Water Quality and The Environment of Mary Lake

Water quality is one of the big draws to our Mary Lake Paradise. Vigilant attention to monitoring programs and asking questions when unusual conditions or biological activity occurs is our common responsibility.

Flooding and Flood Plain Mapping

See the Flood Maps of Mary Lake here

Ice in and Out Data

Aerial Photos of Muskokaback to 1969

Interactive map of the topography of Mary Lake bottom

map of depths of mary lake

Dr Peter Sale’s Presentation On Global Warming in Muskoka

2022 View Presentation Slides

2019 View the Presentation Slides


Information on Lake Monitoring Programs

Benthic Monitoring

Our benthic (bugs in the mud) counting and identifying nearshore creatures provides us with an excellent early warning of threats to our water quality. Each year a survey is done.

Fish in the Lake

Invasive Species

Jane Earthy’s MNR Report

Municipal Report

Muskoka Resorts and Tourism Recommendations

UOW Lake Studies

Recommendations from the freshwater summit 2010

The Loon Survey July 2013

Shoreline Buffers

2018 -2019 Environmental Studies

Lake Data/Lake Partner Program

  • (Jane Earthy Program) gives you all our Mary Lake Secchi (clarity) results and our Total Phosphorus readings for nutrient loading. We have been participating since 2002

    by collecting a water sample for total phosphorus after the spring freshet in May and sending it to Dorset. Every few weeks during the summer we drop a Secchi disc down into the water over the deep basin north of Crown Island and measure when it disappears to get our clarity readings.

  • Lake System Health/Monitoring Your Lake/EMAN/Ice watch is where our full-year resident volunteers will register Mary Lake to track when the ice comes on and off the lake. They have data back to 1987
  • Lake System Health/Monitoring Your Lake/Terrestrial Plot Monitoring will be the place

    we reestablish our 20m by 20m plot of forest on top of Rocky Island that was first measured

    in 2003. Unfortunately, a wind event in September 2006 took out the north side and we need professional expertise to set it up again.

Other Initiatives

  • Well Aware and drinking water testing.
    • You heard from “Well Aware” at our AGM and in the

      past we have had Jim Steele of Jim’s Pump Shop speak to us about up to date UV

      lights filter systems reminding us of the importance of regular sampling through the public

      health testing service that should be done until you get three perfect 0 coliform and 0 e-coli results each summer.

    • promotes natural shoreline buffers, septic care & maintenance.FOCA supplies materials

      to educate us and our neighbours about best practices around the water. Some of our members have

      signed up for private site visits with a bio-technician. Lake-friendly products are encouraged and we are constantly reminding ourselves of our stewardship responsibility to avoid phosphates, fertilizers and to follow the “GO WILD” philosophy.

    • This year we welcome the aid of our new directors to attend as many meetings, lectures and workshops

      as we can to keep up to date on what makes a merrier Mary. Please set aside some time to use the

      water web to learn as much as you can about how we can all be better lake stewards in our local paradise.

  • Canada Geese
    • There is serious concern about goose droppings on the Port Sydney Beach as well as along cottage shorelines. Your association is working on strategies to control this. The best strategy, since geese like grass, is to leave your shoreline in a natural state. Watch for more information at the AGM.