Desert Lake

Where Desert Lake is

Desert Lake lies in the County of Frontenac, within the Township of South Frontenac.

How deep is Desert Lake?

The deepest mapped contour on Desert Lake is 67.1 meters, and the water within that boundary descends even farther. Ontario’s bathymetry record holds 41 depth contours for Desert Lake.

See also Ontario's Largest and Deepest Lakes

Surveyed Depths

Ontario has surveyed the depths of several thousand of its lakes over more than half a century. Later surveys were conducted by boat with satellite positioning and produced hundreds of thousands of soundings per lake. Earlier surveys were charted by running transects across the water and drawing depth contours by hand.

Water quality

Ontario’s Lake Partner Program is a volunteer monitoring network. Participants collect water samples for phosphorus analysis and measure water clarity through the summer with a Secchi disk. Most sites are sampled for phosphorus once a year, in spring, and some several times a year between spring and fall. Phosphorus in many lakes rises through the summer, so the two kinds of average are measured on different bases.

Phosphorus is the nutrient that controls how much algae a lake can grow. A lake with little phosphorus stays clear and supports cold-water fish such as lake trout. As phosphorus rises, algae increase, the water clouds, and oxygen in the deep water falls as the algae decay. The province classifies each monitoring site by its average phosphorus:

• Oligotrophic, below 10 micrograms per litre: clear water and low algae.
• Mesotrophic, from 10 to 20: moderately productive water, with more algae and weed growth than an oligotrophic lake but rarely a bloom.
• Eutrophic, above 20: nutrient-rich water, prone to algal blooms and low oxygen at depth.

Desert Lake has 8 Lake Partner monitoring sites. Three have reported phosphorus for the three or more years the province requires before a status is assigned. Two of those sites are classified oligotrophic and one mesotrophic.

The longest record is held by site 6266/1 at S end, deep spot, with phosphorus sampled once a year over 18 years to 2021. Its long-term mean phosphorus concentration is 10.5 micrograms per litre, within the mesotrophic band, which runs from 10 to 20.

A Secchi disk is a white or black-and-white plate lowered on a marked line until it disappears from view. The depth at which it vanishes is the Secchi depth, a direct measure of water clarity. Clearer water gives a deeper reading.

The 195 clarity readings at site 6266/1 give a median Secchi depth of 5.5 meters.

Median Secchi depth by year at site 6266/1

See also Lake Water Quality and Blue-Green Algae in Ontario

Desert Lake Weather

The weather page for Desert Lake carries the forecast over the water, wave heights across the lake, and the modelled water temperature.

Desert Lake weather

Water temperature

Ontario’s aquatic resource records class Desert Lake as a cold-water lake, with a mean depth of 22.4 meters against its maximum of 67.1.

A deep lake separates into layers through the summer. Sunlight and wind warm and mix the upper few meters, and beneath a band of rapid cooling, the thermocline, the water stays cold through the whole season. A mean depth of 22.4 meters places most of Desert Lake’s volume in that cold layer, which is the condition lake trout and lake whitefish require.

No provincial monitoring station records water temperature on Desert Lake. The LastLake model computes the temperature of its surface water for each day from the daily mean air temperature at Environment Canada’s Centreville climate station, 29 kilometers from the lake, or the next nearest station when its record is incomplete, and from the lake’s area of 382 hectares and its mean depth of 22.4 meters.

Each day’s figure carries the model’s typical error for that month on lakes of the same size. The figure in the chart below is the temperature near the surface, away from the shoreline. Bays, shallows and water deeper below the surface differ in temperature. Temperature is not measured when ice covers the lake. The weather page for Desert Lake carries the model’s figures for the past weeks and the coming week.

See also Lake Water Temperature in Ontario

Fish in Desert Lake

Ontario’s aquatic resource records name 18 fish species in Desert Lake.

Popular species in the province’s records

• Lake Trouttrout and whitefish
• Ciscotrout and whitefish
• Northern Pikepike
• Yellow Perchperch
• Smallmouth Basssunfish
• Largemouth Basssunfish
• Black Crappiesunfish
• Rock Basssunfish
• Pumpkinseedsunfish
• Bluegillsunfish
• Brown Bullheadcatfish

Spawning areas

Ontario maps 34 fish spawning records within the Desert Lake outline, for five different species, and all of them are mapped below.

By number of records

By area mapped

• Lake Trout13 areas0.6 ha
• Blue Gill6 areas0.9 ha
• Largemouth Bass5 areas0.8 ha
• Smallmouth Bass5 areas0.8 ha
• Pumpkinseed5 areas0.8 ha

The federal Fisheries Act prohibits the harmful alteration, disruption or destruction of fish habitat without an authorization, so a dock, dredging, infill or shoreline work at a mapped spawning area is reviewed on that basis.

Stocking history

Ontario’s stocking records for Desert Lake run from 1947 to 1990 and hold 51 releases. Lake Trout account for most of the fish: 139,450 released in 39 of the years between 1947 and 1990. The last recorded release was 5,000 lake trout yearlings in 1990.

The province’s record of stocking for recreational fishing, kept from 2016, lists no release into Desert Lake.

Eating the fish

The 2026 Guide to Eating Ontario Fish carries consumption advice for seven species taken from Desert Lake, tested for contaminants at a sampling location in South Frontenac Twp., Frontenac Co. Each figure below is the most meals a month the guide advises for a fish of that length. Where mercury sets the advice, the figure falls as the fish gets longer, because mercury accumulates over a fish’s life. A zero means the guide advises no meals of that fish at that size.

General population: adultsSensitive population: children under fifteen, women who are or may become pregnant

Fisheries Management Zone 18

Desert Lake lies in Fisheries Management Zone 18. Ontario sets its fishing seasons and catch limits by zone.

Fisheries management zones around Desert Lake

See also Fishing Seasons in Ontario, Zone by Zone and Fish Stocking in Ontario Lakes

Desert Lake Ice Fishing

An ice hut on Desert Lake must be removed by March 15. The province sets dates for ice hut removal as a safety measure to ensure huts are removed before thawing occurs. One date applies to an entire fisheries management zone (FMZ). Desert Lake lies within FMZ 18.

An ice hut must also be removed before the ice breaks up, whether or not that date has passed. The deadline clears huts from the ice ahead of the thaw and does not close the fishing season.

Registration is required in FMZ 18 for an ice hut built of anything other than fabric, and for a fabric tent covering seven square meters or more. Registration is free, and the number is displayed on the outside of the hut.

Ice conditions

No public record reports the thickness or the condition of the ice on Desert Lake on any given day. Ontario publishes ice safety guidance for anyone going out on the ice, at ontario.ca.

See also Lake Ice in Ontario and When the Lakes Will Freeze This Winter

Islands and names

Desert Lake contains ten islands in the Ontario Hydro Network’s outline, zero of them over 10 hectares and five under a tenth of a hectare.

Nearby lakes

• Devil Lake11 km away
• Bobs Lake13 km away
• Sydenham Lake13 km away
• Loughborough Lake17 km away

All lakes

Questions about Desert Lake

• How deep is Desert Lake?

  Its deepest charted contour is 67.1 meters, and the water within it is deeper.

• How big is Desert Lake?

  Its surface covers 3.8 square kilometers and it holds 10 islands. Of its 32 kilometers of shoreline, 31 kilometers is the mainland shore and 1 kilometer is the shore of the islands.

• What fish are in Desert Lake?

  Ontario’s aquatic resource records name eighteen species, among them lake trout, smallmouth bass, largemouth bass, northern pike, yellow perch and black crappie.