|Lat / Long||53.8833333, -114.2000000|
|Max depth||8 m|
|Mean depth||4.5 m|
|Dr. Basin Area||44.9 km2|
|Drainage Basin||Athabasca River Basin|
|Sport Fish||Yellow Perch, Northern Pike|
|TP x||88 µg/L|
|CHLORO x||44.2 µg/L|
|TDS x||167 mg/L|
Nakamun Lake is an attractive lake set in rolling hills in the counties of Lac Ste. Anne and Barrhead. It is located about 95 km northwest of Edmonton and 28 km south of the town of Barrhead. To reach the lake from Edmonton, take Highway 16 west to its junction with Highway 43. Turn north on Highway 43 and drive north and then west to Highway 33. Turn north and drive 17 km to Secondary Road 650, then drive east along this road to the west end of Nakamun Lake. The north and south sides of the lake can be reached by municipal roads running west from Secondary Road 777 (FIGURE 1).
Nakamun is Cree for "song of praise" or "songbird" (Geog. Bd. Can. 1928). Settlers arrived in the area at the end of the nineteenth century and began clearing land for agriculture to the east and northeast of the lake. Most of the land around the lake is privately owned and the south shore is extensively developed. The first subdivision was established in 1960; it was incorporated as the summer village of Nakamun Park in 1966. Four Oakes subdivision was founded in 1962 about 400 m east of Nakamun Park, and Nakamun Court subdivision (also called Losie Glade) was built in 1975 adjacent to the west side of Four Oakes. The north shore is mostly undeveloped except for a Bible camp and a few cottages.
The only public access to Nakamun Lake is on the south shore at several public reserves. Two of these reserves have facilities (FIGURE 2). The Nakamun Park reserve has a boat launch, a dock, a day-use area and a small sand beach. The reserve in Nakamun Court has a boat launch, a picnic shelter, a hand water pump and a few campsites. In Four Oakes, the reserve provides only a hand pump and access to the lake. Activities that are popular at Nakamun Lake include boating, fishing, hiking, photography, nature study, picnicking and relaxation. There are no boating restrictions over most of the lake, but in posted areas, power boats are restricted to maximum speeds of 12 km/hour (Alta. For. Ld. Wild. 1988). High nutrient levels in the lake cause excessive algal growth, which impairs water-contact recreation. Sport fishing has been hampered by fish kills in winter, but stocking with yellow perch from 1984 to 1986 has revived the sport fishery. A few northern pike, and many sticklebacks and minnows, also inhabit the lake. There are no sport fishing regulations specific to Nakamun Lake, but provincial limits and regulations apply (Alta. For. Ld. Wild. 1989).
Nakamun Lake's drainage basin is about 13 times the size of the lake (Tables 1, 2). There are no major inflows to the lake, and the small inflowing creeks tend to dry up after snowmelt in the spring. A small permanent water body, Kakina Lake, is located to the southeast (FIGURE 1); it flows intermittently into Nakamun Lake. The outflow, located at the northwest end of the lake, connects Nakamun Lake to Lac la Nonne only during periods when water levels are high. Groundwater inflow to Nakamun Lake has not been estimated, but the direction of flow is from the southeast part of the watershed to the northwest (Edm. Reg. Plan. Commis. 1979).
The topography of the drainage basin is quite varied. To the south and west, the land is gently rolling to rolling, with slopes from 5 to 15%; frequently, sloughs have formed in depressions. To the northwest, the terrain is undulating to gently rolling, with slopes from 1 to 8%, and to the northeast the land is gently rolling to rolling, with some slopes greater than 15%. The elevation of the land ranges from 732 m at the northeastern and southern edges of the drainage basin to 683 m at the lakeshore.
The watershed is located in the Moist Mixedwood Subregion of the Boreal Mixedwood Ecoregion (Strong and Leggat 1981). The soils are mainly well-drained to moderately well-drained Orthic Gray Luvisols and moderately well-drained to imperfectly drained Solodic Gray Luvisols. Both of these soils developed on moderately fine-textured to medium-textured glacial till. Significant areas of very poorly drained Mesisols are located throughout the watershed, as well. The forest cover is dominated by trembling aspen and balsam poplar on well-drained soils and balsam poplar in moister areas and at the lakeshore. Black spruce grows on poorly drained Organics and Gleysols, most of which are located to the north and east of the lake. There are a number of wet depressions throughout the drainage basin; they generally contain peat, sedges and slough grass and are surrounded by willow, dwarf birch and alder (Twardy and Brocke 1976).
