French Hill Pond: A Decade of Evolution David W. Lind, BA, MSfrenchhillpond.org/PDF/French Hill Pond...

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French Hill Pond: A Decade of Evolution

David W. Lind, BA, MS

Introduction

This paper discusses changes in the character of French Hill Pond, Bar Harbor, Maine as

observed by the author. The physical chemistry of the pond is discussed followed by the changes

in the flora and fauna in the pond and the adjacent area. The conclusions are not definitive. The

evolution of a microenvironment requires a significant amount of time. A decade is not, in the

opinion of the author, enough time to draw conclusions that will survive the test of time.

However, trends can be identified and help guide future studies that may develop definitive

conclusions.

Most observations were not made during 2015 because the author was recovering from a medical

condition. All photographs and graphics, except the topographic map, are by the author.

Another paper by this author titled: French Hill Pond 2009 Study Report, dated July 2010,

contains detailed information about a study of French Hill Pond most of which will not be

repeated. However, an updated map of French Hill Pond is necessary for the discussion that

follows.

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This map has more detail than the 2010 report map and it shows the character of French Hill

Pond after the removal of a stand pipe at the northern end of the pond and the construction of a

small dam to replace the stand pipe in the natural creek that flows out of French Hill Pond and

into the Fresh Meadow section of Acadia National Park. Fresh Meadow is a part of the Northeast

Creek watershed, considered by many experts to be the most pristine watershed on the east coast

of the United States. The numbers on the pond show the depth of the water in feet at those

locations. The number 10 in the box is the location on the pond where the physical chemistry

analyses were performed. This point is designated the DEEP point and is at 44⁰ 24.163' North

and 68⁰ 18,774' West or 0554714 East and 4916833 North in the Universal Transverse Mercator

(UTM) coordinate system. The State of Maine assigns a number for the Maine Information

Display and Analysis System (MIDAS) to each lake and pond in Maine. The MIDAS number for

French Hill Pond is 4593. The Global Positioning System (GPS) uses the UTM coordinate

system; therefore, the above map uses that system. The coordinate points on the map were

determined by a GPS device with an average accuracy of ±15 feet or less. The following section

of a United States Geological Survey map shows the relationship of French Hill Pond with

respect to Fresh Meadow and the Northeast Creek watershed.

The removal of the stand pipe became necessary when a leak in the conduit caused subsidence

near the road. The road was also flooded after heavy rains making it impassable. With the

assistance from the Town of Bar Harbor, the stand pipe was removed, a small dam constructed,

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some fill added to prevent road flooding and a dry fire hydrant installed. The Bar Harbor Fire

Department has used this dry hydrant to fight nearby fires. The State of Maine has also used the

pond as a source of water for fire-fighting buckets dangling from helicopters. After these

improvements, the character of the pond changed starting in 2012 as will be seen in the data

contained in this report.

Physical Chemistry

The physical chemistry analysis of French Hill Pond includes the measure of the water’s

turbidity (clarity) using a Secchi disk, the pH of the water, water temperature and dissolved

oxygen levels. Beginning in 2016, the phosphate, nitrite and ammonia levels in the pond water

were also measured. These latter measurements were more of an analytic chemistry nature than a

physical chemistry nature but are included in this discussion.

The Secchi disk used is an eight-inch disk connected to a plastic measuring tape graduated in

meters and centimeters. This disk was used with a slant-glass scope and mask. These items were

provided by the Lake Stewards of Maine organization (formerly the Maine Volunteer Lake

Monitoring Program) with the support of the Maine and federal environmental protection

agencies.

The pH of the pond water was determined in three ways. An electronic pH meter and pH strips

were used on the pond. A sample of the pond water was obtained at the DEEP point and later

chemically analyzed. This sample was also analyzed for phosphate, nitrate and ammonia

beginning in 2016 using a water analysis kit specifically designed to analyze pond water. No

phosphate, nitrite or ammonia was found in the pond water indicating that the pond is not being

polluted by septic systems, composted animal or plant waste etc.

The water temperature and dissolved oxygen was determined initially by a Hanna Instruments

dissolved oxygen meter and then by a Yellow Springs Instruments dissolved oxygen meter.

