|Lat / Long||49.6500000, -110.3000000|
|Max depth||8.4 m|
|Mean depth||3.5 m|
|Dr. Basin Area||25.7 km2|
|Drainage Basin||South Saskatchewan River Basin|
|Sport Fish||Yellow Perch, Northern Pike|
|TP x||43 µg/L|
|CHLORO x||5.9 µg/L|
|TDS x||255 mg/L|
Elkwater Lake is a popular recreational lake located on the northwest corner of Cypress Hills Provincial Park. The closest population centres are the city of Medicine Hat, 65 km northwest, and the town of Irvine, 40 km north. Highway 41 provides easy access to the eastern arm of the lake and to the hamlet of Elkwater on the south shore (FIGURE 1).
The lake's name is a translation of the Blackfoot name Ponokiokwe (Alta. Cult. Multicult. n.d.). Historically, the lake was a favourite drinking spot for the many ungulates that inhabited the Cypress Hills.
The earliest inhabitants of the Cypress Hills were Plains Indians (Cree, Blood, Assiniboine, Stoney, Peigan, Blackfoot and Gros Ventre), who used the area for hunting, fishing and semipermanent habitation. Anthony Henday, the first European explorer to reach the Cypress Hills, arrived in 1754. The first white settlers arrived at the lake in 1883 and established a lumber mill on the north shore, floating logs across the water. Logging continued until 1912, when most of the timber had been removed (Michael and Johnson 1981). Cattle ranching began in the early 1880s and grazing continues to the present day. The townsite of Elkwater was founded in 1913 when a subdivision was completed on the south shore; by the 1920s, the Elkwater Lake area was a major summer camping spot.
Cypress Hills Provincial Park was originally established in 1929 as Elkwater Resort. It was transferred to the province in 1945, and was designated a provincial park in 1951 (Alta. Rec. Parks n.d.). The present facilities include several launch ramps, boat docks and a marina, which provide boaters with excellent access to the lake (FIGURE 2). The launch ramp and dock in the eastern bay are for nonmotorized boats only, and there is a 12 km/hour speed limit in the bay (Alta. For. Ld. Wild. 1988). Power boating and water skiing are allowed in the north and west bays. Children's playgrounds, picnic sites, parking, interpretive trails, overnight camping facilities and a swimming area are also available on, or adjacent to, the south shore.
The water in Elkwater Lake is clear and the sandy beach is clean. The lake supports a year-round sport fishery for northern pike and yellow perch, and is a popular area for swimming and wildlife and waterfowl viewing. Hiking, cross-country skiing and downhill skiing are activities pursued in the surrounding park. There are no sport fishing regulations specific to the lake, but general provincial limits and regulations apply (Alta. For. Ld. Wild. 1989). Users of the marina and boat launches are often concerned about the extensive beds of aquatic plants in the lake, which can foul propellers.
The watershed of Elkwater Lake (FIGURE 1) lies almost entirely within Cypress Hills Provincial Park. The Cypress Hills are a dissected, flattopped plateau 145-km long and 25-km to 40-km wide that rises approximately 760 m above the surrounding plain. They are the highest point of land in Canada between Labrador and the Rocky Mountains. Elkwater Lake was formed in a depression at the base of the hills. A forested escarpment rises approximately 220 m from the lake's south shore to a plateau in the southern section of the watershed. To the north, the land is flat and reaches an elevation about 8 m higher than the lake. The lake's main inflows are diffuse runoff from the watershed, and numerous underground springs (Alta. Envir. 1982). The outlet, Ross Creek, flows from the northern bay to the South Saskatchewan River.
The bedrock geology beneath the drainage basin is varied (TABLE 1). The Eastend Formation, which underlies and surrounds the lake, and the Whitemud and Battle formations, which lie to the south of the lake, are groundwater aquifers. The more recent Ravenscrag Formation appears along the upper slopes of the Cypress Hills plateau and the youngest rock, the Cypress Hills Formation, caps the plateau (Alta. Res. Counc. 1972; Lombard North Group 1976). The tops of the hills were not glaciated by any of the great ice sheets that flowed down from the Rocky Mountains or from the Hudson Bay area.
