I gave a talk at Auburn Public Library 6/29/2022 and had a request to post the slides which can be found here.

I gave a talk at Auburn Public Library 6/29/2022 and had a request to post the slides which can be found here.
Matthew Scott spoke at our Annual Meeting August 27, 2023. The slides for his talk can be found here. Matt created the Maine DEP Lakes Program in 1970 and after working for the State of Maine for 42 years retired from his most recent position as Deputy Commissioner for Inland Fisheries and Wildlife. A list below tallies some of his other accomplishments:
By Woody Trask
This report summarizes the findings of the 2022 water quality monitoring program for Taylor Pond. Clarity readings and water quality measurements were conducted monthly from June through September by Woody Trask with additional clarity readings taken mid-May to late September by Michael Heskanen. Since 2004, Taylor Pond Association has been collecting its own water samples and performing most tests. Phosphorus analyses are conducted by the DHHS Health and Environmental Testing Laboratory.
2022 was an exceptionally good year for Taylor Pond. A record high single clarity reading (7.38m) and a new high average clarity reading (6.12m) were recorded. In addition, there was a low level of coloration especially in June and September. Both conditions might be attributed to having had very little precipitation; hence less run-off and infiltration.
Collecting a water sample for phosphorus.
The average 5 meter core sample phosphorus reading was lower than last year, but slightly higher than the historical average. The average 12 meter bottom phosphorus reading was much higher than last year due to a very high reading in September (an anomaly?). All other monthly readings were in the low to normal range.
Values for pH, alkalinity and conductance were all within the normal range of variation from the historic mean.
The average surface temperature taken at 1 meter depth was 23.9°C (75°F), 0.6°C (1.1°F) higher than last year and 1.0°C (1.8°F) higher than the average for the past 10 years. In spite of the high temperatures, there were no algal blooms reported in 2022.
“Ice in” occurred on January 11, 2021, about a month later than last year, and the “ice out” date was April 4th making for a much shorter than average iced-over period. The historical average for “ice out” is April 14.
There’s a new way to connect with Taylor Pond neighbors when you are looking for that kayak that floated away, are wondering who to call to check out your dock’s drooping edge, or wanting to share a picture of the loons playing just offshore. A private FaceBook group, Taylor Pond Ripples, is now open to Taylor Pond residents, property owners, and TPA members. Within the first month of the group, 108 members have shared pictures, asked advice, and helped return wayward watercraft to owners.
Joining the group is simple, just click on the link for Taylor Pond Ripples on FaceBook. (You do need a FaceBook account to join.) When you ask to join, you’ll answer two simple questions about your connection to the pond and your agreement with the group rules. An admin will respond within 24 hours and you’ll be able to see and add posts to the group. If you are a member, you can also invite neighbors to join. Thanks for joining and connecting with neighbors online (as well as in real life).
Joan Macri
Part of the experience of living on or near Taylor Pond is hearing the loon calls and seeing our resident loons circumnavigate the pond each day. But, according to many longtime residents, it has been more than fifteen years since a loon chick has been spotted on Taylor Pond. This is a concern as we look toward the future. This summer, local residents are working with Maine Audubon to address this issue.
While multiple attempts have been made in the past to provide a stable nesting platform for loon pairs, those efforts have failed. This year, in collaboration with the Maine Loon Restoration Project led by Maine Audubon, we are trying again.
Loon family, feeding the chick.
Maine Audubon started the Maine Loon Restoration Project in 2021 in partnership with Maine Lakes, the Lakes Environmental Association, and the Penobscot Nation. The project is funded by an oil spill settlement, administered by the U.S. Fish and Wildlife Service Trustees, resulting from an oil spill in Buzzards Bay, Massachusetts in April 2003. It was estimated that 531 loons died as a result of that accident. Maine Audubon decided to focus a portion of the grant on efforts to increase the hatching success of loon pairs on Maine lakes that haven’t successfully fledged a loon chick in 3 or more years. Taylor Pond clearly qualifies and a floating nesting platform was launched in early May of this year.
According to Tracy Hart, Maine Audubon Wildlife Ecologist and head of the Maine Loon Restoration Project, other parts of the project involve outreach to reduce nesting disturbance and egg washout from boat wakes, as well as loon mortality from threats like boat strikes and lead tackle poisoning.
