|Map Sheets||821/14, 82P/3|
|Lat / Long||51.0000000, -113.3166667|
|Max depth||4.9 m|
|Mean depth||2.6 m|
|Dr. Basin Area||120 km2|
|Drainage Basin||Bow River Basin|
|Sport Fish||Walleye, Yellow Perch, Northern Pike|
|TP x||334 µg/L|
|CHLORO x||39.5 µg/L|
|TDS x||1299 mg/L|
Eagle Lake is set in gently rolling prairie near the town of Strathmore, approximately 40 km east of the city of Calgary. To reach the lake from Calgary, travel east on Highway 1 until you are 8 km east of Strathmore, then turn south onto the road that leads to the locality of Namaka. Drive 6 km, and you will reach a commercial recreation area on the east shore of the lake (FIGURE 1, 2). The lake is located in the County of Wheatland.
The Blackfoot name for Eagle Lake, Pataomoxecing, means "many eagles" (Geog. Bd. Can. 1928). On nearby Eagle Hill, just southeast of the lake, Indians would lie in baited holes waiting for eagles to land; when an eagle approached the bait, the hunter would grab its legs and pull its tail feathers out to use for headdresses (Namaka Commun. Hist. Commit. 1983).
Settlement began when the Canadian Pacific Railroad came through the area in 1883. In the same year, Strathmore was founded on the west side of Eagle Lake; it was moved 6 km along the track to the present townsite in 1904. Before refrigerators were common, hundreds of tons of ice were cut from the lake each winter. Covered in sawdust and stored in buildings, the ice was available all summer. A heavy snow accumulation in the spring of 1948 caused serious flood damage to a secondary rail line cutting across the southern end of the lake. In the same year, the railway company built a control structure and dug a drainage ditch from Eagle Lake to Namaka Lake to lower the water level of Eagle Lake and prevent future flooding. This secondary rail line was abandoned in 1982, but the berm still crosses the lake except for a 4-m-wide channel (FIGURE 2), which at one time was spanned by a bridge. The control structure on the outlet canal is now operated by the Western Irrigation District (WID). In 1958, a small-scale sand dredging operation commenced on the southeast shore. Sand was hard to find in quantity so the business was abandoned in 1970 (Namaka Commun. Hist. Commit. 1983).
There is no Crown land around the lake. The major land use is irrigation farming or grazing. A subdivision of 100 lots is situated on the northwest shore; by 1988, 20 lots had been developed (Clark 1988). There is a commercially operated campground on land owned by the County of Wheatland on the east shore of the lake (FIGURE 2). The campground has 80 campsites, tap water, a beach and a boat launch (Alta. Hotel Assoc. 1988). There are no boating restrictions specific to the lake (Alta. For. Ld. Wild. 1988), but sudden strong winds can make boating treacherous.
Eagle Lake is very nutrient rich and has dense blooms of blue-green algae all summer. Submergent aquatic plants form a ring around the lake, extending about 100 m from shore. The lake supports a moderate sport fishery. Walleye were stocked from 1966 to 1972 and from 1978 to 1980 and are now the major species in the sport fishery; pike are also caught (Sosiak 1988). Provincial regulations regarding the size and number of fish caught apply, but there are no additional regulations specific to Eagle Lake (Alta. For. Ld. Wild. 1989).
The drainage basin of Eagle Lake is fairly small, being only 10 times the area of the lake (Tables 1, 2). The basin is in the Fescue Grassland Ecoregion, an area that lies between the moister Aspen Parkland and the drier Mixed Grass ecoregions. Fescue grassland is typified by gently rolling terrain, Black and Dark Brown Chernozemic soils and vegetation dominated by rough fescue grass, with Parry oat grass in secondary quantities. Shrubs grow on moister sites such as on northfacing slopes and around seepage sites (Strong and Leggat 1981). The Eagle Lake drainage basin is a gentle depression with relief of only 50 m to the top of Eagle Hill, the highest point in the basin at approximately 970 m. Most of the watershed has been cleared for irrigation farming, but grazing is the primary use around the lake (Charlton et al. 1982). The drainage basin also includes the town of Strathmore; its sewage effluent is retained in lagoons, and until 1988 the effluent was released into a creek draining into the southwest bay of the lake (FIGURE 1). In 1988 and 1989, the effluent was used by a private landowner for irrigation.
