SHUSWAP LAKE

View of Station 5 looking north, Copper Island in the background


Photo: J.Stockner

 
 

A. LOCATION

• British Columbia, Canada.
• 50:0-51:0N, 119:0-119:0W; 347 m above sea level.

B. DESCRIPTION

Shuswap Lake is situated in the Columbia Mountains region of British Columbia where the landscape is characterized by mountainous terrain covered by dense coniferous forests. White birch lines settled areas of the lake shore adding to the beauty of the lake during fall. The mountains surrounding the lake are formed of granite which results in a very low input of nutrients. As a result, Shuswap Lake is very clear and relatively oligotrophic. The high mountains around this lake may reduce its annual solar radiation.

This multi-basin lake is comprised of 4 arms which are joined by a short shallow passage known as the "narrows." The two south arms are developed for recreational use while the two north arms remain undeveloped. The lake has several inflow rivers in each arm but only one outlet, Little River, which flows from the southwest arm to Little Shuswap Lake. Shuswap is a nursery lake for the underyearlings of sockeye salmon which spawn in several of the lake's inflow streams. Adams River is the most conspicuous of these spawning streams, accommodating up to 2 million spawners in dominant years.

Besides being of considerable value to the west coast salmon industry, moderate weather, clear water and easy accessibility make Shuswap Lake highly desirable as a recreational area. This is evidenced by the many provincial parks surrounding the lake and the hundreds of houseboats and pleasure crafts present during the summer months (Q).
 

C. PHYSICAL DIMENSIONS

 

Surface area [km2]	310
Volume [km3]	19.1
Maximum depth [m]	161
Mean depth [m]	62
Water level	Unregulated
Normal range of annual water level fluctuation [m]	3.0
Length of shoreline [km]	1,430
Residence time [yr]	2.1
Catchment area [km2]	16,200

 

D. PHYSIOGRAPHIC FEATURES

D1 GEOGRAPHICAL

• Bathymetric map: Fig. NAM-47-01.
• Names of main islands: Copper.
• Number of outflowing rivers and channels (name): 1 (Little R.).

D2 CLIMATIC

• Climatic data at Sicamous, 1951-1980 (2)

 

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Ann.
Mean temp. [deg C]	-5.0	-1.4	2.4	7.8	13.1	17.1	20.0	19.2	14.0	7.7	1.5	-2.6	7.8
Precipitation [mm]	77	48	37	32	51	64	46	53	56	51	66	80	660

 

• Number of hours of bright sunshine (Salmon Arm): 1,632 hr yr-1 (2).
• Solar radiation (Summerland)[MJ m-2 day-1]*

 

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Ann.
3.4	6.5	11.5	16.7	20.8	22.6	23.7	19.6	14.5	8.5	3.8	2.5	12.8

* Means for Shuswap area are lower than at Summerland which is 100 km south and in a slightly sunnier climate.

Fig. NAM-47-01
Bathymetric map [50 ft=15.24 m](8).

• Water temperature [deg C](1)

 

Station 5*1, 1987 

Depth J[m]	an	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
S*2	-	-	-	11.6	11.3	19.2	21.0	18.9	17.7	12.5	9.6	-
3	-	-	-	8.3	-	18.6	20.0	18.8	17.7	12.5	9.6	-
6	-	-	-	7.0	10.4	17.7	19.1	18.7	17.6	12.5	9.6	-
9	-	-	-	5.9	9.8	14.3	17.6	18.4	17.3	12.5	9.6	-
12	-	-	-	5.6	-	11.7	13.2	14.8	17.2	12.5	8.2	-
15	-	-	-	5.0	8.5	-	12.2	11.7	16.9	12.5	6.6	-
18	-	-	-	4.8	-	-	11.4	-	10.0	-	6.4	-
21	-	-	-	4.6	4.6	-	-	-	-	-	-	-
28	-	-	-	4.5	-	5.8	5.6	5.2	5.7	5.2	-	-

*1 Sorrento, located middle lake in the main basin adjacent to the Adams River which enter Shuswap Lake from its southwest arm.
*2 Surface.

• Freezing period: January-March (not freeze every year and not freeze over).
• Mixing type: Dimictic.

E. LAKE WATER QUALITY

Water quality is variable. The Salmon Arm is the most productive area because of considerable nutrient input from agricultural drainage via the Salmon River. Levels of nutrients are highest in Salmon Arm and lowest in Austy and Seymour Arms.

