Water Quality Report for LC 2013
Last year we did follow up tests on selected bacteria based on the full study of 2008. We determined that the results remained variable with only one continuing hot spot. This year we did Dissolved Oxygen (DO) at the two deep water sites again to see if the results showed deterioration. In 2008, we noted that some deep water results were low. This is of concern because Lake Trout live in deep cool water during the summer months, and avoid the warmer shallow water. If the DO in the deep water gets too low during the summer, trout would be forced to make a trade-off between temperature and oxygen. They would have to move up into water that is too warm, in search of sufficient DO. A healthy lake trout population is key to retaining our Highly Sensitive Lake Trout status.
On August 14, I set out with Lisa Thompson to sites 7 and 13 under a light overcast. Lisa joins her family every summer from her scientific academic job in California. We were accompanied by Jon Keeble who took down the data.
Using the 2008 GPS location off El Mardon at site 7 our depth finder showed 150 feet though we knew we would only be able to test to 90. Lisa had carried the DO meter and deep-testing Kemmerer bottle with her from her lab but had a limited amount of rope for the Kemmerer bottle. This device is an open tube that can be lowered to preset depths. A weight is sent down the same rope and triggers two rubber gates to seal the water in the tube. When hauled up, the water can be quickly sampled by the meter to establish the temperature and DO for that depth. This was the same technique used in 2008 but that unit was unavailable.
Site 13 inside the entrance to Otter Lake was within the 90 foot range of the rope and Kemmerer bottle so we obtained a complete set of data parallel to the 2008 tests.
A comparison with 2008 shows there is a similar slow decline in DO in the deep water but we are still in the safe zone for the trout however, we are trending in the wrong direction. As cottagers we can individually reverse this trend and collectively make a difference by using phosphate free soaps, ensuring our septic tanks are in good working order and for those cottages without septic systems, we would want the grey water to be dispersed on as deep a soil bed as possible.
Jon and I have proposed that the LWCA buy our own DO meter with a long cable (no Kemmerer bottle needed) so we can accurately measure on a consistent basis whenever and wherever we wish.
Kevin Moyser and Jon Keeble (in consultation with Lisa Thompson)
2011 Water Quality Study Summary
The 2011 water quality sampling was completed in about 3 hours on Sunday August 21st. The following day 36 bottles were delivered in ice to Caduceon Labs in Ottawa. There were 18 sites in this year’s study because two new ones were added to test water courses that feed into the lake…and they produced the most interesting samples.
As you know, the testing costs for the lab were underwritten by the Environment Fund which was approved at the 2011 AGM. We reduced the testing to four parameters this time: e-coli, total coliform, phosphorous and nitrogen. E-coli is associated with all animal waste but is also a significant marker for human waste in the water. Total coliforms capture mostly natural sources including forest animals. Nitrogen and Phosphorous support plant life in fresh water and high numbers usually mean that plants are taking up oxygen leaving less for the fish population.
A table that compares the 2008 results with the 2011 ones is posted on the LWCA website. A map is included.
The summary is as follows:
Sites in 2008 that revealed higher than average total coliform counts (#4, 9,10,15) had come down closer to the average while in 2011 sites 1, 2, 10 and 11 were elevated this time. The two new sites where the stream enters the lake at the most southerly end (#17) and Seymour Creek (#18) had higher than average total coliforms.
It is worth noting that previous lake studies dating back to the 1970’s have revealed fluctuations in total coliforms over 24 hours. Indeed the 1971 study had a rainfall during the three day sampling period and the numbers soared after the rain and then settled the following day after sun and wave action. However, it will be worth revisiting these two sources of water to the lake.
E-coli numbers were marginally higher at most of the sites compared to 2008.
Nitrogen was still higher than the standards call for but not significantly different from the 2008 study. Phosphorous remains below the established standards
We were unable to take direct readings of Dissolved Oxygen (DO) this year as the Ministry of Natural Resources devices were out of service. LWCA member Lisa Thompson, who spoke at the Annual Meeting, is hoping to bring a measuring probe to the lake this upcoming summer. We have DO measurements from 2008 and noted at that time that some deep water results were low. This is of concern because Lake Trout live in deep water during the summer months.
