Pond Study

Skinequit ongoing Pond Study

Harwich Natural Resources Department

Skinequit Pond is located in South Harwich. Click map for enlarged map.

Beware the snapping turtle of Skinequit

By Douglas Karlson, Oracle
Wednesday, December 7, 2005

Skinequit Pond, once facing serious algae blooms and fish kills, appears to be on the mend. But it isn’t out of danger yet, not by a long shot. Scientific data suggest that more study and treatment is needed. "I remember when it was much clearer. This one was pristine in the 70’s" remembered Deborah Aylesworth, who lives on Skinequit, and is a Water Quality Task Force pond captain. But she said the pond’s water quality has gotten better since 1998, when a big algae bloom and fish kill occurred. Located south of Route 28 in South Harwich, Skinequit is only eight feet above sea level, yet is 32 feet deep. The bottom of pond is therefore below sea level. "If you swim there you can feel where it gets cold," noted harbormaster Tom Leach. The cold water is the spring that feeds the pond. Like many Harwich ponds, it’s a kettle pond, formed by ice boulders during the Ice Age. It discharges to the south through Red River. Accessible by a path off Ocean Street, there’s limited public access to it. Recreational uses include fishing, swimming and boating. In the winter the pond is used for ice skating and ice fishing.

History
According to Brooks Free Library research librarian Joanne Latimer, the pond is named after John Skinequit, a Native American who owned land and had a cabin on the east side of the pond. Simeon L. Deyo’s "1890 History of Barnstable County" notes that Skinequit sold the land to Jeremiah Howes, of Yarmouth, in 1692. A barrel factory now known as the Cooperage in East Harwich was located on the pond. It moved after a big fire in the 1950’s, said Leach. Ice may have been harvested at one time. "I suspect that ice was cut there. It’s the kind of pond that would hold a nice freeze," said local historian John Roche.

Fauna
The pond is not stocked, but there are plenty of fish, according to Aylesworth. A herring run leads from the southwest corner of the pond under Uncle Venie’s Road, through the Red River and then out into Nantucket Sound. No one is allowed to harvest herring from the run. There are also sunfish and other species. "Someone caught a small bass this summer," said Aylesworth Skinequit is also home to painted turtles and box turtles in the woods surrounding it. There’s also at least one big snapping turtle, "apparently there’s a really large one," said Aylesworth. Incidentally, according to Leach, Uncle Venie’s Road was named for Uncle Venue, a snapping turtle that lived in Skinequit Pond. "That’s what I always understood, that was the big joke in the neighborhood," said Leach. Aylesworth has also seen muscrats. Bird life includes night heron, and regular visits by an osprey. She also said that peepers have returned. They’re small tree frogs that make a distinctive peep sound. "That means spring when the peepers come out," said Aylesworth.

Well buffered
Skinequit Pond is fairly well buffered, that is, there a band of vegetation along its edge, filtering out pollutants and protecting the water. An adjacent, abandoned bog on the north side is now conservation land and protects the pond from Route 28 run-off - at least to some degree. Members of the community surrounding the pond are taking steps to prevent pollutants from seeping into Skinequit. Aylesworth, who in addition to being pond captain is president of the Watershed Association of South Harwich (WASH), a neighborhood association, said she has been trying to encourage residents to let vegetation grow around the pond. "Most people understand that it’s to their advantage," she said. "Most of us prefer [unfertilized] Cape Cod lawns."

Science
Following an algae bloom in 1998, Leach devised a program to restore the pond’s health. "Back then it was in sorry shape. Everything was dead in the pond," he recalled. The solution, he said, was to get dissolved oxygen back into the pond. To do this the town used an electric aerator for two seasons. It also used bales of barley straw and a Fukui rack, which are submerged in the water to encourage algae which denitrifies the water. "I think it was the pond aeration that turned the thing around," he said. But the pond is still far from healthy. Secchi disc readings, which measure water clarity, continue to show a problem. Algae make visibility poor near the surface. While the algae produce oxygen, after they die and decay, they form sediment which exerts an oxygen demand at lower depths. That’s why oxygen levels are low at the bottom of Skinequit. Frank Sampson, chairman of the Harwich Water Quality Task Force, compared it to a compost pile on the bottom of pond. It’s a nasty cycle: the lack of oxygen causes more sediment to accumulate, which in turn feeds more bacteria to consume more oxygen in the pond. In other ponds, this type of phenomenon is associated with excess phosphorus. "The question always is where’s it coming from?" said Sampson. "The data I’m looking at show a pond that’s being impacted. We’ve always been curious as to why." Based on recent data, he thinks he may have the answer. Phosphorus readings at the bottom of the pond are 10 times the accepted level found at the surface. The readings show phosphorus level of 300 micrograms per liter, the acceptable level is 10. Sampson theorized that over the years high levels of the poison have accumulated in the pond sediment. Some of it may have come from natural sources, like rainfall. Some may be the result of household detergents in sewage. It’s difficult to say. Now that poison is bleeding back into the lake. The solution in such cases, he suggested, is either aeration or alum treatment. In addition, Sampson said people living near ponds should be encouraged to use low or zero phosphorous dishwasher detergents. Despite the data, Aylesworth said she thinks the pondlooks cleaner. "We are very pleased at how much clearer it was this summer. Not clear enough for our tastes, but it’s healthier," she said. The Cape Cod Commission is slated to review data about the pond and make recommendations for the next step. "I’m going to be surprised if they don’t recommended some action," said Sampson. "It needs to go to the doctor’s and be examined," said Sampson. But a diagnostic study would cost money, as much as $30,000, to fully understand what’s going on, said Sampson. The best source of those funds would be from a grant. "The good news is we already have a lot of data," said Sampson. He added that aeration might be the best solution. "This is a classic opportunity for a Solar Bee," he said, referring to an aerator mechanism that had been considered for Long Pond.

