|Lat / Long||54.5666667, -113.6333333|
|Max depth||28 m|
|Mean depth||9.4 m|
|Dr. Basin Area||30.3 km2|
|Drainage Basin||Athabasca River Basin|
|Sport Fish||Yellow Perch, Northern Pike|
|TP x||12 µg/L|
|CHLORO x||3.3 µg/L|
|TDS x||No Data mg/L|
Long Lake is a deep, peaceful lake set in a little valley among gently rolling, treed hills. It is located in the County of Athabasca southwest of the town of Athabasca. To reach the lake from the city of Edmonton, take Highway 2 north for about 133 km to Secondary Road 663 near the locality of Meanook, the population centre closest to the lake. Follow Secondary Road 663 west for about 16 km, then south for 3 km and west for 1.6 km. Next, take a narrow gravel road north for 1 km then west for 1 km to reach Forfar Park on the east shore of the lake (FIGURE 1).
The land around Long Lake is all Crown land and is mostly undeveloped (FIGURE 2). The best access is at Forfar Park, which is operated by the county and offers camping and day-use facilities, a concrete boat launch, two sandy swimming areas, tap water, docks and a sewage disposal station. There is also a small day-use area at the north end of the lake. There are three institutional camps on the lake: a Junior Forest Warden's Camp, a Boy Scout Camp and the Athabasca Fish and Game Club Camp. Power boats are restricted to speeds of 12 km/hour or less in posted areas of the lake (Alta. For. Ld. Wild. 1988).
The water of Long Lake is clear most of the summer and algae in the surface water are inconspicuous. Aquatic plants ring most of the lake. The lake provides moderately popular sport fishing for northern pike and yellow perch. Provincial limits for size and catch apply to the sport fishery, but there are no specific regulations in effect (Alta. For. Ld. Wild. 1989).
The drainage basin of Long Lake is primarily a meltwater channel that was carved in glacial till as the last continental glaciers receded. The valley runs in a north-south direction and includes the basin of Narrow Lake just north of Long Lake (FIGURE 1). The land is moderately to strongly rolling (TABLE 1), with slopes of 9 to 30% (Kjearsgaard 1972). The highest point in the basin is the hill that rises 40 m above the lake to an elevation of 735 m just west of the south end of Long Lake.
The watershed lies in the Dry Mixedwood Subregion of the Boreal Mixedwood Ecoregion (Strong and Leggat 1981). The dominant trees are trembling aspen. Balsam poplar, white spruce and birch are common in slightly wetter areas. Soils under these forests are Orthic Gray Luvisols (Kjearsgaard 1972). Wetlands are common in the drainage basin; the sedges, willows and black spruce in these areas are underlain by Humic Gleysols and Mesisols. The arability of the land is poor and most of the basin is still forested. Some land in the eastern portion, however, has been cleared for pasture and mixed farming. There are no population centres in the drainage basin.
Most of the inflow to Long Lake is unchannelized runoff and groundwater. The few streams that do run into the lake are interrupted by beaver dams. Narrow Lake, 600 m north of Long Lake, overflows into Long Lake only during spring snowmelt and after unusually wet summer storms (Prepas et al. n.d.). Long Lake flows into a creek that enters Bolloque Lake; its outflow, Bolloque Creek, eventually reaches the Pembina River via Dapp Creek.
Long Lake is a small, elongate lake with a surface area of 1.62 km2 (TABLE 2), a maximum length of 5.4 km and a maximum width of 0.9 km. It is surprisingly deep for its small size-the sides of the south basin slope steeply to a maximum depth of 28 m (FIGURE 2). The north basin is shallower and has a more gently sloping bottom than the south basin. In years when water levels were low, the lake was separated into two lakes, with the division at the narrows in the centre of the lake.
The maximum depth of macrophyte growth is 3.8 m (Prepas et al. n.d.). Approximately 27% of the lake is less than this depth (FIGURE 3). The substrate in the littoral zone is mainly organic material with areas of sand and boulders. The substrate in deeper areas is mostly rich organic material.
The water level was monitored in 1983 and has been monitored every summer since 1985 (FIGURE 4). From 1986 to 1987 the level varied almost 1 m. Changes in the level of Long Lake are often linked to changes in the beaver dams on the outflow and to the outflow from Narrow Lake. In May 1986, groundwater flow into the lake averaged 0.9 x 10-8 m/second in the area within 30 m of shore. Groundwater was estimated to be a relatively small fraction (6%) of the total inflow to Long Lake (R. Shaw and Prepas 1989).
The water quality of Long Lake was studied by researchers from the University of Alberta from May through August from 1983 through 1986 in conjunction with long-term studies on Narrow Lake. These studies included detailed evaluation of phosphorus cycling within the open water, between the open water and bottom sediments, and the role of groundwater in transporting phosphorus from the sediments to the open water (Prepas et al. n.d.; 1988; Prepas and Trimbee 1988; J. Shaw and Prepas 1989[a]; 1989[b]; 1989[c]; R. Shaw and Prepas et al. 1989).
Long Lake is well-buffered, moderately alkaline and slightly coloured, but not turbid. Dominant ions are bicarbonate and calcium (TABLE 3). The lake mixes only partially in spring before it becomes strongly thermally stratified in May. It remains thermally stratified for the rest of the summer (FIGURE 5). Water over the bottom sediments becomes anoxic by late summer (FIGURE 6). Summer hypolimnetic dissolved oxygen depletion rates are low for lakes in this region; 0.305 g O2/m2 per day was the average for the summers of 1984 and 1986.
