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- Presented To:
- White Salmon River Festival & Symposium
- June 6, 2007
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- An overview of the ecological functions of Large Woody Debris (LWD) in
streams & rivers
- Human interactions with LWD (with a focus on raftable rivers in the
Pacific Northwest)
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- Generally, any piece of wood:
- => 2m (~6.6’) long
- and
- => 10cm (~4”) diameter
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- 2% LWD content in the bed can account for 50% of the roughness (Magna
and Kershner 2000)
- Frequency of quality pools decreased in 52-54% of Columbia Basin rivers
draining managed watersheds since roughly 1940 (McIntosh et al. 2000)
- Resistance to flow in vegetated floodplain channel is 40% greater with
LWD than without. Velocities were
higher and depths were lower without LWD. (Abt et al. 1998)
- In western Washington:
- Average diameter, length, and volume of LWD pieces increases with stream
size (Bilby and Ward 1989)
- In streams <7m channel width, 40% of LWD pieces were oriented
perpendicularly to flow (Bilby and Ward 1989)
- In streams >7m channel width, 40% of LWD pieces were oriented
downstream (Bilby and Ward 1989)
- Pool area correlated with the volume of the LWD forming the pool in
streams of all sizes (Bilby and Ward 1989)
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- Recruitment rates
- Stream type
- Natural history of reach & watershed
- Flood events Disease / Bugkill
- Debris flows Fire
- Management history of reach & watershed
- Riparian harvest stream cleaning
- Splash damming road crossings
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- species (related to decay and density)
- Position in the water column (wet/dry)
- Stability
- Association with other pieces
- Association with bed and or bank materials
- Association with vegetation
- Presence of rootwad
- Size
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- Two large jams on the Skagit River appear on the GLO plat maps in 1873
- One jam (~1/2 mile downstream of Mt. Vernon) had been in place
sufficient to block river traffic for nearly 100 years
- A second jam (roughly one mile upstream of Mount Vernon) was younger,
but was “rapidly increasing in size at the rate of a quarter mile every
three years.”
- The only way around the jam was “A rude skid road built by Upper Skagit
Indians to haul their canoes…”
- In the summer of 1876, removal began using crosscuts saws and axes
- Removal involved cutting “through five to eight tiers of logs three to
eight feet in diameter, totaling 30 feet deep”
- Removal was completed in 1879.
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- “It's legal to manually manipulate woody debris on rivers--that doesn't
include chain saws, but does allow crosscut saws, z-drags, ropes or
however you can move something via pure muscle or mechanical advantage.
So, if managing agencies say "NO" to manually manipulating
woody debris, it's BS and simple intimidation. Besides, studies have
shown that cross-river tree falls do not improve the fish & wildlife
habitat, but tree falls along the banks do improve fish and wildlife
habitat--even on the Metolius.”
- quote was posted to the
PNWwhitewater yahoogroup on 1/28/07
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- WDFW has authority for issuing hydraulic project approval (HPA) in the
State of Washington. As a rule of
thumb, if your proposed action might affect the bed, banks, and/or
nature of flow, an HPA is required (even if the action is above the
ordinary high water line)
- does not generally write permits for removing LWD from streams.
Relocation/repositioning of LWD is permitted
- timing of that work is dependent upon many factors such as fish species
present, life history stages that may be impacted (spawning, rearing,
etc.), what habitat exists at the site or in close proximity, extent of
the work.
- work is evaluated on a case by case basis to make a determination on
specific timing. General timing
dates are available at WDFW’s website under "Habitat", in the
back of the Gold and Fish Pamphlet. Information regarding the RCW and
WAC's that require an HPA be secured for work that will, "use,
divert, obstruct or change the natural bed or flow of state waters” is
available on the WDFW website
- If in doubt about applicable regulations, the Washington State Office of
Regulatory Assistance for help in making this determination.
1-800-917-0043 E-mail: assistance@ora.wa.gov, Web: www.ora.wa.gov.
