|Lat / Long||53.6166667, -114.0833333|
|Max depth||14 m|
|Mean depth||4.2 m|
|Dr. Basin Area||0.49 km2|
|Drainage Basin||North Saskatchewan River Basin|
|Sport Fish||Rainbow Trout|
|TP x||35 µg/L|
|CHLORO x||5.4 µg/L|
|TDS x||135 mg/L|
Sauer is a charming, tiny lake set among the rolling hills west of the city of Edmonton in the County of Parkland. It is a quiet spot for canoeing or fishing for rainbow trout. To reach Sauer Lake from Edmonton, drive west on Highway 16 to the town of Stony Plain, then turn north onto Secondary Road 779 and drive for 6 km, then drive west on Chickakoo Lake Road for 4.2 km, then north for 1.8 km. Public walk-in access to the lake is available along a road allowance that leads from the road on the east side of the lake. Hand-carried boats can be launched there. Only electric-powered motors are allowed on Sauer Lake (Alta. For. Ld. Wild. 1988). There are no public facilities such as camping areas, toilets or picnic tables, nor are there any commercially operated resort facilities. Day-use facilities are available at Chickakoo Lake, less than 1 km away. The land around Sauer Lake is all privately owned, but as of 1988 there was no development at the lake and all of the shoreline was treed and undisturbed (FIGURE 1). The lake was named after George Sauer, who homesteaded on the shore around the turn of the century (Alta. Cult. Multicult. n.d.).
The majority of users who come to Sauer Lake are anglers seeking the rainbow trout stocked annually by Fish and Wildlife Division. No fishing with, or for, bait fish is permitted (Alta. For. Ld. Wild. 1989). Sauer Lake has very clear water and algae are not usually conspicuous. Aquatic plants ring the lake, but as the lake is deep they do not interfere with angling from boats.
The tiny drainage basin of Sauer Lake is only 5 times the lake area (Tables 1, 2). The lake has no defined inlet or outlet and groundwater plays a major role in maintaining lake levels.
The watershed lies within the Moist Mixedwood Subregion of the Boreal Mixedwood Ecoregion near its interface with the Aspen Parkland Ecoregion (Strong and Leggat 1981). Surficial materials are Pleistocene-age, pitted deltaic material and the terrain is hilly, with some slopes exceeding 15%. Hills rise approximately 25 m above the lake (En. Mines Resour. Can. 1974). The soils are Orthic Gray Luvi sols (Lindsay et al. 1968) and the dominant vegetation is trembling aspen and balsam poplar, with willow and alder bordering the lake. The drainage basin has not been cleared except for a small area south of the lake that is being developed as a subdivision. As of 1988, no residences had been built.
Sauer Lake is an elongated, oval shape with three tiny bays at the south end. The main body of the lake has 2 deep areas, one 14-m deep and one 12-m deep (FIGURE 2). The lake is 0.58-km long and has a maximum width of 0.38 km. The lake basin slopes steeply on all sides except near the three little bays at the south end. Aquatic plants grow to a depth of 5 m (Chambers and Prepas 1988). Approximately 67% of the lake area is less than this depth (FIGURE 3).
The water level of Sauer Lake has not been monitored. Because there is no surface outflow from the lake, the residence time is likely very long. A good estimate of the water residence time of Sauer Lake would require an estimate of groundwater inflow and outflow.
The water quality of Sauer Lake was monitored by researchers from the University of Alberta from May through July in 1981, from May 1982 through March 1983 and in March and August of 1986 (Prepas and Babin n.d.; Prepas 1983; Prepas and Trew 1983; Babin 1984; Prepas and Vickery 1984[a]; 1984[b]; Babin and Prepas 1985) and by Fish and Wildlife Division (R.L. & L. Envir. Serv. Ltd. 1987).
Sauer Lake contains fresh water; concentrations of alkalinity and hardness are relatively low compared to those in other Alberta lakes (TABLE 3). The dominant ions are bicarbonate and calcium.