Inflowing streams to Eagle Lake are mostly intermittent. Most of them are dry by late spring and flow only during periods of very heavy rain. Inflow to the lake is augmented by irrigation return flows and seepage from the WID Main Canal; this volume is approximately equal to the volume derived from natural runoff. One permanent stream enters the southwest corner of the lake (Thompson 1971).
Eagle Lake is a simple, shallow depression that slopes gently to a maximum depth of 4.9 m (FIGURE 2). The near-shore sediment is fairly sandy, with soft mud at the northern end, in the southwest bay and in bays along the western shore (Thompson 1971).
The control structure on the outlet helps to keep the water level of Eagle Lake quite stable, but there are no data on water levels. The outflow from the lake is irregular. In 1988, water flowed out of the lake all year; the volume was estimated to be approximately 2 x 106 m3 (Hamilton 1989).
Eagle Lake water quality was sampled by Alberta Environment in 1982, 1983, 1985, 1986 and 1988 (Alta. Envir. n.d.[a]). Fish and Wildlife Division briefly surveyed the lake in 1969 (Thompson 1971).
Eagle Lake is a moderately saline, well-buffered lake. The water is very hard and the dominant ions are sodium, bicarbonate and sulphate (TABLE 3). Comparison of the 1988 data to that of a September 1969 sample indicates that the salinity of Eagle Lake has increased over the last 20 years, possibly due to the input of irrigation return flows. In 1969, total alkalinity was 353 mg/L, hardness 180 mg/L, chloride 2 mg/L and sulphate 390 mg/L. By 1988, total alkalinity had increased to 527 mg/L, total hardness to 297 mg/L, chloride to 30 mg/L and sulphate to 449 mg/L.
Eagle Lake is shallow and exposed to winds; it probably mixes all summer except for brief periods. In 1988, it was isothermal for most of the open-water season (FIGURE 3). Dissolved oxygen concentrations were depleted throughout the water column in early July, possibly due to algal die-off, and near the lake bottom in mid-September when the lake was very weakly thermally stratified (FIGURE 4). Dissolved oxygen concentrations under ice have been measured only once, in March 1988 (FIGURE 4); at that time, they were surprisingly high.
Total phosphorus concentrations in Eagle Lake are very high (TABLE 4, FIGURE 5). In 1988, the total phosphorus concentration reached a peak in June. The phosphorus concentration fell until late July, then rose following a period of low dissolved oxygen concentration throughout the entire water column. The phosphorus concentration peaked a second time in early October, after a brief period of weak thermal stratification in September. The pattern in 1985 was similar to that in 1988; the total phosphorus concentration increased from early May (290 5g/L) to late September (380 5g/L). The pattern in 1986 was quite different; the total phosphorus concentration was highest in mid-June (370 5g/L), then fell steadily to a low in late September (300 5g/L).
Chlorophyll a concentrations indicate the heavy bloom of blue-green algae that occurs throughout the summer (FIGURE 5). Chlorophyll a concentrations tend to parallel fluctuations in phosphorus concentration, but chlorophyll a concentrations are not as high as might be expected from the high phosphorus levels. It is quite likely that the high salinity, particularly the sulphate concentration, suppresses algal production, a characteristic of other moderately saline lakes in Alberta (Bierhuizen and Prepas 1985). The high phosphorus concentrations, heavy blue-green algal blooms and very low Secchi depths (FIGURE 5) all indicate that Eagle Lake is hyper-eutrophic.
There are no detailed data on phytoplankton species in Eagle Lake. In 1969, the blue-green algal bloom that dominated the lake all summer was largely composed of Aphanizomenon sp. (Thompson 1971).
Submergent macrophytes form a dense ring around the lake, extending out from shore for approximately 100 m (Thompson 1971; Trew 1988). The bay south of the old railroad berm becomes choked with aquatic plants, and boat traffic is impossible there in summer. Cattails (Typha sp.) and bulrushes (Scirpus spp.) are present mostly in the southwest bay and in bays along the west shore.
The zooplankton and benthic invertebrate fauna of Eagle Lake were surveyed by Fish and Wildlife Division in 1969 (Thompson 1971). Cladocerans (Daphnia sp.) and copepods (Cyclops sp.) were the most abundant zooplankters.
