Interaction Between Rivers and Aquifer

Michael BarberDirector, State of Washington Water Research Center

Washington State University

May 8, 2007

Spokane Valley – Rathdrum Prairie Aquifer Study

Surface/Groundwater Interaction Options

Dingman, S. Lawrence. 2002. Physical Hydrology 2nd Edition.

Quantifying Aquifer/River Interaction

• This concepts explains why the total volume of the SVRP is not as important as the active portion – the part above the river bottom

• To determine gaining, losing and neutral reaches of surface/groundwater exchanges, additional Seepage Runs were conducted.

QD

QC

QB

QA

Losing reach

QB < QA

Transitionalreach

QC ≈ QB

Gaining reach

QD > QC

river

aquifer

Nearly simultaneous measurement of river discharge (Q) at different locations (A, B, C, D) to determine streamflow gains and losses between sites.

ABCD

What are Seepage Runs?

Seepage Runs

• In addition to previous data, 2 seepage runs were conducted as part of this project– August 30, 2005– August 8, 2006

• The August 30th run was the most comprehensive

nearPost Falls

near Coeurd’Alene Lake

near OtisOrchards

Greenacres

Flora Rd

Centennial Trail Bridge

below Greene St

below Upriver Dam

Spokane

below Meenach Bridge

RifleClubRdbelow

NineMileDam

at Dartford

Waikiki Road

near Dartford

near confluence

Sullivan Rd

Seepage Run Measurement SitesSpokane & Little Spokane Rivers

-600

-400

-200

0

200

400

600

J I H G F E D C B A

Streamflow gain (+) or loss (-) in cfs

near Coeurd’Alene Lake

near Post Falls

near OtisOrchardsGreen

acresFloraRoad

CentennialTrail Bridge

Spokane

below GreeneStreet

Rifle ClubRoad

below NineMile Dam

Seepage Run, August 26-31, 2005

-600

-400

-200

0

200

400

600

A B C

Streamflow gain (+) or loss (-) in cfs

Seepage Run, August 26-31, 2005Little Spokane River

at Dartford

Waikiki RdnearDartford

nearconfluence

-600

-400

-200

0

200

400

600

A B C

Streamflow gain (+) or loss (-) in cfs

CentennialTrail Bridge

Spokane

below GreeneStreet

Limited Seepage Run, August 8, 2006

belowUpriver

Dam

Spokane

at Dartford

near Dartford

nearPost Falls

near OtisOrchards

Monthly average gains and losses(next 3 slides)

-1500

-1000

-500

0

500

1000

1500

1/1/00 12/31/00 1/1/02 1/1/03 1/1/04 12/31/04 1/1/06

Str

eam

flow

gai

n (+

) or

loss

(-)

in c

fs

Monthly average streamflow gain (+) or loss (-)Spokane River: near Post Falls – near Otis Orchards

This stream segment is: • always losing • loss is typically greater during winter and spring than summer and fall

2000 2002 2003 2004 20052001

-1500

-1000

-500

0

500

1000

1500

1/1/00 12/31/00 1/1/02 1/1/03 1/1/04 12/31/04 1/1/06

Str

eam

flow

gai

n (+

) or

loss

(-)

in c

fs

Monthly average streamflow gain (+) or loss (-)Spokane River: near Post Falls – Spokane

This stream segment typically is: • gaining during period of lower streamflow (summer and fall) and • losing during periods of higher streamflow (winter and spring)

2000 2002 2003 2004 20052001

-500

-400

-300

-200

-100

0

100

200

300

400

500

1/1/00 12/31/00 1/1/02 1/1/03 1/1/04 12/31/04 1/1/06

Str

eam

flow

gai

n (+

) or

loss

(-)

in c

fs

Monthly average streamflow gain (+) or loss (-)Little Spokane River: at Dartford – near Dartford

2000 2002 2003 2004 20052001

This stream segment is: • always gaining • gain is relatively constant over time

Surface/Groundwater in MODFLOW

• Streamflow Routing Package– Segment to segment flow is determined– Spokane River

• River Package– Define stage, bottom elevation, & conductance– Little Spokane River

Controlling Parameters

arrb hhm

LwKQ

Where:

K = Hydraulic conductivity of bed material [ft/day]

W = River width [ft]

L = Length of river segment [ft]

m = Thickness of bed deposits [ft]

hr = Elevation of river surface [ft]

ha = Groundwater elevation in cell adjacent to river [ft]

11 Spokane River Zones

Description of Zones

From To

KVSR-1: Coeur d’Alene Lake Post Falls

KVSR-2: Post Falls Otis Orchards

KVSR-3: Otis Orchards Greenacres

KVSR-4: Greenacres Sullivan Road

KVSR-5: Sullivan Road Myrtle Point

KVSR-6: Myrtle Point Upriver Dam

KVSR-7: Upriver Dam Downtown Spokane (E)

KVSR-8: Downtown Spokane (W) Above Meenach Bridge

KVSR-9: Above Meenach Bridge Rifle Club Road

KVSR-10: Rifle Club Road Nine Mile Dam

KVSR-11: Nine Mile Dam Long Lake

Little Spokane River Connection

LSR Inflow Reach

USGS gaging station on the Little Spokane River near Dartford

Little Spokane River Inflow

0

100

200

300

400

500

600

700

800

900

1000

1 2 3 4 5 6 7 8 9 10 11 12

Time (Jan-Dec)

Dis

ch

arg

e (

cfs

)

12431500 near Dartford - RM 3.8

12431000 @ Dartford - RM 11.4

Difference

Any Questions?