BC lake · 42 km² · Alberni Inlet watershed

Sproat Lake

Too few readings to judge this lake: 50 summer readings from open water between 1992 and 2020, and we need at least 10 summer readings from open water, spread over at least 3 different years, since 2012 before we summarise or compare it. The readings are below.

The readings

50 summer readings from open water on record from 1992 to 2020, at 5 sampling sites.

	Median since 2012	Compared with BC lakes
Secchi depth	Too few readings to judge last sampled in 2009, before 2012	Too few readings to compare (last sampled in 2009, before 2012).
Total phosphorus	Too few readings to judge 16 readings since 2012, in 2 years	Too few readings to compare (16 readings since 2012, in 2 years).
Chlorophyll a	Too few readings to judge 14 readings since 2012, in 2 years	Too few readings to compare (14 readings since 2012, in 2 years).

Secchi depth how deep a black-and-white disc stays visible: deeper means clearer water

Total phosphorus the nutrient that most often feeds algae in BC lakes

Chlorophyll a the green pigment in algae: a direct measure of how much is growing

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 2009, before 2012); total phosphorus (16 readings since 2012, in 2 years); chlorophyll a (14 readings since 2012, in 2 years).

Year by year

Year	Secchi depth	Total phosphorus	Chlorophyll a
2020	–	2.2 µg/L (8)	0.2 µg/L (6)
2019	–	2.0 µg/L (8)	0.2 µg/L (8)
2009	15.6 m (1)	2.0 µg/L (1)	0.5 µg/L (1)
2007	14.3 m (4)	2.0 µg/L (4)	1.0 µg/L (4)
2006	11 m (3)	–	–
1992	13.5 m (1)	3.0 µg/L (1)	–

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

Where it was sampled

E267902 Taylor arm 22 readings
E267903 Stirling arm 19 readings
E267905 Faber arm 4 readings
E267904 Weiner arm 3 readings
0131180 At Sproat Lk Park 2 readings

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.