Nutrient concentrations, both total phosphorus and inorganic nitrogen, are relatively low in the euphotic zone and are consistently low from year to year (TABLE 4). The concentration of total phosphorus in the euphotic zone usually remains low all summer, as typified by 1984 data in Figure 7. The total phosphorus concentration increases in the hypolimnion during the summer from less than 15 5g/L in May to more than 80 5g/L in August. Ammonium concentrations also increase in the water near the bottom sediment over the summer to more than 200 5g/L by late August. Because the total phosphorus concentration in the euphotic zone is fairly low, algal biomass in this zone is also fairly low. Secchi depths are deep and the water is clear. However, because phosphorus is much more abundant below 7 m, and because sufficient light for algal growth can penetrate to 12 m in Long Lake, it is at depths from 7 to 12 m that algal biomass is the greatest. At these depths, biomass can reach to 22 5g/L compared to concentrations of less than 5 5g/L above the thermocline.
An unusual pattern in euphotic zone total phosphorus concentrations occurred in 1986. In this year, the total phosphorus concentration increased sharply in the epilimnion in July. This increase was attributed to an unusually severe storm that resulted in a large amount of phosphorus-rich runoff entering the lake. (Note in Figure 4 the sudden rise in lake level at the same time.) In many lakes it would be expected that the increase in phosphorus would be accompanied by an increase in algal biomass (chlorophyll a). However, in this instance, the phytoplankton biomass did not increase and it was found that the algae were nitrogen-limited for a brief period of time (Prepas and Trimbee 1988).
Long Lake is a mesotrophic lake, but as most of the algae are below a depth of 7 m, the surface water is much clearer than in many other mesotrophic lakes in Alberta. When the cycling of phosphorus within the lake was examined, it was found that the lake sediment underlying 2.5 to 5 m of water has a high water content (an average of 87% in the top 10 cm). The porewater (water within the sediment) in these shallow areas in Long Lake has a relatively low phosphorus concentration (an average of 249 5g of soluble reactive phosphorus per litre in the top 10 cm) and a high ferrous iron concentration (942 5g/L). The movement of phosphorus from the sediment under shallow water to the water in the euphotic zone was estimated to be between 0.47 and 1.6 mg total phosphorus/m2 per day, throughout the summer. In contrast, the movement of total phosphorus from the deep water across the thermocline into the euphotic zone is insignificant, about 0.01 mg/m2 per day. The external total phosphorus loading is estimated to be 1.03 mg/m2 per day. Therefore, the return of phosphorus from the sediments under shallow water to the euphotic zone constitutes a substantial proportion (31 to 61%) of the total phosphorus load to the euphotic zone of the lake.
The phytoplankton in Long Lake has been studied briefly by researchers at the University of Alberta. The densest growth of algae, which occurred at depths of 7 to 12 m, was dominated by the blue-green alga (Cyanophyta) Aphanizomenon flos-aquae in 1984. In June 1986, the phytoplankton at depths of 7 to 12 m was dominated by both the diatom (Bacillariophyta) Asterionella formosa and the blue-green Aphanizomenon flos-aquae (Prepas et al. n.d.).
The aquatic macrophytes in Long Lake were surveyed during 1985 and 1986 during University of Alberta studies (Prepas et al. n.d.; Chambers and Prepas 1988; 1990). Thirteen species of submergent plants and five species of emergent plants were identified (TABLE 5). The zone from a depth of 1 to 2 m was dominated by coontail and northern watermilfoil. At depths of 2 to 5 m, stonewort was most prevalent with lesser amounts of common bladderwort and Richardson pondweed. Yellow water lilies grew sparsely around the lake and densely in the narrows between the two basins. The dominant emergents were bulrush, especially in the narrows, and bur-reed, both of which occasionally formed large floating mats. In July and August 1985, the average biomass of macrophytes in the 0- to 5-m depth zone was 193 g/m2 (geometric mean, linear average 536 g/m2 ).
There are no data on the zooplankton or benthic invertebrates in Long Lake.
Five species of fish are known to occur in Long Lake: northern pike, yellow perch, burbot, Iowa darter and brook stickleback. The lake is locally popular for sport fishing for northern pike; fish over 75 cm are occasionally hooked and one individual of 90 cm was caught and released from a gillnet in 1987 (Prepas et al. n.d.). Pike grow slowly here - fish of age seven were only 50-cm long (fork length). Yellow perch are not sought by anglers, as they grow very slowly in Long Lake. Few perch over 15-cm in length were caught by seining or gill netting from 1985 to 1987. Perch that hatched at a length of 6 mm in May of these years were only 48 mm by mid-August (Abbey and Mackay n.d.). Kokanee were stocked annually in Long Lake from 1967 through 1969, but they could not successfully reproduce and now there are none in the lake (Watters 1989).
Long Lake is not heavily used by waterfowl. A few Mallards, Common Goldeneye and Red-necked Grebes nest on the lake and two pairs of Common Loons nested on the lake each spring from 1985 through 1988. An Osprey nested near the south end of the lake in 1988 (Prepas et al. n.d.).
Muskrats and beaver are often seen in the south basin and there is a large beaver lodge at each end of the lake. White-tailed and mule deer are seen near the lake and coyotes are common in the area. Black bears are seen occasionally.
J.M. Crosby and E.E. Prepas
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