The Natural Environment

At first glance, Bridge Lake and its surroundings can seem much like the rest of the south Cariboo, but closer inspection reveals considerable diversity. The mosaic of streams, ponds, lakes, and forest supports a varied array of habitats. More than half of the bird species that occur in the Cariboo can be seen here. Predatory species are especially well represented, mammals as well as birds, which speaks of a well-structured, intact ecology. Topographic relief is slight, but Windy Mtn, the highest point at 1970m (6450 ft), is a small ‘island’ of alpine ground above the timberline. It is also the starting point of the Bridge Creek watershed.

The lake itself has a complex underwater topography, with a maximum depth of about 55m (180 ft) but a number of steep-sided rocky rises and shallow shelves of marl that pose a hazard to larger boats. Depths can vary as much as 15m (50 ft) in as little as 15m (50 ft) laterally. Use of a depth finder and bathymetric chart is advisable.

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Geology     

The lake lies at the eastern edge of the Fraser Plateau with its history of volcanic intrusion followed by Ice-Age glaciation, leaving an undulating terrain of old lava beds overlain by coarse stony soils, sandy gravel and clay. When the glaciers were melting, the Bridge Lake shoreline was about 20 metres higher than at present. Drumlins (small rounded gravelly hills) left behind by the glaciers occur along Hwy 24 at various places west of the lake. An outcrop of ‘columnar’ basaltic lava can be seen at the roadside just east of the turnoff to the Bridge Lake Store.

Columnar Basaltic Lava
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Climate     

The Plateau is in the ‘rain shadow’ of the Coast Mountains, but the Bridge Lake area gets more rainfall and snow than places further west, owing to its relatively high elevation (3700 ft) and easterly position near the Cariboo Mountain Range. In a typical year the lake freezes over in early December, and opens up during early May. Night-time frosts can continue into June and begin again as early as September. Consequently, the growing season at Bridge Lake is quite short. July is the warmest and wettest month, December the coldest and snowiest.

Temperature (°C) JanFebMarApr MayJunJulAug SepOctNovDec
Avg daily High -2.31.15.79.8 15.218.221.221.7 16.58.80.8-3.7
Avg daily Low -11.0-9.3-6.5-2.6 1.65.17.16.6 3.0-1.0-6.3-11.9
record high 1)32.5 record low 2)-43.0
Precipitation
Monthly avg (mm) 43.624.526.639.5 57.176.380.157.6 45.640.952.155.4
Avg snowfall (cm) 39.721.920.018.4 8.20.80.00.0 0.711.438.554.6
Avg snowdepth (cm) 5150281 0000 031542
record daily rainfall 3)40.0 record daily snowfall 4)41.0
record snowdepth 5)98.0
Source: Environment Canada, from the years 1971 to 2000
 
  1) 27.07.1998 2) 29.12.1990 3) 22.07.2000 4) 19.12.1989 5) 25.12.1984
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Vegetation     

The Bridge Lake area sits in a transition zone amongst three forest types: Interior Douglas-fir, Sub-boreal Spruce, and, on higher ground, Engelmann Spruce/Sub-alpine Fir (the very narrow needle-like trees along the MacDonald Summit portion of Hwy 24). All three types have been much modified by a history of old forest fires, leaving a present-day patchwork of mature spruce and firs interspersed with younger aspen and lodgepole pines. In recent years, an insect outbreak has killed almost all of the pines except the youngest. Many of the dead ones are presently being removed by salvage logging. The thick bark of Douglas-fir is fire-resistant, and numerous large old fire-survivors remain within younger patches of spruce. Most of the spruce at Bridge Lake are hybrids between two closely-related species, Engelmann and White Spruce. Birch and Cottonwoods indicate pockets of more fertile soil or groundwater seepage on hillsides and along the shoreline of the lake.

Meadows among the forest, and grassy south-facing slopes with sparse tree cover, formed the basis of early farms and ranches in the Bridge Lake area. But as many a local gardener will attest, the glacial soils of the Cariboo won’t produce much more than a crop of hay or trees unless a generous layer of good topsoil is added. Much of the rainfall in summer occurs in the form of thundershowers, although the benefits to lawns and gardens dissipate quickly when the sun reappears.

Bridge Lake Hayfields
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Human Impacts     

Thus far, Bridge Lake has escaped the worst excesses of human activity. Despite growth in lakeside housing development, the lake’s water quality still remains high, wildlife are still abundant, and the lake as a whole still retains a primarily ‘natural’ character. Yet, speedboat disturbance to birds is now commonplace, and native shoreline vegetation is increasingly being replaced by lawns and boat launches, in apparent disregard of Cariboo Regional District’s Shoreland Management Guidelines for property developers.

The well-being of Bridge Lake and its surroundings is monitored by local residents and environmentally-minded seasonal visitors. Contact us at friendsofbridgelake@gmail.com to find out how you can participate.