Regular Water Sampling
Since 2008, we have collected water samples from Great and Little Herring Pond several times a year. When we started out, we were trained by Environmental Management (Kim Michaelis) of the Town of Plymouth. We collected water samples from several sites on Great Herring Pond, all about 50 ft from shore at storm drain discharge Locations.The following year, we added sites on Little Herring Pond and Carter's River. Samples were collected when there had been no rain for at least two days. They were immediately delivered to Envirotech Laboratory in Sandwich for analysis. The laboratory tested for parameters typically used to analyze drinking water, as can be seen from the data (side bar). Sample locations are marked on the two maps available on the water sampling map page.
Our sampling has evolved since. Details of our procedures can be found in our quality assurance project plan (QAPP). Our water sampling is supported at this time by a grant from Massachusetts Environmental Trust and by the Town of Plymouth as well as our association members.
At present we collect water samples at 9 locations on Great and Little Herring Pond, and on Carter’s and Herring Rivers as marked on the two maps. Two of these locations are away from shore at the deepest points of Great Herring Pond, where samples are drawn from near the pond bottom as well as from the surface. The other locations sample only surface water. They are identical to the earlier locations. In addition, there are sites in the middle of Little Herring Pond and the streams connecting the two ponds, and at the outlet of Great Herring Pond.
During each sampling event, we also collect a duplicate sample, as required by EPA procedures.
The laboratory analysis has also changed. At present, the laboratory analyzes for e-coli, total phosphorus, nitrates, nitrites, Kjeldahl (organic) nitrogen and total nitrogen, pH, electrical conductance, total suspended solids.
Results
Some early results can be summarized as follows: e. coli counts are generally very low – we do not see any problems from septic systems, bird or other animal pollution. Nutrients (phosphorous) are low in winter, increase dramatically in Spring to very worrisome levels, cause serious algae blooms in summer and early fall, which are obvious from the reduction of water transparency, and then begin to decrease. The cause of the spring peak is of great interest, it may be, at least partially, due to human activities. It is, after all, the time when fertilizer is spread, but this is purely speculative. Nitrogen is fairly low. pH is neutral to slightly acidic.
Our sampling has evolved since. Details of our procedures can be found in our quality assurance project plan (QAPP). Our water sampling is supported at this time by a grant from Massachusetts Environmental Trust and by the Town of Plymouth as well as our association members.
At present we collect water samples at 9 locations on Great and Little Herring Pond, and on Carter’s and Herring Rivers as marked on the two maps. Two of these locations are away from shore at the deepest points of Great Herring Pond, where samples are drawn from near the pond bottom as well as from the surface. The other locations sample only surface water. They are identical to the earlier locations. In addition, there are sites in the middle of Little Herring Pond and the streams connecting the two ponds, and at the outlet of Great Herring Pond.
During each sampling event, we also collect a duplicate sample, as required by EPA procedures.
The laboratory analysis has also changed. At present, the laboratory analyzes for e-coli, total phosphorus, nitrates, nitrites, Kjeldahl (organic) nitrogen and total nitrogen, pH, electrical conductance, total suspended solids.
Results
Some early results can be summarized as follows: e. coli counts are generally very low – we do not see any problems from septic systems, bird or other animal pollution. Nutrients (phosphorous) are low in winter, increase dramatically in Spring to very worrisome levels, cause serious algae blooms in summer and early fall, which are obvious from the reduction of water transparency, and then begin to decrease. The cause of the spring peak is of great interest, it may be, at least partially, due to human activities. It is, after all, the time when fertilizer is spread, but this is purely speculative. Nitrogen is fairly low. pH is neutral to slightly acidic.
Data Files
Chemistry November '11
Chemistry September '11
Chemistry 10.12.10
Great Herring Pond
Little Herring Pond/Carters River
Chemistry September '10
Great Herring Pond
Little Herring Pond/Carters River
Chemistry 7.23.10
Great Herring Pond
Little Herring Pond/Carters River
Chemistry 8.01.09
Chemistry 6.18.09
Chemistry 5.04.09
Chemistry 9.09.08
Chemistry 7.23.08
Chemistry 6.11.08
Staff Guage to measure water flow