These devices were owned by the author. The dissolved oxygen levels are important because fish

require at least 5 parts per million (ppm) of dissolved oxygen to thrive in a pond.

Secchi Disk Results

The following charts are X-Y scatter charts showing the trends of the Secchi disk readings

during the months of May through October for each year from 2010 through 2019 except 2015.

The first chart shows the Secchi disk readings taken at two-week intervals. No attempt was made

to fit the data to a continuous curve. However, it is apparent that the Secchi disk readings in the

spring are high, decrease during the summer, level off in the late summer into fall and rise again

in the winter,. This pattern may be explained by the facts that plant decay will be slowed in cold

weather, pollen and other excretions from plants and animals increase during late spring and

summer, warmer water accelerates decay and the growth of organisms accelerates in summer.

The winter months slow all processes and allow the suspended particles in the water to settle on

the pond floor. Assuming a smooth transition during the months not included in the study, the

Secchi disk readings follow a broad and shallow sinusoidal pattern suggesting that this pattern

could be statistically analyzed using a Markov process model. Such an analysis is beyond the

scope of this report and, in the opinion of the author, the existing data is insufficient to construct

such a model.

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Secchi disk readings in Maine lakes or ponds range from 0.2 meters to 21.3 meters*. The Secchi

disk readings in French Hill Pond range from 0.72 meters to 1,6 meters. Normally, low Secchi

disk readings are due to algae growth but the major factor reducing the readings in French Hill

Pond appears to be tannin from the surrounding forest. Secchi disk readings of less than 4 meters

indicate the pond is productive*, that is, there is significant flora and fauna growth in the pond.

The next scatter chart shows the average Secchi disk reading for each year except for 2015. The

level of the pond began to drop from 2009 to 2012 because of the leaking standpipe. When this

standpipe was removed and replaced by a dam, the level of the pond became more constant and

the turbidity of the pond began to change.

The change in turbidity seems to be trending to a steadier state in a sinusoidal pattern best seen in

the following scatter chart showing the minimum and maximum Secchi disk readings for each

observed year. Mini/max analysis is a better way of analyzing trends than averaging data because

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

26-Mar 15-May 4-Jul 23-Aug 12-Oct 1-Dec

2010

2011

2012

2013

2014

2016

2017

2018

2019

SECCHI DIISK READINGS IN METERS 2010 to 2019

0.95

1

1.05

1.1

1.15

1.2

2008 2010 2012 2014 2016 2018 2020

Average Secchi Reading in Meters by Year

Average Secchi Reading

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it emphasizes extremes. For example, comparisons of the earth’s average, yearly temperature

over a decade may show little or no change but the mini/max analysis of temperature over the

same period may show a clear warming or cooling trend.

pH Readings

The following chart shows the changes in pH of the pond water during the monitoring period.

The pond water tends to be slightly acidic except during the hottest part of summer. These results

are typical of this area. Well water adjacent to the pond, for example, tends to be slightly acidic.

The pH of the water encourages the growth of certain plants and discourages others. The pond

water is becoming less acidic each year.

0

1

2

3

4

5

6

7

8


2009

2013

2014

2016

2017

2018

2019

pH

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Surface-water Temperature Readings

The next chart shows the surface-water temperature during the observation period. One might

conclude that the surface-water temperature is on average decreasing with time but the data is

insufficient to draw this conclusion. The temperatures follow a sinusoidal pattern that remains

close to a tight, least-squares curve fit.

The following chart shows the average surface-water temperature for each observation year. The

yearly average surface-water temperature trend is neither increasing nor decreasing.