The project launched 27 loon nesting platforms in Maine in the summer of 2022. Of these, 9 were used for nesting, 8 chicks were hatched and 7 survived, which is an excellent success rate given that it can sometimes take multiple years for loons to start nesting on rafts. When asked how they defined “success”, David Morrill, a Seasonal Wildlife Biologist with Maine Audubon, said it was when a chick fledged. In other words, a chick has to hatch, be cared for by its parents for 12 weeks, learn to feed itself and be strong enough to fly away in the fall in order for that specific platform to be deemed a success. However, the rafts themselves can only help to address certain threats and once a chick hatches, the platforms no longer provide any protection.
For 2023, Maine Audubon Society is launching another 33 platforms, including Taylor Pond’s, for a total of 60. The plan is to relaunch these platforms each year that threats to nesting remain, understanding that it may take time for a breeding pair to become accustomed to the platform.
Hart believes, based on the data collected to date, that loon platforms can increase productivity for breeding pairs that struggle to hatch chicks year after year. But she emphasizes that rafts take maintenance and pose some risks, so should only be used in cases where loons continually fail to hatch chicks due to reasons that the nesting platforms can help address–like nest flooding from water level fluctuations or boat wakes, predation, or loss of nesting habitat. The platforms, made of cedar logs or other materials, are anchored but float so that rising water won’t swamp them. Some have extra protections like avian guards and wake guards. Our platform does have an avian guard.
Some of the greatest dangers to nesting loons are excessive wakes which flood nests, predators, rising and falling water levels, and disturbance by people who get too close to the nest. Lead contamination from lost or discarded fishing tackle remains a leading cause of death for adult loons, but it appears that boat strikes are now killing more loons and their chicks than lead poisoning. In terms of predation, raccoons, mink, skunks, gulls, crows, and even dogs predate loon nests. Eagles are new on the scene as predators and may well be part of the reason why we have seen so few chicks on Taylor Pond.
The nesting platforms, once launched, are essentially floating islands, complete with vegetation. Maine Audubon supplies the raft, flotation, and green avian guards made of lobster trap wire in locations where there is heavy predation from bird predators. Local volunteers working alongside trained Maine Audubon biologists then spread 2’” of topsoil over which they lay large pieces of moss to help hold the soil on the raft. Small native trees and perennials are then planted, in our case a cedar tree, a dogwood whose trunk reached through the avian guard, and a small patch of blue flag iris. The moss is smoothed to create a bowl or hollow in the center of the raft. The avian guard has to be at least 27” high at the apex of the arch over the raft to give the loons room to nest and sometimes, even mate on the raft. Cedar or pine boughs are then woven through the avian guard to provide shade until the planted vegetation is established and leafs out.
Now that the platform has been launched, it will be monitored on a weekly basis by Debbie Hammond, the new Taylor Pond Loon Counter. She will make online reports to Maine Audubon. Debbie is continuing a family tradition by taking over from her father, Peter Durgin, our long time Loon Counter, who died last spring. Maine Audubon will check on the platform several weeks post-launch and provide volunteers with additional information about how to conduct the surveys and observations about loon behaviors. Greg Hammond, Jan Phillips and Joan Macri worked with Maine Audubon’s Toni Rabasco and David Morrill to prepare the platform for launch.
It will be years before we know if the program has been successful. Loons are born and fledge on fresh water lakes. They migrate to the coast and winter on the ocean where they remain for several years. When they are strong enough to defend their territory, they return to their lake of origin to breed the next generation. Hopefully these efforts will ensure that the Taylor Pond community will continue to enjoy its loons for many generations to come.
by Dana Little
The quick and simple answers to this question is no and maybe. Water from Taylor Pond is not considered safe to drink without treatment. The water is, however, safe for swimming but with some concerns.
Last summer the TPA board raised these questions about safety. Bill Turner offered to test some water samples as he had the expertise and an available boat. We only looked at Escherichia coli, abbreviated as E. coli. This bacterium is found in the intestines of wild animals, pets, and humans. The presence of E. coli in water indicates contamination with fecal matter. Because we have many wild birds, beavers, muskrats, and other animals that live on and around Taylor Pond we would expect to find some E. Coli. We are fortunate that most houses around Taylor Pond tie into Auburn’s sewer system and only a few homes around the pond rely on septic systems. Therefore, we are not likely to have significant amounts of E. coli due to human waste. The concern with the presence of E. coli is that if it is human in origin, other bacteria, viruses or parasites could cause disease.
