North Saskatchewan River Planning Area HydrologyBart Oegema, MASc, PEng

Senior Hydrologist, SWA

November 24-25, 2004

Hydrology Outline

Climate Runoff Streamflows Lake levels

Climate

Mean annual precipitation varies from 360 mm/yr at Unity to 470 mm/yr at Waskesiu.

Temperatures warmest in southwest, cooler in north and northeast.

Average evaporation from lakes varies from 925 mm/yr in southwest to 750 mm/yr in northeast.

Climate generally reflected in Ecoregions

Climate

Precipitation varies year to year, 208 mm to 528 mm at Battlefords.

And seasonally, maximum in July, minimum in February.

What is “normal”? Now 373 mm at North Battleford. Long term average is 350 mm.

0

100

200

300

400

500

600

Annual P

recip

iation (

mm

)

1891 1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001

Annual 3-yr Moving Avg30-yr "Normal"

Battlefords Annual PrecipitationBattleford 1891-41, N Battleford 1942-

Monthly Precipitation (1971-2000)

0

10

20

30

40

50

60

70

80

90

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Ave

rage

Pre

cipi

tatio

n (m

m)

Scott CDA

Loon Lake EPF

Waskesiu Lake

Prince Albert

North Battleford

Lloydminster

Runoff

Runoff = surface water flow from landscape into wetlands, lakes or streams.

Only happens when rainfall or snowmelt is in excess of soil infiltration and surface detention capacity, including vegetative canopy storage.

Median runoff varies from less than 10 mm to over 250 mm across the province

Median runoff varies from less than 10 mm to over 30 mm across planning area.

Runoff

Prairie hydrology is dominated by precipitation, soil moisture storage, transpiration, wetland storage, and evaporation.

Runoff is what is left over, generally less than 10% of annual precipitation.

Streamflow

Streamflow = that portion of runoff which makes it into a stream network, may include a groundwater contribution.

Two types of streamflow in Planning Area; North Saskatchewan River itself – dominated by

mountain/foothill hydrology, All other streams – prairie hydrology.

North Saskatchewan River Streamflow Peak flows generally in June or July with

mountain snowmelt and foothills rainfall. Most (almost 90 %) of the annual flow is

generated upstream of Edmonton (212 m3/s vs 238 m3/s at PA).

Two hydro-electric reservoirs upstream of Edmonton; Brazeau, and Bighorn.

N Sask R at Edmonton

0

100

200

300

400

500

600

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Ave

rag

e F

low

(cm

s)

before 1963

From 1963

North Saskatchewan River Streamflow Average annual streamflows vary from 140

m3/s to 363 m3/s. Range is about 110 % of median average flow.

Alberta Environment has detected a downward trend in recorded annual flows at Edmonton. Upstream use was not factored into analysis.

N. Sask R. at Edmonton

0

50

100

150

200

250

300

350

400

1912 1917 1922 1927 1932 1937 1942 1947 1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 2002

Avg

Ann

ual F

low

(cm

s)

North Saskatchewan River Streamflow Annual flow volumes at the Saskatchewan –

Alberta boundary are very close to natural.

North Saskatchewan River at the Alberta/Sask Boundary

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Years

An

nu

al F

low

s (X

1000

) D

ams

RECORDED

NATURAL

50 % Nat

Streamflows – Prairie Hydrology Streamflow peaks usually in April or May due

to snowmelt. Declining flows through remainder of the year. Smaller streams may go to zero flow after

spring runoff in most years (ephemeral). High variability between years. Battle River is the largest tributary in

Saskatchewan.

Battle River near AB-SK Border

0

5

10

15

20

25

30

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Mon

thly

Avg

Flo

w (c

ms)

Median

Average

Battle River

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1912 1917 1922 1927 1932 1937 1942 1947 1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 2002

Year

Annu

al F

low

Volu

me

(dam

3)

At Battleford

Near Unwin

at AB-SK bdr

Lake Levels

Lake levels reflect the dynamic balance between inflow, outflow, and evaporation.

Most lakes have an outlet stream. “Terminal” lakes have streams flowing in but

no stream flowing out, hence they are the end point or terminal for that stream system.

Turtle Lake

652

652.5

653

653.5

654

654.5

655

655.5

656

1964 1969 1974 1979 1984 1989 1994 1999 2004

Wat

er L

evel

(m

)

Jackfish Lake

527

527.5

528

528.5

529

529.5

530

530.5

531

1964 1969 1974 1979 1984 1989 1994 1999 2004

Wat

er L

evel

(m

)

Anglin Lake

512

512.5

513

513.5

514

514.5

515

515.5

516

1960 1970 1980 1990 2000

Wat

er L

evel

(m

)

Emma Lake

512

512.5

513

513.5

514

514.5

515

515.5

516

1960 1970 1980 1990 2000

Wat

er L

evel

(m

)

Christopher Lake

512

512.5

513

513.5

514

514.5

515

515.5

516

1960 1970 1980 1990 2000

Wat

er L

evel

(m

)

Manitou Lake Levels

20

21

22

23

24

25

26

27

1960 1965 1970 1975 1980 1985 1990 1995 2000

Ele

va

tio

n t

o a

ss

um

ed

da

tum

(m

)

Redberry Lake

502

502.5

503

503.5

504

504.5

505

505.5

506

1974 1979 1984 1989 1994 1999 2004

Wat

er L

evel

(m

)

Questions