Although undesirable soil structure, adverse topography and, in some areas, excessive moisture, have limited agriculture in the drainage basin, more than half of the land has been cleared for agriculture. The predominant agricultural activity is beef production and most of the cleared land is used for either improved pasture or forage production (Twardy and Brocke 1976; Edm. Reg. Plan. Commis. 1979).
Much of the land near the lake has been developed for seasonal and permanent residences. About 23% of the shoreline is developed, mostly on the south shore, which is extensively subdivided (FIGURE 1). There are a few cabins on quarter sections on the northeast shore. Development near Nakamun Lake was restricted in 1977, when the lake became subject to the provincial government's Regulated Lake Shoreland Development Operation Regulations, which were administered by Alberta Environment. The regulations ensured that additional development did not take place until a lake management plan and an area structure plan were prepared and the area structure plan was adopted by the counties of Lac Ste. Anne and Barrhead as part of their land-use bylaws. This process was completed by 1981 (Edm. Reg. Plan. Commis. 1979; 1980; 1981). Lake management plans determine the extent of future land developments, allocate land use and determine ways to minimize environmental impacts and conflicts in the use of the lakeshore. They also recommend preferred lake uses and ways to minimize lake-user conflicts.
Nakamun Lake is a medium-sized, fairly shallow lake that has a maximum length of 2.2 km and a maximum width of 0.8 km (TABLE 2, FIGURE 2). The deepest area (8.0 m) is located in the centre of the basin. There is one small island at the west end of the lake, and an island of reeds at the east end. The lake's elevation has been monitored since 1968 (FIGURE 3). The difference between the minimum elevation (682.06 m), recorded in September 1968, and the maximum elevation (683.03 m), recorded in July 1974, is 0.97 m. From 1980 to 1987, the lake level fluctuated by a maximum of 0.46 m. Changes in the lake's surface area and capacity with fluctuations in water level are illustrated in Figure 4.
Nakamun Lake was studied from 1977 to 1979 and since 1983 by Alberta Environment (Alta. Envir. n.d.[a]; 1985), and from 1980 to 1983 by the University of Alberta (Prepas and Babin n.d.; Prepas 1983[b]; Prepas and Trew 1983; Riley 1983; Riley and Prepas 1984; Babin and Prepas 1985). It is one of six lakes in Alberta with extensive long-term water quality data. The lake was chosen for long-term study because it is representative of shallow, eutrophic lakes.
The dominant ions in Nakamun Lake are calcium, sodium and bicarbonate. The water is alkaline and moderately hard (TABLE 3), and turbidity (25 NTU) and colour (22 mg/L Pt) measurements are moderate (Prepas and Trew 1983).
The water column mixes almost completely after ice-out, and is thermally stratified by early June (FIGURE 5). In summer, the lake periodically mixes and restratifies. The water column is well-mixed by late summer, and remains so until ice forms on the surface. Under ice in most years, dissolved oxygen decreases until, between January and March, a large part of the water column is anoxic, as in 1983 (FIGURE 6). Surface concentrations of dissolved oxygen, however, are adequate for fish survival in most years.
Nakamun Lake is hyper-eutrophic. The average total phosphorus and chlorophyll a concentrations are high and the Secchi transparency is low (TABLE 4), indicating high concentrations of algae. In one study, the annual external supply of phosphorus to the lake was estimated to be 779 kg/year, or 0.22 g/m2 of lake surface area (TABLE 5). Almost 60% of this phosphorus originates from cleared areas, many of which are agricultural, whereas only 23% comes from forested areas. The remaining 17% originates from urban runoff, precipitation, dustfall, inflow from upstream lakes and sewage from residential areas. The value for sewage was not measured directly; it was calculated from data collected for other Alberta lakes. In another study, the internal loading of phosphorus from the sediments was estimated. Water next to the sediments goes anoxic during stratified periods (FIGURE 6) and total phosphorus and total dissolved phosphorus levels in the deeper water increase rapidly. A substantial amount of total phosphorus is released from the sediments: in 1982, it was estimated that 1468 kg were released during stratified periods from May to November (Riley 1983; Riley and Prepas 1984). In the same study, terrestrial and atmospheric inputs for the period were estimated to be 82 kg (not including spring runoff). The estimated internal load calculated for the six summer months of 1982 is about twice that of the annual external load of 779 kg of phosphorus. In winter, the internal phosphorus load to the surface water is probably equal to that in summer. In March 1986, for example, total phosphorus levels under ice exceeded 100 µg/L (Prepas and Babin n.d.). Therefore, at least 80% of the annual loading of phosphorus to the surface waters originates from the lake sediments.