0

10

20

30

40

50

60

70

80

90

100

25-Apr 15-May 4-Jun 24-Jun 14-Jul 3-Aug 23-Aug 12-Sep 2-Oct 22-Oct 11-Nov

Surface-water Temperature oF

2010

2011

2012

2013

2014

2016

2017

2018

2019

68

70

72

74

76

78

2008 2010 2012 2014 2016 2018 2020

Average Surface-water Temperature Degrees Fahrenheit

Average SurfaceTemperature DegreesFahrenheit

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Dissolved Oxygen Readings

Dissolved oxygen analysis is the most difficult process requiring the collector of this data to be

certified yearly by an approved representative of the Environmental Protection Agency. The

meter used requires careful calibration before each use. The dissolved oxygen readings are

coupled with the water temperature at each measurement point to determine the percentage of

oxygen dissolved compared with the maximum amount of dissolved oxygen possible in water at

the measured temperature. The nature of the pond water in French Hill Pond keeps the actual

dissolved oxygen at less than 100%. Only the amount of dissolved oxygen in parts per million is

included in this report because the actual percentage of dissolved oxygen contributes little to the

scope of the report.

The following nine scatter charts show the dissolved oxygen in parts per million during the

observation period. The amount of dissolved oxygen in pond water determines where organisms

will thrive in the pond. Generally, pond regions with dissolved oxygen levels of less than one

part per million are considered devoid of oxygen (anoxic)*. Most organisms cannot thrive under

such conditions. Fish will avoid regions with less than five parts per million of dissolved

oxygen*.

The charts show that there are regions in French Hill Pond that have dissolved oxygen levels that

remain above five parts per million year-round. Therefore, the pond supports fish, tadpoles and

other aquatic animals*. Fishermen should take care to place their bait at less than a meter in the

heat of summer but much deeper at other times of year.

In 2019, a family caught enough catfish in French Hill Pond for dinner that day.

0

2

4

6

8

10

12


Dissolved Oxygen at 1 Foot (ppm)

2013

2014

2016

2017

2018

2019

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0

2

4

6

8

10

12


Dissolved Oxygen at 2 Feet (ppm)

2013

2014

2016

2017

2018

2019

0

2

4

6

8

10

12



2013

2014

2016

2017

2018

2019

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0

2

4

6

8

10

12



2013

2014

2016

2017

2018

2019

0

2

4

6

8

10

12



2013

2014

2016

2017

2018

2019

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Plant Surveys

The following table lists all the plants observed in French Hill Pond or on the immediate shore

during the decade of observations.

0

2

4

6

8

10

12



2013

2014

2016

2017

2018

2019

0

2

4

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2013

2014

2016

2017

2018

2019

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Plant Common Name (Genus species)

Date First Observed

Algae Blooms (spp.) 2014

Aquatic Moss (spp.) 2011 Blue Flag (Iris versicolor) 2010

Bottlebrush Sedge (Carex hystericina) 2010

Cattails (Typhaceae) 2010

Common Bladderwort (Utricularia macrorhiza) 2010 Common Cattail (Typha latifolia) 2014

Common Mallow (Malva neglecta) 2014

Common Waterweed (Elodea canadensis) 2011

Earth Loosestrife (Lysimachia terrestris) 2014 Erect Bur Reed (Sparganium americanum) 2010

False Baby's Breath (Galium mollugo) 2014

Fern Pondweed (Potamogeton robbinsii) 2011 Filamentous Algae (spp.) 2014

Flatstem Pondweed (Potamogeton zosteriformis) 2010

Floating Bur-reed (Spaganium fluctuans) 2011

Floating-leaf Pondweed (Potamogeton natans) 2011

Fraser's Marsh St. Johnswort (Triadenum fraseri) 2012

Large-Leaf Pondweed (Potamogeton amplifolius) 2010

Little Floating Heart (Nymphoides cordata) 2010

Metaphyton (algae sp.) 2011

Muskgrass (spp.) 2011

Narrow-leaved Cattail (Typha augustifolia) 2014

Northern Snail-seed Pond Weed (Potamogeton spirillus) 2011

Ribbon-leaf Pondweed (Potamogeton epihydrus) 2011

Round-leaved Sundew (Drosera rotundifolia) 2016 Sensitive Fern (Onoclea sensibilis) 2018 Slender Pondweed (Potamogeton pusillus) 2018