WATER QUALITY ARTICLE FROM 2008
By Jon Keeble and Barrie Evans
In recent years various inquiries have come to Board members about the water quality in Lakes Weslemkoon and Otter. Many members with long memories will recall occasional annual meetings over the last decades in which water study results sponsored by the Association were released. In more recent years, the Ontario Ministry of the Environment did an extensive series of testing of nutrient enrichment of the lake and levels of dissolved oxygen. The results were significant enough that the lakes changed to “highly sensitive lake trout lake” status which indicated a decrease in oxygen available to our valued fish population. The usual culprit in this situation is an increasing amount of both phosphorous and nitrogen in the water which spawns algae and other oxygen- depleting plant growth. Some of the phosphorous and nitrogen come from natural causes but also increased cottage use of septic systems which have showers, laundry and dishwashers as feed sources. This recent testing was related directly to the Ministry’s role in management of Lake Weslemkoon in supporting a lake trout population. There are other concerns related to water quality such as the levels of bacteria (primarily coliform and e-coli) which are of interest and concern to all recreational lake users.
Last year the Ministry of the Environment ceased doing annual testing as the results had not changed significantly in recent years. But the Board was concerned that the locations and restricted chemical analysis used by the Ministry might not have been capturing changes that reflect the lake as a whole. LWCA has historical data from a series of tests from specific sites on both lakes.
So, as raised at the last annual meeting, we resumed the more significant testing process developed for the lake in the 1970s using the same sites with some additions. This resulted in sampling from a total of 16 locations from the south end stream to the dam in the north and including two locations in Otter Lake.
Rather than farming out the whole study process to an environmental company as in the past, the Board combined cottager volunteers as sample takers with the professional expertise of Conestoga Rovers Association and Caduceon labs. Some of you will know that cottager and former Association President Mike Benson works for CRA. Through Mike we acquired the expertise of lab technician Brian Sinclair. Brian was essential in teaching us how to sample properly, bringing us on site sampling devices (the “Horiba”) and managing the many samples with the care necessary to prove the “chain of custody” from sampling to laboratory so the results can withstand scrutiny if required.
Two sampling days were set aside—July 29th and the Thanksgiving weekend which comes after the cool water has “turned over”. The July team set out in three boats. Mike and Brian took on the deep water sampling off El Mardon and in Otter Lake while Dominic Angelozzi took Glen and Judy Hogg to the south end sampling points and Jon Keeble and Betty Ann Glassford worked north to the dam and Otter Lake. Each team had GPS units to try and establish the sampling points for the Thanksgiving teams to duplicate. The gusty winds made holding positions difficult.
In contrast, the October day was a beautiful balmy day and a delight to be out on the lake. Because the lab was closed on the Thanksgiving weekend, a team was assembled which was available for Friday October 10th. Again, three boats participated. Mike and Brian did the deep water testing. Barrie and Marion Evans did the north end while Ken Senter and Chris Morden took the south end. It was nip and tuck to get the samples to the lab in Ottawa before it closed given the Friday night traffic but thanks to Brian, we were successful.
The 16 shallow water samples sites were field analysed using the Horiba device. We gathered data on temperature, dissolved oxygen, acidity and conductivity which related to salinity (dissolved mineral salts). A black and white secchi disk was lowered over the side until the pattern disappeared revealing clarity. This reading could be compared to the turbidity readings from the Horiba. Reaching under the surface we gathered bottled samples for lab testing by Caduceon. These tests revealed chlorophyll, phosphorous and nitrogen levels. A second bottled sample was tested for e-coli and total coliform bacteria which source from both animal and human waste.
The deep water team also gathered similar bottled samples from 10 foot intervals down to the bottom of the lake. They were tested as above for chlorophyll, phosphorous, nitrogen, e-coli and total coliform bacteria.
Please see the attached article from Mike Benson which interprets the results from the many samples taken in 2008. Over the next few months, and, we hope, in time for the AGM, we will be able to comment on the results and how they compare to the historical samples.
Horiba is an interesting company of Japanese origin which produces scientific instruments for various purposes including environmental analysis and medical diagnostics (www.horiba.com). This particular instrument is designed to provide an immediate reading of several parameters: water temperature, dissolved oxygen, conductivity and ph (acidity). The device is a long tube like device which is connected to a console which gives an electronic read-out of the values. The user dips the device in the water to a prescribed depth (about 2-3 feet for the shallow water samples). The one we used was similar to the one pictured here.
The Secchi disk, created in 1865 by Pietro Angelo Secchi, is a circular disk used to measure water transparency in oceans and lakes. The disc is mounted on a pole or line, and lowered slowly down in the water. The depth at which the pattern on the disk is no longer visible is taken as a measure of the transparency of the water. This measure is known as the Secchi depth and is related to water turbidity. http://en.wikipedia.org/wiki/Secchi_disk