LAC SAINT-JEAN (LAKE SAINT-JOHN)

A view on the lakeshore


Photo: M. Quelett  
 

A. LOCATION

Quebec, Canada. 48:5 -48:5 N, 71:5 -72:0 W; 99.6 m above sea level.

B. DESCRIPTION

The Saguenay-Lake-Saint-Jean hydrographic system located within the south- central part of the Province of Quebec (Canada), has been since 1926 an important source of hydro-electric power. From the late twenties to the end of the fifties six hydro-electric power dams were built on the Peribonca and the Saguenay Rivers for a total installed capacity of 2,700 MW. These are owned and operated by the Aluminium Company of Canada (ALCAN) which uses this energy for the electrolysis of alumina in its three nearby aluminium smelters having a total annual metal production of 606,000 t. The whole hydrographic system covers a total area of 85,000 km2 within the northern latitudes of 47¡¦0' to 52¡¦1' and the western longitudes of 69¡¦1' to 74¡¦0'. The catchment, of typical Canadian Shield landforms, is made up of three distinct physiographic units. The forested head water unit, varying in altitude from a maximum of 1,500 m to a minimum of 180 m, drains 80% of the whole system. In its northern part, it is drained by several large rivers (Peribonca, Mistassini, Mistassibi, Chamouchouane, Ouasienmsca, Samaqua) all running in a southern direction through nearly parallel glacier-carved valleys. The southern smaller part of the Highlands is drained by the Metabetchouane, the Ouiatchouane and the Ouiatchouaniche. All these converge toward Lake Saint- Jean which acts as the main central reservoir for power dams located on the head of the Saguenay River.
Although the Saguenay Fiord physiographic unit is very rugged, it is of majestic beauty and this has recently lead our governments to create national parks within that part of the country. Moreover, it is the most southerly fiord of the North Hemisphere and has been sustaining since postglacial times a typical arctic inland-entrapped fauna within its cold water which reaches a depth over 350 m. The white whale (Delphinapterus leucan) has been, till lately, the most important species representative of this northern fauna. Presently, because of industrial pollution originating since half a century largely from the aluminium smelters, their numbers are rapidly diminishing. From its asymmetric population age structure, it is only a matter of time before being completely wiped out from that peculiar range habitat.
The climate of the area is humid continental, with cold summer but without dry season. At near the lake level (Roberval), July mean temperature of the area is 17¡¦ while January average is -17¡¦. The growing season lasts from May 18th to October 4th, for a period of about 100 days without frost.
Because of the large volume of low mineralized waters (1,457 m3 sec-1) originating from unpopulated forested areas and the short retention time (93 days) within the lacustrine basin, the water quality of the pelagic zone is almost unaffected by anthropogenic activities (Q).

C. PHYSICAL DIMENSIONS

 

Surface area [km2]	1,053
Volume [km3]	11.9
Maximum depth [m]	63.1
Mean depth [m]	11.4
Water level	Regulated
Normal range of annual water
level fluctuation [m]	5.5
Residence time [yr]	0.3
Catchment area [km2]	71,947

 

 

D. PHYSIOGRAPHIC FEATURES

D1 GEOGRAPHICAL (Q) Bathymetric map: Fig. NAM-10-0l. Number of outflowing rivers and channels (name) 2 (Yarge and a small discharge).
D2 CLIMATIC (Q) Climatic data at Roberval* Mean temp. [deg C]

 

Jan	Feb	Mar	Apr	May	Jul	Jul	Aug	Sep	Oct	Nov	Dec	Ann.
-16.1	-15.8	-2.0	1.9	10.1	15.1	20.1	16.6	11.8	4.2	-1.2	-12.8	2.66

Precipitation [mm]
 

Jan	Feb	Mar	Apr	May	Jul	Jul	Aug	Sep	Oct	Nov	Dec	Ann.
61	52	54	54	66	91	118	101	103	78	78	73	929

 
* 30-year mean.

Number of hours of bright sunshine (Quebec): 1,669 hr yr-1. Snowfall (Quebec): 3,044 mm.

Fig. NAM-10-01
Bathymetric map (Q).