Sauer Lake is strongly thermally stratified all summer (FIGURE 4). The top of the thermocline is at a depth of about 3 m by late June; it descends to about 7 m by October. In 1982, the water was anoxic below 12 m when sampling began in early May just after the ice melted; it was anoxic below 8 m from the first of June through August and dissolved oxygen concentrations were less than 1 mg/L below 6 m during the same period. In years when there is little wind in the autumn and the onset of ice cover is rapid, Sauer Lake likely does not mix completely and the bottom water may be anoxic all year. In 1982, some mixing did occur in the autumn, and by late November temperature and dissolved oxygen were uniform from the lake surface to the bottom before freeze-up. However, mixing did not continue for a sufficiently long period to fully oxygenate the lake. By freeze-up, the water was only 72% saturated with dissolved oxygen. Under-ice oxygen-depletion rates were moderately high (0.363 g O2/m2 per day); by mid-February 1983, dissolved oxygen levels had dropped to less than 1 mg/L throughout the water column. Fish cannot survive these conditions and winterkills are common in Sauer Lake. In Figure 5, note that the dissolved oxygen concentration increased through March of 1983. This was due to an algal bloom that developed under the ice; chlorophyll a concentrations peaked at 23 µg/L, higher than values reached through the entire preceding summer (FIGURE 6).
The temperature patterns of lakes have a strong effect on the distribution of phosphorus throughout the water column. In lakes like Sauer, with strong thermal stratification, the amount of phosphorus moving from the sediment into the water is different between shallow and deep areas. In 1982, it was estimated that 0.7 mg total phosphorus/m2 per day returned from the sediments in shallow areas (less than 8-m deep) into the water of the euphotic zone (Shaw and Prepas 1989). In deeper areas of Sauer Lake, there is well-developed anoxia in the bottom stratum, and phosphorus is released from the sediment more quickly than at the shallow sites. By 4 August 1982, the total phosphorus concentration below a depth of 8 m averaged 138 µg/L; in the top few meters it was 20 µg/L (Prepas 1983). There is virtually no mixing across the thermocline (Shaw and Prepas 1989). Thus, when phosphorus in the surface water is taken up by small organisms, it is precipitated to the hypolimnion in waste products or when the small organisms die. Therefore, total phosphorus in the upper layer of the lake is at its highest concentration after partial mixing in spring, then it decreases throughout the summer (FIGURE 6). As the total phosphorus concentration above the thermocline drops, so does the chlorophyll a concentration, and water clarity (measured by Secchi depth) increases. However, light can penetrate the water column to depths below the thermocline and into the upper portion of the phosphorus-rich hypolimnion. It is at this depth (approximately 8 m in Sauer Lake) that a fine balance of high phosphorus concentrations and sufficient light provides the best conditions in the lake for algae to grow; it is here that chlorophyll a and bacteria concentrations are highest. For example, on 29 July 1981, the chlorophyll a concentration from the surface to a depth of 4 m was only 1.3 µg/L, whereas the concentration of a sample incorporating water from the surface to 9 m was 9.2 µg/L. Thus, although Sauer Lake is mesotrophic and fairly nutrient-rich (TABLE 4), most of the algal biomass is well below the surface and the upper water remains clear and attractive for recreation.
In the winter, the bottom stratum is again anoxic and phosphorus is released from the sediment to the water. In March 1983, the total phosphorus concentration in the surface water was only 28 µg/L, while at 13 m it was 164 µg/L. Some of this phosphorus mixes into the surface water soon after the spring thaw.
There are no data on the species of algae in Sauer Lake.
The entire shoreline of Sauer Lake supports emergent vegetation to a depth of 1 m. Common cattail (Typha latifolia) and common horsetail (Equisetum arvense) dominate. Submergent plants grow to a depth of 5 m (Chambers and Prepas 1988). Richardson pondweed (Potamogeton richardsonii), flat-stemmed pondweed (P. zosteriformis) and stonewort (Chara sp.) are the most abundant species. At the south end of the lake, the weed beds are extensive and provide good wildlife habitat.
The zooplankton in Sauer Lake was sampled from May through July in 1981 and from May through September in 1982 (Prepas 1983; Prepas and Vickery 1984[a]). The cladoceran Daphnia galeata mendotae was the dominant species. The copepods Mesocyclops edax and Diacyclops bicuspidatus thomasi were very abundant in 1981 and Diaptomus oregonensis was common in both years. As in many lakes, the abundance of zooplankton is variable from year to year; in Sauer Lake, the total weight of zooplankton in 1982 was consistently more than 50% greater than that in 1981.
Benthic invertebrates in Sauer Lake have not been sampled.
