SOUTHERN INDIAN LAKE

An aerial view of the lake


Photo: R. E. Hecky  
 

A. LOCATION

Manitoba, Canada.
56:6-57:1N, 98:9-99:9W; 258* m above sea level.
* 257-258 m Manitoba Hydro operating range.

B. DESCRIPTION

Southern Indian Lake is a widening of the Churchill River located in northern Manitoba. It has a long complex shoreline with many islands, long peninsulas and deep bays. It is 145 km long and up to 19 km wide (2). The Churchill River rises in Alberta, drains central Saskatchewan and a portion of northern Manitoba into Southern Indian Lake.
Southern Indian Lake may be divided into seven regions using natural boundaries. Opachuanau Lake forms an eighth region.
The lake is situated on the Precambrian Shield. The dominant surface material is glaciolacustrine clays deposited by glacial Lake Agassiz. The relief is greater in the southern region. Prior to 1976 Southern Indian Lake drained into Hudson's Bay via the lower Churchill River. In that year Manitoba Hydro diverted the greater portion of the Churchill River flows from Southern Indian Lake at South Bay into the Nelson River drainage system and via that river into Hudson's Bay. This was accomplished by damming the Churchill River at Missi Falls, constructing a diversion channel at South Bay and then raising the lake level 3 m to permit gravity flow into the headwaters of the Rat River tributary of the Nelson River.
Before 1974 Southern Indian Lake was remote and accessible only by air and boat in the summer and by air and winter road in the winter. This remoteness permitted the lake to remain relatively immune from human influence except for a commercial whitefish fishery organized in 1942. Early in the 20th century people from the Nelson House Indian Reserve settled on Southern Indian Lake and established the community of Southern Indian Lake (population approximately 700 people in 1974). The present economy is composed of subsistence hunting and fishing, a severely damaged commercial fisheries and trapping supplemented by government services and compensation payments (Q).

C. PHYSICAL DIMENSIONS (1, 3)

 

Surface area [km2]	2,391*1
Volume [km3]	23.4
Maximum depth [m]	30
Mean depth [m]	9.8
Water level	Regulated
Normal range of annual water
level fluctuation [m]	0.9*2
Length of shoreline [km]	3,798*1
Residence time [yr]
(Region 1)	0.17 (1)
(Region 2)	1.4 (1)
Catchment area [km2]	242,000

*1 Including Opachuanau Lake. *2 3 feet by law.

 

D. PHYSIOGRAPHIC FEATURES

D1 GEOGRAPHICAL
Sketch map: Fig. NAM-33-0l.
Sketch map: Fig. NAM-33-02.
Number of outflowing rivers and channels (name) 2 (Churchill R. and South Bay Diversion Channel).

Fig. NAM-33-01
Sketch map of Prairie Provinces drainage (Q).

 

Fig. NAM-33-02
Sketch map of the lake with location of sampling stations (Q).

 

D2 CLIMATIC Climatic data at Southern Indian Lake, 1978-1987
Mean temp. [deg C]

 

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Ann.
-24.1	-20.3	-13.6	-3.4	5.3	11.5	15.7	14.4	7.4	0.7	-12.0	-21.2	-3.3

 

Precipitation [mm]

 

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Ann.
12	10	12	18	21	27	52	45	31	25	16	11	279

 

Number of hours of bright sunshine (Lynn Lake A): 2,003 hr yr-1 (3a).
Solar radiation (Churchill A)[MJ m-2 day-1]

 

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Ann.
2.27	5.80	12.27	18.89	20.04	21.92	20.36	15.28	8.80	4.22	2.37	1.48	11.4

Water temperature [deg C]*(4) Region 1, 1978
 

[m]
Depth	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	0	0	0	0	0-7	7-12	12-15	15-13	13-9	9-0	0	0

 
* Open water season. Region 4, 1978
 

[m]
Depth	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	0	0	0	0	0-2	2-9	9-12	12-11	11-7	7-0	0	0

 
Freezing period: Middle October or early November-middle May or middle June.
Mixing type: Polymictic.
Notes on water mixing and thermocline formation
Southern Indian Lake is polymictic; due to its shallowness it is well mixed at most times of the year and any stratification is weak.