Total phosphorus concentrations of 100 to 200 µg/L in the euphotic zone are not uncommon in Nakamun Lake in late winter. These concentrations remain high after ice-out, as in May 1982 (FIGURE 7). Algal biomass (measured as chlorophyll a) was very high in May 1982 as well, but decreased to relatively low levels during June (FIGURE 7). Lower concentrations of phosphorus and extensive grazing by zooplankton may limit the algal population at this time. During July and August, recycling of phosphorus from the sediments and subsequent growth of blue-green algae, which may be inedible to zooplankton, turn the lake water to "pea soup". Most of the internal phosphorus load during stratified periods is total dissolved phosphorus, which is rapidly assimilated by algae when it is mixed into the surface water (Prepas 1983[b]; Riley and Prepas 1984). The amount and timing of phosphorus loading from the sediments varies considerably from year to year. Consequently, average total phosphorus and chlorophyll a levels during summer can vary considerably between years (TABLE 6). Between 1980 and 1987, average total phosphorus concentrations ranged from a minimum of 59 µg/L in 1987 to a maximum of 163 µg/L in 1981. During the same period, average chlorophyll a concentrations ranged from a minimum of 28 µg/L in 1985 to a maximum of 174 µg/L in 1981. These changes are probably due to weather patterns, but the precise aspects are not yet understood.
The phytoplankton in Nakamun Lake was surveyed in 1978, 1979 and 1983 by Alberta Environment (Alta. Envir. n.d.[a]) and in 1982 by the University of Alberta (Riley 1983; Riley and Prepas 1984). In 1983, algal biomass averaged about 12 mg/L; the biomass remained below 5 mg/L until late August, when it increased to almost 65 mg/L (TABLE 7). The biomass decreased to less than 8 mg/L during September. Cryptomonads (Cryptophyta) were the dominant group from early May to the end of June in 1983. The main species were Cryptomonas rostratiformis and C. erosa reflexa in May and C. rostratiformis and C. Marsonii in June. From late July through October, blue-greens (Cyanophyta) were the dominant group. The most important species were Gloeotrichia echinulata in late July, Anabaena spiroides crassa, A. circinalis and Aphanizomenon flos-aquae in late August, and Oscillatoria agardhii during September and October. High phosphorus concentrations and frequent periods when anoxic water overlies the bottom sediments contribute to the dominance of the algal community by blue-green algae (Trimbee and Prepas 1987; 1988).
Aquatic macrophytes were surveyed in 1979 and 1984 by Alberta Environment (Alta. Envir. n.d.[a]; Stocked and Kent 1984). In 1984, 22 species were identified (FIGURE 8). The dominant emergent species was common great bulrush (Scirpus validus) and the most abundant submergent species were northern watermilfoil (Myriophyllum exalbescens) and Sago pondweed (Potamogeton pectinatus). Three emergent species found in 1984-water smartweed (Polygonum amphibium), arrowhead (Sagittaria cuneata) and giant duckweed (Spirodela polyrhiza) - were not present in the 1979 samples. Similarly, two submergent species-stonewort (Chara sp.) and smallleaf pondweed (Potamogeton pusillus) - were not identified in 1979.
The distribution of emergent species underwent only minor changes between 1979 and 1984. Along the north shore, the most frequently occurring emergent species was common great bulrush, whereas common cattails (Typha latifolia) were dominant at the lake's east and west ends. Along the south shore, wave action and mechanical harvesting by cottage owners had considerably reduced the abundance of these plants. Submergent species grew densely along much of the shoreline, with the exception of the south shore. Between 1979 and 1984, northern watermilfoil replaced Richardson pondweed (Potamogeton richardsonii) and large-sheath pondweed (P. vaginatus) as the most common submergent species in many areas along the south shore. As well, northern watermilfoil was very abundant along the east half of the north shore in 1984. The macrophyte communities of highly eutrophic lakes such as Nakamun are often dominated by only a few species.
Data on zooplankton numbers are not available. Bosmina longirostris and either Acanthodiaptomus denticornis or Diaptomus oregonensis were very common in samples taken on 22 June 1981 by researchers with the University of Alberta (Prepas 1983 [a]). Mesocyclops edax and Acanthocyclops vernalis were also present, but less abundant. The biomass of large plankton (greater than 250 µm) was more variable within a season and between years in Nakamun Lake than in 12 other central Alberta lakes (Prepas and Vickery 1984).
