PlaceDossier / BC places / Lakes

BC lake · 28.2 ha · Victoria watershed

Cusheon Lake

Too few readings to judge this lake: it was last sampled in open water in 2011, and a record that old can't say what the lake is like now. The readings are below.

The readings

120 summer readings from open water on record from 1974 to 2011, at 2 sampling sites.

Median since 2012Compared with BC lakes
Secchi depthToo few readings to judge
last sampled in 2011, before 2012		Too few readings to compare (last sampled in 2011, before 2012).
Total phosphorusToo few readings to judge
last sampled in 2011, before 2012		Too few readings to compare (last sampled in 2011, before 2012).
Chlorophyll aToo few readings to judge
last sampled in 2011, before 2012		Too few readings to compare (last sampled in 2011, before 2012).
Secchi depth how deep a black-and-white disc stays visible: deeper means clearer water
0246 1980199020002010 1974: median 3.7 m from 6 readings1975: median 4.6 m from 2 readings1976: median 0.8 m from 3 readings1980: median 1.4 m from 6 readings2003: median 3.4 m from 1 reading2004: median 3.5 m from 1 reading2005: median 5.0 m from 1 reading2006: median 2.7 m from 2 readings2011: median 4.5 m from 3 readingsm
Total phosphorus the nutrient that most often feeds algae in BC lakes
1030100 1980199020002010 1974: median 18 µg/L from 8 readings1975: median 11 µg/L from 3 readings1976: median 14 µg/L from 8 readings1980: median 18 µg/L from 22 readings1989: median 8.5 µg/L from 2 readings1999: median 90 µg/L from 1 reading2000: median 61 µg/L from 9 readings2001: median 15 µg/L from 4 readings2003: median 14 µg/L from 2 readings2004: median 9.0 µg/L from 1 reading2005: median 11 µg/L from 3 readings2006: median 12 µg/L from 1 reading2011: median 7.5 µg/L from 2 readingsµg/L
Chlorophyll a the green pigment in algae: a direct measure of how much is growing
13 1980199020002010 1980: median 6.7 µg/L from 20 readings2003: median 1.7 µg/L from 1 reading2004: median 1.3 µg/L from 1 reading2005: median 2.1 µg/L from 2 readings2006: median 6.8 µg/L from 2 readings2007: median 1.9 µg/L from 1 reading2011: median 1.5 µg/L from 2 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

Unclear: too few readings to judge this lake's nutrient level.

Left out for too few recent readings (we need at least 10 summer readings from open water, spread over at least 3 different years, since 2012): secchi depth (last sampled in 2011, before 2012); total phosphorus (last sampled in 2011, before 2012); chlorophyll a (last sampled in 2011, before 2012).

Year by year

YearSecchi depthTotal phosphorusChlorophyll a
20114.5 m (3)7.5 µg/L (2)1.5 µg/L (2)
2007––1.9 µg/L (1)
20062.7 m (2)12 µg/L (1)6.8 µg/L (2)
20055.0 m (1)11 µg/L (3)2.1 µg/L (2)
20043.5 m (1)9.0 µg/L (1)1.3 µg/L (1)
20033.4 m (1)14 µg/L (2)1.7 µg/L (1)
2001–15 µg/L (4)–
2000–61 µg/L (9)–
1999–90 µg/L (1)–
1989–8.5 µg/L (2)–
19801.4 m (6)18 µg/L (22)6.7 µg/L (20)
19760.8 m (3)14 µg/L (8)–
19754.6 m (2)11 µg/L (3)–
19743.7 m (6)18 µg/L (8)–

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

  • 1100123 Midlake west. arm 104 readings
  • 1100122 Midlake east arm 16 readings

Left out: 18 readings at 2 sites whose names put them away from the open lake

  • E236220 North shore 9 readings; on the shore
  • E236222 South shore 9 readings; on the shore

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.