E. LAKE WATER QUALITY

E1 TRANSPARENCY [m](4)
1978
 

	Min	Max	Ann.
Region 1	0.7	1.4	0.9
Region 4	1.0	1.4	1.1

 
E2 pH*
Region 1, 1975-1978: 12.
Region 4, 1975-1978: 6. * Measured after equilibration with atmosphere.
E4 DO
Oxygen saturation degree [%]
Region 1, May-September 1978: 94-102.
Region 4, May-September 1978: 95-105.
E6 CHLOROPHYLL CONCENTRATION [micro g l-1](5)
Region 1, 5 July-4 September 1978: 4.
Region 4, 5 July-4 September 1978: 3.8.
E7 NITROGEN CONCENTRATION
Total dissolved-N [micro mol l-1]
Region 1, May-September 1978: 18.6-22.1.
Region 4, May-September 1978: 17.1-24.3.
Suspended nitrogen [micro mol l-1]
Region 1, May-September 1987: 4.0-6.4.
Region 4, May-September 1987: 2.4-5.1.
E8 PHOSPHORUS CONCENTRATION
Total dissolved P [micro mol l-1]
Region 1, May-September 1978: 0.10-0.26.
Region 4, May-September 1978: 0.20-0.58.
Suspended P [micro mol l-1]
Region 1, May-September 1978: 0.29-0.52.
Region 4, May-September 1978: 0.16-0.39.
E9 CHLORIDE CONCENTRATION [micor mol l-1]
Region 1, 1978: 34.
Region 4, 1978: 34.

F. BIOLOGICAL FEATURES

F1 FLORA
Macrophytes: None.
Phytoplankton
Melosira islandica and M. italica develop high biomasses in spring and late summer-fall; Anabaena spp. is visually prominent in August; see (6) for list of taxa.
F2 FAUNA
Zooplankton (8)
Cyclops bicuspidatus thomasi, Diaptomus ashlandi and Chydorus sphaericus were dominant in 1972 before impoundment; Senecella calanoides, Diaptomus sicilis and Limnocalanus macruras increased from 1977 to 1980 after impoundment but failed to replace the pre-impoundment dominants.
Benthos (9, 10)
Ablabesmyia monilis, Procladius sp., Parakiefferiella bathophila, Chironomus hyperboreus, Microtendipes pedullus var. pedellus and Paratanytarsus laccophilus were the dominant chironomids in the littoral zone of Southern Indian Lake 1977-79; a total of 158 species were identified.
Fish
Coregonus clupeaformis* (lake whitefish), C. artedii (lake cisco), Stizostedion vitreum* (walleye), S. canadense, Esox lucius* (northern pike), Salvelinus namycush (lake trout), Lota lota, Perca flavescens, Catostomus commersoni, C. catostomus, Hiodon alosoides, Pungitius pungitius, Cottus cognatus, spottail shiner, Iowa darter, Johnny darter, trout-perch, spoonhead sculpin, brook stickleback, longnose duce, lake chub.
* Economically important.
F3 PRIMARY PRODUCTION RATE [mg C m-2 day-1]
Region 4, 1975
 

	Jun	Jul	Aug	Sep
Gross production	200	200	500	580

 
Annual [g m-2 yr-1]: 50.
F4 BIOMASS (8, 8a)
Plankton [mg l-1]
June-July: 0.1.
August-September: 1.
Crustacean zooplankton density [no l-1]
1972: 76*.
* The density value is comparable to that of Lake Ontario.
F5 FISHERY PRODUCTS
Annual fish catch: See F6.
F6 PAST TRENDS
Rates of phytoplankton primary productivity were for the most part not significantly altered by impoundment and diversion. Limiting factor however changed from phosphorus limitation before impoundment to light limitation because of siltation after impoundment (4, 5). Benthos lakewide standing stocks increased in response to impoundment but decreased shortly after (9).
Annual Commercial Fishery Yields (7a)
All yields are in marketed kilograms. The "other" category includes goldeye, cisco and lake trout. DEL = number of daily deliveries = fishing effort. No fishing in 1974.
 

Year	Walleye	Pike	Whitefish	Other	Total	DEL
1941	544	0	8,799	0	9,343	M
1942	590	0	70,943	0	71,533	M
1943	2,812	1,497	1,286	45	5,640	M
1944	10,886	3,310	186,247	0	200,943	M
1945	10,342	1,542	356,437	0	368,321	M
1946	10,841	3,719	408,555	0	423,115	M
1947	5,035	0	262,814	0	267,849	M
1948	6,486	0	163,295	0	169,721	M
1949	7,394	0	172,866	0	180,260	M
1950	1,905	45	271,251	0	273,201	M
1951	953	0	304,091	0	305,044	M
1952	0	0	272,340	0	272,340	M
1953	5,443	0	268,303	0	273,746	M
1954	36,605	0	221,401	0	258,006	M
1955	53,252	0	95,618	0	148,870	M
1956	32,568	0	163,749	0	196,317	M
1957	5,307	0	249,070	0	254,377	M
1958	5,942	0	243,128	0	249,070	M
1959	4,763	771	166,697	544	172,775	M
1960	3,719	2,359	262,088	0	268,166	M
1961	2,495	227	373,220	0	375,942	M
1962	1,315	227	309,353	0	310,895	M
1963	1,270	635	274,925	0	276,830	M
1964	3,629	2,359	271,705	0	277,693	M