Slender Pondweeds (Potamogeton sp.) 2010

Slender Waterweed (Elodea nutallii) 2011

Small Cranberry (Vaccinium oxycoccos) 2014

Soft Rush (Juncus effusus) 2010

Spatterdock (Nuphar lutea spp.variegata) 2010

Sphagnum Moss (spp.) 2012 Stoneworts (Charales order) 2014

Three-petal Bedstraw (Galium trifidum) 2014

Three-way Sedge (Dulichium arundinaceum) 2013

Tufted Loosestrife (Lysimachia thrysiflora) 2014 Variable Pondweed (Potamogeton gramineus) 2011 Vernal Water-starwort (Callitriche palustris) 2010

Waterwort (Elaine minima) 2012

Wild Celery (Vallisneria americana) 2011 Wool Grass (Scirpus cyperinus) 2010

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The primary purpose of the plant surveys was to find invasive species in the pond. Some

suspicious plants were observed and ultimately identified by experts, but no invasive species

were found.

The plants in French Hill Pond were divided into four distinct communities for study purposes

shown on the following map.

Community four, designated the “Sparse” community because of its low density, has decreased

in size since the construction of the dam. Communities one, the “Shore” community, and three,

the “southern” community, have increased in size. Community two, around the island, has

maintained the same size. The densities of community 1 and community 3 have increased

significantly.

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The most common planst in French Hill Pond are members of the Cattail family. There are three

species of cattails in French Hill Pond: Common Cattail, Narrow-leaved Cattail (shown below)

and a hybrid. Virtually all the cattails are in community 1, the Shore community, with a few in

the island community.

The next most common plant is the Bur Reed family. There are two species of Bur Reed in

French Hill Pond: Erect Bur Reed (shown below) and Floating Bur-reed. The Erect Bur Reed is

much more common than the Floating Bur-reed. Bur Reeds are found in the Shore community,

the Island community and are dominant in the Southern community.

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The next table lists all the plants observed in French Hill Pond or on the immediate shore during

2019.

Plants Identified in 2019 Date

Identified

Round-leaved Sundew (Drosera rotundifolia) 05/16

Small Cranberry (Vaccinium oxycoccos) 05/18

Spatterdock (Nuphar lutea spp.variegata) 06/15

Blue Flag (Iris versicolor) 06/28

Soft Rush (Juncus effusus) 06/28

Sphagnum Moss (spp.) 06/28

Erect Bur Reed (Sparganium americanum) 06/28

Large-Leaf Pondweed (Potamogeton amplifolius) 06/28

Three-way Sedge (Dulichium arundinaceum) 06/28

Sensitive Fern (Onoclea sensibilis 06/28

Common Cattail (Typha latifolia) 07/16

Narrow-leaved Cattail (Typha augustifolia) 07/16

Bottlebrush Sedge (Carex hystericina) 07/16

Variable Pondweed (Potamogeton gramineus) 07/30

Slender Pondweed (Potamogeton pusillus) 07/30

Fraser's Marsh St. Johnswort (Triadenum fraseri) 09/30

Note that a great many plants listed in the table above were not observed in 2019. The cattails

and bur reeds have grown so aggressively that many other plants are unable to compete. After

the construction of the dam, algae species have virtually disappeared. Some plants that

disappeared in previous years have reestablished themselves in recent years in areas where

cattails and bur reeds are less numerous, notably the Variable Pondweed and Slender Pondweed.

Certain plants grow among the dominant plants, specifically the Round-leaved Sundew, Small

Cranberry, Blue Flag, Soft Rush, Sphagnum Moss, Three-way Sedge, Sensitive Fern,

Bottlebrush Sedge and Fraser’s Marsh St. Johnswort. These plants are likely to thrive in spite of

the dominant plants.

Plants like Spatterdocks and Large-leaf Pondweed grow in waters too deep for cattails or bur

reeds. However, the pond floor drops off quickly outside the communities. Therefore, it is

unlikely that plant communities will expand significantly in the near future or new communities

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will develop outside the current communities. Another factor that prevents expansion of

communities is the fact that the pond is too turbid for sunlight to penetrate far enough into the

deeper water to allow plant growth in deeper areas of the pond.

The Tarn in Acadia National Park is evolving from a pond to a wetland as plants fill the entire

pond. However, French Hill Pond is not likely to evolve in this way. French Hill Pond is too

deep and the turbidity is too high for plants to grow in deeper areas.

