OWL WATER SAMPLING DATA ANALYSIS REPORT
2002

INTRODUCTION

During this past summer water quality samples were collected from June 5th through September 4th. Twenty volunteers collected twenty-five samples weekly for testing at the City of Auburn Waste Treatment Plant for Coliform and turbidity. The volunteers also measured air and water temperatures and noted wind direction and relative strength. They recorded the sky condition and also reported any unusual observations during the week. All of the information was entered in a computer spreadsheet for later analysis. In addition, the City of Auburn provided data on four sites they monitored at the North end of the lake and in the Owasco River to the State Dam near the Lake Avenue Bridge which was also entered into the database. Rainfall data was provided by Tony DeCaro from the Auburn Weather Monitoring Station at the Water Filter Plant on Swift Street. The daily data was converted into weekly totals and entered into the database this fall.

SUMMARY

The overall conclusion reached from an analysis of the data is that the water quality in Owasco Lake remains good. In fact, the coliform results from the two sampling sites on the Inlet were consistently the lowest numbers that were ever recorded in the ten years that OWL has been collecting data. The weather this year was somewhat different from 2001 with little rainfall in July and August; the rain that did fall generally occurred at night. As a result the Coliform numbers were generally lower than in 2001. Turbidity numbers were also lower and water temperatures were elevated.

DETAILED ANALYSIS

As we had done in recent years, several selected sites were plotted comparing Fecal Coliform and weekly rainfall over the course of the collection period. The actual data is attached as Data Sheet 1 and the plots are presented as Charts 1 and 2. All of the fecal coliform samples on July 2nd and August 14th were lost due to temperatures in excess of 90 degrees in the laboratory during the evening. One of the first notable observations was that the Coliform results from Rounds Lane and Long Hill Road were lower throughout the summer than in previous years. This is attributed to the lower rainfall and, consequently, the lower amount of run-off. Data for these sites for 2001 and 2002 along with the rainfall are shown in Data Sheet 4. Chart 7 shows a comparison of the fecal Coliform results for Rounds Lane and Long Hill Road for 2001 and 2002. It is apparent that the overall values are lower in 2002. A comparison of the weekly rainfalls were plotted for 2001 and 2002 and are shown in Chart 8. The rainfall in 2002 was heavier in June and lighter in July and August compared to 2001. The rainfall that did occur near the end of July and again near the end of August did not cause noticeable flow in the streams entering the lake. Also, the local drought reports for 2002 were more severe than in 2001. Week after week in July and August the clarity of the Inlet was reported as well as the low water level. All of this information strongly points to run-off as a major contributor to high fecal Coliform results in the Inlet.

The rest of the sample sites including the City of Auburn sites were generally very low also with many, many readings of <10 recorded. From the middle of July until the end of August the fecal Coliform results were very low with the exceptions of Sucker Brook and Dutch Hollow. The Dutch Hollow results can be explained by the low water level and the fact that there was essentially no flow in the stream during that time period. No obvious explanation can be suggested for Sucker Brook unless the work on the Owasco sewer line disturbed areas that contained pockets of fecal coliform. It will be interesting to see if the results next year show a noticeable drop in fecal Coliform in Sucker Brook, which might be credited to the sewer.

The turbidity data is presented in Data Sheet 2 and graphically in Charts 3 and 4 for the same selected sites used for the fecal Coliform charts. As one might expect, the turbidity numbers are also down compared to 2001. In 2001 the average value was around 10 while the average value in 2002 was closer to 7. The Zebra mussels are continuing to increase the clarity of the water. The low rainfall and run-off decreased the level of silt added to the Lake further reducing the turbidity. However, as every lake stakeholder knows, the increased clarity fostered the increase in seaweed growth and algae bloom. Many bathers complained of the difficulty in wading because of the dense weed growth. Everyone near the Lake as well as those people supplied with its water through their municipal water lines knows of the algae bloom that caused the smell and taste.

The water temperature data is recorded in Data Sheet 3 and presented graphically in Charts 5 and 6 for the same selected sites used for fecal Coliform and turbidity. The trend this year is generally upward for the time period studied. A closer inspection does show a slight decrease when rain occurred in July and August. The high temperature recorded this summer was 27 C. (81 F.) with the average temperature in July and August 23 to 24 C. (73 to 75 F.). Even Rounds Lane and Long Hill Road sites reached into the 70 F. ranges this year. I think all would agree that it was indeed a hot summer.

Each year OWL hopes that it can learn a little more about the complex factors that are impacting Owasco Lake while at the same time realizing that there are inherent year-to-year variations superimposed on these study parameters. The invaluable assistance of the OWL Water Quality Monitors allows OWL to produce a vast amount of data to be studied and evaluated in an attempt to better understand our watershed. Only with the continued dedicated efforts of this special class of volunteers can OWL hope to achieve the level of knowledge and understanding that is sought. On behalf of the OWL Board, I want to personally thank them for all of their fine efforts and to assure them that their contributions are deeply appreciated.

Submitted by:
Dick Coalson
Water Quality Coordinator
OWL Executive Board

2002 OWLA Water Quality Correlation Table
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