 
 

Year	Walleye	Pike	Whitefish	Other	Total	DEL
1965	3,719	7,847	238,320	0	249,886	M
1966	5,489	5,625	129,457	0	140,571	M
1967	2,223	4,037	157,625	0	163,885	M
1968	363	1,678	184,977	0	187,018	M
1969	272	1,406	151,229	0	152,907	M
1970	1,270	227	141,477	0	142,974	3,625
1971	635	771	123,786	0	125,192	1,124
1972	45	227	103,738	0	104,010	492
1973	0	181	12,701	0	12,882	1,996
1974	0	0	0	0	0	M
1975	45	318	50,712	0	51,075	1,581
1976	63,144	23,378	349,926	67	436,515	3,185
1977	37,068	34,240	359,599	332	431,239	2,970
1978	18,941	36,878	331,852	84	387,755	3,292
1979	16,739	57,324	357,245	12,620	443,928	3,480
1980	11,913	25,212	354,192	7,380	398,697	3,817
1981	18,615	28,276	256,695	11,587	315,173	3,687
1982	16,820	10,329	96,457	7,831	131,437	1,500
1983	5,699	10,108	200,096	4,385	220,288	1,825
1984	19,674	13,579	215,522	6,123	254,898	2,182
1985	26,807	35,522	196,932	1,204	260,465	2,197
1986	19,848	32,512	135,742	83	188,185	1,883

 
F7 NOTES ON THE REMARKABLE CHANGES OF BIOTA IN THE LAKE IN RECENT YEARS
General collapse of fishery due to effects of river diversion and impoundment over the period 1976-81 (13).
Decline in populations of burrowing mayflies (Hexagenia limbata and H. rigida) from 1979 to 1983 was attributed to a very cold year in 1978. The extended recovery period was due to the long development period of these organisms in the lake (13).
Increases in the relative abundance of Diaptomus sicilis, Senecella calanoides and Limnocalanus macruras was attributed to impoundment (8).

G. SOCIO-ECONOMIC CONDITIONS

G1 LAND USE IN THE CATCHMENT AREA
 

	[%]
Natural landscape
Woody vegetation*	100
Total	100

* Including herbaceous vegetation and swamp.
Types of important forest or scrub vegetation
Boreal forest (black spruce, pine, aspen, birch).
G2 INDUSTRIES IN THE CATCHMENT AREA AND THE LAKE
Wilderness.
Number of domestic animals in the catchment area: None.
G3 POPULATION IN THE CATCHMENT AREA
Early in the 20th century native people from the Nelson House Indian Reserve settled on Southern Indian Lake. In 1974 approximately 700 people had established themselves in the community of Southern Indian Lake.

I. DETERIORATION OF LAKE ENVIRONMENTS AND HAZARDS

I1 ENHANCED SILTATION
Extent of damage: Serious.
Supplementary notes
Altered fish distribution, and caused high mortality in fish eggs.
I2 TOXIC CONTAMINATION
Mercury concentration in fish muscle [mg kg-1] (11)
Walleye: 0.80 in 1978.
Whitefish: 0.31 in 1979.
Northern pike: 1.18 in 1984.
From 1975 to 1986 the mean concentration (mg kg-1) of fish muscle mercury in whitefish taken from South Bay ranged from a low of 0.07 to a high of 0.31 with the peak concentrations occurring in 1979. During the same period northern pike muscle mercury ranged from a low of 0.67 in 1985 to a high of 1.18 in 1984. South Bay walleye muscle mercury ranged from a low of 0.47 in 1979 to a high of 0.80 in 1978. The only contaminant for which fish contaminant data are available is mercury.
Environmental quality standards for contaminations in the lake: None.
Food safety standards or tolerance limits for toxic contaminant residue
National standard for Hg is 0.5 micro g-1 in food.
Past trends of the above concentrations (11, 12, 14)
Sharp increases in mercury in fish muscle immediately after impoundment of the lake; trends in recent years are variable, depending on species.
I3 EUTROPHICATION
Nuisance caused by eutrophication
Unusual algal bloom;Anabaena becomes visually prominent in August in this pristine lake environment.
Nitrogen and phosphorus loadings to the lake [g m-2 yr-1]
 

Sources	Natural
T-N	0.25
T-P	4.8

 
I4 ACIDIFICATION Extent of damage: None (system is well buffered).

J. WASTEWATER TREATMENTS

J1 GENERATION OF POLLUTANTS IN THE CATCHMENT AREA
a) Pristine lake environments.
J3 SANITARY FACILITIES AND SEWERAGE
Cottage density extremely low.

