be trending upward towards further eutrophic levels, but secchi depth, calcium, and chlorophyll a levels seem to be remaining steady from year to year. CLMP standards include a shoreline survey that quantifies the health of the riparian zone. However, our survey did not exactly follow protocol and although we were thorough with our assessment of the available data, we did not include a quantified assessment. It is recommended that in the future the established kayak methodology is used. If a drone is used, it is required that altitudes remain low enough to maintain constant view of the shoreline and recommended that filming occurs in 1000 foot sections (per CLMP guidelines). 4 This year we evaluated the shoreline of Mickey Lake, with CLMP standards as a guideline for our survey. Types of vegetation, downed debris, docks, houses, and seawalls are observable shoreline attributes that determine its health. We found that large sections were heavily wooded, with developed lots grouped together taking up a smaller percentage of the shoreline. Mickey Lake is in a very wooded area and has a lot of habitat for wildlife. However, shoreline management techniques are recommended for those shorelines that are hardened (seawalls, rip/rap, concrete). Highly manicured lawns are also a concern due to fertilizer runoff. A natural shoreline with a vegetation buffer is a great way to reduce erosion, create habitat for wildlife, and reduce pollutants. 5 Section I: 2019 Lake Water Quality Assessment on Long Lake, Mickey Lake, and Ruth Lake ​ The 2019 Lake Monitoring for Long Lake, Mickey Lake, and Ruth Lake was initiated by the Long Lake Association, Long Lake Foundation, Oleson Foundation, and Long Lake Township in partnership with the Great Lakes Environmental Center (GLEC), the Great Lakes Water Studies Institute, and the Cooperative Lake Monitoring Program (CLMP). The Association is now using the CLMP protocols for water quality monitoring, including protocols for monitoring dissolved oxygen and temperature, obtaining secchi disk readings, obtaining phosphorus and chlorophyll a samples, identifying exotic aquatic plants, and conducting nearshore habitat assessments. The CLMP works with many lake associations and volunteer lake monitors around the state and has set state-wide standards for water quality monitoring. CLMP requirements included sampling in the early spring (two weeks after ice out) and sampling in the fall after the lakes have turned over. The only exception is chlorophyll a which is sampled twice yearly. The continuation of this lake monitoring program is essential for the assessment of lake water quality across the state, and it facilitates the comparison of data across monitoring years since protocols and meta data match each other across distance and time. This is crucial for establishing trends and taking appropriate actions during lake management. Physical data collected during the 2019 water quality monitoring season was obtained with a secchi disk and a YSI multiparameter water quality probe which was supplied by CLMP. A YSI meter, supplied by GLEC, was also used. Both of these instruments measure physical water quality parameter levels such as temperature, dissolved oxygen, pH and conductivity. A plankton net was used this year, as it was in 2018, to sample for zooplankton and phytoplankton. Water samples were taken for the analysis of total phosphorus, both at the surface and near the bottom of the lakes. Calcium, chlorophyll a, and nitrate/nitrite levels were also tested at each sampling site. 6 Long Lake: Water Chemistry Total Phosphorus: Surface and bottom phosphorus were steady compared to 2018, remaining on the ​ border of mesotrophic and oligotrophic. The overall trend is decreasing but levels should be carefully monitored. Chlorophyll a: Chlorophyll a levels are down down from the 2018 levels in Long Lake, falling well ​ within the oligotrophic range. This may be due to a shift in activity due to the later warm up of the lakes. It may also be indicative of lower plant life in the lake. However all lakes had a small decrease so it may be natural fluctuations in the lakes; the historically high lake levels around the region may be a factor. Chlorophyll a fluctuates frequently over the summer and over the years but overall it has remained steady and this year was in the normal range. Secchi Depth: Regular secchi depth measurements were continued this year; readings were taken every ​ week (with one exception) in Long Lake. This nearly tripled the amount of measurements compared to past years. This allowed us to calculate a very accurate average summer reading. We were able to see further down into Long Lake this year, an average secchi depth of 8.32m, which is within the oligotrophic range. This is consistent with historical data, but slightly deeper than 2018. This may correlate with the lower Chlorophyll a levels. Historically the maximum depth is much deeper. Calcium: Calcium levels were lower this year than in 2018. The number has dropped below the amount ​ required for Zebra Mussels to make their shells.