PlaceDossier / BC places / Lakes

BC lake · 16 km² · Columbia River watershed

Windermere Lake

Its median summer Secchi depth over 2015–2025 was 4.4 m, from 37 readings. Murkier than 56% of the 62 BC lakes with enough recent readings.

The readings

442 summer readings from open water on record from 1971 to 2026, at 3 sampling sites.

Median since 2012Compared with BC lakes
Secchi depth4.4 m
2015–2025, 37 readings		Murkier than 56% of the 62 BC lakes with enough recent readings.
Total phosphorus5.4 µg/L
2015–2026, 95 readings		Lower than 66% of the 100 BC lakes with enough recent readings (lower is clearer).
Chlorophyll a1.1 µg/L
2015–2026, 43 readings		Lower than 76% of the 83 BC lakes with enough recent readings (lower is clearer).
Secchi depth how deep a black-and-white disc stays visible: deeper means clearer water
0246 19801990200020102020 1971: median 3.4 m from 4 readings1972: median 2.7 m from 6 readings1973: median 4.0 m from 4 readings1975: median 5.2 m from 1 reading1976: median 3.1 m from 2 readings1977: median 4.9 m from 4 readings1978: median 2.5 m from 2 readings1982: median 4.9 m from 8 readings2015: median 4.7 m from 1 reading2016: median 5.3 m from 1 reading2017: median 4.0 m from 1 reading2018: median 3.7 m from 2 readings2019: median 4.3 m from 1 reading2020: median 5.7 m from 1 reading2021: median 4.8 m from 2 readings2022: median 5.2 m from 1 reading2023: median 3.9 m from 6 readings2024: median 4.8 m from 12 readings2025: median 5.0 m from 9 readingsm
Total phosphorus the nutrient that most often feeds algae in BC lakes
310 19801990200020102020 1971: median 5.5 µg/L from 4 readings1972: median 11 µg/L from 6 readings1973: median 6.0 µg/L from 7 readings1974: median 6.0 µg/L from 3 readings1975: median 6.0 µg/L from 4 readings1976: median 7.0 µg/L from 5 readings1977: median 7.0 µg/L from 7 readings1978: median 5.5 µg/L from 2 readings1982: median 7.0 µg/L from 13 readings2005: median 3.0 µg/L from 1 reading2006: median 4.0 µg/L from 40 readings2007: median 5.0 µg/L from 35 readings2008: median 6.0 µg/L from 39 readings2009: median 5.0 µg/L from 4 readings2010: median 4.0 µg/L from 3 readings2015: median 5.2 µg/L from 2 readings2016: median 3.3 µg/L from 2 readings2017: median 2.9 µg/L from 2 readings2018: median 6.2 µg/L from 4 readings2019: median 6.5 µg/L from 2 readings2020: median 3.8 µg/L from 2 readings2021: median 5.8 µg/L from 4 readings2022: median 7.2 µg/L from 2 readings2023: median 6.1 µg/L from 17 readings2024: median 5.4 µg/L from 27 readings2025: median 5.4 µg/L from 24 readings2026: median 5.4 µg/L from 7 readingsµg/L
Chlorophyll a the green pigment in algae: a direct measure of how much is growing
0.313 19801990200020102020 1976: median 2.4 µg/L from 2 readings1977: median 1.0 µg/L from 2 readings1978: median 0.7 µg/L from 2 readings1982: median 1.2 µg/L from 27 readings2006: median 1.1 µg/L from 9 readings2007: median 1.5 µg/L from 10 readings2008: median 0.6 µg/L from 11 readings2015: median 1.1 µg/L from 1 reading2016: median 1.6 µg/L from 1 reading2017: median 2.2 µg/L from 1 reading2018: median 1.9 µg/L from 2 readings2019: median 1.5 µg/L from 1 reading2020: median 0.3 µg/L from 1 reading2021: median 1.5 µg/L from 2 readings2022: median 1.9 µg/L from 1 reading2023: median 1.1 µg/L from 7 readings2024: median 0.7 µg/L from 12 readings2025: median 1.0 µg/L from 9 readings2026: median 1.4 µg/L from 5 readingsµg/L

Median each year (bigger dot, more readings)Middle half of BC lakesBC median

Source: BC Environmental Monitoring Data System (EnMoDS) results, Environmental Monitoring and Analysis Branch, Province of BC, records to September 19, 2026 (Open Government Licence – British Columbia); lake outlines and names: Freshwater Atlas lakes, Province of BC (Open Government Licence – British Columbia). Summaries by PlaceDossier.

Nutrient level Inferred

Reads as oligotrophic (few nutrients, little algae, usually clear).