M. LEGISLATIVE AND INSTITUTIONAL MEASURES FOR UPGRADING LAKE ENVIRONMENTS

M1 NATIONAL AND LOCAL LAWS CONCERNED
Names of the laws (the year of legislation)
1. Federal Fisheries Act Responsible authorities
2. Department of Fisheries
3. Manitoba Ministry of the Environment, Fisheries Branch Main items of control
4. Protection of fish species
5. Fishing and hunting regulations
6. Monitoring mercury levels in fish muscle
M3 RESEARCH INSTITUTES ENGAGED IN THE LAKE ENVIRONMENT STUDIES
1. Department of Fisheries and Oceans, Freshwater Institute, Winnipeg, Manitoba (research began in 1972 and is continuing to date)
 

N. SOURCES OF DATA

17. Questionnaire filled by Dr. R. E. Hecky, Canada Department of Fisheries and Oceans, Freshwater Institute, Winnipeg, Manitoba.
1. McCullough, G. K. (1981) Water Budgets for Southern Indian Lake, Manitoba, Before and After Impoundment and Churchill River Diversion, 1972-79. Can. Manuscr. Rep. Fish. Aquat. Sci. 1620. 22 pp.
2. Cranstone, J. R. (1972) Geology of the Southern Indian Lake Area, Northeastern Portion. Manitoba Department of Mines, Resources and Environmental Management.
3. Newbury, R. W., McCullough, G. K. & Hecky, R. E. (1984) The Southern Indian Lake impoundment and Churchill River diversion. Can. J. Fish. Aquat. Sci., 41: 548-557.
4. Canadian Climate Normals (1951-80) Environment Canada, Atmospheric Environment Service.
5. Hecky, R. E. (1984) Thermal and optical characteristics of Southern Indian Lake before, during and after impoundment and Churchill River diversion. Can. J. Fish. Aquat. Sci., 41: 579-590.
6. Hecky, R. E. & Guildford, S. J. (1984) Primary productivity of Southern Indian Lake before, during and after impoundment and Churchill River diversion. Can. J. Fish. Aquat. Sci., 41: 591-604.
7. Hecky, R. E., Kling, H. J. & Brunskill, G. J. (1986) Seasonality of phytoplankton in relation to silicon cycling and interstitial water circulation in large shallow lakes of central Canada. Hydrobiologia, 138: 117-126.
8. Planas, D. & Hecky, R. E. (1984) Comparison of phosphorous turnover times in northern Manitoba reservoirs with lakes of the Experimental Lakes Area. Can. J. Fish. Aquat. Sci., 41: 605-612.
9. Lysek, W. Manitoba Department of Natural Resources, Fisheries Branch, Winnipeg, Manitoba R3H 0W9 (204-945 7796).
10. Patalas, K. & Salki, A. (1984) Effects of impoundment and diversion on the crustacean plankton of Southern Indian Lake. Can. J. Fish. Aquat. Sci., 41: 613-637.
11. Patalas, K. (1975) The crustacean plankton communities of fourteen North American great lakes. Int. Verein. Limnol. Verh., 19: 504-511.
12. Wiens, A. P. & Rosenberg, D. M. (1984) Effect of impoundment and river diversion on profundal macrobenthos of Southern Indian Lake, Manitoba. Can. J. Fish. Aquat. Sci., 41: 638-648.
13. Rosenberg, D. M., Bilyj, B. & Wiens, A. P. (1984) Chironimidae (Diptera) emerging from the littoral zone of reservoirs with special reference to Southern Indian Lake, Manitoba. Can. J. Fish. Aquat. Sci., 41: 672-681.
14. Bodaly, R. A., Strange, N. E. & Fudge, R. J. P. (1988) Mercury Content of Fish in the Southern Indian Lake and Issett Reservoirs, Northern Manitoba, Before and After Churchill River Diversion. Can. Data Rep. Fish. Aquat. Sci. 706. 59 pp.
15. Bodaly, R. A., Hecky, R. E. & Fudge, R. J. P. (1984) Increases in fish mercury levels in lakes flooded by the Churchill River diversion, northern Manitoba. Can. J. Fish. Aquat. Sci., 41: 682-691.
16. Bodaly, R. A., Johnson, T. W. D., Fudge, R. J. P. & Clayton, J. W. (1984) Collapse of the lake whitefish (Coregonus clupeaformis) fishery in Southern Indian Lake, Manitoba, following lake impoundment and river diversion. Can. J. Fish. Aquat. Sci., 41: 692-700.
17. Summary report (1987) Canada-Manitoba Agreement on the Study and Monitoring of Mercury in the Churchill River Diversion.
The following people have contributed information to this submission:
Drs. R. E. Hecky, R. A. Bodaly, K. Patalas, D. M. Rosenberg, H. J. Kling, C. Allan, C. Anema, G. K. McCullough and S. J. Guilford.