Use of Available Information to Infer Groundwater-Use of Available Information to Infer Groundwater-Surface Water InteractionsSurface Water Interactions - Practical Examples from BC- Practical Examples from BC

Jacek Scibek M.Sc.

1. BC observation well network – examples of water levels and interactions with

surface water

2. Delineating areas of aquifers where GUDI wells are likely to occur

3. Aquifer heterogeneity

OUTLINE:

Nanaimo River

Nanaimo River gauge

CASSIDY

Obs 312

Obs 228

Obs 330

N

Cassidy Aquifer (Nanaimo)Example 1:

Nanaimo River Obs 312

Obs 228

Obs 330

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

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

Month

Gro

undw

ater

Lev

el(m

ab

ove

low

est

wat

er le

vel r

ecor

ded)

Obs 228 water level

Obs 312 water level

Obs 330 water level

2003 2004

Obs 330

Obs 312

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

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

Month

Gro

undw

ater

Lev

el(m

ab

ove

low

est

wat

er le

vel r

ecor

ded)

Obs 312 water level

Obs 330 water level

2003 2004

Wellfield drawdown

Recovery event

Nanaimo River

Obs 312

3.0

3.2

3.4

3.6

3.8

4.0

4.2

4.4

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

Month

Gro

undw

ater

Lev

el(m

ab

ove

low

est

wat

er le

vel r

ecor

ded)

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

Nan

aim

o R

iver

Wat

er L

evel

(m

eter

s,

conv

erte

d fr

om f

low

dat

a)

Obs 312 water level

Nanaimo River water level(computed from discharge)

2003 2004

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Oct Nov Dec Jan Feb Mar Apr

Wa

ter

Le

ve

l (m

a

bo

ve

loc

al d

atu

m)

Obs 228 water levelObs 312 water levelObs 330 water levelNanaimo River water level

2003 2004

Nanaimo River

Obs 312

Obs 228

Obs 330

Wells near rivers are potentially GUDI

Cowichan River Valley (Duncan)Example 2:

318

204

River Gauge

211

205

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Oct-95 May-96 Dec-96 Jun-97 Jan-98 Jul-98 Feb-99 Aug-99 Mar-00 Oct-00 Apr-01

Wa

ter

Le

ve

l (m

ab

ov

e lo

ca

l da

tum

)

0

100

200

300

400

500

600

Riv

er

Flo

w (

m3

/s)

#205

#318 FISH HATCHERY#211

#208Cowichan River 08HA011

Note flow magnitude in river!!

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Feb-05 Feb-05 Mar-05 Mar-05 Mar-05 Apr-05 Apr-05 Apr-05 May-05 May-05 May-05

Wa

ter

Le

ve

l (m

ab

ov

e lo

ca

l da

tum

)

0

20

40

60

80

100

120

140

Riv

er

Flo

w (

m3

/s)

#318 FISH HATCHERY

#211

Cowichan River 08HA011

Rough sketch of area of interaction of groundwater with surface water

Grand Forks ValleyExample 3:

Obs well

Kettle River

504.0

504.5

505.0

505.5

506.0

506.5

507.0

1982 1983 1984 1985 1986 1987 1988 1989 1990 1991

Date

Riv

er W

ater

Ele

vatio

n (m

a.s

.l.)

509.0

509.5

510.0

510.5

511.0

511.5

512.0

512.5

Gro

undw

ater

Ele

vatio

n (m

asl

)

Kettle River (channel elev 509.6 m) near Obs Well 217

Obs Well 217 (elev 513.5 m)

River recharging aquifer

Aquifer discharging to river

Effect of aquifer heterogeneity on connection with surface water:

head difference map = Aquifer Scenario 1 – Aquifer Scenario 2

(homogeneous K) (heterogeneous K)

- 0.5 m

+ 0.5 m

0 m

Fraser Valley (Abbotsford)Example 4:

No GUDI wells up-gradient from rivers? How far?

Stream leakage?

Complex flow patterns (modeling results)

CONCLUSIONS:

1. Available information:

- often not used- significance missed- objective is to avoid expensive tests done that

confirm what is already known

2. BC observation well network

- free source of data- most wells too close to rivers to help characterize

aquifer behaviour