Lake water is generally not considered safe to drink without at least chlorination to kill the bacteria. For drinking water, no level of E. coli is considered acceptable. For swimming, levels up to 88 (colonies of E. coli/100 milliliters) should not be exceeded in any one sample and no more than 47 on average of three samples over a 60-day period.
When Bill Turner performed testing in 2022, he found that E. coli levels ranged from 5 to 114. Of five samples taken, none were free of E. coli. He tested levels at the outlet on two occasions. We thought that the outlet would have an average amount of E. coli because it represented a mixture of all the water in the pond. On the two occasions he measured it, the numbers came back at 72 and 55, both below the acceptable level of 88 but above the 60-day average of 47 considered safe for swimming. On a private beach he obtained levels that ranged from 15 to 114. One measurement in the middle of the pond came back at the low of 5.
It is concerning that levels of E. coli exceed maximum levels recommended for safe swimming in certain areas at certain times last year. The drought and associated low water levels may have been an important factor. It is reassuring that most homes are connected to the city’s sewer, likely indicating that most of the E. coli found is wildlife in origin and not a hazard to humans. Anecdotally, I swim almost daily in Taylor Pond during the summer without any ill effects.
You can take certain actions to decrease your risk of disease. If you have a septic system, have an expert check to make sure it is functioning properly, especially if it is an aging system. Avoid attracting ducks, geese or other wildlife that will leave their feces on your lawn or waterfront. Finally, if you want to be certain that the water is safe, you can test the water in your swimming area. A&L Laboratory, 155 Center Street in Auburn performed the E. coli testing undertaken by TPA and will test your water samples for a fee. You can pick up a water quality test kit at the lab or order online. As with testing well water, they can test for various bacteria/minerals and the price will vary according to the tests you request.
By Woody Trask
On April 13 of this year, The Sun Journal published an article detailing the relationship between ice cover on Lake Auburn and water quality. This scenario applies equally to Taylor Pond. The less time a body of water is covered with ice, the longer the time for sunlight and warmth to stimulate algae growth and degrade water quality. Unfortunately, the effects of global warming have been reducing the duration of beneficial ice cover.
Ice melts from the shore, April 4, 2022.
“Ice-out” dates for Taylor Pond have been recorded since 1969. In 2018, recognizing the importance of having “ice-in” data as well, we started recording the date, although it’s sometimes hard to pinpoint exactly . We can now calculate the total number of days that the pond is iced in and therefore less supportive of algae growth, however, we don’t have much historical data. We are responsible for reporting both dates to the Lake Stewards of Maine (www.lakestewardsofmaine.org) for compilation with data from ponds and lakes all over the state.
The average “ice-out” date for Taylor Pond since 1969 is April 14th. The records reveal that recently ice-out has been occurring earlier, with April 11th being the average for the last 15 years. The average “ice-in” date since 2018 is December 24th. However, there were two years – 2016 and 2021 – when total ice-in didn’t occur until well into January making for very short periods of total ice cover.
In the short time that ice-in has been recorded, the average number of days that the pond is totally covered with ice is 110 days – the shortest being 83 days and the longest 137 days. This year we had 104 days of ice cover, which looks good compared to the 70 days reported in the Sun Journal for Lake Auburn. To take a quote from the paper, “the less time the lake is covered in ice, the more likely the lake will have problems later in the year.” We hope that 104 days translates into another good year for Taylor Pond.
We had a successful day despite drenching rain, wind and cool weather, we visited over 800 properties in the watershed. We had seven teams of three or more people who spread out over the area in seven separate sectors to cover over 13 square miles. A technical expert led each team, four paid for by Taylor Pond Association (TPA) and three paid for by the Department of Environmental Protection (DEP). Twenty-four volunteers provided valuable assistance. A team with Alaina Chormann from the DEP, Emma Lorusso from Androscoggin Soil and Water Conservation District; Barbara Mitchell and Dana Little from the board of Taylor Pond Association, led the effort. Results will be tabulated by Emma and presented to TPA when completed. Sites of soil erosion into the pond were identified and each given a priority score based on the severity of the problem. Once the final report is completed, the TPA board will have a blueprint on how to keep our pond healthy.
