Save the Best, Restore the Rest
Originally written December 19, 2013, and published in early January, 2014
'Save
and Restore' summarizes the practice of many land conservation
organizations. Here in Pacific County, hundreds of fish-passage
barriers, including undersized culverts, collapsed culverts,
un-swimmable fish ladders, other structures, and streams devoid of
shade and large woody debris, have been located and replaced or
replanted over the past decade. Many structures were installed
several decades ago, using best available ideas at the time, but the
times have changed. We have learned a lot about what does not work,
and what does work, with decades of applied science. The easy
projects have now been completed, which is good news. Today the focus
is on the remaining, larger, more expensive barriers, many of which
are low in these river systems, and run along or under highways.
Fixing these will open up more miles of access for salmon, and in
some cases reduce flooding and restore historic stream capacity.
Low Elevation Barriers
In
early December I saw a proposed restoration site in the Willapa basin
on Forks Creek, one of four county projects proposed by the
Washington Coast Sustainable Salmon Partnership (www.wcssp.org), and
supported by local stream habitat and fish groups. This low elevation
fish-passage barrier is an old weir, located near the main stem of
the Willapa River that keeps salmon out of 28 miles of streams. Above
this weir, there were many other barrriers, but those are now gone.
This is the last, and biggest, barrier left on this stream. The
stream was home to five species of salmon, and those species are
still in the main river and ready to return. In terms of breeding
habitat alone, there is room for thousands of redds (gravelly nests
where salmon lay eggs) in those 28 miles. Restoration will cost two
million dollars, including the planning, permitting, and engineering.
There are several streams like this in Pacific County, where one big,
low elevation barrier remains, and continues to block access to miles
of streams. These projects not only improve fish habitat, they
provide weeks to months of work for restoration crews, who live in
our county.
Weir on Forks Creek, off the Willapa River, photo by Kathleen Sayce |
Orders of Magnitude More Fish
Low
elevation barriers can keep a surprising number of fish out of their
historic feeding and breeding areas. When the tiny culvert at the
south end of Chinook on Highway 101 was replaced in 2011 with a 12 ft
by 12 ft box culvert, the number of young salmon feeding in the south
end of Chinook marsh leaped by two orders of magnitude. In just a few
weeks, the numbers went from under one hundred to over one thousand
fish in net surveys. Even better, those salmon came from all over the
Columbia basin, including the upper Columbia in north central
Washington, and the Snake River, not just from lower Columbia
tributaries. The Chinook marsh is tiny, 96 acres; but because of its
position near the Pacific Ocean, it's important feeding habitat for
all the juvenile fish that come downriver from higher streams. The
project cost $750,000, and was led by CREST with USFWS and LCREP as
partners.
New channel downcutting at a private hydrology restoration site, photo by Kathleen Sayce |
Flood Reduction and Fish Habitat
A
large marsh restoration on Highway 101 west of South Bend on Potters
Slough took place several years ago. A couple miles of the highway
west of Potter Slough was raised and widened to become a levee, then
the old dike along the Willapa River was removed, including tide
gates and other water control structures. The purpose of this
restoration was to open up several hundred acres to tidal activity,
to improve flood holding capacity and salt marsh habitat along the
Willapa River. Over the next several years, the marsh began to
function again, like a giant sponge; it takes in and stores inches of
new sediment every year. This site includes a couple hundred acres on
the south side of the highway, totaling 580 acres.
The
salt marsh is still partly bare, because plants grow from seeds each
spring, and are buried by freshly deposited sediments each winter.
Meanwhile, during major floods, the river level isn't as high as it
used to be in South Bend and Raymond. Bird use, including ducks and
shorebirds, is impressively high: More than fifty thousand
shorebirds and thousands of ducks may feed at one time in this marsh
in the spring. Young fish also use the marsh, as evidenced by
attentive herons and gulls along the channels.
HIgh tide behind new box culvert, Chinook Marsh, on Hwy 101, photo by Kathleen Sayce |
The Waits Are Worth The Time
The
culvert flowed under a highway; the levee was built on the footprint
of a highway. Replacing culverts, bridges, and raising sections of
highways are expensive. The money comes from an agency's budget,
often through a competitive evaluation program. Traffic has to be
rerouted or flagged for months. Weather can hold up work for weeks,
including windstorms, high storm tides, heavy rain, and cold fronts.
Insects can grow out of control for the first few years while the new
ecologies establish. Yes, it's annoying to sit at an automated light
and wait for it to go green. Yet all these small changes in our
landscape add up to more resilience for local communities, and over
their lifetimes as landscape structures, improved survival for
millions of fish.
When the Weather Changes Again
Remember
the warmer, drier weather of past decades, starting in 1976 and
ending in the late 1990s? There were El Nino-Southern Oscillation
events every few years, adding to the warmth. It was glorious for
beach visitors and gardeners, great for sitting out on warm summer
nights, but terrible for salmon. Our local salmon species had lost
hundreds of miles of breeding and rearing habitat by 1976, and when
the weather dried and warmed, the number of fish returning to breed
dropped off dramatically. Habitat restoration projects were
implemented to improve fish access to streams, including in-stream
wood, stream-side vegetation, barrier removal, side channel habitat,
increasing culvert sizes, gravel beds for redds, and the replacement
of fish ladders that did not work as planned. Hatchery management
methods were overhauled, along with genetic evaluations of wild and
hatchery populations. Salmon numbers slowly came up in the 1990s.
Then the weather shifted to wetter and cooler, and populations really
rebounded, with all the links from redds to ocean conditions working
in unison. Returns of Chinook salmon to the mid Columbia River were
higher this year than at any time in the past seventy years, due to
this combination of habitat improvements and ocean conditions.
The
problem is we don't know how long the present weather will last.
There's a saying that the best time to plant a tree was twenty years
ago; the second best time is now. The same is true for salmon
streams. Now is a great time to open up the last remaining barriers
in the streams and help all the salmon populations swing up. Right
now, the weather is cool and wet, and ocean conditions are good, but
the future is uncertain. With global climate change (for this area,
ocean warming and acidification), and the normal PDO shift due in a
few years, salmon will soon have two or more decades of poor
conditions to cope with. The more habitat our salmon regain now, the
better their chances will be to survive future warmer and drier
weather, and make it to the next cool, wet shift, when they can
thrive once more.
Many
habitat improvements are simple: Put nature back in charge of
streams. Where humans have to interface with streams, such as along
and under roads, we have learned how to do this better, and it's our
task now to use the best possible science with each restoration.
Which means, I suspect, that a few decades from now, we'll be stopped
again on the highway during the installation of newer and better
fish-passage structures, bridges and culverts. But let's get it done,
and keep doing it well, so that we have salmon in abundance in the
future.
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