IndexClass
From secchi depth (4.4 m, 2015–2025)39oligotrophic
From total phosphorus (5.4 µg/L, 2015–2026)28oligotrophic
From chlorophyll a (1.1 µg/L, 2015–2026)31oligotrophic

Inferred by us, not a provincial classification. The index was built for summer readings from the middle of a lake; ours mix sites and months, so treat the class as a rough guide.

How we worked this out

Carlson's trophic state index (Carlson 1977, Limnology and Oceanography 22:361) turns each median into a score: 60 − 14.41 ln(Secchi m), 14.42 ln(phosphorus µg/L) + 4.15, 9.81 ln(chlorophyll µg/L) + 30.6. Classes after Carlson and Simpson (1996): under 40 oligotrophic, 40 to 50 mesotrophic, 50 to 70 eutrophic, 70 and over hypereutrophic.

Year by year

YearSecchi depthTotal phosphorusChlorophyll a
2026–5.4 µg/L (7)1.4 µg/L (5)
20255.0 m (9)5.4 µg/L (24)1.0 µg/L (9)
20244.8 m (12)5.4 µg/L (27)0.7 µg/L (12)
20233.9 m (6)6.1 µg/L (17)1.1 µg/L (7)
20225.2 m (1)7.2 µg/L (2)1.9 µg/L (1)
20214.8 m (2)5.8 µg/L (4)1.5 µg/L (2)
20205.7 m (1)3.8 µg/L (2)0.3 µg/L (1)
20194.3 m (1)6.5 µg/L (2)1.5 µg/L (1)
20183.7 m (2)6.2 µg/L (4)1.9 µg/L (2)
20174.0 m (1)2.9 µg/L (2)2.2 µg/L (1)
20165.3 m (1)3.3 µg/L (2)1.6 µg/L (1)
20154.7 m (1)5.2 µg/L (2)1.1 µg/L (1)
2010–4.0 µg/L (3)–
2009–5.0 µg/L (4)–
2008–6.0 µg/L (39)0.6 µg/L (11)
2007–5.0 µg/L (35)1.5 µg/L (10)
2006–4.0 µg/L (40)1.1 µg/L (9)
2005–3.0 µg/L (1)–
19824.9 m (8)7.0 µg/L (13)1.2 µg/L (27)
19782.5 m (2)5.5 µg/L (2)0.7 µg/L (2)
19774.9 m (4)7.0 µg/L (7)1.0 µg/L (2)
19763.1 m (2)7.0 µg/L (5)2.4 µg/L (2)
19755.2 m (1)6.0 µg/L (4)–
1974–6.0 µg/L (3)–
19734.0 m (4)6.0 µg/L (7)–
19722.7 m (6)11 µg/L (6)–
19713.4 m (4)5.5 µg/L (4)–

Median of each year's May to October readings; the number of readings is in brackets.

Source: BC Environmental Monitoring Data System (EnMoDS) results, Environmental Monitoring and Analysis Branch, Province of BC, records to September 19, 2026 (Open Government Licence – British Columbia); lake outlines and names: Freshwater Atlas lakes, Province of BC (Open Government Licence – British Columbia). Summaries by PlaceDossier.

Where it was sampled

  • 0200052 . off Timber Ridge 287 readings
  • 0200051 . off Windermere 103 readings
  • E262793 . south station 52 readings

Left out: 26 readings at 3 sites whose names put them away from the open lake

  • E207048 Parr Utilities water intake 10 readings; a water intake
  • E207044 Windermere water intake 8 readings; a water intake
  • E207049 Timber Ridge water intake 8 readings; a water intake

Site names are tidied from the provincial records; the IDs find each site's full record there.

What this record doesn't cover

Algae bloom reports and invasive mussel checks aren't in this record: the province's Algae Watch map and mussel monitoring aren't published as open data. For swimming, check the regional health authority's beach advisories; for blooms and mussels, ask the province's regional environment office or the local lake association.

Readings are from the province's monitoring database: samples taken by provincial staff, volunteer lake monitors, and companies and local governments that sample under their permits. We keep the ice-free season (May to October), and for phosphorus and chlorophyll only samples from the top 5 m. We leave out sites whose names put them at a water intake, a sewage or industrial outfall, a mine or a permit holder's works, or on the shore (a beach, dock or boat launch): water there can differ a lot from the open lake. Each year's figure is the median of that year's readings. We give a lake a summary, a comparison with other lakes and a nutrient level only when it has at least 10 summer readings from open water, spread over at least 3 different years, since 2012; the summary is the median of those readings. With fewer, or only older ones, we show the readings and say there are too few to judge the lake. A reading below the lab's detection limit counts at that limit. One site can be a bay rather than the open lake, so a lake's figures can differ from one end to the other.

Water quality changes with the season, the weather and the part of the lake. These are past readings, not a test of the water today: before you buy, ask the local government and the lake association what's known, and test a drinking-water intake yourself.