Lake Health Data
Nearly 30 years of water quality readings on our seven lakes, taken by volunteer stewards through Ontario's Lake Partner Program.
The 2025 picture is good: readings on all seven lakes were within published guidelines, and aquatic vegetation surveys found healthy native plant communities on every lake.
The latest readings at a glance
Each lake's most recent reading, classified against published guidelines — hover any value for details, or read the full guidelines and citations.
| Total phosphorusµg/L | Water clarity (Secchi depth)m | Calciummg/L | Chloridemg/L | Sulphatemg/L | Dissolved oxygenmg/L | |
|---|---|---|---|---|---|---|
| Redstone | 3.6’25 | 5’25 | 1.8’25 | 0.9’25 | 2.6’24 | soon |
| Little Redstone | 4.5’25 | 4.2’25 | 1.5’25 | 0.3’25 | 2.1’24 | soon |
| Bitter | 4.6’25 | 5.4’25 | 3.6’25 | 4.3’25 | 2.6’24 | soon |
| Burdock | 3’25 | 7.4’25 | 5.8’25 | 44.4’25 | 2.4’24 | soon |
| Coleman * | 15.2’25 | 3.1’25 | 5.6’25 | 0.8’25 | 3.2’24 | soon |
| Pelaw | 8.2’24 | 3.2’25 | 1.45’24 | 0.2’24 | 1.9’24 | soon |
| Long (Tedious) | 3.75’25 | 5.6’25 | — | 28.9’25 | — | soon |
* Coleman is a shallower, naturally mesotrophic lake — moderate clarity and somewhat higher phosphorus are expected and normal there.
Explore Each Lake's Record
Pick a lake to see every measurement since the 1990s, charted — with our lake steward's notes on what stands out.
Redstone Lake
Steward’s notes
- High transparency in 2025 (5.0 m Secchi depth, above the 4 m high-transparency mark).
- Calcium is on the low side (below 3 mg/L), typical of Canadian Shield lakes still recovering from acid rain.
- The 2025 vegetation survey found purple loosestrife at three shoreline points — low-level, long-established, and unlikely to cause significant ecological impact.
●Total Phosphorus
Latest: 5.8 µg/L (Jun 2024) · 24 samplesThe nutrient that most controls algae growth in Ontario lakes. Below 10 µg/L is oligotrophic (low nutrient, clear); 10–20 µg/L is mesotrophic; above 20 µg/L lakes are at risk of nuisance algae blooms.
View annual means table
| Year | Mean (µg/L) | Samples |
|---|---|---|
| 2024 | 5.8 | 1 |
| 2023 | 4.3 | 1 |
| 2022 | 5 | 1 |
| 2021 | 2.4 | 1 |
| 2020 | 4.4 | 1 |
| 2019 | 3.4 | 1 |
| 2018 | 3.4 | 1 |
| 2016 | 3.8 | 1 |
| 2015 | 6.07 | 3 |
| 2014 | 4.7 | 1 |
| 2013 | 4 | 1 |
| 2012 | 5.9 | 1 |
| 2011 | 9.5 | 1 |
| 2010 | 4.3 | 1 |
| 2009 | 4.8 | 1 |
| 2008 | 3.9 | 1 |
| 2007 | 3.3 | 1 |
| 2006 | 3.7 | 1 |
| 2005 | 3.5 | 1 |
| 2004 | 4.05 | 2 |
| 2003 | 4 | 1 |
●Water Clarity (Secchi Depth)
Latest: 6.1 m (Sep 2023) · 116 samplesHow deep a standard black-and-white disk stays visible from the surface. Deeper readings mean clearer water — typical Precambrian Shield lakes read 3–8 m.
View annual means table
| Year | Mean (m) | Samples |
|---|---|---|
| 2023 | 5.72 | 5 |
| 2022 | 5.1 | 3 |
| 2021 | 4.75 | 4 |
| 2020 | 5.7 | 6 |
| 2019 | 4.6 | 5 |
| 2018 | 5.42 | 12 |
| 2017 | 4.69 | 7 |
| 2016 | 5.7 | 6 |
| 2015 | 4.49 | 7 |
| 2014 | 4.1 | 5 |
| 2013 | 4.75 | 4 |
| 2011 | 5.56 | 5 |
| 2010 | 6.92 | 5 |
| 2009 | 6.97 | 6 |
| 2008 | 6.5 | 4 |
| 2007 | 7.02 | 5 |
| 2006 | 5.67 | 3 |
| 2004 | 5.73 | 3 |
| 2003 | 5.76 | 5 |
| 2001 | 7.15 | 6 |
| 2000 | 5.03 | 6 |
| 1998 | 7 | 2 |
| 1997 | 8.1 | 2 |
●Calcium
Latest: 1.86 mg/L (Jun 2024) · 16 samplesShield lakes are naturally calcium-poor, and levels have declined since the acid-rain era. Below about 1.5 mg/L, calcium-rich organisms like Daphnia (a key algae grazer) begin to struggle.