Only two species of fish are indigenous to Sauer Lake: redbelly dace and brook stickleback. The only other fish in the lake are rainbow trout, which have been stocked annually, except from 1957 to 1959 and from 1963 to 1964, by Fish and Wildlife Division. Because winterkill is common, Sauer Lake is managed as a put-and-take fishery. Each spring, approximately 9,000 yearlings (15+ cm) are put in the lake, with the expectation that most will be taken in the sport fishery in the same year (Alta. For. Ld. Wild. n.d.).
Angling pressure is moderately high and success rates are also high. In a 1982 creel survey, 232 anglers caught 438 trout at an average rate of 0.66 trout per hour. This is a much higher rate than the estimated 0.24 trout/hour at nearby Big Chickakoo Lake or 0.12 trout/hour at Hasse Lake (Berry 1986[a]; 1986[b]; 1986[c]).
There are no commercial or domestic fisheries on Sauer Lake.
There is no detailed information on waterfowl use of Sauer Lake. The south end appears to be good waterfowl habitat and Common Loons nest on the lake.
J.M. Crosby and E.E. Prepas
Alberta Culture and Multiculturalism. n.d. Hist. Resour. Div., Hist. Sites Serv. Unpubl. data, Edmonton.
Alberta Environment. n.d. 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 Research Council. 1972. Geological map of Alberta. Nat. Resour. Div., Alta. Geol. Surv., Edmonton.
Babin, J. 1984. Winter oxygen depletion in temperate zone lakes. MSc thesis. Univ. Alta., Edmonton.
----- and E.E. Prepas. 1985. Modelling winter oxygen depletion rates in ice-covered temperate zone lakes in Canada. Can. J. Fish. Aquat. Sci. 42:239-249.
Berry, D.K. 1986[a]. Catch rate and trout harvest for the "put and take" sportfishery at Sauer Lake, Alberta, 1982. Alta. For. Ld. Wild., Fish Wild. Div., Edmonton.
-----. 1986[b]. An assessment of the spring sportfishery at Big Chickakoo Lake, Alberta, 1982. Alta. For. Ld. Wild., Fish Wild. Div., Edmonton.
-----. 1986[c]. Angler harvest and population estimate of rainbow trout in Hasse Lake, Alberta, 1982-83. Alta. For. Ld. Wild., Fish Wild. Div., Edmonton.
Chambers, P.A. and E.E. Prepas. 1988. Underwater spectral attenuation and its effect on the maximum depth of angiosperm colonization. Can. J. Fish. Aquat. Sci. 45:1010-1017.
Energy, Mines and Resources Canada. 1974. National topographic series 1:50 000 83G/9 (1974). 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.
Lindsay, J.D., W. Odynsky, J.W. Peters and W.E. Bowser. 1968. Soil survey of the Buck Lake (NE 83B) and Wabamun Lake (E1/2 83G) areas. Alta. Soil Surv. Rep. No. 24, Univ. Alta. Bull. No. SS-7, Alta. Res. Counc. Rep. No. 87. Univ. Alta., Edmonton.
Prepas, E.E. 1983. The influence of phosphorus and zooplankton on chlorophyll levels in Alberta lakes. Prep. for Alta. Envir., Res. Mgt. Div. Rep. 83/23, Edmonton.
----- and J. Babin. n.d. Univ. Alta., Dept. Zool. Unpubl.data, Edmonton.
Prepas, E.E. and D.O. Trew. 1983. Evaluation of the phosphorus-chlorophyll relationship for lakes off the Precambrian Shield in western Canada. Can. J. Fish. Aquat. Sci. 40:27-35.
Prepas, E.E. and J. Vickery. 1984[a]. The contribution of particulate phosphorus (>250 µm) to the total phosphorus pool in lake water. Can. J. Fish. Aquat. Sci. 41:351-363.
----- . 1984[b]. Seasonal changes in total phosphorus and the role of internal loading in western Canadian lakes. Verh. Internat. Verein. Limnol. 223:303-308.
R.L. & L. Environmental Services Ltd. 1987. County of Parkland fisheries inventory: Sauer Lake. Prep. for Alta. For. Ld. Wild., Fish Wild. Div., Edmonton.
Shaw, J.F.H. and E.E. Prepas. 1989. Potential significance of phosphorus release from shallow sediments of deep Alberta lakes. ms submitted to Limnol. Oceanogr.
Strong, W.L. and K.R. Leggat. 1981. Ecoregions of Alberta. Alta. En. Nat. Resour., Resour. Eval. Plan. Div., Edmonton.