Taylor Pond Association (TPA) plans to conduct a watershed survey on Saturday June 3rd. The last survey was conducted in 2006. We are working with the Department of Environmental Protection and the Androscoggin Soil and Water Conservation District. The goal is to identify areas of erosion that carry phosphorus into Taylor Pond which can cause a decline in water quality.
Using the results of this survey, individuals and road associations can then apply for grants from TPA or through Maine’s DEP 319 grant program to fix identified problems.
The Information collected will not be used for enforcement or regulatory purposes. A follow-up letter will be sent to owners identified as having a significant problem with information on how to obtain help to fix the problem.
We have contracted with seven technical experts who will be leading teams of two to three volunteers on each of seven sectors in the Taylor Pond watershed areas of Minot and Auburn. We will be visiting every property in the area unless the owner opts out.We are looking for volunteers. Each volunteer will be trained in a live Zoom/webinar on May 31st from 1-3 pm or with a video at your convenience. If you are interested in volunteering, please contact Dana Little at [email protected].
This report summarizes the findings of the 2022 water quality monitoring program for Taylor Pond in Auburn, Maine (MIDAS ID#3750).
Clarity readings and water quality measurements were conducted monthly from June through September by Woody Trask with additional clarity readings taken mid-May to late September by Michael Heskanen.
Since 2004, Taylor Pond Association has been collecting its own water samples and performing most tests. Phosphorus analyses are conducted by the DHHS Health and Environmental Testing Laboratory.
Result summary: 2022 was an exceptionally good year for Taylor Pond. A record high single clarity reading (7.38m) and a new high average clarity reading (6.12m) were recorded. In addition, there was a low level of coloration especially in June and September. Both conditions might be attributed to having had very little precipitation; hence less run-off and infiltration.
The average 5 meter core sample phosphorus reading was lower than last year, but slightly higher than the historical average. The average 12 meter bottom phosphorus reading was much higher than last year due to a very high reading in September (an anomaly?). All other monthly readings were in the low to normal range.
Values for pH, alkalinity and conductance where all within the normal range of variation from the historic mean.
The average surface temperature taken at 1 meter depth was 23.9°C (75°F), 0.6°C (1.1°F) higher than last year and 1.0°C (1.8°F) higher than the average for the past 10 years. In spite of the high temperatures, there were no algal blooms reported in 2022.
“Ice in” occurred on January 11, 2021, about a month later than last year, and the “ice out” date was April 4th making for a much shorter than average iced-over period. The historical average for “ice out” is April 14.
The results of this year’s monitoring are given below and in a separate DO/Temperature report.
Parameter | 2022 | Mean for Taylor Pond since 1975 | Historic Mean for all Maine Lakes |
Color | 15 | 20.91 | 28 |
pH | 7.0 | 7.01 | 6.82 |
Alkalinity | 20 | 17.2 | 11.9 |
Conductance, µS/cm | 114 | 91.9 | 46 |
Total Phosphorous 5m core sample, µg/L | 10.75 vs. 12 in 2021 | 10.26 | 12 |
Total Phosphorous bottom grab, µg/L | 52.8 vs. 23 in 2021 | 24.55 | (not published) |
Secchi depth (meters) minimum | 4.3 vs. 4.0 in 2021 | 1.7 (minimum ever recorded) | 0.5 (0.9 in 2012) |
Secchi depth mean (m) | 6.12 vs. 5.14 in 2021 | 4.74 | 4.81 (5.2 in 2012) |
Secchi depth max (m) | 7.38 vs. 6.2 in 2021 | 7.38 (2022) | 15.5 (13.4 in 2012) |
Trophic State (by Secchi disk) | 33.9 | 47.56 | 45 |
Trophic State (by core Total Phosphorus) | 38.40 | 41.69 | (not published) |
Color: Organic material that remains from dead plants and animals provides most of the water color. Lakes drained by areas with more coniferous forests tend to be brown in color due to the slow degradation of the leaves of these trees. Taylor Pond had a color measurement of 15.0, which is significantly lower than last year’s average of 21.25 and lower than the mean for all Maine lakes of 28. When the color is greater than 25 a lake is considered “colored” and the transparency is reduced.
PH: A measure of the acid-base status of the pond. Taylor Pond had a pH of 7.0 in 2022 which is slightly higher than the mean of 6.82 for all Maine Lakes. Acid rain caused by industrial pollutants can cause the pH in lakes to drop below 6. This drop in pH kills off the healthy zooplankton (microscopic animals) leading to death of fish and overgrowth of algae. The pH of Taylor Pond has been very stable year to year.