 

Water temperature [deg C] Lake centre, 1979

 

Depth[m] Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	-	-	0.9	0.3	-	11.1	20.4	18.4	15.6	9.8	7.8	0.3
5	-	-	0.2	0.5	-	9.4	16.5	17.7	15.3	9.6	7.8	0.3
10	-	-	0.5	0.3	-	9.2	16.5	17.5	15.1	9.6	7.8	0.5
20	-	-	0.5	0.5	-	8.5	12.4	17.0	15.3	9.6	7.75	2.0
30	-	-	0.5	1.5	-	6.7	11.0	12.5	15.1	9.6	7.75	3.0
40	-	-	1.5	1.5	-	6.3	9.7	11.5	14.8	9.6	7.1	4.0
50	-	-	1.5	2.0	-	5.6	9.0	10.5	14.8	9.6	7.0	4.0
60	-	-	1.5	2.0	-	5.8	8.5	10.0	12.5	9.5	6.5	4

 

Freezing period: December-May. Mixing type: Dimictic. Notes on water mixing and thermocline formation Mixing from 25 November to 15 May.Thermocline from July to end of August. E. LAKE WATER QUALITY E2 pH (Q) Lake centre, 1977: 6.93òÒ.21. E3 SS [mg l-1](Q) Lake centre, 1979

 

Depth[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	-	-	-	-	-	1	1	1	1	1	-	-
10	-	-	-	-	-	1	1	1	1	1	-	-
20	-	-	-	-	-	1	1	1	1	1	-	-
30	-	-	-	-	-	1	1	1	1	1	-	-
40	-	-	-	-	-	1	1	1	1	1	-	-
50	-	-	-	-	-	1	2	2	2	1	-	-
60	-	-	-	-	-	1	2	2	3	1	-	-

 

E4 DO [mg l-1](Q) Lake centre, 1979

 

Depth[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	-	-	-	-	12.5	12.5	9	8	8.7	8.8	9	-
10	-	-	-	-	12.5	12.5	9	8	8.5	8.8	9	-
20	-	-	-	-	12.5	12.5	9	7.7	8.5	8.7	9	-
30	-	-	-	-	12.5	13	9	7.7	8.4	8.7	9	-
40	-	-	-	-	12.5	13	9	7.6	8.0	8.6	9	-
50	-	-	-	-	12.5	13	9	7.5	7.5	8.6	9	-
60	-	-	-	-	12.5	13	9	7.5	7.5	8.5	9	-

 

E5 COD [mg l-1](Q) Total organic carbon Lake centre, 1979

 

Depth[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	-	-	-	-	-	-	11	13.5	12.5	12	-	-
10	-	-	-	-	-	-	11	13.5	12.5	12	-	-
20	-	-	-	-	-	-	11	13.5	12.5	12	-	-
30	-	-	-	-	-	-	11	13.5	12.5	12	-	-
40	-	-	-	-	-	-	11	13.0	12.5	13	-
50	-	-	-	-	-	-	11	12.5	13	12	-	-
60	-	-	-	-	-	-	11	12.5	13	13	-	-

 

Total inorganic carbon Lake centre, 1979

 

Depth[m]	Jan	Feb	May	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	-	-	-	-	-	-	0.5	1.0	0.5	1.0	-	-
10	-	-	-	-	-	-	0.5	1.0	0.5	1.0	-	-
20	-	-	-	-	-	-	0.5	1.0	0.5	1.0	-	-
30	-	-	-	-	-	-	0.5	1.0	0.5	1.0	-	-
40	-	-	-	-	-	-	0.5	1.0	0.5	1.0	-	-
50	-	-	-	-	-	-	0.5	0.8	0.5	1.0	-	-
60	-	-	-	-	-	-	0.5	0.8	0.5	1.5	-	-

 

E6 CHLOROPHYLL CONCENTRATION [micro g l-1]*(Q) Lake centre, 1979

 

Depth[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	-	-	-	-	-	-	11.0	0.65	0.5	0.3	-	-
10	-	-	-	-	-	-	0.87	0.65	0.45	0.3	-	-
20	-	-	-	-	-	-	0.4	0.6	0.4	0.3	-	-
30	-	-	-	-	-	-	0.25	0.3	0.35	0.3	-	-
40	-	-	-	-	-	-	0.2	0.25	0.3	0.3	-	-
50	-	-	-	-	-	-	0.1	0.2	0.2	0.3	-	-
60	-	-	-	-	-	-	0.08	0.1	0.1	0.3	-	-

 

* Percentage of active chlorophyll a: ca. 60% of total at 0 m and ca. 30% in deep layer.
E7 NITROGEN CONCENTRATION (Q) Total Kjeldahl-N [mg l-1] Lake centre, 1979

 

Depth[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	-	-	-	-	-	-	-	0.08	0.1	0.15 -	-
10	-	-	-	-	-	-	-	0.08	0.1	0.15 -	-
20	-	-	-	-	-	-	-	0.08	0.1	0.15 -	-
30	-	-	-	-	-	-	-	0.08	0.1	0.15 -	-
40	-	-	-	-	-	-	-	0.08	0.1	0.15 -	-
50	-	-	-	-	-	-	-	0.08	0.1	0.15 -	-
60	-	-	-	-	-	-	-	0.08	0.1	0.15 -	-

 

E8 PHOSPHORUS CONCENTRATION (Q) Total-P [micro g l-1]* Lake centre, 1979

 

Depth[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	-	-	-	-	-	-	-	6	6	-	-	-
10	-	-	-	-	-	-	-	6	6	-	-	-
20	-	-	-	-	-	-	-	6	6	-	-	-
30	-	-	-	-	-	-	-	6	6	-	-	-
40	-	-	-	-	-	-	-	6	6	-	-	-
50	-	-	-	-	-	-	-	6	6	-	-	-
60	-	-	-	-	-	-	-	6	6	-	-	-

* Too close to detection limit.