E1 TRANSPARENCY [m](Q)

 

Station 5, 1987 

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
-	-	-	11.5	8.2	13.7	10.5	11.0	10.8	10.6	8.6	-

 

E2 pH (Q)

 

Station 5, 1987 

Depth J[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
S*	-	-	-	7.8	7.6	7.7	7.3	7.7	7.9	7.5	7.3	-

* Surface.

E6 CHLOROPHYLL CONCENTRATION [micro l-1](Q)

 

Station 5, 1987 

Depth J[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
ME*	-	-	-	0.91	0.70	1.60	1.18	0.98	1.04	1.62	2.29	-

* Mean epilimnetic.

E7 NITROGEN CONCENTRATION (Q)

• NO3-N+NH4-N [mg l-1]

 

Station 5, 1987 

Depth J[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
ME*1	-	-	-	.094	.068	.013	.002	.001	.006	.008	.026	-
*2	-	-	-	.015	.007	.011	.003	.003	.006	.006	.007	-

*1 Mean epilimnetic. *2 NO3-N+NH4-N.

E8 PHOSPHORUS CONCENTRATION (8)

• Total-P [micro l-1]

 

Station 5, 1987 

Depth J[m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
ME*	-	-	-	5.7	3.0	3.8	4.0	2.9	2.4	2.4	3.6	-

* Mean epilimnetic.

E9 CHLORIDE CONCENTRATION [mg l-1](4)

Station 5, 1982: 0.5.

F. BIOLOGICAL FEATURES

Fl FLORA (4)

• Emerged macrophytes

Equisetum sp., Alisma plantago-aquatica, A. gramineum, Scheuchzeria palustris, Acorus calanus, Ranunculus flabellaris, Sium sauve, Eleochoris palustris.
• Floating macrophytes

Polygonum amphibium, Azolla filiculoides, Nuphar variegatum.
• Submerged macrophytes

Myriophyllum exalbescens, M. ussuriense, M. spicatum, Potamogeton zosteriformis, P. robbinsii, P. pectinatus, P. praelongus, P. noclosus, P.
crispus, P. epihydrus, P. illinoensis, P. perfoliatus, P. pusilus, Chara sp., Nitella sp., Callitriche hermaphroditica, C. heterophylla, C. stagnalis, Hippurus vulgaris, Zannichellia palustris, Bidens beckii, Utricularia vulgaris, U. intermedea, Elodea canadensis, Najas flexilis, Ceratophyllum demersum, Heteranthera dubia.
• Phytoplankton

Cyclotella spp., Rhizosolenia spp., Asterionella spp., Dinobryon spp., Melosira spp.

F2 FAUNA

• Zooplankton (5, 6)

Bosmina coregoni (longispina), B. longirostris, Diaphanosoma leuchtenbergianum, Daphnia thorata, D. longiremis, Holopedium gibberum, Sida crystallina, Cyclops bicuspidatus thomasi, Diaptomus ashlandi, Epischura nevadensis.
• Fish

Oncorhynchus nerka*, O. tshawytscha*, Salmo gairdneri*, Salvelinus malma, S.
namaycush, Coregonus clupeaformis, Prosopium williamsoni, Richardsonius balteatus, Lota lota, Cottus asper.
* Economically important.

F3 PRIMARY PRODUCTION RATE [mg C m3 hr-1](1)

 

Station 5, 1987 
Net production 

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
-	-	-	0.23	1.0	1.3	1.67	1.0	0.67	0.93	1.29	-

 

F4 BIOMASS (6)

Station 5 (Sorrento), 1987*

• Bacteria [cells ml-1]: 480,000.
• Zooplankton [mg (dry wt.) m-3]: 45.9.

* Early mean values.

F5 FISHERY PRODUCTS(Q)

• Annual fish catch [metric tons]

20
• Supplementary notes

Anadromus sockeye salmon is caught at sea during the commercial catch in the dominant year. Its returns are cyclic with a dominant return occurring every four years. This cyclic dominance is thought to have varying degrees of influence on all trophic levels, since dominant returns are 230 times greater than low year returns. Sockeye underyearling grazing structures the zooplankton community of the hypolimnion-thermocline area but, because of warm surface temperatures of the epilimnion in summer, the zooplankton community there is less affected. Depending on the time of year, nutrients affect community composition and size-structure of phytoplankton.