Alkalinity: A measure of the capacity of the water to buffer against a change in the pH. Taylor Pond’s alkalinity in 2022 was 20.0 compared to a mean for all Maine lakes of 11.9. This indicates that our pond is unlikely to have a problem with acidity. The level of alkalinity in Taylor Pond has remained constant and is not of concern.
Conductance: Conductance indirectly measures the relative number of dissolved ions in the water — the higher the concentration of ions the greater the conductance. Conductance is used as a rough estimate of the amount of pollutants which usually are present as ions. Although conductance is easy to measure it is not considered highly reliable. Taylor Pond’s conductance for 2022 was 114 compared to a historical mean of 91.9 and a mean of 46 for all Maine lakes.
Total Phosphorous: A phosphorus analysis provides the most reliable measure of the capacity of Taylor Pond to have an algal bloom. Algae in Maine waters tend to be limited by the phosphorous content of the water. If provided with enough phosphorous, algae grows rapidly. Algae cause depletion of oxygen in the water which kills animal life, colors the water green and when it dies creates unpleasant odors. Taylor Pond’s phosphorous was done using a 5 meter core and bottom grab sampling technique. Taylor Pond’s core sample phosphorous readings this year averaged 10.75 µg/L which is comparable to the historical mean of 10.26 and lower than the 12 reported for all Maine lakes. In 2022 there were no 5 meter core results close to the 15 µg/L level that can initiate algal blooms. Lakes are categorized as oligotrophic (low level of biologic productivity), mesotrophic (intermediate) or eutrophic (high biologic productivity) based on how much phosphorous they contain. A lake with a phosphorous of less than 10 is considered oligotrophic, between 10 and 30 is considered mesotrophic and over 30 is considered eutrophic.
The bottom grab sample average of 52.8 µg/L was much higher than last year’s average due to an abnormally high September ready of 150 µg/L.
Secchi Disk: Secchi disk readings provide the easiest method for measuring the clarity of the water. Algae, zooplankton (microscopic animals), natural water color and suspended soil all reduce the transparency of the water. Algae cause most of the change in transparency in Taylor Pond, but pine pollen at times is also a major contributor. The mean transparency for 2022 was 6.12 meters, about one meter higher than last year, much higher than the historic average for Taylor Pond of 4.74 and higher than the historical average for all Maine lakes.
Trophic State: This is a measure of the biologic productivity of the pond — the higher the number, the more biologically productive the lake and typically the poorer the water quality. The scale ranges from zero to over 100. Ponds in the range between 40 and 50 are considered mesotrophic (moderately productive). Values greater than 50 are associated with eutrophy (high productivity) and values less than 40 are associated with oligotrophy (low productivity). Taylor Pond measured at 33.9 by Secchi Disk readings and 38.4 by phosphorous readings (considered the most accurate). Taylor Pond’s Trophic State as measured by the Secchi disk is lower than the state average of 45.
Dissolved Oxygen and Temperature Profiles: The amount of dissolved oxygen is measured at the surface and at one meter depth intervals monthly throughout the summer. Generally down to a depth of 5 meters the oxygen level remains at a high enough level to sustain all animals. Below 5 meters the oxygen levels early in the summer are high, but as the summer progresses the oxygen levels drop to levels (below 5 ppm) unable to sustain fish and other aquatic animals. Warm water fish (such as Sunfish, Perch, Pickerel and Bass) have no difficulty in Taylor Pond because they stay near the surface where the water is well oxygenated. Cold water fish (such as Trout and Salmon) need the deeper colder water, below 20 degrees Celsius, to thrive. By July or August, this colder, deeper water no longer contains enough oxygen for fish. In addition to the difficulty for fish, oxygen depletion near the bottom of the pond tends to release phosphorous into the water. This is demonstrated by the higher phosphorous levels found in the bottom grab samples by the middle of the summer. The oxygen depletion found below 4-8 meters was less than what we have measured historically and is consistent with lower phosphorus readings, less coloration and higher clarity. The DO and Temperature profiles for 2022 are on a separate chart (attached).
