8/8/2019 Elwha Dam Project

1/1

During phase one, all four spillway gates

on the south side will open, allowing

water in Lake Aldwell reservoir to drop

18 feet.

Phase two

involves removing

the south gates

and digging a

diversion channel.The blasting a

large plug of

bedrock to reroute

the river through

the gap.

Phase three

takes out the

north spillway

and upper

portion fo the

dam and installs

a road in order

to accesss the

penstock tubes.

1.

2.

Phase 4 will

remove the steel

penstocks, the

concrete intake

structure and the

powerhouse.

4.

3.

Phase ve

involves

removing

200,000 cubic

yards of rock,

concrete and r

trees behind the

dam.

Phase six

involves

removing

the

concrete

dam using

explosives.

6.

5.

Lake Aldwell

South Gates

Left Spillway

Original Channel

Large Penstock

Surge Tower

Small Penstock

Powerhouse

Elwha Dam

Glines Canyon Dam

Lake Aldwell

Lake Mills

Lake Crescent

Strait of Juan de Fuca

Elwha River

P O R T A N G E L E S

Da Prjct | Removal of two dams on the Elwha River is the second largest ecosystem restorationproject in the National Park System behind efforts to restore the Everglades National Park in Florida..

A Pa t Rstr Sa, Stad ad Trt

Here are the restoration strategies for various populations, as laid out in Elwha Fish Restoration Plan:

Chinook

Coho

Pink

Bull TRouT

SoCkeye

Chum

STeelheADChinook salmon in the Elwha historically included a stock that re-

turned in the spring and one that returned in summer or fall. To-

day, the chinook run is considered a composite of hatchery and

wild genes, mostly from the Elwha. In addition to natural spawn-

ing, the restoration strategy calls for hatchery production of this

composite stock with normal release into the Elwha after hatch-

ing. Other chinook will be held and grown for a year before re-

lease. Biologists believe that over time the population may sort

itself into groups returning at different times. In addition, a re-

serve population will be reared in a facility on nearby Morse

Creek to ensure that Elwha chinook genes survive.

Two winter steelhead populations have been identified: an ear-

ly run associated with a hatchery stock from outside the Elwha

and a late run derived from the native stock. In some years, the

native stock has been as low as 60 or 70 fish.Strategies are fo-

cused on the native stock. In addition to natural spawning, they

include growing steelhead eggs and fry to adults in a captive

broodstock program, designed to boost the numbers while be-

ing careful about inbreeding. Other strategies include releasing

year-old fish at downstream stations and releasing a variety of

ages at upstream locations. Production of the early, nonnative

stock will continue for now at low numbers. If a summer steel-head population exists, the numbers are critically low.

Elwha River coho are believed to be a native stock heavily influ-

enced by hatchery production. The strategy is to rear them for

a year in the hatchery before release. As the numbers build up,they may be released at a younger age in the upper river or even

planted as eggs.

Historically, pinks may have been the most abundant salmon in

the watershed, but today they are at critically low levels, worse

off even than the chum. It is believed that before the damswere built pinks went all the way to Lake Mills. Today, they cant

find the right size of gravel below the dams but that should

change when gravel begins to move downstream during demo-

lition. In addition to natural colonization, restoration strategies

may include a captive broodstock program or simply distributing

fry and eggs to various upstream locations.

Historically, two runs of Elwha chum probably existed, accord-

ing to genetic studies. Both are considered at critical levels. Their

numbers are being boosted by capturing and spawning adults,then outplanting their fry and eggs at various locations in the

river.

Sockeye salmon, which once returned to Lake Sutherland, are

considered extinct because the Elwha Dam blocked their return

from the ocean to the lake. Kokanee, which are essentially resi-dent sockeye, still live in the lake. The restoration strategy is to

see if some of the offspring from residents become anadromous

(migrating) once they are free to leave the lake. Otherwise, non-

native sockeye from other areas may find their way into the lake.

Two stocks of bull trout have been identified above the dams.

The strategy is to leave them as unmolested as possible during

dam removal. Bull trout will be captured in Lake Mills before

dam removal and moved upstream. During dam removal, trout

in the middle stretches may take refuge in the smaller tributary

streams, which is why efforts are being made to remove obsta-

cles. One example is the replacement of a 5-foot culvert on Griff

Creek with a 26-foot bottomless arch culvert. Once the dams areremoved, bull trout are expected to benefit from a greater range

of movement as well as access to salmon fry, which they will eat.

Bull trout, like chinook and steelhead, are listed as threatened

species under the Endangered Species Act.

graphics by J.D.Williams