PlaceDossier / BC places / Lakes
BC lake · 3 km² · Lower Chilako River watershed
Bednesti Lake
Its median summer total phosphorus over 2018–2021 was 19 µg/L, from 31 readings. Higher than 76% of the 95 BC lakes with enough recent readings. It lies in Fraser-Fort George, Electoral Area C.
The readings
139 summer readings from open water on record from 1978 to 2021, at 4 sampling sites.
| Median since 2012 | Compared with BC lakes | |
|---|---|---|
| Total phosphorus | 19 µg/L 2018–2021, 31 readings | Higher than 76% of the 95 BC lakes with enough recent readings. |
| Chlorophyll a | 4.8 µg/L 2018–2021, 29 readings | Higher than 78% of the 83 BC lakes with enough recent readings. |
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).
| Index | Class | |
|---|---|---|
| From total phosphorus (19 µg/L, 2018–2021) | 46 | mesotrophic |
| From chlorophyll a (4.8 µg/L, 2018–2021) | 46 | mesotrophic |
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
| Year | Total phosphorus | Chlorophyll a |
|---|---|---|
| 2021 | 19 µg/L (10) | 2.6 µg/L (11) |
| 2019 | 17 µg/L (12) | 4.6 µg/L (9) |
| 2018 | 19 µg/L (9) | 6.5 µg/L (9) |
| 2010 | 8.0 µg/L (11) | – |
| 2008 | 9.0 µg/L (7) | 1.2 µg/L (1) |
| 2007 | 14 µg/L (11) | – |
| 2000 | 23 µg/L (14) | – |
| 1999 | 20 µg/L (11) | – |
| 1998 | 16 µg/L (9) | – |
| 1997 | 26 µg/L (2) | – |
| 1988 | 12 µg/L (2) | – |
| 1985 | 13 µg/L (2) | 7.2 µg/L (1) |
| 1983 | 14 µg/L (1) | 2.5 µg/L (1) |
| 1978 | – | 1.9 µg/L (6) |
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
- E231760 Central deep station 124 readings
- 0400490 Deep station near northeast shore 8 readings
- 0400820 Station 4 near deep station north shore 6 readings
- E227133 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 the water receiving its discharge, 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.