Conclusions: The conclusion is that 2022 was a better than average year for Taylor Pond as shown by all the quality indicators: phosphorus, clarity and color. The water quality of Taylor Pond is considered to be average compared to other Maine lakes. The potential for an algal bloom continues to be low to moderate, with the average Phosphorus of 10.75 µg/L for 2022 being in line with the historical average. Taylor Pond remains one of the 181 Maine lakes on the Maine Department of Environmental Protections Nonpoint Source Priority Watershed list. This list contains those lakes considered to be threatened or impaired by nonpoint source pollution from land use activities on the surrounding watershed. In addition the Stormwater Management Law considers Taylor Pond to be a lake “most at risk”.
Taylor Pond fails to meet standards for the highest water quality due to the depletion of oxygen found at depths below 5 meters during the summer (see DO/Temp chart). In addition, phosphorous levels historically remain just below the threshold of 15 which can trigger an algal bloom. Monitoring of Taylor Pond has been conducted regularly since 1975. During this time there has been no consistent trend in the parameters measured. Since 2004, the years Taylor Pond has been monitored by volunteers, there have been no appreciable algae blooms.
Because of the shallow depth of the pond (mean depth 17 feet) and low flushing rate (1.34 flushes per year, the number of times the water, on average, empties from the pond) Taylor Pond will likely always remain vulnerable to phosphorous loading and therefore algal blooms. Because of oxygen depletion of deep water during the summer, the pond will likely never sustain a cold water fishery. Finally, each new structure or expansion of an existing structure, whether a home, garage, driveway, road, lawn or beach, potentially increases the phosphorous loading of the pond.
Taylor Pond continues to have many attractive qualities. The shallow depth means that it quickly warms in the summer to provide excellent swimming close to the towns of Auburn and Lewiston. It freezes quickly in the winter to provide skating, skiing and ice fishing during the winter. It has an abundant bass, pickerel, and recently pike populations that thrive in its warm waters and attract people who enjoy fishing. The Department of Marine Resources considers the pond to be prime spawning habitat for alewives and trucks adult fish above the dams on the Androscoggin River into Taylor Pond. It has a naturally high level of biologic productivity that sustains an abundant wildlife population for all to enjoy. It remains a place that never ceases to astound us with its beauty.
METHODOLOGY:
Samples are collected at the deepest point in the pond. This point has been determined previously and the historic location has been noted on maps available to the samplers along with GPS coordinates. This spot is reached by boat and verified each time by visual triangulation or GPS reading. In addition to visual triangulation an ultrasound depth meter is used before collecting core and grab samples. Grab samples are taken using a Van Dorn Water Sampler. Core samples are taken with a core sampler home-manufactured from a 50 foot flexible PVC tube. The method for grab samples at a specified depth and core samples are done according to the protocol of the Maine Bureau of Land and Water Quality, Division of Environmental Assessment.
COLOR: Performed on core samples using a Hach color wheel (CO 20-100) and units are in Standard Platinum Units (SPU).
PH: Performed on core samples using a Hach Bromothymol Blue test kit for pH.
CONDUCTANCE: Performed on core samples using a HM Digital, Inc. Model COM-100 water quality tester for EC/TDS/Temp. Conductivity is measured in uS/cm.
ALKALINITY: Performed on core samples using a titration method with a Hach color wheel measured in milligram per liter.
PHOSPHOROUS: Performed on core samples and bottom grab samples. Samples are collected in the field, refrigerated and sent to the DHHS lab by mail. Measurements are in micrograms per Liter (parts per billion). The results are the average of four samples taken once a month from June to September.
SECCHI DISK: Performed using the method taught by the Maine Volunteer Lake Monitoring Program. Only certified users performed this task. Measurements of depth are in meters.
DISSOLVED OXYGEN: Performed in the field using a YSI 550A DO meter with 13 meter probe which measures temperature and dissolved oxygen from the surface to maximum depth. The sampler and meter is yearly certified by the Maine Volunteer Lake Monitoring Program as to method and accuracy. Measurements of dissolved oxygen are in milligrams per liter (mg/l). Water temperature is recorded at each depth tested.
TROPHIC STATE: Carlson’s Trophic State Index (TSI) is used in these calculations. For Secchi disk depth TSI = 60 – 14.41 x (Natural Log of Secchi disk depth in meters). For total phosphorus TSI = 14.42 x (Natural Log of total phosphorous) + 4.15.
Woody Trask
12/17/22