Skinequit stats
Location: South Harwich
Size:18 acres
Maximum depth: 32 feet

Grass Pond
Since 1982, cranberry grower John Sennott has used the waters of Grass Pond to flood his bog as needed on Bank Street. Sennott, who owns the water rights, also carefully monitors the ponds water levels to prevent flooding, especially during the spring. By opening a sluice on Bank Street, water is admitted from the pond into his 10 acre bog. It can then either flow though Cardings Brook or be trapped in the bog for harvesting to freeze over for the winter. Sennott informed the Oracle that the pond used to support nearly 60 acres of bogs, now that number is down to ten. "I’ve seen it drain down to nothing," he recalled. He reported he has also observed algae blooms caused by septic run-off from the Country Meadows housing development directly to the north of Grass Pond.

Paddocks Pond
Paul Laffin, a resident of Paddocks Pond Road, was interested to read of the freeze which killed fish in Paddocks Pond several winters ago and was reported by coastal resources director Tom Leach. Three of four years ago, said Laffin, "the same thing happened to the frogs, they used to serenade me every night, but there are no more in there." For the past year and a half Laffin said he has enjoyed watching a family of ducks that were born near his house. He has also seen several muskrats.

Pond Study HNRD

Skinequit Pond HNRD Report 1

Skinequit Pond HNRD Report 2

Skinequit Pond HNRD Report 3

Skinequit Pond HNRD Report 4

Skinequit Pond HNRD Report 5

Skinequit Pond HNRD Report 6

Skinequit Pond HNRD Report 7

Skinequit Pond HNRD Report 8

Skinequit Pond HNRD Aeration Plan Reasoning

Skinequit Pond (and surrounding zone of contribution) Topographic Map

OTHER INFO SITES
Example Non-Point Source Pollution Program (Puget Sound)
Eutrophication is a word most people have never heard of.
Freshwater/Saltwater Parameter Table
What steps are we planning to take toward a Recovery Plan for Skinequit Pond
Algae Information Links
Barnstable Counts Department of Health and Environment

Skinequit Pond (15.4 acres) is a small Kettle Pond in South Harwich, Massachusetts that has been experiencing signs of 2nd stage eutrophication. The pond is located within 1/4 of a mile from the southern Cape Cod shore on Nantucket Sound. The pond is 17th in size among Harwich's 23 ponds. The largest lake being Long Pond (743 acres) and the smallest listed as Island Pond (4.5 acres). There are an additional 15 unnamed water bodies of smaller dimmension including vernal pools within the borders of the Town. Skinnequit Pond shares its geologic history as a kettle pond with so many lakes on the Cape Cod landscape, where geologically speaking the lake was formed from a block of ice which had calved from the retreating glacier and was left in the outwash plain along what is today the south side of the Cape.

The surface elevation of this pond is 8 feet above sea level while the deepest part of the lake is more than 25'. Therefore the bottom of the lake is 17' below sealevel. The pond is spring fed from the surrounding watertable and the water exits the pond from a man made canal dug in mid 1800's for purpose of creating a commercial Herring run. Inspite of its nearness to the ocean and its direct connection to Nantucket Sound, the salinity of the pond remains fresh (o1/ooo).

Harwich Natural Resources Report

NRO Report 8

07 October 1998

Skinequit Pond – 1130am

Sunny, calm day

Heinz Proft - Asst. NRO

Received a call on Monday, October 5th from Connie Burton informing us that the greenish algae she had once noticed was beginning to dissipate. On Wednesday, October 7th I made a trip to Skinequit pond in order to continue our monitoring study of Skinequit Pond. Water around the Burton’s dock, and the whole pond in general, was much clearer than previous visits to the pond. I could see the bottom of the pond as I stood at the end of the dock (3 feet). Small fish were seen swimming underneath and around the dock and many empty freshwater clams shells (100+) were seen on the sandy bottom of the pond. Most likely these were present in previous visits to the pond but unable to be seen due to the algae bloom. The following water data were recorded.

