FODS Mainstem Channel Types:

Artificially Constrained Channel: Manipulated channels usually altered by dredging, filling or bank hardening in an attempt to stabilize and/or deepen the system. Figure HM-2 Nearshore Subwatershed Estuarine: Intertidal channels that are associated with marsh habitat and deltas. Channel Types Palustrine: Very low gradient (>1%) unconfined channels with low velocity flows. They Elliott are typically associated with wetlands and sloughs, often used by salmon for rearing Bay habitat. Delineated for the Mainstem Green River in WRIA 9 Seasonally Inundated: Areas that become periodically inundated by impoundments (i.e., SEATTLE dam reservoirs).

D u Green-Duwamish w a m Floodplain: Low gradient meandering channels (1-2%) composed of pools and riffles with is Estuary Subwatershed h a gravel to cobble substrate. Side channels, bars and islands are common with this channel R i ve r type. Floodplain channels provide spawning and rearing habitat for many species of

SEATTLE 99 salmon. Mainstem areas of this channel type are especially important for chinook and

5 steelhead. 60 River Mile and Number H

a

m m Large Contained: Channels that are greater than 20 meters wide and confined between C 5 P

r

u 900 steep side slopes. Low to moderate gradient (1-3%), patchy areas of gravel among bedrock Major Road g 509 TUKWILA e B and boulders. High flows contained within a single active channel. BURIEN 10 l t a c 405 S k R o i v u River/Stream e Moderate Gradient Mixed Control: Channels with a moderate to steep gradient (2-8%). r n RENTON This channel type often consists of tributary channels where high flows are contained in Vashon d NORMANDY the active channel. Used by coho, cutthroat and some chinook. Island PARK SEATAC 15 167 515 FODS Subwatershed Boundary High Gradient Contained: Steep, incised channels with high gradients (>4%), high stream power and usually with steep banks. These tributaries often convey sediments to 10 downstream areas. Resident trout use these streams. King County WRIA 9 Boundary S

o o s 1906 1992 These are abbreviated channel type descriptions which can DES 20 KENT MOINES C

r be viewed entirely in Table HYDROMOD-2. e e Open Water

nd k la Is MAPLE ry COVINGTON u k VALLEY a e M e N r 25 C 516

99 k s

e in

e k r 5 5 en

FEDERAL C J

WAY l 167 l i

M 30 C AUBURN ov Lake 0 2 4 6 Miles Nearshore in Sawyer Vashon g ton r C BLACK 55 Subwatershed DIAMOND 60 April 2000 Subwatershed 18 164 ALGONA 50 G Tacoma Howard R Lower E RIVER Headworks Hanson 35 EN 45 Dam 40 Green River 65

Subwatershed 169 Howard Hanson Reservoir

k Middle e e r C m Green River auku 5 ew 75 N 10 70 GR Subwatershed EE N 85 RI ENUMCLAW VER 80 Location Map

SNOHOMISH COUNTY Notes: Upper KITSAP 90 COUNTY 1. Basin boundaries were developed for FODS study use only. Green River

KING COUNTY Subwatershed KITTITAS 2. River miles were estimated from "Catalog of Washington Streams and COUNTY Salmon Utilization", (Williams, et al. 1975). STUDY AREA 3. Channel types were delineated based on topography, channel gradient, PIERCE COUNTY soils and planform characteristics. King County Produced by: GIS/Visual Communications Unit, WLR File Name: 0009 W9Recon-ChannelTypes.ai LP Department of Natural Resources