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- The FS was designated the Federal agency responsible for the Wild and
Scenic portions of the White Salmon and Klickitat Rivers
- The Wild & Scenic Rivers the Act gives the agency jurisdiction to
protect the free flowing nature of the river and enhance its values, as
long as limiting other uses does not substantially interfere with public
use & enjoyment of those values.
- WA State maintains full jurisdiction over the waters as long as it
doesn't impair the purpose of the Act.
- While there is no USFS paperwork per se, the USFS requests to be be
informed of the situation & proposed actions to alleviate the hazard.
The Forest Service will help fill out HPA form (if asked) to remove wood
if:
- 1. It was a
life-threatening situation, or
- 2. A high water event would
did not take it out before commercial rafting season.
- All White Salmon outfitters operating plans specifically state:
- "Conservation measures for the White Salmon River includes keeping
large wood and fallen trees in the river system. Large wood and fallen
trees found between RM 6.5 and RM 5.1 will remain in the river
channel. In instances where this
material poses a hazard to boaters, the debris would be moved to a safe
location, but remain in the river."
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- The raft runs on the White Salmon River as well as the Klickitat River
from roughly 3 miles upstream of the hatchery are located in Klickitat
County.
- Depending the extent to which woody debris is removed from streams (e.g.
removal of one dead tree vs. removal of several living or dead trees),
the following may apply:
- Klickitat County’s Shoreline Plan may prohibits removal of natural
vegetation 50’ landward from the OHWM (e.g. removal of trees or branches
that overhang the river)
- Klickitat County’s Floodplain Ordinance may apply if the removal of
woody debris will cause flooding downstream
- Klickitat County’s Critical Areas Ordinance may apply if fish habitat is
adversely affected. The WDFW or other qualified professional
biologist would need to substantiate such a claim prior to the County
taking action.
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- The Klickitat River from roughly 3 miles upstream of the Klickitat
Hatchery is located in Yakima County.
- From the Yakima County Planning Department:
- “Large Woody Debris found in log jambs, rootwads, etc. are some of the
most important parts of the river. Log jambs are primary in-stream
features that can greatly affect sediment transport and fish
habitat. Their removal can have big repercussions upstream and
downstream on both natural functions, and on adjacent landowners
(through flooding and bank erosion).”
- “There are opportunities to be exempt from the permit process - some of
which might allow dead wood removal under certain circumstances.”
- “They would have to apply for and meet the criteria of the exemption,
and would still have to protect the functions of the stream corridor.”
- “If done carefully, the limited removal of wood for rafting safety might
be possible, but it would have to be the minimum needed and it couldn't
remove the log jamb etc. completely.”
- “If the work can't qualify for an exemption, it might be approved under
a permit or variance with appropriate mitigation.”
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- Has federal jurisdiction for marine species as well as species that
spend a portion of their life history in freshwater (e.g. salmon and
steelhead)
- NMFS is actively working to increase the amount of wood in stream
channels where ESA listed fish migrate, hold, spawn or rear, it is one
of the limiting factors for healthy populations.
- If a person wants to remove wood from a stream channel on private
property, they are subject to Section 9 of the ESA which states
"except as provided in sections 6(g)(2) (State agreements or plans)
or section 10 (research permits)...it is unlawful for any person....to take
any such species...“. The word
"take" means "harass, harm, kill, disturb, disrupt normal
behaviors.." If a Federal agency, a federal permit, or
any federal funding is involved in the proposed wood removal that would
fall under section 7 consultation.
- In 2002 NMFS consulted on the proposal to remove Condit Dam and approved
the action. At the present
time the river downstream of the dam is designated critical habitat.
- According to the law, actions are not allowed to "destroy or
adversely modify" critical habitat to the point that it reduces the
conservation value of that habitat for the survival and recovery of the
species.
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- Side-channel formation / channel complexity
- Sediment sorting and storage
- Cover
- Increased pool quantity
- Increased pool quality (depth and cover)
- Grade control
- Slows downstream transport of matter and energy
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Notes