Skinnequit Pond (8/17/98)
Station	Depth	Water Temp.	Dissolved Oxygen
On Shore	6 inches	16.5 oC	45.0 % and 3.0 mg/l
End of Burton Dock	6 inches	16.4 oC	40.0 % and 3.0 mg/l
End of Burton Dock	2 feet	16.0 oC	28.0 % and 2.1 mg/l
Middle of Pond	6 inches	16.0 oC	35.0 % and 2.2 mg/l
Middle of Pond	5 feet	15.4 oC	27.0 % and 1.8 mg/l
Middle of Pond	15 feet	10.5 oC	3.10 % and 0.7 mg/l
Skinequit Outlet	6 inches	16.2 oC	38.0 % and 2.8 mg/l
Southwest Corner	5 feet	15.9 oC	30.0 % and 2.0 mg/l

*** A Secchi disc reading was taken in the middle of the pond: 1.75 M ***

It appears that the fall cooling and water turnover of the pond has started to take place. The difference in water temperature from the surface to the bottom is now 6 degrees as compared to August’s 16 degree difference. Oxygen levels have declined somewhat and could be due to the lack of oxygen producing algae no longer present in such high densities, shorter days (daylight) which decreases the amount of photosynthesis taking place. Also, the onset of the fall turnover is taking place, in other words, as the pond surface cools in the late summer evenings the top waters sink, and when it chills in the fall it drops even farther. The Harwich Natural Resources department will continue to monitor Skenequit pond and note any significant changes.

Harwich Natural Resources Report

NRO Report 7

05 October 1998

Skinequit Pond 10:00 am

Sunny, dry NW Fo55

Connie Burton

Connie Burton reports that the pond seems to becoming clear this day. Anabeana is dying off?

An excellant early description of Anabeana appears in Field Book of Ponds and Streams (Morgan 1930). "Blue-Green algae - During midsummer blue green algae often become very abundant in lakes, especially in reservoirs where they sometimes form surface film known as "water-bloom". Among the commonest of the blue-green algae is the free-floating Anabeana which forms the water bloom on ponds and lakes and is one of the principal foods of swimming crustaceans.They are microscopic, but commonly form simple chains as in Anabeana. When light is thrown directly through them they look blue-green, but when it merely falls upon them, as does in ponds, they make the water appear red or purplish (early reports of Skinequit Pond this year were of a red-brown color)."

Enhanced photo of Skinequit Pond courtesy Goopgle.

Harwich Natural Resources Report

NRO Report 6

17 September 1998

Skinequit Pond 10:00 am

Sunny, dry

Tom Leach and Heinz Proft

This field visit was to understand the nature of the reported ruptured dike at the north end of the pond. This is a man made dam separating the pond from an abandoned cranberry bog sytem which lies between Rte 28 and the shore of the pond. We waded to the site along the northern shore starting from the Campbell property and easily found the ditch reported by Malcolm Campbell which enters the pond draining this fallow bog. A blank has been placed in the ditch to hold back water. It would appear that the stream contributes to the pond, however, it seems hard to believe that the flow is signicant enough to contribute to superheating the pond as was suggested at the public meeting. Neighbors report that they feel the pond level had been dropping. It is indeterminant whether this is due to the stream being dammed or from evaporation and/or exit stream flow.

The shells of expired (caused by the absence of DO) Little Pond Snails Amnicola limnosa drifted to the the surface as we waded along the pond shore

The fallow bog is over grown with pine, red cedar and swamp maple and the shade from the over story is contributing to cooling of the bog stream(s). One source of water to the old bog is reported via storm drains on the Coombs property on Route 28. During this visit, eviscerated clam meats were seen floating and the intensely homogenous green algae color of this algae bloom has continued for nearly a month as the die-off rate lags behind bloom. Disturbance of the nearshore bottom, simply by wading, kicked up hundreds of decomposing or dying freshwater snails.

Deep green penetrating color of the water near the Burton Family dock in the northeast corner of the Skinnequit pond shows water column full of anabaena a chained cell blue-green algae. Connie Burton photo.

Harwich Natural Resources Report

NRO Report 5

15 September 1998

Skinequit Pond – 10:00 am

Sunny, dry

Tom Leach

Microscopy conducted by the Barnstable County Laboratory has confirmed the identity of algae causing the pea green colored water at Skinnequit Pond in South Harwich. According to report yesterday on a sample taken 9/15/98 and preserved with Lugols solution, most of the algae was a type called anabaena with some pollen particulate present. However this concentration is considered light compared with other examples as seen at the Harwich Reservoir last September. When it is present in large quantities, it has been known to take enough oxygen from the water to cause a fish kill. Neighbors along the pond have reported seeing signs of expired freshwater mussels and hornpout since mid August. It needs to be stated, e.coliform bacteria samples taken early on by the HNRD and Health Department show levels for swimming well within the safe limits.

Water sample 9/16/98 from the pond was centrifuged to concentrate algae material. Anabaena is an example of a cyanobacterium. Note that the magnification of this image is 1000X, Purdue University photo.