Areas within the Cypress Hills are associated with different micro-climates depending on their position relative to the prevailing winds. Low pressure fronts from the northwest encounter the hills and lose their moisture as rain from May through September, mostly on the north-facing slopes. An annual average of 7 cm more rainfall and 11 cm more snowfall have been recorded in the Cypress Hills than in nearby Medicine Hat (Envir. Can. 1982[a]).
The Cypress Hills are part of the Boreal Foothills, Aspen Parkland and Mixed Grass ecoregions. Vegetation on the slopes of the hills varies with moisture conditions. For the most part, the south- and west-facing slopes are covered with mixed-grass prairie on Dark Brown Chernozemic soils, whereas north-facing slopes, seepage areas and creek banks support trembling aspen and spruce on Black Chernozemics and Gleysols. At elevations between 1,200 m and 1,300 m, the grasslands are predominantly rough fescue on Black and Dark Brown Chernozemics, and above 1,300 m, the vegetation is trembling aspen, balsam poplar, lodgepole pine and white spruce on Gray Luvisols (Strong and Leggat 1981; Looman and Best 1987). Approximately 80% of the watershed is forested, and about 17% is open grassland, mostly north of the lake and in the southern portion at the basin (FIGURE 1). Cattle graze on the park uplands south of the lake and on the lowlands to the northwest. The remaining 3% of the land has been used for residential and recreational development, mainly at Elkwater townsite and along the south shore.
Elkwater Lake has three bays and a shoreline that is almost 11-km long (TABLE 2, FIGURE 2). It is a moderate-sized lake with a maximum length of 3.7 km and a maximum width of 2.3 km. A small, deep area, with a maximum depth of 8.4 m, is located near the centre of the lake.
The lake's outflow has been controlled since 1908 (Alta. Envir. n.d.[e]). In 1907, area landowners complained about unauthorized deepening of the outlet by the Canadian Pacific Railway, to increase flow to its reservoir at Irvine. The railroad company built a headgate at the outlet in 1907, but only closed the gates in 1908 after repeated requests. The embankments beside the weir washed out in 1917, and repairs were made by the federal government in 1918. In 1948, the timber spillway was rebuilt by the provincial government. In 1978, Alberta Environment replaced the old structure with a drop inlet spillway, which has the capacity to discharge water at a rate of 4.79 m3 /second (WER Eng. 1981). The control structure is operated to meet the needs of downstream water users, users of the lake and the fisheries resource.
The elevation of Elkwater Lake has been monitored since 1962 (FIGURE 3). The difference between the minimum elevation (1,225.25 m), recorded in October 1962, and the maximum elevation (1,226.67 m), recorded in June 1982, is 1.42 m. Changes in the lake's surface area and capacity with fluctuating water levels are illustrated in Figure 4. Since the latest control structure was installed in 1978, the maximum range in elevations has been 0.98 m. The target elevation for the lake is 1,226.36 m.
The water quality of Elkwater Lake has been monitored since 1982 by Alberta Environment and Alberta Recreation and Parks (Alta. Envir. n.d.[a]).
The water chemistry of Elkwater Lake is similar to that of many freshwater lakes in southern and central Alberta. The lake is well-buffered, and the dominant ions are calcium and bicarbonate (TABLE 3). The turbidity is low, and recreational water quality is good, as indicated by relatively low chlorophyll a concentrations and reasonable Secchi depth transparencies (TABLE 4).
During the open-water period, the entire water column tends to be well-mixed by wind action and therefore well-oxygenated, with a uniform temperature (FIGURE 5). Under ice in winter, the water in the deeper portions of the lake can become anoxic, but the surface waters remain well-oxygenated.
Total phosphorus in Elkwater Lake, as in many other shallow lakes in Alberta (Prepas and Trew 1983), increases in late summer and is followed by peak chlorophyll a values (FIGURE 6). The phosphorus increase is probably due to internal loading from the sediments or phosphorus release from macrophytes (Riley and Prepas 1984). The lake is classified as mesotrophic. The chlorophyll level is less than expected given the total phosphorus values in TABLE 4; nevertheless, the similar seasonal patterns in chlorophyll, phosphorus and Secchi depth suggest that algal productivity is limited by phosphorus availability.