In 25 bottom samples (13 at 0- to 2-m depth, 4 at 2- to 4-m depth, 8 at 4- to 5-m depth), an average of 15.8 g/m3 (dry weight) of benthic invertebrates were found (Thompson 1971). By number, 80% were large midge larvae (Chironomidae), 15% were scuds (Amphipoda) and 2% were aquatic earthworms (Oligochaeta). Distribution did not appear to be affected by depth.
Eagle Lake contains six species of fish indigenous to the lake: northern pike, yellow perch, white sucker, longnose sucker, brook stickleback and fathead minnow. Walleye were introduced as eyed-eggs annually from 1966 to 1972, and as fingerlings annually from 1978 to 1980. Walleye now constitute the major target of the sport fishery in Eagle Lake and test netting in 1986 confirmed that they are reproducing successfully (Alta. For. Ld. Wild. n.d.).
Angling is popular from boats or from the old railroad causeway and at the campground. Angling from other points around the shore is difficult due to the dense growth of macrophytes that rings the lake. Despite the high algal production and shallow depth, major winterkills of fish have not been recorded in Eagle Lake (Sosiak 1988).
Eagle Lake provides good nesting habitat for dabbling and diving ducks, especially along the west shore and in the south bay. The lake is also a good place to spot numerous shorebirds: American Avocets, Marbled Godwits and yellowlegs are often seen (Sosiak 1988).
Alberta Department of Agriculture. 1970. Preliminary report on Eagle Lake Reservoir. Water Resour. Div., Edmonton.
Alberta Environment. n.d.[a]. Envir. Assess. Div., Envir. Qlty. Monit. Br. Unpubl. data, Edmonton.
-----. n.d.[b]. Tech. Serv. Div., Hydrol. Br. Unpubl. data, Edmonton.
Alberta Forestry, Lands and Wildlife. n.d. Fish Wild. Div. Unpubl. data, Edmonton.
-----. 1988. Boating in Alberta. Fish Wild. Div., Edmonton.
-----. 1989. Guide to sportfishing. Fish Wild. Div., Edmonton.
Alberta Hotel Association. 1989. Alberta campground guide 1989. Prep. for Travel Alta., Edmonton.
Alberta Research Council. 1972. Geological map of Alberta. Nat. Resour. Div., Alta. Geol. Surv., Edmonton.
Bierhuizen, J.F.H. and E.E. Prepas. 1985. Relationship between nutrients, dominant ions, and phytoplankton standing crop in prairie saline lakes. Can. J. Fish. Aquat. Sci. 42:1588-1594.
Charlton, S.E.D., D. Hammond and H.R. Hamilton. 1982. Trophic status of Eagle Lake. Alta. Envir., Poll. Contr. Div., Water Qlty. Contr. Br., Calgary.
Clark, B. 1988. Co. Wheatland, Strathmore. Pers. comm.
Energy, Mines and Resources Canada. 1977. National topographic series 1:50 000 82I/14 (1977), 82P/3 (1977). Surv. Map. Br., Ottawa.
Environment Canada. 1982. Canadian climate normals, Vol. 7: Bright sunshine (1951-1980). Prep. by Atm. Envir. Serv. Supply Serv. Can., Ottawa.
Geographic Board of Canada. 1928. Place-names of Alberta. Dept. Interior, Ottawa.
Hamilton, H.R. 1989. Hydroqual Consult. Ltd., Calgary. Pers. comm.
Namaka Community Historical Committee. 1983. Trails to Little Corner. Namaka Commun. Hist. Commit., Namaka.
Sosiak, A. 1988. Alta. Envir., Envir. Assess. Div., Envir. Qlty. Monit. Br., Calgary. Pers. comm.
Strong, W.L. and K.R. Leggat. 1981. Ecoregions of Alberta. Alta. En. Nat. Resour., Resour. Eval. Plan. Div., Edmonton.
Thompson, G.E. 1971. The limnology and fishery management of Eagle Lake, Alberta. Alta. Ld. For., Fish Wild. Div., Edmonton.
Trew, D.O. 1988. Alta. Envir., Envir. Assess. Div., Envir. Qlty. Monit. Br., Edmonton. Pers. comm.
Wyatt, F.A., T.W. Peters and W.E. Bowser. 1943. Soil survey of Blackfoot and Calgary sheets. Alta. Soil Surv. Rep. No. 39, Univ. Alta. Bull. No. SS-2. Univ. Alta., Edmonton.