F7 NOTES ON THE REMARKABLE CHANGES OF BIOTA IN THE LAKE IN RECENT YEARS

Increase in Eurasian milfoil (Myriophyllum spicatum) colonization of the littoral zone.

G. SOCIO-ECONOMIC CONDITIONS

G1 LAND USE IN THE CATCHMENT AREA (8)

 

1986 

	Area [km2]	[%]
Natural landscape
- Woody vegetation	12,393	76.5
- Herbaceous vegetation	1,377	8.5
Agricultural land
- Crop field	729	4.5
- Pasture land	1,458	9
Residential area	243	1.5
Total	16,200	100

 

• Types of important forest vegetation

Pseudosuga menziesii (Douglas fir), Pinus contorta (lodge-pole pine), Betula papyrifera (white birch).
• Main kinds of crops and/or cropping systems

Corn, various fruit, hay, alfalfa
• Levels of fertilizer application on crop fields: Light.
• Trends of change in land use in recent years

Increase in recreational boating, fishing and shoreline development of summer houses.

G2 INDUSTRIES IN THE CATCHMENT AREA AND THE LAKE

1987
This is an area of little urban industrial development. The largest agglomeration, Salmon Arm, has a population, in 1981, of 10,780 and only a few service functions.

G3 POPULATION IN THE CATCHMENT AREA (9)

 

1986 

	Population	Population density [km-2]	Major cities (population)
Urban	ca. 10,000		Salmon Arm
Rural	ca. 5,000		(10,780)
Total	15,000*	0.9

* Increases during summer.

H. LAKE UTILIZATION

H1 LAKE UTILIZATION

Source of water, navigation and transportation (not commercial except for some log transport), sightseeing and tourism (no. of visitors in 1987: over 10,000), recreation (swimming, sport-fishing and yachting), fisheries and hundreds of house boats cruise the lake each year.

H2 THE LAKE AS WATER RESOURCE

 

1988 

	Use rate
Domestic	From wells+tributaries
Irrigation	Not estimated
Industrial	Saw mill

 

I. DETERIORATION OF LAKE ENVIRONMENTS AND HAZARDS

I1 ENHANCED SILTATION

• Extent of damage: None.

I2 TOXIC CONTAMINATION

• Present status: No information.

I3 EUTROPHICATION

• Nuisance caused by eutrophication

Increase of Eurasian milfoil (Myriophyllum spicatum). There has been mild eutrophication of the Salmon Arm.

I4 ACIDIFICATION

• Extent of damage

Slight acidification detected in watershed, but not serious.
• Supplementary notes

Hydrogen ion concentrations in lake water, stream and rain water have been stable. The lake water has a hardness of 39 and an alkalinity of 34 mg l-1 (conductivity 81 micro S cm-1), and relatively well-buffered with a pH value typically above 7 (1982 pH mean was 7.4).

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 (agricultural, natural and dispersed settlements)	75
Point sources Municipal	25

 

J3 SANITARY FACILITIES AND SEWERAGE

• Municipal wastewater treatment systems

Tertiary treatment with outflow to the lake at depth of 3 m. The effluent contains <10 ppm suspended solids.

L. DEVELOPMENT PLANS

Development and activity in the Shuswap Lake watershed has intensified in recent years. Upland residential development, increased residential use and selected commercial developments along the lake's shorelines have impacted on its environmental resources. As a result, the Shuswap Lake Environmental Management Plan was undertaken by the B. C. Ministry of Environment (10). During 1985 the Regional District of Columbia Shuswap initiated a management program for the lake. The following are some of the actions and recommendations taken by this agency.
The spread of Eurasian water milfoil in Shuswap Lake has resulted in the implementation of a mechanical harvesting control program in 1981. To date, the density of this macrophyte remains low (11, 12).
Water quality in the relatively enclosed portion of Tappen Bay and Salmon Arm (Fig. NAM-47-0l) failed to meet the Provincial guidelines for phosphorus for fisheries and recreational uses (10). Tributary streams are also enriched with phosphorus from agricultural inputs rather than from septic systems. A major water quality monitoring program has been set up to determine the optimal waste treatment management program for the lake and to determine appropriate methods for reducing phosphorus loadings (10).
Given the historical patterns of activity and risk that have been commonly associated with alluvial fans, it was recommended that no more development occur on five of the major alluvial fans in the Shuswap Watershed (13).
Given the importance of shoreline areas in the production of fisheries and waterfowl resources, a shoreline habitat protection program was recommended and special action has been taken to protect the Western Grebe colony along the foreshore east of the Salmon River as well as the Bighorn Rocky Mountain Sheep near Chase. Finally, wildlife habitat areas in the Salmon River estuary, the mouth of the Eagle River, Seymour River estuary and Bughouse Bay areas have been kept free of development (10). A fisheries management study is currently underway to assess fishery production and to determine areas for special attention (10).