Harwich Natural Resources Report

NRO Report 4

17 August 1998

Skinequit Pond – 1200 noon

Hazy day

Tom Leach and Sally Bradford

Tom Leach met Sally Bradford at her home on the west side of Skinequit Pond for a planned sampling data gathering mission to gather baseline data. Water samples were taken near shore and in the middle of the pond at a depth of 20" using canoe. Also the spring fed area of the mid pond was rediscovered and temperature readings at depth 20+ feet showed water temperature dropping to below 15 oC while in the upper column remain above 25 oC.

Skinnequit Pond (8/17/98)
Station	Depth	Water Temp.	Dissolved Oxygen	Coliform	Conductivity	Iron	Nitrate	Phosphate
Dock 92 Uncle Venies Rd.	20"	27.1 oC	9.55 ppm	<4/100ml	186	0.54	0.4 ppm	<0.05 ppm
Mid Pond(from canoe)	20"	26.8 oC	9.66 ppm	24/100ml	175	0.48	0.4 ppm	<0.05 ppm

Harwich Natural Resources Report

NRO Report 3

06 August 1998

Skinequit Pond – 1200 noon

Sunny, dry day

Heinz Proft and Jeff Ebel

On this day, 6 August 1998 several dead freshwater clams and dead tadpoles were washed ashore at Skinnequit Pond. The water at Skinequit has a "green pea soup" appearance to it. An algae bloom. Paddocks Pond had good visibility, many jumping frogs near the edge of the pond and no evidence of poor oxygen or dead clams. Herring Reservoir near Bells neck road had poor visibility and some dead clams washed ashore. Elbow pond had good visibility, relatively high oxygen and the pond looked good, no evidence of anything dying. Both Seymour and Hinckleys pond had good visibility and only Hinckleys had a few dead clams, but nothing severe.

Several water quality readings were taken at several ponds in the Harwich area in order to make comparisons to the Skinnequit data.

Skinnequit Pond (8/6/98)
Station	Depth	Water Temp.	Dissolved Oxygen
End of Dock	6 inches	27.8 oC	98 %	7.65 mg/l
End of Dock	2 feet	26.9 oC	67.5 %	4.8 mg/l
Middle of Pond	6 inches	27.0 oC	100.2 %	7.95 mg/l
Middle of Pond	5 feet	23.5 oC	34 %	3.05 mg/l
Middle of Pond	15 feet	11.7 oC	2.5 %	0.25 mg/l
Skinnequit Outlet	6 inches	27.0 oC	100.1 %	8.0 mg/l
(Southwest corner)	5 feet	25.1 oC	7.0 %	0.4 mg/l
Paddocks Pond (8/6/98)
Station	Depth	Water Temp.	Dissolved Oxygen
Access path to edge of pond	6 inches	26.8 oC	51 %	4.17mg/l
Herring Reservoir (8/6/98)
Station	Depth	Water Temp.	Dissolved Oxygen
East side (Bells Neck)	6 inches	29.7 oC	78 %	5.7 mg/l
Elbow Pond (8/6/98)
Station	Depth	Water Temp.	Dissolved Oxygen
West side access	6 inches	26.9 oC	58 %	4.5 mg/l
West side access	5 feet	23.0 oC	26 %	2.2 mg/l
Middle of Pond	15 feet	13.2 oC	3.5 %	0.44 mg/l
Seymour Pond (canal) (8/6/98)
Station	Depth	Water Temp.	Dissolved Oxygen
Herring run outlet	6 inches	27.0 oC	71 %	5.6 mg/l
Hinckleys Pond (8/6/98)
Station	Depth	Water Temp.	Dissolved Oxygen
Princess Raceway	6 inches	29.5 oC	65 %	4.95 mg/l
Seymour Pond (8/6/98)
Station	Depth	Water Temp.	Dissolved Oxygen
Seymour pond beach	5 feet	27.5 oC	71 %	5.5 mg/l
Seymour pond off	15feet	24.4 oC	2.5 %	0.20 mg/l

Harwich Natural Resources Report

NRO Report 2

04August 1998

Skinequit Pond – 10:00 am

Sunny, dry day

Heinz Proft and Mark Stines

Responded to a second call at Skinequit Pond. We returned to the same dock belonging to Connie Burton. The same clams were found to be agape having already expelled their visceral mass.(20-30) large tadpoles were also found dead washed up along the shore. Water quality samples were taken and recorded just as they had been the previous week.

