2009 AUGUST WATER TESTING SUMMARY

The testing of the streams for August was completed on Wednesday, August 12th. The testing of the lake was completed on Friday, August 14th.
We experienced an equipment issues with the In-Situ Troll 9500 MP this month. A valid but marginal calibration result on the RDO dissolved oxygen sensor is being worked with the manufacturers support team. Indications are that the sensor is calibrating correctly and the test results are accurate, but the reader has a software issue in converting and displaying the calibration data. In-Situ has committed to provide a software update for the hand held unit to correct this issue.
A second issue began showing up last month when the Conductivity sensor calibration returned marginal calibration parameters. This month, a new bottle of calibration solution was used and the sensor failed calibration. The cleaning procedure requested by In-Situ support also did not correct the problem. As a result, the Conductivity readings for this month are slightly lower than the correct reading. In-Situ estimates the results will be with 5% of their true value. In-Situ is sending a replacement sensor which will arrive next week. A test of the calibration solution will be done to validate the results.
This month showed some significantly different test results then have ever be observed. Clearly the unusual weather pattern we have experience this spring and summer is a major factor. Many people have raised issues of sightings of very unusual matter and objects in the water. Many of these observations seem to be related to elevated levels of algae that have existed in the lake for much of the summer.
Streams Testing
The streams testing on Wednesday showed that all streams and major runoff area continue to flow. In past years one or more of the streams would be dry at this point and the wet weather runoff flows would also be dried up. That has not been the case this year and the streams are still showing moderate flow rate levels.
Turbidity and Nitrate levels tested higher in the streams than has normally been seen. This is most likely due to the run off flushing more matter into the streams. The higher Nitrate levels are likely caused by the prolonged algae growth this season. A lot of extra sediment is being observed from algae in all stages of it life cycle resulting in reported odors and green and brown sediment that is decomposing. Most other readings in the streams reflect the norms for the season. Water temps are slightly lower this year again related to the cooler summer and higher flow rates.
An unusual condition was observed at testing location at LKQ20. The surface of the water contained a brown foam type matter most likely the result of algae but observer comments ranged from oil foam, sewage, and algae. LKQ was asked by the town to have it tested to verify what it is.
Lake Testing
During the last few weeks, many reports of sightings were raised from around the lake. Sightings included:
1. Large white colored melon sized round objects that were hard, had a leathery looking surface with a lot of raised bumps on the surface.
2. Green balls which appear to be from the very hard rain and high winds knocking the nearly ripe heads off the lily pad stems.
3. Flakes in the water of various colors from grey, to green, and brown, and brown foam. These most likely are from the high levels of algae in the water.
The results for the July Chlorophyll-a samples tested by Microbac labs that come back a few weeks after the sample is taken, showed the Chlorophyll-a level in the water in mid July was nearly 3 mg/liter vs. the June results of .06 mg/liter. These significantly elevated levels of Chlorophyll-a, indicates high levels of algae in the water. The currently available results for August, also indicates that unlike prior years where an algae bloom was observed, lasting for 1-2 weeks and was gone. This year, the data suggests that the algae bloom formed in the early July timeframe and has lasted for the 6 week period through the tests this week. The colorimeter test person reported elevated nitrate levels and a foul smell to the water samples from the bottom on North Pond. This combination suggests that the some of the algae sediment is decomposing on the bottom resulting in higher nitrate readings and decomposition gas odors.
The troll instrument readings also indicate a very different water quality picture then has been seen in prior years. The nitrate sensor normally yields readings of .5-.8 ppm(parts per million). The readings this month are in the 1.5-7.0 ppm range which has never been seen before in the lake. The EPA safe limit is 10 ppm. It should be noted that the higher nitrate readings were from the surface down to the thermal barrier which was observed in the 18-20 ft depth range for all 3 ponds this month. This suggests the algae bloom is still active. Turbidity(clarity) readings, showed higher levels of turbidity at all depths with readings below the thermal barrier being higher than the readings above the thermal barrier. Turbidity readings above the thermal barrier were in the 1-1.5 NTU range for Middle and North Ponds vs. historic values of .1-.4 NTU. Values below the thermal barrier were in the 2.0 NTU range for Middle and North Ponds. South Pond readings were higher being in the 2-3 NTU range.
RDO(dissolved oxygen), and ORP(oxygen reduction potential), readings are also 10-20% lower than is normally seen. These lower values are likely due to the prolonged algae bloom which would tend to consume more oxygen.
The colorimeter tests showed normal phosphorous readings in all tests, but the bottom sample for North Pond and the sample from Sucker Brook showed elevated levels of Nitrates. The test person also indicated that the sample from the bottom of North Pond had a foul smell which was likely associated with decomposing algae sediment from the area near the bottom.
The continued significant flow rates of the streams are likely bringing more nutrients into the lake this season than would be the case in a normal year. Along with the weather, the extended flow of the streams may be supporting the prolonged algae bloom we are observing in the lake this season.
Conclusions
The test data results this month are very different than anything we have seen over the 5 years of testing. For the WLA test team, this is unchartered territory. We believe and hope that these conditions are temporary and that they do not produce long term impact to the lake. We will be talking with our expert contacts about these conditions and the short and long term impact they may have to the lake’s eco system and its marine life. The data might suggest that the Webster water supply be monitored closely for increases in bacteria, and nitrate levels.