|Lat / Long||54.8500000, -113.5333333|
|Max depth||18 m|
|Mean depth||3.7 m|
|Dr. Basin Area||63.2 km2|
|Drainage Basin||Athabasca River Basin|
|Sport Fish||Lake Whitefish, Yellow Perch, Northern Pike|
|TP x||26 µg/L|
|CHLORO x||8.3 µg/L|
|TDS x||216 mg/L|
Island Lake is a picturesque, medium-sized lake that is especially attractive for canoeing. It has several islands and bays, and the water is often fairly clear. The lake is located in the County of Athabasca, about 20 km northwest of the town of Athabasca. The west side is accessible from Highway 2, which passes north through Athabasca from Edmonton then along the west shore of the lake enroute to the town of Slave Lake (FIGURE 1). There is no public access by vehicle to the south and east shores.
Homesteads in the region were first established in about 1908 (Alta. Mun. Aff. 1980). Seasonal cottage development on Island Lake began with subdivision of land on the west side in 1956; the summer village of Island Lake was incorporated the following year. In 1983, a second summer village, Island Lake South, was incorporated (FIGURE 2). Almost all residential development around the lake is located on the west shore within the two summer villages; in 1988 there were about 265 residences, of which approximately 25% were permanent (Brown 1988; Parsons 1988).
Public access at Island Lake is available at several locations on the west side within the summer villages. Boats may be launched at most of these sites (FIGURE 2). An island near the west shore is leased by the Boy Scouts of Canada for camping and pioneering projects and the Young Men's Christian Association (YMCA) operates camping and canoe training programs on its property on the north basin of the lake (Alta. Mun. Aff. 1980). Recreational activities at the lake include swimming, power boating, water skiing, fishing and cross-country skiing. General federal boating regulations apply to island Lake, but there are no specific restrictions (Alta. For. Ld. Wild. 1988). The nearest population centre is Athabasca, and there is a small store in the summer village of Island Lake.
The main basin of Island Lake is fairly shallow. A smaller, deeper northern basin is connected to the main basin by a narrow channel. The main basin may become green at times, but the water quality is quite good, and water quality in the northern basin is excellent. Shallow areas in the main basin support dense beds of aquatic vegetation. A commercial fishery, mainly for lake whitefish, operates every second year. Sport fishing, particularly for northern pike, is a popular pastime. There are no sport fishing regulations specific to Island Lake, but provincial regulations apply (Alta. For. Ld. Wild. 1989).
Island Lake's drainage basin is about 8 times the size of the lake (Tables 1, 2). The main inflow drains from Ghost Lake and the northwestern portion of the drainage basin (FIGURE 1). The watershed of Ghost Lake accounts for over one-third (22.5 km2) of Island Lake's drainage basin. Several intermittent streams carry runoff to the lake from other portions of the drainage basin. The outflow, Island Creek, flows from the east side of the lake southeast for about 5 km to the Athabasca River.
The land in the drainage basin varies from level to gently undulating areas (0 to 5% slope) west of the lake, to gently rolling (5 to 9% slope) in the southern and eastern regions, to moderately rolling (9 to 15% slope) around the north end of the lake and west of Ghost Lake, where there is rough knob and kettle topography. An area of strongly rolling hills (15 to 30% slope) is located just northwest of Island Lake (Alta. Mun. Aff. 1980).
The bedrock underlying the lake is part of the Lea Park Formation. Approximately 45 to 60 m of surficial deposits overlie the bedrock. The surficial deposits are predominantly till and glaciofluvial. Landforms are low to high relief hummocks (Alta. Mun. Aff. 1980). The dominant soils throughout the region are moderately well-drained Orthic Gray Luvisols. Pockets of very poorly drained Organic soils are located to the northeast of Island Lake, along the creek to the west of the lake, in the area of the unnamed lake to the south, and south of Ghost Lake (FIGURE 1). The soils around Island Lake have severe to very severe limitations for agriculture (Alta. Mun. Aff. 1980).
About 27% of the drainage basin has been cleared, including areas of land around the south and west sides of Island Lake; most of the northern and northwestern regions remain forested (FIGURE 1). The most abundant trees are trembling aspen, balsam poplar, white spruce, balsam fir and white birch (Alta. Mun. Aff. 1980). Black spruce grows on poorly drained areas. Mature stands are rare because of past fires and clearing. Mature mixed stands can be found on the large islands and in patches along the north shore of island Lake (Bird and Hale 1976). Agricultural crops consist primarily of wheat, barley, canola and hay (Alta. Mun. Aff. 1980). Cattle grazing is not intensive in the region (Burger 1988). There are extensive areas of Crown land near the lake, including most of the islands (FIGURE 2). Several of these areas have been reserved for recreation.
