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Western Brook Pond NAM-31

Riparian Nation(s) Canada
Lat. 49°45' N Lng. 57°47' W Alt. 30 m
Surface Area 22.8 km2 Mean Depth 72.5 m Volume 1.65 km3
Shoreline 42.5 km Catchment Area 171 km2 Residence Time 15.4 yr
Frozen Period Feb-Mar   Mixing Type Dimictic   Morphogenesis/Dam  
Related Info/Site  

Description

The ultraoligotrophic Western Brook Pond in Gros Morne National Park is a fjord lake which, after the retreat of the ice and the rebound of the land, became separated from the sea. It is accessible by a foot trail of about 4.8 km from the main road along the seashore. Although more than 60% of the lake's volume is below sea level, its water is entirely fresh. The scenic grandeur of Western Brook Pond is overwhelming. It is certainly among the most grandiose lakes in Canada's National Parks. The wide western end of the lake is surrounded by relatively flat, low-lying land. In the gorge where the lake narrows and the topography rises suddenly, the lake is confined by steep rock walls 600 m high. The sudden change in elevation often contributes to sudden atmospheric turbulences and strong shifting winds which make the lake very hazardous for small crafts. The lake was first surveyed in 1972 with the formation of Gros Morne National Park. Prior to that, only the occasional local person visited the lake. It is now a popular destination for park visitors for hiking, sightseeing and taking a cruise on a small tour boat.

The catchment basin is 7.4 times the size of the lake surface area. The lake receives drainage from more than 20 streams. The majority of these streams fall down or cascade from the highland plateau, draining areas lying over igneous rocks with poorly developed soils. These waters are very dilute, low in calcium, and pH is around 5.5. By contrast, the largest inflow, Stag Brook, at the western end of the lake, carries drainage from sedimentary rocks with higher calcium and pH. The frequent atmospheric turbulences keep the water mass well mixed along the length of the lake basin which is sufficient to maintain near circumneutral pH in the lake.

The lake water is very clear, with values of close to 5 Hazen units, but it may reach 10 Hazen units near the surface owing to the dispersion of coloured water from some of the inflows.

The productivity of the lake is extremely low which is well reflected in the hypolimnetic oxygen depletion rate. The oxygen concentration remains very high throughout the water column during stratification period and the depletion of oxygen is almost unmeasurable. Taking differences in water temperature into account and expressing dissolved oxygen as percent air saturation, the water column remains supersaturated from the surface to the bottom (165 m) at the end of summer with dissolved oxygen concentration higher near the bottom than at the surface.

The lake supports Atlantic salmon (Salmo salar)(both land locked and anadromous) and land locked arctic charr (Salvelinus alpinus). The lake was frequented by small groups of anglers in the 1970's, but after a few years of angling, the catches greatly declined. The lake is now closed to angling.

Photo of Western Brook Pond
Photo: J. Kerekes