E9 CHLORIDE CONCENTRATION (Q) Lake centre, 1979 [mg l-1]

 

F. BIOLOGICAL FEATURES F1 FLORA (Q) Emerged macrophytes: Typha angustifolia, Sagittaria sp. Floating macrophytes: Nuphar variegatum. Submerged macrophytes: Chara sp., Potamogeton sp. F2 FAUNA (Q) Zooplankton Diaptomus ashlandi, D. minuius, Epischura lacustris, Daphnia galeata mendotae, D. longiremis, Cyclops bicuspidatus thomasi, Conochilus sp., Kellicottia sp. Fish Salmo salar ouanaiche, Coregonus clupeaformis, Catostoms commersoni, Semotilus margarita, Notropis atherinoides, Lota lota, Gasterosteus aculeatus, Stizostedion vitrem, Cottus cognatus. Supplementary notes on the biota The inland-locked atlantic salmon is the most important species for sport- fishing. Human activities since the 1950's are strongly threatening it. F3 PRIMARY PRODUCTION RATE (Q) Net production rate [g m-2 yr-1] Lake centre, 1979: ca. 48. F5 FISHERY PRODUCTS (Q) Annual fish catch [individuals] 1965-1985: ca. 20,000-25,000. F6 PAST TRENDS (Q) The catch of the atlantic inland-locked salmon was greatly reduced after the building (1950) of high hydroelectric dams on the main effluent of the lake, owing to the loss of spawning ground coupled with increasing demand from sport angler. The modification of shoreline to prevent erosion has also drastically changed the whole dynamics of the large lake. F7 NOTES ON THE REMARKABLE CHANGE OF BIOTA IN THE LAKE IN RECENT YEARS (Q) The floating of logs for pulp and papers has also contributed to the drastic reduction of fish production during the last 50 years. G. SOCIO-ECONOMIC CONDITIONS G1 LAND USE IN THE CATCHMENT AREA (Q) 1975 

	Area [km2]	[%]
Natural landscape
Woody vegetation	56,262	75.2
Herbaceous vegetation	0	0
Swamp	9,928	13.3
Others	1,719	2.3
Agricultural land	Crop
field	685	0.9
Pasture land	400	0.5
Residential area	5,750	7.7
Others	119	0.2 Total	74,863	100

 

Depth[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0	-	-	-	-	-	-	-	0.9	1.0	-	-	-
10	-	-	-	-	-	-	-	0.9	1.0	-	-	-
20	-	-	-	-	-	-	-	0.9	1.1	-	-	-
30	-	-	-	-	-	-	-	0.9	0.9	-	-	-
40	-	-	-	-	-	-	-	0.9	0.85 -	-	-
50	-	-	-	-	-	-	-	0.9	0.9	-	-	-
60	-	-	-	-	-	-	1.0	1.0	-	-	-

 

Main types of woody vegetation Coniferous forest (Picea mariana, P. glauca, Pinus banksiana, Populus, Betula). Types of the other important vegetation: Heath (Ericaceae). Levels of fertilizer application on crop fields: Light. Trends of change in land use Abandoned agricultural land increased. No. of cattle and farm decreased.
G2 INDUSTRIES IN THE CATCHMENT AREA AND THE LAKE (Q) 1975

 

	Gross product	No. of	No. of	Main products
	per year	per persons establish-	or major
	[US$]	engaged	ments	industries
Primary industry			25	Lumber
Secondary industry
Pulp, paper	60 mill.			Paper, metal
Aluminium	14 mill.	3,500*	13*	(Al),
				Dairy
Others				products, beef

* Including Pulp, paper, Aluminium, and Others.

