posted by Dana Little on 07/05/04

prepared by Dana Little

This report summarizes the findings of the 2004 water quality monitoring program for Taylor Pond in Auburn, Maine. Monitoring was conducted by Ralph Gould, Scott Williams and myself. In previous years we have had Scott Williams provide all of the technical monitoring except for the Secchi disk. In 2004 Taylor Pond Association purchased a dissolved oxygen meter and I received training in phosphorous sample collection. We contracted with Scott Williams to come only once in 2004 to provide monitoring. In 2005 we intend to be completely independent in providing our own monitoring. The results of this monitoring are quality controlled and certified by the Maine Volunteer Lake Monitoring Program and will continue to be used at the local, state and federal level for research, protection, restoration and legislative purposes. We have decided to perform the monitoring ourselves due to the overwhelming expense of hiring professionals to do the service for us.

The results of this year's monitoring are summarized in the table below:

Parameter	Year 2004	Mean for Taylor Pond (since 1975)	Mean for all Maine Lakes Measured
Color	19	20	27
PH	7.09	6.97	6.8
Alkalinity	14.8	15.3	12
Conductance	87	74	46
Total Phosphorous core sample	10	11	12
Total Phosphorous surface grab sample	9	(not previously done)	(not published)
Total Phosphorous bottom grab sample	14	26	(not published)
Secchi depth (meters) minimum	3.4	1.7	0.5
Secchi depth mean	4.4	4.6	4.85
Secchi depth maximum	5.5	6.5	15.5
Chlorophyll a	5.8	4.1	5.3
Trophic State (by Secchi disk)	55	53	45

COLOR:

Water color is mainly caused by the organic material that remains from dead plants and animals. 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 measured at 19 in 2004 which is less than the mean for all Maine lakes of 27. When the color is greater than 25 a lake is considered “colored” and the transparency is reduced. The color has varied over the years and is lower now than average.

PH:

A measure of the acid-base status of the pond. Taylor Pond had a pH of 7.09 in 2004 which is slightly greater than the mean of 6.80 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 stable over the years and is not of concern.

Alkalinity:

A measure of the capacity of the water to buffer against a change in the pH. Taylor Pond's alkalinity in 2004 was 14.8 compared to a mean for all Maine lakes of 12.0. This indicates that our pond is unlikely to have a problem with acidity. The level of alkalinity in Taylor Pond is not of concern.

Conductance:

Conductance is an indirect measure of 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 pollutants which are often present as ions. Although conductance is easy to measure it is not considered reliable. Taylor Pond's conductance for 2004 was 87 compared to a historical mean of 74. This does not represent a significant change.

Total Phosphorous:

Phosphorous is 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 you provide 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 new technique with surface grab samples. In addition a bottom grab sample and core sample were used which are considered more reliable methods. By all techniques Taylor Pond's phosphorous was lower than historical means and below the critical level of 15, at which level one tends to see 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.

Secchi Disk:

Secchi disk readings are 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. Most of the change in transparency in Taylor Pond is caused by algae. The mean transparency this year was 4.4 which is slightly less than the mean for Taylor Pond of 4.6 and less than the mean for all lakes of 4.85. In 2004, 51.5% of Maine lakes were clearer, 34.3 were less clear and 14.5% were unchanged compared to their long-term averages.

Chlorophyll a:

This is a measure of the amount of algae found in the water. This measure is less reliable than the phosphorous in determining the potential for a lake to have problems with an algal bloom. For 2004 the level was 5.8 which is slightly above our historical average of 4.1 and the average for all Maine lakes of 5.3.

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. Taylor Pond measured at 55 in 2004 compared to a historical mean of 53 and a mean for all Maine lakes of 45.

Dissolved Oxygen Profiles:

The graph on the next page depicts the level of oxygen versus depth. During the summer, at a depth below 4-8 meters, the level of oxygen drops to levels unable to sustain fish. Warm water fish have no difficulty in Taylor Pond because they stay near the surface. Cold water fish such as Trout need the deeper colder water to thrive. 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 level found in the bottom grab sample. The oxygen depletion found below 4-8 meters is similar to what we have found in the past and continues to reflect the fragile state of Taylor Pond.

Conclusions:

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 moderate and has not changed from prior years. 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 new Stormwater Management Law considers Taylor Pond to be a lake “most at risk”.

Taylor Pond fails to meet standards for the the highest water quality due to the depletion of oxygen found at depths below 6 meters. In addition phosphorous levels remain just below the threshold of 15 which could 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.

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. Each new structure or expansion of an existing structure, whether a home, garage, driveway, road, lawn or beach increases the phosphorous loading of the pond.

Taylor Pond should be recognized for its attractive qualities. The shallow depth means that it quickly warms in the summer to provide wonderful swimming close to the towns of Auburn and Lewiston. It freezes quickly in the winter to provide skating, skiing and ice fishing in the winter. It has an abundant bass and pickerel population that thrives in its warm waters and entertains people who enjoy fishing. It has a naturally high level of biologic productivity that sustains a fascinating wildlife population for all to enjoy. It remains a place that never ceases to astound us with its beauty.

References:

1. Bronmark, C. and Hansson, L., The Biology of Lakes and Ponds, 1998.

2. Kalff, Jacob, Limnology, 2002.

3. Williams, Scott, “2004 Maine Volunteer Lake Monitoring Program Annual Report”

4. mainegov-images.informe.org/dep/blwq/docwatershed/prilist5.pdf, Nonpoint Source Priority Watersheds List, 11/10/98