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STREAMBANK EROSION
CONTROL ALTERNATIVES
Frank Reckendorf, PhD
(Reckendorf and Associates Salem,OR [email protected])
(volunteering for SERNW)
Barry Southerland, PhD
(USDA, Natural Resources Conservation Service, West
National Technical Support Center, Portland, OR
[email protected])
for
PNWSWS & SERNW, Vancouver, WA
May 4, 2005
STREAMBANK EROSION CONTROL
ALTERNATIVES
Planning, Evaluation, and Design Overview Workshop – May 4th, 2006
NW Chapter Society of Ecological Restoration – Vancouver, WA
Understanding
Process
Understanding the
Resource Problem
Understanding the
reference and desired
future condition
Using system(s) (fluvial and
watershed approaches) to
solve streambank erosion
problems
Introduction
Workshop Housekeeping
‹ Participant Introductions
‹ Binder, Design to Dirt CD, Soil
Bioengineering, Hoag and Fripp, 2002
‹ Design to Dirt Contents Review (see
Binder)
‹ Minimum Time Spent in Workshop on
Some Slides Because of Time Frame, but
“All Slides” will be in the Follow-up CD
‹
What Is Streambank Erosion?
‹ Streambank
erosion is that part of
channel erosion in which material is
eroded from the streambank and
deposited at the base of the slope or
in the channel. Streambank erosion
is usually associated with erosion of
the streambed. It occurs along
perennial, intermittent, and
ephemeral streams.
Planning and Evaluation
Any evaluation of streambank
erosion should be done in a
planning and evaluation context
that is cyclic. In other words there
is a cycle and feedback from
objectives to resource evaluation
to cause and effect to solutions to
objectives.
Planning Steps
Determining Objectives
‹ Assessment Including Appropriate
Environmental Assessment
‹
– Physical
– Biological
– Chemical
– Archeological
– Social
Planning Cont.
‹ Interpreting,
and Analyzing
‹ Developing Alternatives
‹ Documenting Decisions
‹ Establish Funding and Env. Clearance
‹ Implementation
‹ Monitoring
Restoration Planning
(see SER PRIMER sec. 3)
A clear rational as to why restoration is
needed
‹ A statement of the goals and objectives of
the restoration project
‹ An ecological description of the site
designated for restoration
‹ An ecological description of the reference
(see page 8 of PRIMMER multiple sites)
‹
East Side Stream in Valley Type “V”,
(Glacial-Fluv. Trough) Refer. Reach
White River, WA
East Slope
Cascades
Restoration Planning Cont.
‹ An
explanation of how the proposed
restoration will integrate with the
landscape and flows of organisms
and materials
Restoration Planning. Cont.
Explicit plans, schedules, and budgets for
site preparation, installation and post
installation activities, including a strategy
for making prompt mid-course
corrections.
‹ Well developed and explicitly stated
performance standards, with monitoring
protocols by which the projects can be
evaluated.
‹ Strategies for long-term protection and
maintenance of the restored ecosystem.
‹
Comparison Std. Plan. Rest.
‹
‹
‹
PLANNING
‹
RESTORATION PLANNING
DET. OBJECTIVES
ASSESSMENT
‹
A clear rational as to why
restoration is needed.
– Physical,Biological
– Chem.,Arch.,Social
‹
‹
Interpreting, and
Analyzing
‹
‹
A statement of the goals
and objectives of the
restoration project.
An ecological description
of the site designated for
restoration.
An ecological description
of the reference (see page
8 of PRIMMER multiple
sites).
Comparison (Cont.)
Developing
Alternatives
‹ Documenting
Decisions
‹
‹
‹
Explain integration
with landscape and
its flows of organisms
and materials.
Explicit plans,
schedules, and
budgets for site
preparation,
installation and post
installation activities,
including a strategy
for making prompt
mid-course
corrections.
Comparison (CONT.)
Developing
Alternatives
‹ Documenting
Decisions
‹
‹
Strategies for longterm protection
and maintenance
of the restored
ecosystem.
Comparison (Cont.)
Establish Funding
and Env. Clearance
‹ Implementation
‹ Monitoring
‹
‹
Well developed and
explicitly stated
performance
standards, with
monitoring
protocols by which
the projects can be
evaluated.