Skinnequit Pond (8/4/98)

Station Depth Water Temp. Dissolved Oxygen

End of Dock 6 inches 25.8 oC 85 % 6.9 mg/l

End of Dock 2 feet 25.6 oC 74 % 6.1 mg/l

Middle of Pond 6 inches 25.8 oC 86 % 7.0 mg/l

Middle of Pond 5 feet 19.7 oC 8.0 % 0.50 mg/l

Middle of Pond 15 feet 12.9 oC 1.8 % 0.22 mg/l/td>

Skinequit Outlet(Southwest corner) 6 inches 25.9 oC 86 % 6.9 mg/l

Skinnequit Pond (8/4/98)
Station	Depth	Water Temp.	Dissolved Oxygen
End of Dock	6 inches	25.8 oC	85 %	6.9 mg/l
End of Dock	2 feet	25.6 oC	74 %	6.1 mg/l
Middle of Pond	6 inches	25.8 oC	86 %	7.0 mg/l
Middle of Pond	5 feet	19.7 oC	8.0 %	0.50 mg/l
Middle of Pond	15 feet	12.9 oC	1.8 %	0.22 mg/l/td>
Skinequit Outlet(Southwest corner)	6 inches	25.9 oC	86 %	6.9 mg/l

Conditions of poor vertical mixing and lack of oxygen were present once again. In the North East corner of the pond over 500 clams and tadpoles were dead and washed against the shore by prevailing winds. The biological stress of low oxygen placed on the fresh water clams and tadpoles at this time may be too great to overcome causing such a large/unusual die off. Two water samples were taken and looked at under a microscope, but the samples were mostly clear not much present. Water was however analyzed for Nitrate density and Carbon dioxide.

Sample 1 (Dock) Nitrate .05 mg/l and Carbon dioxide 103.6 mg/l

Sample 2 (SW corner) Nitrate .06mg/l and Carbon dioxide of 77.2 mg/l

** Note: Nitrate and Carbon dioxide were done 24hrs after samples were obtained and that should be taken into account.

Harwich Natural Resources Report

NRO Report 1

29 July 1998

Skinequit Pond – 3:30pm

Sunny, dry day with high humidity

Tom Leach and Heinz Proft

Responded to a call by Connie Burton who described fresh water clams washing ashore at Skinequit Pond. The clams were found to be agape having already expelled their visceral mass. Several "clam meats" were bobbing at the surface near the shore. A photograph and several water quality samples were taken and recorded.

Skinequit Pond (7/29/98)

Station Depth Water Temp. Dissolved Oxygen

On Shore 6 inches 28.5 oC 103 % 7.8 mg/l

End of Dock 6 inches 26.9 oC 99 % 8.2 mg/l

End of Dock 2 feet 26.2 oC 88 % 6.3 mg/l

End of Dock 3 feet 26.1 oC 81 % 6.6 mg/l

Middle of Pond 6 inches 26.0 oC 100 % 8.6 mg/l

Middle of Pond 5 feet 17.8 oC 15 % 0.80 mg/l

Middle of Pond 12 feet 11.0 oC 1.8 % 0.20 mg/l

Middle of Pond 15 feet 10.8 oC 1.2 % 0.10 mg/l

Skinequit Outlet (Southwest corner) 6 inches 26.1 oC 112 % 9.1 mg/l

Skinequit Pond (7/29/98)
Station	Depth	Water Temp.	Dissolved Oxygen
On Shore	6 inches	28.5 oC	103 %	7.8 mg/l
End of Dock	6 inches	26.9 oC	99 %	8.2 mg/l
End of Dock	2 feet	26.2 oC	88 %	6.3 mg/l
End of Dock	3 feet	26.1 oC	81 %	6.6 mg/l
Middle of Pond	6 inches	26.0 oC	100 %	8.6 mg/l
Middle of Pond	5 feet	17.8 oC	15 %	0.80 mg/l
Middle of Pond	12 feet	11.0 oC	1.8 %	0.20 mg/l
Middle of Pond	15 feet	10.8 oC	1.2 %	0.10 mg/l
Skinequit Outlet (Southwest corner)	6 inches	26.1 oC	112 %	9.1 mg/l

Several indications of poor vertical mixing were present. Temperature readings suggested a sharp thermocline in the pond. Poor vertical mixing was also supported by very low dissolved oxygen readings found beneath the surface. Although stratified water columns are not unsual for summer ponds in New England, the severity of the readings obtained may be connected to the eviscerated clams identified along the shore. Higher than normal densities of algae may also be a contributing factor to this situation. The biological stresses placed on the fresh water clams at this time may be too great for the clams to overcome. Because these are the first readings taken at these locations, further monitoring of this situation is warranted.

RECOVERY PLAN The Harwich Natural Resources Department is preparing a plan to recover the degradation of Skinequit Pond. This project has overwhelming support of the neighborhood association lead by Sally Bradford and Connie Burton. Based on research by Tom Leach and Heinz Proft it is hoped the following steps offer improvement in the overall health of the pond. Further we will be seeking grant to help fund different facets of the project.

STEPS

Aerator pump driving air stones strategically placed in pond bottom. This will create current turning pond over and increase dissolved oxygen for marine life in the pond.

Suspend barley hay "sausages" in rows along the shoreline of the pond.

Bird dropping exascerbate the nitrogen budget of the pond. Generate a plan to herd/harrass waterfowl off the pond.

Place Fukui bio-cord racks on the shallow bottom of the pond (this would need grant support).

