PlaceDossier / BC places / Lakes

BC lake · 13 km² · Crooked River watershed

Summit Lake

Its median summer Secchi depth over 2022–2024 was 2.5 m, from 71 readings. Murkier than 82% of the 62 BC lakes with enough recent readings.

The readings

373 summer readings from open water on record from 1985 to 2024, at 3 sampling sites.

Median since 2012Compared with BC lakes
Secchi depth2.5 m
2022–2024, 71 readings		Murkier than 82% of the 62 BC lakes with enough recent readings.
Total phosphorus13 µg/L
2015–2024, 78 readings		Higher than 64% of the 100 BC lakes with enough recent readings.
Chlorophyll a3.2 µg/L
2015–2024, 71 readings		Higher than 66% of the 83 BC lakes with enough recent readings.
Secchi depth how deep a black-and-white disc stays visible: deeper means clearer water
0246 1990200020102020 2010: median 2.5 m from 2 readings2022: median 2.3 m from 24 readings2023: median 2.6 m from 23 readings2024: median 2.3 m from 24 readingsm
Total phosphorus the nutrient that most often feeds algae in BC lakes
10 1990200020102020 1985: median 18 µg/L from 5 readings1986: median 13 µg/L from 3 readings1987: median 16 µg/L from 1 reading1993: median 14 µg/L from 2 readings1997: median 16 µg/L from 6 readings1998: median 15 µg/L from 23 readings1999: median 16 µg/L from 21 readings2000: median 16 µg/L from 21 readings2008: median 11 µg/L from 16 readings2009: median 9.0 µg/L from 23 readings2010: median 8.0 µg/L from 21 readings2015: median 7.4 µg/L from 1 reading2022: median 14 µg/L from 26 readings2023: median 13 µg/L from 25 readings2024: median 14 µg/L from 26 readingsµg/L
Chlorophyll a the green pigment in algae: a direct measure of how much is growing
13 1990200020102020 2008: median 1.3 µg/L from 4 readings2010: median 3.0 µg/L from 5 readings2015: median 1.3 µg/L from 1 reading2022: median 3.0 µg/L from 23 readings2023: median 3.8 µg/L from 23 readings2024: median 3.3 µg/L from 24 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 mesotrophic (moderate nutrients and algae).

IndexClass
From secchi depth (2.5 m, 2022–2024)47mesotrophic
From total phosphorus (13 µg/L, 2015–2024)42mesotrophic
From chlorophyll a (3.2 µg/L, 2015–2024)42mesotrophic

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
20242.3 m (24)14 µg/L (26)3.3 µg/L (24)
20232.6 m (23)13 µg/L (25)3.8 µg/L (23)
20222.3 m (24)14 µg/L (26)3.0 µg/L (23)
2015–7.4 µg/L (1)1.3 µg/L (1)
20102.5 m (2)8.0 µg/L (21)3.0 µg/L (5)
2009–9.0 µg/L (23)–
2008–11 µg/L (16)1.3 µg/L (4)
2000–16 µg/L (21)–
1999–16 µg/L (21)–
1998–15 µg/L (23)–
1997–16 µg/L (6)–
1993–14 µg/L (2)–
1987–16 µg/L (1)–
1986–13 µg/L (3)–
1985–18 µg/L (5)–

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

  • E206640 Southeast deep station 187 readings
  • E206639 North arm deep station 185 readings
  • E227181 Littoral site 1 reading

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.