View annual means table
| Year | Mean (mg/L) | Samples |
|---|---|---|
| 2024 | 1.86 | 1 |
| 2023 | 1.87 | 1 |
| 2022 | 2.19 | 1 |
| 2021 | 2.26 | 1 |
| 2020 | 1.8 | 1 |
| 2019 | 1.6 | 1 |
| 2018 | 2.14 | 1 |
| 2017 | 2.32 | 1 |
| 2016 | 2.3 | 1 |
| 2015 | 2.16 | 1 |
| 2014 | 2.26 | 1 |
| 2012 | 2.16 | 1 |
| 2011 | 1.62 | 1 |
| 2010 | 1.92 | 1 |
| 2009 | 2.06 | 1 |
| 2008 | 2.24 | 1 |
●Chloride
Latest: 0.8 mg/L (Jun 2024) · 10 samplesMostly a road-salt signature. Undeveloped Shield lakes sit well below 5 mg/L; rising chloride indicates runoff from salted roads and driveways.
View annual means table
| Year | Mean (mg/L) | Samples |
|---|---|---|
| 2024 | 0.8 | 1 |
| 2023 | 0.7 | 1 |
| 2022 | 0.7 | 1 |
| 2021 | 0.7 | 1 |
| 2020 | 0.7 | 1 |
| 2019 | 0.6 | 1 |
| 2018 | 0.6 | 1 |
| 2017 | 0.6 | 1 |
| 2016 | 0.7 | 1 |
| 2015 | 0.8 | 1 |
●Sulphate
Latest: 2.6 mg/L (Jun 2024) · 7 samplesLargely a legacy of acid rain. Declining sulphate across the Shield reflects cleaner air — a long-term recovery signal.
View annual means table
| Year | Mean (mg/L) | Samples |
|---|---|---|
| 2024 | 2.6 | 1 |
| 2023 | 2.6 | 1 |
| 2022 | 2.6 | 1 |
| 2021 | 2.9 | 1 |
| 2020 | 3 | 1 |
| 2019 | 2.8 | 1 |
| 2018 | 3 | 1 |
The guidelines & sources
Total phosphorus (µg/L)
The nutrient that drives algae growth. Ontario’s interim Provincial Water Quality Objective for lakes is an ice-free-season average of no more than 20 µg/L to avoid nuisance algae; 10 µg/L provides a high level of protection, and lakes between 10 and 20 µg/L are considered mesotrophic.
Water clarity (Secchi depth) (m)
The depth at which a standard black-and-white disk disappears from view. There is no regulatory objective for clarity; it is monitored for trends. In our steward reporting, more than 4 m is described as high transparency and 2–4 m as moderate.
Calcium (mg/L)
Decades of acid rain leached calcium from Shield watersheds. Below about 1.5 mg/L, reproduction of calcium-rich zooplankton such as Daphnia — a key food-web link — becomes impaired. Several of our lakes sit close to this threshold, which is why we track it.
Chloride (mg/L)
Mostly from road salt. The Canadian long-term water quality guideline for the protection of aquatic life is 120 mg/L, though research shows effects on sensitive zooplankton can begin around 10–20 mg/L — one reason we watch rising trends (such as Burdock Lake) well before the guideline is approached.
Sulphate (mg/L)
A legacy of acid deposition. There is no Ontario or federal freshwater guideline for sulphate at the low concentrations found in our lakes (2–3 mg/L); it is monitored to track the watershed’s continuing recovery from acid rain.
Dissolved oxygen (mg/L)
Cold-water fish such as lake trout depend on oxygen-rich deep water at the end of summer. Ontario assesses lake trout lakes against a mean volume-weighted hypolimnetic dissolved oxygen of 7 mg/L. Our stewards begin September deep-point profiles — data coming soon.
- Ontario Ministry of Natural Resources (2010). Inland Ontario Lakes Designated for Lake Trout Management.
Live Water Level
Current and historical Redstone Lake water levels, updated continuously from the Parks Canada gauge.
Current Redstone Lake Water Level
Redstone Lake Water Level Trends (Full Year)
Current Conditions
Current Level
Historical Average (Today's Date)
Historical Max (Today's Date)
Historical Min (Today's Date)
Data Source
Water level data provided by Parks Canada through their official API
Station ID: 17 | Data updated continuously