Island Lake is a medium-sized water body with a surface area of 7.81/km2 (TABLE 2). The main basin is shallow: the maximum depth is about 12 m, but most of the basin is less than 6-m deep (FIGURE 2). The deepest part of the lake is in the north basin; it reaches a depth of 18 m.
Extensive low lying and wetland areas are located near the northeast, east, and south shores, and along a section of the northwest shore of Island Lake (Bird and Hale 1976). Steep banks (beach scarp) extend along much of the west shore and parts of the north basin and east side. Recreational development is limited around much of the lakeshore because soils are poorly drained. Several islands are located in the main basin. Most, including the large island near the east side, are low lying and poorly drained, but the large island in the western part of the main basin is relatively well drained.
The lake's outlet, Island Creek, is choked with aquatic plants and has limited flow (Bird and Hale 1976). Between 1968 and 1987 the water level fluctuated between a recorded low of 600.97 m in 1968 and a high of 601.75 m in 1974, a difference of 0.78 m (FIGURE 3). Changes in the lake's area and capacity, to an elevation of 601.0 m, are shown in Figure 4. Groundwater inflow was measured by University of Alberta researchers in 1986 (R. Shaw and Prepas 1989). Groundwater inflow was greatest near shore, and decreased with depth of lake water. Rates varied from 0.56 x 10-8 to 1.3 x 10-8 m/second, which is relatively low among lakes measured. Groundwater was estimated to contribute 4% of total water inflow.
The water quality of Island Lake was studied by Alberta Environment in 1983 and 1984 (Alta. Envir. n.d.[a]; 1989). The north basin was studied by Alberta Environment during 1976 and 1977 as part of an intensive study of Baptiste Lake (Trew et al. 1985), and was sampled by the University of Alberta in 1986 (Prepas et al. n.d.; Prepas and Trimbee 1988; J. Shaw et al. 1989; J. Shaw and Prepas 1989[a]; 1989[b]; 1989[c]).
The lake has well-buffered, fresh water; the dominant ions are bicarbonate, sodium and calcium (TABLE 3).
The deepest regions of the main basin are weakly thermally stratified during summer (FIGURE 5), but it is likely that the shallow areas mix completely much of the time. The north basin is strongly thermally stratified during summer. Hills to the north and west protect the small basin from prevailing winds, and turnover is often incomplete or does not occur in spring, nor sometimes in fall.
Dissolved oxygen concentrations near the bottom decline during summer (FIGURE 6). In deeper areas in the main basin and below about 10 m in the north basin, dissolved oxygen concentrations also decline under ice cover.
Island Lake is mesotrophic (TABLE 4). Total phosphorus in the main basin increases in late summer (FIGURE 7), probably as a result of transport of phosphorus from the bottom sediments. In 1986, there was a phosphorus pulse in the surface water due to an unusually heavy rain event. In the north basin, hypolimnetic phosphorus concentrations reached high levels (200 µg/L). However, the strong thermocline in the north basin discourages mixing of phosphorus-rich waters from the hypolimnion to the surface waters. The rate of phosphorus transport across the thermocline was estimated to be very low (0.05 mg/m2 per day). In contrast, the release of phosphorus from the bottom sediments in the euphotic zone (to depths of 7.5 m), is estimated to be fairly high (up to 2.5 mg/m2 per day). Chlorophyll a concentrations tend to increase in fall (FIGURE 7). In 1986, chlorophyll a concentrations generally followed phosphorus concentrations in the north basin; the peak chlorophyll a concentration was 5.7 µg/L. In 1976, in the north basin, chlorophyll a rose from a summer average of 2.3 µg/L to 8.6 µg/L in the top 3 m in September, and to 12.8 µg/L in November.
An estimate of the total phosphorus loading to Island Lake from external sources indicated that agricultural land in the watershed was the largest single source (TABLE 5). Phosphorus loading from internal sources may exceed that of all external sources combined.
Purple sulphur bacteria (Thiorhodaceae) are dense below 10m in the north basin (Prepas et al. n.d.; Trew et al. 1985). These photosynthetic bacteria live in anaerobic conditions and oxidize hydrogen sulphide and other sulphur compounds to sulphur (Wetzel 1983).
