2002 to 2006


Water Samples Collected And Interpretation of Results

Other Studies Conducted During This Period

Runoff and Salt Components

Re-examination of 2 Baseline Studies from the 1970s

Other observations (algae and pond weed)

E-coli results from several years

Water Samples Collected by Six Ponds Volunteers

From 2002 through 2006, the Six Ponds organization collected water samples more often each year and from more locations in each pond than it had in earlier years, and this amount of data was sufficient to identify some consistencies and some trends. 


During this period, chemical analysis of water samples and multiparameter water quality testing equipment connected to a computer were used to provide data for 19 of the variables that were measured in 2001. From 2002 through 2006 data was collected for these same 19 variables. 

The equipment used to augment the data obtained from water samples was a state-of-the-art EXO Sonde manufactured by YSI Incorporated having multiple water testing sensors. This equipment was being used primarily in a grant supported multi-year study of the water column in Long Pond.

It should be noted that the data file stored on this website looks slightly different than the corresponding one stored on the Town website since a couple of the identification fields were recoded to make some later analyses possible. 

Analyses of this water sample data focused on identifying factors or combinations of factors which differentiated the condition of our 6 ponds from one another. 

One clear trend was that eutrophic levels of phosphorus were found in Halfway Pond and Little Long Pond far more often than they were found in the other four ponds in the Six Ponds area. The data also revealed that nitrates were detected in Little Long Pond more often than in any other pond. 

In three different studies, Halfway Pond stood out as having high levels of Phosphorus (see the section on Other Studies below) 

Analysis of data from this period also revealed some important things regarding road runoff and salt components (see the section below dealing with this).

A general observation

An important point to emphasize regarding the more intensive sampling regimen pursued from 2002 to 2006 is that it is impossible to see patterns and trends in data without gathering data for a sufficient number of variables and without gathering this data a sufficient number of times. Looking at water sample results for a single year in isolation from data from other years doesn't reveal much.

Also, in order to understand the condition of our water resources, it is necessary to compare and contrast both the condition of water bodies and the characteristics of the locations.

_____________________________________________________________

Other Studies Conducted during this period


The summer-long study of Halfway Pond in 2003 focused on water that flowed from the cranberry bogs around the pond. Phosphorus readings in the water flowing from the bogs ranged from 3 to 4 times to more than 10 times the critical eutrophic level of .03.

The Town of Plymouth testing in 2002 and 2003 included all six of our ponds. Halfway Pond and Little Long Pond were the only ponds in this study where all of the Phosphorus readings were above the critical level. The study indicated that both of these ponds were in trouble.

Halfway Pond was the only one of our Six Ponds included in the 2002 Pond Watchers study, and all of the Phosphorus readings for Halfway Pond were above the critical level of .03. This again indicated that this pond was in trouble.
____________________________________________________________

Runoff and Salt components



It was during this period that analyses revealed that salt components (ions) were more prevalent in Bloody Pond, Little Long Pond and Long Pond (decreasing in that order) than in our other 3 ponds. The levels observed seemed alarming at the time, but it will be seen later that these levels were much lower than those measured in 2020.

__________________________________________________________


Re-examination of Two Baseline Studies from the 1970s


In 2005, the earlier studies of Halfway Pond and Little Long Pond from the 1970s were reexamined in light of the fact that there had been serious recurring algae and pond weed problems in Halfway Pond and Little Long Pond during this period.

Halfway Pond water samples collected from 2002 through 2006 showed that Phosphorus levels were often well above the eutrophic level and that Phosphorus was a bigger problem than it was in 1979, and Phosphorus levels in readings taken near outlets from the cranberry bogs were especially high. The results for Nitrates in 2002 through 2006 were somewhat mixed, but the overall the levels seemed to be lower than they were in 1979 even though readings taken at outlets from the cranberry bogs showed highly eutrophic levels of Nitrate and Kjeidahl Nitrogen (KTN). 

It must also be noted that, aside from a fact that a couple of the very few homes on Halfway Pond were upgraded to Title V septic systems during this period, virtually none of the mitigation and remediation recommendations made in the 1979 report have ever been implemented.

Little Long Pond water samples collected from 2002 through 2006 showed that Phosphorus levels were generally higher than in 1979 and were often well above the eutrophic level. Likewise, Nitrate levels were higher than in 1979 and were generally well above the eutrophic level. The condition of the pond was serious in 1979, and the condition was worse 20-plus years later. 

A number of homes were built around Little Long Pond a few years prior to 1979, some of the existing older homes were sold around this time, a number of additional homes were built over the next 15 years, and some of the older and newer homes were resold during this period. In any case, all of this activity occurred prior to enactment of Title V legislation in 1995 which required more advanced septic systems for new homes and for existing homes that were sold. In other words, a substantial number of homes had cesspools and many of these were quite old. It should be no surprise that phosphorus and nitrate levels were higher by the early 2000s. It must also be mentioned that there is no indication that any of the remediation recommendations in the 1979 report on this pond have ever been implemented.

In both of these studies from 1979, the authors concluded that algae and pond weed problems in these ponds were likely to get worse unless measures were taken to mitigate a wide range of problems. Little to nothing has been done by residents, the town or the state in the intervening years to improve matters, and, as expected, there have been years when pond conditions were bad. It is not surprising that conditions got worse. 
________________________________________________________________

Other observations (algae and pond weed)


In 2002, algae and pond weed problems were particularly bad in both Halfway Pond and Little Long Pond. The situation observed in Halfway Pond is described in the above link.

However, it should be apparent from the discussion of these 2 ponds in the previous section that the reasons for these problems are very different from one another and that the solutions must also be very different.

__________________________________________________________


E-Coli Testing results

E-Coli results highlighted in 2002

Other E-Coli result from 1999 - 2003

The e-coli readings obtained from 1999, 2000 and 2001 were quite good. However, there were readings in 2002 and 2003 that were terribly dangerous. Most of these were recorded in road runoff, and all of them were obtained near a stream that runs adjacent to a swimming beach.

_____________________________________________________________


YSI Study

Ed, can you write up something about Terry's research?