Get entire neighborhood and secondary neighborhood to use phosphate free dishwasher detergent. (commercial dishwasher detergent unlike laundry detergent is not phosphate free. This means contribution of almost 50 lbs of phosphate per two person family per annum. A low phosphate dishwasher detergent is available at Stop & Shop. This will mean pre-rinsing dishes. Connie Burton has gotten information from one such detergent company called Seventh Generation@.

Challenge neighborhood to reduce lawn fertilizing activity, turn to indigenous plants and remove lawn clippings, leaves etc. to compost pile at Town Dump.

Block up the cranberry dike on the north side of pond.

Prepare and follow through a water monitoring plan to determine the success of these measures.

Full details and background information on the steps and there alternatives will be prepared into a report and posted hear at this website as soon as possible. This is being done in preparation for a grant application to fund some of the pieces as bio-cord and aerator(s). Since Harwich is applying under the "1999 Pond Improvement Grant" for road runnoff mitigation at Lond Pond. We will be seeking alternative grant sources rather than the Town competing against itself on the same grant site.

If you have other ideas along lines of improvement that we have not thought of or any questions about anything in this report please contact us at tleach@town.harwich.ma.us

Biological Basic Definitions

Aerobic Biostimulation - is the process in which aerobic bacteria are stimulated by a circulation process that provides oxygen throughout their environment. This circulation process delivers the bacteria and oxygen to the food source, also exposing the complete system to sunlight when they are drawn to the surface. This positive circulation is constantly mixing the system to maintain an "Aerobic Nutrient Recycling Pond". Aerobic bacteria work very efficiently at the normal temperatures found in a pond, (liquid temperatures of approximately^o Fahrenheit). Aerobic bacteria work 4 to 6 times faster than anaerobic bacteria at liquid temperatures of 50^o Fahrenheit. Anaerobic bacteria work best at liquid temperatures of 100 ^o Fahrenheit.

Biodegradation - is the process in which naturally occurring bacteria convert or degrade natural and manmade organic compounds.

Bioremediation - is the use of naturally occurring microorganisms (bacteria) to destroy potentially hazardous contaminants, transforming them to less harmful forms.

Microorganisms - degrade organic compounds to obtain energy. The organics are converted to simpler organic compounds and ultimately, in the aerobic process to carbon dioxide and water. The microbes will also use part of the compounds as building blocks for new microbial cell.

Wastewater Definitions

Aerobic Bacteria - need oxygen to live. Aerobic bacteria can breakdown organic material at a much faster rate than their anaerobic counterparts. The by-products of their metabolism include carbon dioxide and water.

Anaerobic Bacteria- do not require oxygen to live. The by-products of their metabolism include ammonia, and hydrogen sulfide.

BOD₅ (Biochemical Oxygen Demand) - measures the amount of oxygen used over a five-day period by the microorganisms (bacteria) as they decompose the organic matter at a liquid temperature of 20 ^oC - (68^o F).

Facultative Lagoon - a lagoon with aerobic activity occurring near the surface, and anaerobic activity prevailing in the bottom region where conditions are in a septic condition.

Eutrophication - The process in which pollutants cause a body of water to become over- rich in organic and mineral nutrients so algae grow rapidly and deplete the oxygen supply. Unfortunately, this condition will adversely affect fish populations and other aquatic life.

The purpose of the bottom aeration stones driven by air pumps is to accomplish Aerobic Biostimulation within a "Nutrient Recycling Pond".

Physical and Chemical Properties of Pond Water

Many of the physical and chemical properties of water must be considered in its management. Some of these properties are temperature, pH, hardness, dissolved oxygen, source of the water in the pond, uses made of the water, and where it goes if it flows from the pond.

Temperature

Water temperature as it affects the spawning of fish is discussed in a later section (see page 12) as is the effect of temperature on the survival of trout (see page 11). Water temperature also must be considered when using chemicals in the management of a pond. As is mentioned in other sections of this bulletin, some fish toxicants and herbicides are more effective when the water temperature is above 60 degrees F in the top two feet. Some herbicide labels discourage application when water temperatures exceed 75 degrees F because there is an increased risk of oxygen depletion due to decomposition of dead vegetation, and a fish kill could result.

Finally, copper compounds used as algaecides may be safe for fish at recommended rates but may kill fish eggs or fry (newly hatched fish). Thus, temperature provides a clue as to when fish are spawning and may influence the timing of algaecide applications. Water temperature should be measured at a depth of one foot.

Dissolved Oxygen

The amount of dissolved oxygen (DO) in water is measured in parts per million (ppm) and is inversely related to water temperature. The chart presented here shows the decrease in dissolved oxygen as water temperature increases.

Pond water is not pure, nor are the Ohio ponds at sea level, so the amount of DO will be slightly different. Pond fish require about 4 ppm of DO, and other organisms in your pond, both plants and animals, also require dissolved oxygen.

When the dissolved oxygen level in the upper 4 feet of the pond drops to or below 4 ppm, fish and other organisms will start to show stress. Fish will come to the surface and appear to gulp air, and snails, crayfish, and other organisms may actually climb out on the bank or up on emergent objects.