Numbers of domestic animals in the catchment area Cattle 72,606, Horse 200, Sheep 5,523, Swine 18,264, Poultry 389,983.
G3 POPULATION IN THE CATCHMENT AREA (Q) 1971

 

		Population	Major cities
	Population	density [km-2]	(population)
Rural	103,308	18.1	Alma

 

 

H. LAKE UTILIZATION

H1 LAKE UTILIZATION (Q) Source of water, navigation, transportation (wood floating), sightseeing, tourism (no. of visitors in 1985: 5,000), recreation (swimming, sport-fishing, yachting) and hydroelectric generation.
H2 THE LAKE AS WATER RESOURCE (Q) 1987

 

	Use rate
Domestic	Negligible
Irrigation	None
Industrial	For pulp and paper
Power plant	1,453,000 [kW]

 

 

I. DETERIORATION OF LAKE ENVIRONMENTS AND HAZARDS

I1 ENHANCED SILTATION (Q) Extent of damage: Serious. Supplementary notes Landslide of marine clay and severe erosion of shoreline due to the artificial maintenance of high water level (+5.5 m) for power generation.
I2 TOXIC CONTAMINATION (Q) Present status: Detected but not serious. Main contaminants, their concentrations and sources Lake centre, 1977

 

Name of	Concentrations [ppm]	Main
contaminants	Bottom mud	sources
As	4	Natural
Zn	120	Natural
Hg	0.25	Natural
Pb	30	Car

 

Distribution of metals in the surficial sediments.

Fig. NAM-10-02
Acid soluble Zn distribution in surface sediments [ppm].

 

Fig. NAM-10-03
Total Hg distribution in surface sediments [ppm].

 

Fig. NAM-10-04
Acid soluble Pb distribution in surface sediments.

 

Past trends Trace metals increased in the lake sediments since 1840 (at 16 cm level).
I3 EUTROPHICATION (Q) Nuisance caused by eutrophication Unusual algal bloom: Rhodomonas sp. Nitrogen and phosphorus loadings to the lake [kg km-2 day-1] 1976

 

Sources	Industrial	Domestic	Agricultural	Natural	Total
T-N	-	Minor	Major	5.3	16.5
T-P	-	Minor	Major	0.6	1.08

 

Supplementary notes Urban wastewater treatment and agricultural improvement have been important in the last 5 years.
I4 ACIDIFICATION (Q) Extent of damage: None. Not for that large lake, but detected in many small ones in the same catchment.
I5 OTHER HAZARDS Pulp and paper mills, log floating and hydroelectric dam operation.

J. WASTEWATER TREATMENTS

J1 GENERATION OF POLLUTANTS IN THE CATCHMENT AREA

c) Limited pollution with wastewater treatment.

J2 APPROXIMATE PERCENTAGE DISTRIBUTION OF POLLUTANT LOADS

 

	[%]
Non-point sources	95
Point sources
Industrial sources	5

 

J3 SANITARY FACILITIES AND SEWERAGE Percentage of municipal population in the catchment area provided with adequate sanitary facilities (on-site treatment systems) or public sewerage: 80%. Percentage of rural population with adequate sanitary facilities (on-site treatment systems): 80%. Municipal wastewater treatment systems No. of tertiary treatment systems: None. No. of secondary treatment systems: 25. No. of primary treatment systems: 30. Industrial wastewater treatment systems No. of industrial wastewater treatment systems: 5.

K. IMPROVEMENT WORKS IN THE LAKE

K3 OTHERS Artificial shoreline structure to prevent erosion. Filling nice sandy beaches with coarse gravel and stones, etc. to prevent erosion.

M. LEGISLATIVE AND INSTITUTIONAL MEASURES FOR UPGRADING LAKE

ENVIRONMENTS M1 NATIONAL AND LOCAL LAWS CONCERNED Names of the laws (the year of legislation)

1. Law related to the Quality of the Environment of the Quebec Province Government. Responsible authorities
2. Quebec Ministry of Environment Main items of control
3. Urban waste treatment

M2 INSTITUTIONAL MEASURES

1. Service de la Protection de l'Environment in 1979, Quebec city
2. Ministry of Environment, Quebec city

M3 RESEARCH INSTITUTES ENGAGED IN THE LAKE ENVIRONMENT STUDIES

1. Quebec University

 

N. SOURCES OF DATA

17. Questionnaire filled by Dr. M. Ouelett, Institut National de la Recherche Scientifique, Universite du Quebec, Canada, based on the following sources.
1. Ouellett, M. & Jones, H. G. (1987) Verh. Intern. Verein Limnol., 23 (in press).
2. Jones, H. G., Ouellett, M., Leclerc, M., Cluis, D., Couture, P., Potvin, L. & Sochanska, W. (1980) INRS-Eau (Quebec University), rapport scientifique No. 76, 642 pp.
3. Ouellett, M. (1984) INRS-Eau (Quebec University), rapport scientifique No. 137, 630 pp.
4. Talbot, J. & Lapointe, A. (1988) Ministere du Tourisme, de la Chasse et de la Peche du Quebec, Quebec.
5. Ouellett, M. (1979) INRS-Eau (Quebec University), rapport scientifique No. 104, 934 pp.