1

Raging R

i ve

r

Eagle Cr

Lennox Cr

Sunday Cr

Martin C r

Taylor River

Money Cr

E Fo

rk F

oss R

i v e r

Index

Cr

Dingfor d Cr

Hancock Cr

Burnt boot Cr

Deep Cr

Calligan Cr

W

Fo

rk

M

il ler

R iver

Ca

m

p Robber C

r

Ha

ll C

r

Am

es Cr

Sa

lmo

n C

r

H ar r is

Cr

To

ku

l C

rT

ok

ul

Cr

Tuck C

r

Tuck C

r

Pra

tt Rive r

Pra

tt Rive r

Ch erry CrCh erry Cr

Ha

rris

C

r H

arr

is

Cr

B

eckl

er

Riv

er

Bec

kler

R

iver

Miller C

rM

iller Cr

Foss R

iverF

oss River

Decep

tion C

r

Decep

tion C

r

S Fork Tolt River

S Fork Tolt River

North

Fork Tolt River

North

Fork Tolt River

Tye

Riv

er

Tye

Riv

er

Tol

t R

iver

Tol

t R

iver

Griffin C

r

Griffin C

r

Mid

dle F

ork S

noq

ualmie R

iver

M

id

dle F

ork S

noq

ualmie R

iver

N F

ork

S

noq

ua

lmie

R

iver

N F

ork

S

noq

ua

lmie

R

iver

S Fork Snoqualmie River

S Fork Snoqualmie River

S Fork Skykomish River

S Fork Skykomish River

Patterson C

rSNOQUALM

IE R

IVER

SNOQUALMIE R

IVER

Stossel Cr

N

Fork Cr

CalliganLake

LakeHancock

LakeJoy

AmesLakeAmesLake

PhilippaLake

Big HeartLake

OtterLake

CopperLake

AngelineLake

LakeDorothy

MarmotLake

SnoqualmieLake

Tolt-Seattle WaterSupply Reservoir

LakeMargaretLakeMargaret

LakeMarcelLake

Marcel

2

203

202

202

90

18

SNOHOMISH COUNTY

KING COUNTY

DUVALL

SAMMAMISH

SNOQUALMIE

SKYKOMISH

CARNATION

NORTHBEND

FallCity

Preston

During the summer of 2014, the King County Water and Land Resources Division removed a 1600’ levee and revetment and constructed a new 1200’ revetment along Neal Road. These actions have begun to restore natural river processes along this reach and reconnect the river with 50 acres of forested floodplain.

The set-back revetment includes four log structures intended to protect the road and private property from the river as it migrates across the floodplain, while also providing good fish habitat. The log structures are backed by a new 850-foot long rock revetment at the lower end of the site to provide additional protection where the river is most likely to migrate.

About 300 trees were felled to remove the levee. With their rootballs and much of their length left intact, they were placed in the floodplain, where they will be recruited to the river as it migrates. As placed and standing trees fall into the river, log jams should form, providing high quality edge habitat for salmon.

Removing the levee and rock bank has allowed the channel to widen and begin to migrate, restoring the river’s connection to its floodplain. Initially the river channel may widen rapidly, followed by slower migration as wood falls into the river. These processes will form gravel bars and log jams that provide salmon spawning and rearing habitat that has been missing from the area for many years.

Sixteen acres of invasive knotweed were also treated across the floodplain, and the site is being planted with about 11,000 native trees and shrubs. Soil excavated from the project area was provided to nearby farmers to build farm pads that help protect farm animals and equipment during flooding while reducing disposal costs.

King County will continue to assess the project’s impacts on both flooding and salmon habitat. The ten-year monitoring plan includes mapping habitat features, documenting channel changes, tracking fish use, and monitoring water levels and vegetation.

PURPOSE/NEED:The Upper Carlson levee removal project

was undertaken to restore critical habitat for threatened Chinook salmon and steelhead on the

Snoqualmie River. The current channel was excavated in the 1930’s to straighten the river and the levee was built

to stabilize it, but doing so removed fish habitat.This project replaces needed flood and erosion protection

in a way that allows high quality habitat to be restored in the river and floodplain.

Upper Carlson Floodplain Restoration Project

1505_4579_WRIA7_FactSht_UPPER_CARLSON.indd skrau

Looking upriver, this aerial view shows the completed project in October 2014.

PROJECT SITE AT FALL CITY NATURAL AREA

★

PHOTO BY NED AHRENS

Department of Natural Resources and ParksWater and Land Resources Division

2

Upper Carlson Floodplain Restoration Project

FUNDING FOR ACQUISITION, DESIGN AND CONSTRUCTION FOR THIS PROJECT WAS PROVIDED BY:

n Washington State Salmon Recovery Funding Board (SRFB);n Puget Sound Partnership’s Puget Sound Acquisition and

Restoration (PSAR); n National Oceanic and Atmospheric Administration (NOAA)

from the Nature Conservancy;n Department of Ecology’s Floodplains by Design grant with

support from The Nature Conservancy;n U.S. Environmental Protection Agency from the Snoqualmie

Tribe;n King County Flood Control District’s Cooperative Watershed

Management Grant; n King County Conservation Futures Levy; andn King County Department of Natural Resources and Parks

COST: $3.5 million

FOR MORE INFORMATION: www.kingcounty.gov/environment/animalsAndPlants/restoration-projects/upper-carlson-floodplain-restoration.aspx

The white lines show how the right bank of the river is expected to move into the forested floodplain over the years.

Pile-supported structures constructed at the site will provide flood protection as the river migrates into its newly-accessible floodplain.

During flooding in January 2015, the riverbank moved right significantly; the river is about 40’ wider than before construction.

Engineered LogjamsNew Rock RevetmentPredicted 10yr MigrationPredicted 20yr MigrationPredicted 50yr Migration

0 500 1,000Feet

E