Oxygen depletion can be caused by a number of factors, including the decomposition of aquatic plants that have died of natural causes, large decomposing masses of aquatic plants killed with a herbicide, run-off waters rich in nutrients and organic matter such as that from a livestock feedlot or a poorly maintained septic system, or from pond turnover.

Amount of Dissolved Oxygen (ppm) in Pure Water at Different Water Temperatures (at sea level)
Temperature (F)	Approximate PPM
35	13.4
40	12.7
45	11.8
50	10.9
55	10.2
60	9.7
65	9.2
70	8.7
75	8.3
80	7.9

Other Properties

Other pond water properties are also important, though less so than temperature and dissolved oxygen. Usually Ohio ponds have a pH (hydrogen ion concentration) from 7 (neutral) to 9.5 (alkaline). Most freshwater fish are able to survive and reproduce when the pH is between 5 and 10. Most Ohio ponds range from 75 to 200 parts per million in total alkalinity (hardness). The hardness of water may influence the effectiveness of some herbicides and is discussed on page 20 of this bulletin.

Finally, management of the watershed that contributes run-off water to a pond is important. Land uses that leave the soil surface unprotected may contribute large amounts of sediment. Some chemicals applied to crops in the watershed, especially insecticides, may be detrimental to the fish and other organisms in the pond as well as to water quality.

Fertility

Microscopic plants and animals, called plankton, are basic fish foods. The production of plankton is directly related to the fertility of the water. Plankton are eaten by small fish and other animal organisms such as aquatic insects and their larvae, which in turn are eaten by larger fish. If any link in this food web is weak or missing, an unbalanced condition will result and fish production will suffer. The density of the plankton population also determines the depth to which light will penetrate the water. This affects the growth of undesirable plants (weeds), which is discussed later.

The principal source of water for most Ohio ponds is run-off from the pond's watershed. This run-off carries fertile matter from soils into the pond. As a result, the fertility of the soils in the watershed determines fertility of the pond water and the density of the plankton population. Most Ohio ponds do not need additional fertilizer. An exception may be ponds where most of the watershed is forested. Also, where springs or water pumped into the pond from a ditch, a tile drain, or a well provides the principal source of water, low fertility may be a problem.

Determining Fertility

The "dipstick" method can be used to measure the fertility of a pond. You can make a dipstick by nailing a shiny can lid to the end of a stick at least three-feet long and marking one inch graduations on the stick. Immerse the dipstick vertically in the water until the image of the can lid begins to blur. You are actually measuring the depth of light penetration. A plankton population that permits light to penetrate 15 to 18 inches deep is an indicator of good fertility.

Should I Fertilize My Pond?

Pond fertilization is a common practice in the South and among people who raise fish commercially. However, due to the good fertility of most Ohio soils, ponds used for recreational fishing usually do not need to be fertilized. Owners prefer to improve the fertility of the watershed and let nutrients be carried into the pond with run-off water.

If you determine that your pond needs additional fertility and are willing to make the commitment a fertilization program requires, here's how to proceed.

Starting in late March or early April, apply 80 to 100 pounds of fertilizer per surface acre of water. Inorganic fertilizers balanced for the three main components (N-P-K) such as 10-10-10 or 12-12-12 are suitable. Avoid fertilizers that contain lime, gypsum, or tobacco dusts as "inert" ingredients, and supplemental ingredients such as herbicides or insecticides. The first application should produce a plankton "bloom" that is green or brown. Check depth of light penetration. If no bloom results, repeat the application in 10 days. Once you have achieved the desired level of fertility, make additional fertilizer applications as determined to be necessary by the dipstick test. Your pond may require fertilizer applications as often as every two to four weeks. Continue your program until mid-August. Do not apply fertilizer after August 15.

Over-fertility is possible. It can result from too much fertilizer or from the natural introduction of high-fertility materials such as barnyard run-off, silo drainage, or septic system effluents. Excessive fertility may exist if light penetration is less than 12 inches and can contribute to fish kills. Fertilize only when needed, do not over-fertilize, and do not start a fertilization program unless you plan to continue it. Improperly done fertilization may actually increase undesirable weed growth and contribute to other problems.

Should I Aerate My Pond?

Pond owners are frequently interested in providing artificial aeration in their ponds. The benefits of artificial aeration are:

Increase in the amount of dissolved oxygen available to aerobic bacteria for decomposition of organic matter, such as dead aquatic vegetation and algae.
Circulation of the pond water. This can eliminate the layering (stratification) that develops between the bottom oxygen-poor water and the top layer of oxygenated water. Good water circulation can create an isothermal (equal water temperature throughout) condition in the pond.
Prevention of complete freezing of the pond surface. By circulating water and creating surface turbulence, complete freeze-over can be prevented. Open water allows for gas exchange between the pond and the atmosphere, permits sunlight to penetrate so that photosynthesis and oxygen production can occur, and provides some open water for waterfowl in the winter.
Creation of an aesthetic benefit with water spraying into the air from a fountain head.