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
2. Canada Water Act
• Responsible authorities
(l) Department of Fisheries and Oceans
1. Ministry of Environment, Waste Management Branch
2. Ministry of Environment, Fish and Wildlife
• Main items of control
1. Protection of anadromous fish species
2. Waste disposal
3. Fishing and hunting regulations
4. Domestic and commercial water usage

M2 INSTITUTIONAL MEASURES

1. British Columbia Ministry of the Environment, Kamloops, BC.
2. British Columbia Ministry of Forests, Kamloops, BC.
3. Environment Canada, Atmospheric Environment Service, Kamloops, BC.
4. Salmon Arm Chamber of Commerce, Mclead Avenue, Salmon Arm, BC.
5. Mr. Fred Harper, Regional Wildlife Biologist

M3 RESEARCH INSTITUTES ENGAGED IN THE LAKE ENVIRONMENT STUDIES

1. Canada Department of Fisheries and Oceans, Biological Sciences Branch, West Vancouver, BC.
2. British Columbia, Ministry of the Environment, Fish and Wildlife Branch
3. British Columbia, Ministry of the Environment, Waste Management Branch

N. SOURCES OF DATA

17. Questionnaire filled by Dr. J. G. Stockner, Department of Fisheries and Oceans, West Vancouver Laboratory, West Vancouver, British Columbia.
1. Stockner, J. G. & Shortreed, K. S. (1983) A Comparative Limnological Survey of 19 Sockeye Salmon (Oncorhynchus nerka) Nursery Lakes in the Fraser River System, British Columbia. Department of Fisheries and Oceans. Can. Tech. Rep. of Fish. and Aquat. Sci. 1190 pp.
2. Canadian Climate Normals. 1951-1980. Temperature and Precipitation. Environment Canada, Atmospheric Environment Service.
3. Canadian Climate Normals. 1951-1980. Solar Radiation. Environment Canada, Atmospheric Environment Service.
4. Hebdem, B., Ministry of Environment. Personal communication.
5. Ward, F. J. (1957) Seasonal and Annual Changes in Availability of the Adult Crustacean Plankters of Shuswap Lake. International Pacific Salmon Fisheries Commission, Progress Report no. 3.
6. Goodlad, J. C., Gjernes, T. W. & Brannon, E. L. (1974) Factors affecting sockeye salmon (Oncorhynchus nerka) growth in four lakes of the Fraser River system. J. Fish. Res. Board Can., 31: 871-892.
7. Ward, F. J. & Larkin, P. A. (1964) Cyclic Dominance in Adams River Sockeye Salmon. International Pacific Salmon Fisheries Commission, Progress Report no. 11.
8. NTS scale 1:250,000 Vernon British Columbia Sheet 82L/edition 1 (1963).
9. Census of Canada (1981) Population Series, British Columbia, pp. 93-910, Table 4.
10. B. C. Ministry of Environment (1987) Shuswap Lake Environmental Management Plan. B. C. Ministry of Environment, West Vancouver, British Columbia.
11. Einarson, E. D. (1986) The 1985 Eurasian Water Milfoil Surveilance and Control Program in Shuswap Lake. Littoral Resources Unit, Water Management Branch, B. C. Ministry of Environment Resource Quality Section, Water Management Branch, B. C. M. 0. E., Victoria.
12. Einarson, E. D. (1986) Preliminary Assessment of Water Quality of Shuswap Lake Area. Unpublished manuscript. Resource Quality Section, Water Management Branch, B. C. M. 0. E., Victoria, B. C. 15 pp.
13. Thurber Consultants (1983) Floodplain Management on Alluvial Fans. Report to the Ministry of the Environment, Water Quality Branch, B. C. M.

0. E., Victoria.