WATER QUALITY TESTING

 

The South Channel sites were last tested immediately following the August long weekend. This is about midway through our 4th year of the Water Quality Testing Program.

In the course of three years of testing we have accumulated a significant data base that covers the Archipelago and Georgian Bay Township. The water chemistry data - conductivity or total dissolved solids, PH, and clarity - does not in itself imply better or poorer water quality, but these data are our best indicators of water source, flow, and mixing patterns.

Water chemistry data in the South Channel area indicates that the mixing and exchange of our South Channel water with the open bay water is restricted to a considerable extent, much more than had been previously assumed. Given that, runoff to the South Channel is much more of an influence than had been expected. The South Channel proves to be by far the most complex flow system in the tested area.

There are areas of restricted flow at numerous spots between and including the Swing Bridge and Devil's Elbow. The flow pattern is further complicated by the two large bays included in the South Channel. They further restrict mixing by acting as sumps. Water mixing over a season is probably only 50% at best and may be as low as 30%. Mixing would be considerably less than that in the smaller cottage bays and most of these bays have some source of runoff from beaver empondments and wet lands.

Total Coliform levels at virtually all South Channel locations that were tested in 2001 were extremely high throughout the summer, although corresponding e coli levels remained at low natural levels in most locations. These abnormally high TC levels were not found in adjacent tested areas, however, this phenomena was observed in two locations in Georgian Bay Township. Those were Go Home Bay and Go Home Lake. Both of these areas also showed relatively low e coli levels. The inference from this is that the high Total Coliform levels have a natural origin and are not associated with pathogens of human health concerns. According to provincial standards, most of our water in the South Channel was not acceptable for recreational use over most of July and August of 2001.

Water temperatures were extremely elevated from early May through October and encouraged many kinds of organic blooms including coliforms. These blooms were largely responsible for the considerable reduction of water clarity over the entire testing period.

The readings taken so far this year have shown a steady increase in Total Coliform levels, as would be expected, over June and most of July, and have again been excessive in some areas, but not as pervasively as in 2001. Also the levels for the most part, although high in some areas, have not reached last year's levels. Then, for whatever reason, the TC levels declined over the remaining test period. This year a few extreme readings were recorded in the San Souci Area and Pointe au Baril Islands. There may well be others that I have not heard about at this time.

Happily the e coli levels this year have been somewhat lower at almost all South Channel sites than they were last year. Last year's e coli levels were a bit reduced as well, from the previous year's.

The septic reinspection program has now been completed for the so called at risk locations, those with systems 25 years old or more, and those properties with no record of a septic system. The of the South Channel cottage bays that we have been monitoring for water quality have a great many of these older cottages and over the three years that the reinspection program has been carried out, a considerable number of septic system replacements and upgrades have been completed there. Also, many gray water systems have been improved. It is becoming increasingly apparent that these waste water improvements and the improved e coli levels in some areas have a rather direct relationship.

The 2002 water monitoring will be continued until sometime around the Thanksgiving weekend. We hope that by then we will have the results of the testing at individual sites available for viewing on line and for 2003, we plan on posting this data on line as they are gathered over the entire season.

 

Stan Topping