Workshop Focus
‹ Physical
Assessment
‹ Overlap to Biological Assessment
Especially for Riparian Area and
Pools
‹ Overlap to Water Quality Especially
During Construction
Precursors to Streambank
Accelerated Erosion
‹ Watershed
Level Conditions
‹ Reach Level Conditions
Watershed Precursors
Excess Sediment Supply, Especially from
Landslides, Debris Flow & Debris Torrents
(Tillamook Co. Oregon example)
‹ Increased Roads, Railroads, & Culverts
‹ Decreased Cover
‹ Increased Discharge Per Unit Area
‹ Large storms (precipitation and duration)
‹ Rain on snow and frozen soil
‹ Increased precipitation from storm stalling
‹ Climate Change Issues Impacting Runoff
‹
Dynamic Equilibrium
Problem of Excess Supply
E.W. Lane, 1955
W/S Excess Sediment Supply
Definitions
LANDSLIDE--The movement of a mass of
rock, debris, or earth down a slope.
DEBRIS FLOW--Landslides where a
considerable amount of coarse material
are suddenly moved by an excessive
amount of water and transported in an
extremely fast and destructive flow
through a valley.
‹ DEBRIS TORRENT-- Debris torrents are
rapid movements of water charged debris
that are confined to steep headwater
channels.
‹
2004 Landslide-Debris FlowDebris Torrent
Study during 1996-1997 flood season
found 9,582 landslides of all types
‹ Tillamook County accounted for 836 in the
inventory of which 212 were in the Wilson
River Watershed and 159 in the Kilchis
River Watershed
‹ The Little South Fork of
Kilchis River had a typical landslide-debris
flow- debris torrent in December 2003
‹
Landslide and Debris Flow
Landslide Headwall
Spheroidal Weathering
Residual After
Slurry Like Debris Flow
Start of Debris Torrent
Debris Flow Washed Out
Upstream at Start of Debris
Torrent See Rounded Boulder
>500 feet from Source
Downstream of Debris Torrent
& Residual Rounded Boulders
Down Debris Torrent
Debris Flow and Torrent
Deposition on Road
Offsite Effects
‹ 35,000
cubic yards of landslidedebris flow-debris torrent
‹ 800 cubic yards into South Fork of
Kilchis
‹ This sediment moves downstream in
pulses
‹ Chinook spawning redds impacted
Reach Level Precursors
Geometry Alteration ( Walla Walla River
straightening example)
‹ Streambed Alteration (bed excavation like
under bridges example Mill Creek Salem )
Creating Headcuts
‹ Removal of Native Vegetation (physical,
overgrazing, and biological like willow
borer)
‹ Flow Peak and Duration Increase (cyclic as
well as climate change)
‹
Walla Walla River,WA Looking
Downstream Pre-1964
Channelization
football
field &
track
Walla Walla River, WA
December 1964 - January 1965
Walla Walla Looking Upst. Dec.
1964 - Jan. 1965
Dynamic Equiibrium
Modified By
Channelization
Qs=Sediment discharge (especially bed-material load),
D50= Particle Size, Qw= Flow, S = Stream Slope
Walla Walla River, WA
December 1964 - January 1965
Down-cutting & Widening for Load, & Meandering for
Slope, are
the Negative Feedback Mechanism to Return to
Dynamic Equilibrium
Trout Cr. Deschutes,Co. Trying
to Return to Dyn. Equil.
Mill Cr. Gravel Removed Under
Bridge (initiating downcutting by
excavation verses slope caused
like in Walla Walla River)
‹ At
Winter Street 1927 Drawing
‹ See Upstream Effects
Mill Creek at Winter
Bridge x-sect.
Mill Creek, Salem (upstream
at Summer St.) Wanted to
Remove Deposition Bar
Mill Creek Salem
Mill Creek Salem
Mill Creek Drawing
Mill Creek Downcutting Along
Wall Downstream of Capitol
(used to justify bank work)
Mill Cr. Island is a Remnant of
1928 Streambed (upstream
from 17th St)
Remnant of Bed
Upstream of Chemeketa St
Mill Cr. Headcut to Check Dam
(1930 diver. to Mill Race)
What Are Reach Causes of
Streambank Erosion
‹ The
reach causes are a combination
of fluvial processes, mass failure
factors, vegetation factors, biological
factors flow factors, and climate
factors