Benthic invertebrates were sampled by Alberta Environment in 1976 (TABLE 8). Aquatic earthworms (Oligochaeta) and midge larvae (Chironomidae) were most numerous and molluscs, phantom midges (Chaoborus sp.), roundworms (Nematoda) and water mites (Hydracarina) were present in lower numbers.
Nakamun Lake is managed by Fish and Wildlife Division for recreational fishing. Severe winterkills of fish were recorded in 1955, 1969, 1971 and 1974. In 1969, the owner of a private campground reported that 200 anglers who used the campground that year caught no fish, although fishing success had been moderate the previous year (Alta. For. Ld. Wild. n.d.). The lake was stocked with adult northern pike in 1969 and 1970, but the winterkills in 1971 and 1974 decimated the population. In 1989, yellow perch, large numbers of sticklebacks and minnows, and a few northern pike inhabited the lake and burbot had been reported (Watters 1989). The pike and burbot probably entered Nakamun Lake from Lac la Nonne during years when high water levels provided flow between the two lakes (Edm. Reg. Plan. Commis. 1979; Alta. Envir. 1985). The yellow perch originate from a stocking program implemented by Fish and Wildlife Division in 1984. A total of 13,550 adult and 20,000 subadult yellow perch were stocked between 1984 and 1986 (Berry 1988) and good catches of perch were reported during the winters from 1986/87 to 1988/89 Matters 1989).
No specific data are available for the wildlife at Nakamun Lake, but shallow bays along the north and east shores are reported to support a variety of waterfowl species (Edm. Reg. Plan. Commis. 1979).
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.
-----. n.d.[c]. Tech. Serv. Div., Surv. Br. Unpubl. data, Edmonton.
-----. 1985. Nakamun Lake. Poll. Contr. Div., Water Qlty. Contr. Br., Edmonton.
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-----. 1989. Guide to sportfishing. Fish Wild. Div., Edmonton.
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-----. 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. 1988. Alta. For. Ld. Wild., Fish Wild. Div., Edmonton. Pers. comm.
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-----. 1980. Nakamun Lake management plan alternatives. Edm. Reg. Plan. Commis., Edmonton.
-----. 1981. Nakamun Lake area structure plan. Edm. Reg. Plan. Commis., Edmonton.
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-----. 1988. Alta. Envir., Envir. Assess. Div., Envir. QIty. Monit. Br., Edmonton. Pers. comm.
Prepas, E.E. 1983[a]. The influence of phosphorus and zooplankton on chlorophyll levels in Alberta lakes. Prep. for Alta. Envir., Res. Mgt. Div. Rep. 83/23, Edmonton.
-----. 1983[b]. Orthophosphate turnover time in shallow productive lakes. Can. J. Fish. Aquat. Sci. 40:1412-1418.
-----. 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. The contribution of particulate phosphorus (>250 µm) to the total phosphorus pool in lake water. Can. J. Fish. Aquat. Sci. 41:351-363.
Riley, E.T. 1983. Internal phosphorus loading from the sediments and the phosphorus-chlorophyll model in shallow lakes. MSc thesis. Univ. Alta., Edmonton.
-----. and E.E. Prepas. 1984. Role of internal phosphorus in two shallow, productive lakes in Alberta, Canada. Can. J. Fish. Aquat. Sci. 41:845-855.
Stockerl, E.C. and R.L. Kent. 1984. Aquatic macrophyte survey of Baptiste and Nakamun Lakes, 1984. Prep. for Alta. Envir., Poll. Contr. Div. by Okanagan Diving Serv. (ODS) Consult., Edmonton.
Strong, W.L. and K.R. Leggat. 1981. Ecoregions of Alberta. Alta. En. Nat. Resour., Resour. Eval. Plan. Div., Edmonton.
Trimbee, A.M. and E.E. Prepas. 1987. Evaluation of total phosphorus as a predictor of the relative biomass of blue-green algae with emphasis on Alberta lakes. Can. J. Fish. Aquat. Sci. 44:1337-1342.
-----. 1988. The effect of oxygen depletion on the timing and magnitude of blue-green algal blooms. Verh. Internat. Verein. Limnol. 23:220-226.
Twardy, A.G. and L.K. Brocke. 1976. Soil survey and land suitability evaluation of the Sandy Lake-Nakamun Lake study area. Prep. for Alta. Envir. by Pedol. Consult., Edmonton.
Watters, D. 1989. Alta. For. Ld. Wild., Fish Wild. Div., Dist. Office, Edmonton. Pers. comm.