Natural Sources of Dissolved Oxygen

The two most significant sources of dissolved oxygen are the atmosphere and photosynthesis. The diffusion of oxygen from the atmosphere is slow, except under conditions of strong turbulence. Transfer of oxygen from the atmosphere into natural waters will occur when the water is undersaturated with oxygen. If the surface film of water is saturated with oxygen there will be no further diffusion until oxygen diffuses from the surface film into the overall body of water. Therefore, oxygen transfer is dependent on the amount of water turbulence at the surface.

The most important source of oxygen is that produced by aquatic plants during the process of photosynthesis. Some factors that control the rate of photosynthesis include temperature, light, nutrient concentration, species of plants, abundance of plants, and water turbulence. Light penetration, to a large extent, is regulated by turbidity, and in many ponds the major source of turbidity is plankton. Therefore, the abundance of plankton is a primary factor affecting light penetration and the production of oxygen. Oxygen production by plankton is greatest near the surface and decreases with water depth because of self-shading. Ponds with high densities of plankton have higher rates of oxygen production near the surface, but ponds with lower densities of plankton have oxygen production occurring at greater depths. Therefore, ponds with low levels of plankton have more stable oxygen regimes, but are less productive because plankton is the base of the food chain in ponds.

Types of Aerators

Subsurface Aerators

Also known as diffusers, subsurface aerators consist of an onshore compressor that pumps air through a hose placed in the deepest part of the pond. This creates a column of air bubbles that are released at the bottom of the pond. As the column of bubbles rises to the surface, it moves water from the bottom of the pond to the surface where it is exposed to atmospheric oxygen which then dissolves into the water. The mixing of water moves oxygenated water to the bottom of the pond where it is used by aerobic bacteria to decompose dead organic material such as vegetation. The bubbles impart very little dissolved oxygen into the water. The primary benefit is the mixing effect.

Surface Aerators

Agitators such as paddlewheel devices and fountain sprayers can be used to create substantial turbulence which results in atmospheric oxygen dissolving into the pond. Fountains consist of a float, nozzle or sprayer head, and a pump that draws water from the pond and sprays it into the air. They are usually powered by an electric pump, or less commonly, by a windmill device. If the water is drawn from the bottom oxygen-poor layer of the pond, fountains can also reduce the layering that develops between oxygenated and unoxygenated water. Surface turbulence can also be created by paddlewheel devices powered by an electric motor or a power takeoff (PTO) from a tractor, or by churning the water surface with an outboard motor propeller. The process of mixing:

Provides oxygen for aerobic bacteria to decompose organic matter.
Provides well-oxygenated water throughout the pond so that the pond is less likely to experience a fish-kill.
Liberates dissolved gases, such as ammonia, carbon dioxide, hydrogen sulfide, and methane, into the environment instead of having them build to harmful levels in the pond.

Locating and Sizing an Aerator

In order to get the maximum benefit from an aerator, it should be properly located and sized. Recommendations for these specifications are based on practical experience. Research-based findings vary due to the wide range of conditions under which aerators have been used. In one study, three sizes (1/3, 3, and 5 horsepower) of electrical, spray-type surface aerators were used, and each failed to appreciably raise the dissolved oxygen concentration in the 1.4-acre study ponds within four hours. But a 1/3-horsepower aerator in a 1/10-acre pond quickly raised the DO concentration and prevented a fish kill. A rule of thumb suggested by one manufacturer is 1.5-2 horsepower per surface acre. In situations where water quality is especially poor, a minimum of 2 horsepower per acre should be provided.

Considerations in sizing and locating aerators include:

Depth of pond. The shallower the pond, the warmer the water, and the greater the potential for low dissolved oxygen.
Water temperature. The warmer the water, the lower the concentration of dissolved oxygen. Algae growth is greater, as is the oxygen demand by bacteria for decomposition of dead algae.
Age of pond. The older the pond, the more likely it is to contain large quantities of sediment, organic matter, and nutrients. The organic material is decomposed more rapidly by aerobic bacteria (bacteria that is only active in the presence of oxygen) than by anaerobic bacteria (bacteria that lives in the absence of oxygen).

Aerators and Vegetation Control

Pond aeration has been promoted as a method of aquatic vegetation control. To date, the benefits supposedly derived by aeration for controlling aquatic weeds or algae have not been fully demonstrated. Artificial aeration may be helpful in reducing algal blooms in ponds and lakes plagued by blue-green algae problems. Also, there may be some indirect benefit of aeration if nutrient-rich water in the bottom of a pond is moved to the upper layer where it serves to increase the density of the phytoplankton which in turn increases the shading of the water which can then reduce the growth of aquatic vegetation. Research has shown that a well-oxygenated layer of water at the pond bottom can keep the mud oxidized. This can keep phosphorus in an insoluble form which is unavailable for plants. The practicality of doing this in small impoundments remains undetermined.