Recent information on the phytoplankton community is not available. A single net sample taken from the bottom to the surface in August 1947 indicated low algal biomass (Miller and Macdonald 1950), which is consistent with the low chlorophyll levels reported in TABLE 4.
Macrophytes were surveyed by Alberta Environment in 1982 and 1983 (TABLE 5). Of the 15 species identified, Richardson pondweed (Potamogeton richardsonii) was dominant at most sites. In 1976, Fish and Wildlife Division reported that a dense band of Canada waterweed (Elodea canadensis) encircled the lake between the 1.5-m and 2.5-m contours (MacNeill 1977), but this species was not found in the later surveys. In 1976, rushes (Juncus spp.) were mainly concentrated in the northern bay and common cattail (Typha latifolia) was present in the eastern and western bays. The free-floating species coontail (Ceratophyllum demersum) was found along the south shore at the east and west ends of the lake. Macrophyte problems have been reported near heavily used areas of the lake, particularly at the marina and boat launches. A 1947 study (Miller and Macdonald 1950) noted extensive macrophyte growth, with plants extending to depths of 5 m in some places. Thus, it appears that macrophytes are no more abundant now than they were historically (Reynoldson 1981).
The zooplankton and benthic communities were sampled in August 1947 (Miller and Macdonald 1950) and on 20 May 1976 (MacNeill 1977). The dominant zooplankton species from the single sample taken in the earlier study was Bosmina sp., a small cladoceran; Cyclops bicuspidatus, Diaptomus sp. and the rotifer Anurea sp. were also present. The later study was less specific.
In the 1947 study, benthic samples (sample size unknown) were taken by a series of dredgings at depths of 0.9, 2.4, 4.9 and 6.4 m. The most abundant animals at the two shallowest depths were scuds (Amphipoda: Gammarus lacustris) and phantom midge larvae (Diptera: Chaoborus sp.). At the two deeper sites, phantom midge larvae were most numerous. Sphaeriid clams were found at all depths except 2.4 m, and caddis fly larvae (Trichoptera) and leeches (Hirudinea) were found only at the 2.4-m depth. The greatest biomass was measured at the 0.9-m (69 g/m2) and 2.4-m (56 g/m2) depths, and the smallest biomass was measured at the 4.9-m (30 g/m2) and 6.4-m (13 g/m2) depths.
Currently, only two sport fish species are present in Elkwater Lake. Northern pike are indigenous to the lake; yellow perch were stocked in 1940 and 1945. Largemouth bass, spottail shiner, walleye and kokanee have also been stocked, but these introductions failed (Fitch 1980). In 1981 and 1982, fathead minnows were planted to provide prey for older northern pike and to buffer the juvenile yellow perch from pike predation. However, no fathead minnows were caught in a 1986 sampling program (Mackay 1988).
A creel survey of Elkwater Lake was conducted by Fish and Wildlife Division in 1979 (TABLE 6). The recreational fishery was very popular with residents of Medicine Hat and other parts of Alberta in spite of low catch rates. Angler number and effort over the summer decreased as interference from aquatic plants, water skiers and power boats increased. The mean catch rate for northern pike in Elkwater was 0.28 fish/hour, which is substantially lower than the mean catch rate of 0.76 pike/hour averaged for 34 other Alberta lakes. Similarly, the mean catch rate of yellow perch (0.05 fish/hour) was much lower than the mean catch rate averaged in the same study for 19 other Alberta lakes (0.75 perch/hour). These low rates are due to the slow growth rate of pike and the small population of perch (Fitch 1981).
Common Loons and four species of grebes nest on Elkwater Lake, and small numbers of Double-crested Cormorants feed there occasionally. The most frequent nesting sites for Blue-winged Teal, American Widgeons, Pintails and Mallards are grasses and sedges, which are common near the shoreline. Rush and cattail marshes provide cover for Lesser Scaup, and White-winged Scoters nest in the few places where shrubby growth extends to the water's edge (Lombard North Group 1976).
Thirty-seven species of mammals live in Cypress Hills Provincial Park (Finlay and Finlay 1987). Beaver, moose and red squirrels were introduced to the area in the 1940s and 1950s, and elk were reintroduced in 1937. Mule and white-tailed deer are native species and are quite common in the park. Coyotes hunt the area, as do mink, badgers, skunks and bobcats.
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