Fauna of French Hill Pond

French Hill Pond is home to a variety of animals. A pair of Canada geese arrives in the spring

each year to nest on the Island in the pond. They rear about half a dozen goslings. When the

goslings are able to fly, the family moves on, no doubt joining other geese further south. The

following photograph shows one of the parents with three goslings.

The next photograph shows the nesting area on the island that they use each year.

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The pond is also frequented by Great Blue Herons as shown in the next photograph. However, no

heron has nested close to the pond.

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Other water loving birds that are frequent visitors on the pond include mallards (shown below).

Black Ducks, Ruddy Ducks and Common Mergansers are also frequent visitors. None of these

ducks were observed nesting near the pond.

Numerous species of birds frequent the shore to catch the many insects the pond produces. The

next photograph shows a Song Sparrow sitting on a cattail flower after catching a fly.

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Snapping turtles (shown below) are in the pond and occasionally found on the shore. Dogs that

swim in French Hill Pond risk being bitten by these creatures.

There are two types of frogs in the pond: Bull Frogs and Northern Green Frogs. The following

photograph shows a Bull Frog on Spatterdock leaves.

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The next photograph shows a Northern Green Frog among some Filamentous Algae before the

dam was built.

The pond also is home to a number of species of fish including the Brown Bullhead Catfish,

Rainbow Trout and minnows. The Rainbow Trout (shown below) were introduced but are vastly

outnumbered by the more hardy catfish.

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The greatest numbers of animals in French Hill Pond observed by the human eye are the insects.

There are far too many to list in this report. The following photograph shows a Half-banded

Toper dragon fly rarely seen in ponds but common on French Hill Pond.

The next photograph shows a Blue Dasher dragon fly. These dragon flies are very numerous

during the summer and many even lite on an observer.

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An insect that can be problematic is the Eastern Yellow Jacket (shown below) that will build

nests in the shore of the pond creating a hazard for people allergic to their sting. Other hazardous

insects common on the shore or water of French Hill Pond are mosquitos and ticks.

There are no indications that the animals in and on the immediate shore of French Hill Pond will

become extinct or be decimated in numbers very soon. They remain as very visible, vibrant,

pond life.

Summary

French Hill Pond has evolved over the last decade. The character of the pond changed more

dramatically since the elimination of a leaking standpipe and the construction of a small dam in

its place. The turbidity of the pond water remains high and seems to be approaching a more

narrow range. The pH of the pond water is becoming more neutral. The surface-water

temperature remains consistent showing neither an increasing nor decreasing trend in average

temperature over the decade.

The dissolved oxygen readings show that the pond water maintains dissolved oxygen readings of

greater than five parts per million down to about one meter year round. The dissolved oxygen

readings at lower levels drop dramatically during the summer but recover by fall to the point that

dissolved oxygen levels rise to above five parts per million down to the bottom of the pond.

These conditions allow aquatic animals like fish and frogs to thrive in the pond*.

No invasive plants were discovered in the pond during the decade. Numerous native plants were

identified and cataloged. Certain plants like cattails and bur reeds have become dominant

crowding out other plants. It is unlikely that plants in French Hill Pond will grow much further

beyond the current plant communities. Therefore, French Hill Pond should be spared an

evolution to a wetland for the foreseeable future.

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There are numerous animals that call French Hill Pond home. Many others are frequent visitors.

One pair of mating geese raise their young on French Hill Pond every spring.

Compared with other similar ponds in Maine, French Hill Pond is fairly typical*. Its importance

lies in the fact that the water from French Hill Pond drains into Fresh Meadow in Acadia

National Park a part of the Northeast Creek watershed. It is important to keep French Hill Pond

as environmentally sound as possible.

The raw data for this report and more detailed information about French Hill Pond can be

accessed through the website: www.frenchhillpond.org.

All photographs were taken on French Hill Pond or on its shore by the author.

Information marked with an asterisk (*) was provided by the Lake Stewards of Maine

organization formerly the Maine Volunteer Lake Monitoring Program.

French Hill Pond: A Decade of Evolution David W. Lind, BA, MSfrenchhillpond.org/PDF/French Hill Pond...

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