The phytoplankton community in Island Lake was studied in 1983 by Alberta Environment (Alta. Envir. n.d.[a]) and in 1986 by the University of Alberta (Prepas and Trimbee n.d.). In the main basin in 1983 (TABLE 6), the common groups were golden-brown algae (Chrysophyta: particularly Uroglena americana) in May, cryptomonads (Cryptomonas erosa reflexa) in June, diatoms (Bacillariophyta: Fragilaria crotonensis) in July and dinoflagellates (Pyrrhophyta: Ceratium hirundinella) in early August. Blue-green algae (Microcystis aeruginosa and Oscillatoria agardhii), which are common in eutrophic lakes, were dominant in late August, but did not develop into a bloom. There is a relationship between sediment phosphorus release and anoxia at the bottom of Island Lake and blue-green algal biomass (Trimbee and Prepas 1987; 1988). The greatest algal biomass was measured in September; diatoms (Melosira italica subarctica) and cryptomonads (Cryptomonas erosa reflexa) were dominant at that time.
In the north basin in 1976, green algae (Ankistrodesmus falcatus) and chrysophytes (Dinobryon divergens) were dominant in early spring. Blue-green algae (Anabaena circinalis and Gomphosphaeria naegelianum) developed by early June and were prominent until fall, when a diatom pulse (Stephanodiscus astraea and F. crotonensis) developed.
Aquatic macrophytes are abundant in Island Lake; their density is considered excessive by many lake users (Alta. Mun. Aff. 1980). Emergent vegetation grows along most of the lakeshore, particularly in the northeastern region of the main basin, along sections of the north and south shores, around islands and along the north shore of the north basin. Along the west shore, macrophyte growth is patchy. Bulrush (Scirpus sp.) and water lilies (Nuphar sp.) are the most common emergent plants (Robertson 1968). Other macrophytes include cattail (Typha sp.), sedge (Carex sp.), pondweeds (Potamogeton spp.) and northern watermilfoil (Myriophyllum exalbescens).
The zooplankton in the north basin was studied in 1976 and 1977 by Alberta Environment (Trew et al. 1985). No information is available on benthic invertebrates. In 1976 and 1977, the dominant copepod, particularly in early spring, was the cyclopoid Diacyclops bicuspidatus thomasi. The most abundant cladoceran was Daphnia galeata mendotae, which was common until late fall. The small cladoceran Chydorus sphaericus occurred in low numbers. Rotifers were numerous: Keratella cochlearis was the most abundant rotifer in midsummer.
Species of fish in Island Lake include lake whitefish, northern pike, white suckers, cisco and yellow perch (Alta. Mun. Aff.1980). Species of forage fish are also present, but they have not been identified. Walleye eggs were stocked in the lake in 1955 but walleye have not been reported in the lake since the 1959/60 commercial catch was taken (Alta. For. Ld. Wild. n.d.). The lake is known for its exceptionally large lake whitefish (Sullivan 1988). Many areas in the main basin support rooted aquatic plants, which provide good spawning and feeding habitat for fish such as northern pike.
Island Lake is managed as a recreational, commercial and domestic fishery. It is moderately popular for sport fishing. Northern pike are the main fish caught although lake whitefish are sought with limited success. The modest commercial fishery concentrates mainly on lake whitefish. In winter, whitefish concentrate in the upper regions of the north basin to avoid the deep layer of anoxic water. Records for the fishery date back to the 1945/46 season (Alta. Rec. Parks Wild. 1976). Since 1976/77, the fishery usually has opened every second year, although it was opened in both 1986/87 and 1987/88 (Alta. For. Ld. Wild n.d.). Between 1980 and 1988, the average harvest of the two commercially important species was 3,235 kg of lake whitefish and 141 kg of northern pike. The largest recorded harvests of fish since 1945/46 were 8,963 kg of lake whitefish in 1958/59, 2,381 kg of northern pike in 1947/48, 816 kg of yellow perch in 1950/51, 816 kg of cisco in 1956/57, and 109 kg of walleye in 1954/55. The record total annual harvest was 9,185 kg in 1958/59.
The islands, sheltered bays and abundant aquatic vegetation in Island Lake provide good waterfowl habitat. Common species observed are Common Loon, Red-necked Grebe, Mallard, American Coot, Bufflehead, Goldeneye and sometimes Canvasback (Alta. Mun. Aff. 1980). An island at the southeast end of the lake supported a Great Blue Heron colony with 43 nests in 1986 (Follinsbee 1988), and Bald Eagles have nested on another island in the lake for several years (Parsons 1988).
L. Hart Buckland-Nicks and P.A. Mitchell
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