defining ecological corridors · the minimum space needed to accommodate the fluvial processes and...
TRANSCRIPT
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Washington Salomon Recovery Conference 2019
Defining ecological corridors (a tool for salmon recovery assessment, planning, and process-based restoration design)
Tim Abbe, Susan Dickerson-Lange and Jennifer O’NealNatural Systems Design
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Washington Salomon Recovery Conference 20191Abbe et al. 2016
Habitat forms in a Spatial and Temporal DomainSufficient space is essential to accommodate natural processesRestoring fluvial ecosystems requires sufficient space
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Washington Salomon Recovery Conference 2019
How much space does a river need?
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Washington Salomon Recovery Conference 20193Halawa Stream, O’ahu
It is very expensive –both economically and environmentally
Marin County, CA
from a traditional flood conveyance perspective, not much
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Washington Salomon Recovery Conference 20194
Hanaford 2D - Straightened Section
Looking DS
Distance (ft)580560540520500480460440420400380360340320300280260240220200180160140120100806040200
Elev
ation
(ft)
209.6
209.4
209.2
209
208.8
208.6
208.4
208.2
208
207.8
207.6
207.4
207.2
207
206.8
206.6
206.4
206.2
Leveed Ditch – Hanaford Creek, Chehalis Basin
2100 ft
2100 ft20 ft
1% of natural domain
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Washington Salomon Recovery Conference 20195
Constraining rivers doesn’t always go well
Walla Walla River near Milton-Freewater, OR
1% of natural corridor
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Washington Salomon Recovery Conference 20196
From a habitat perspective, how much space does a river need?
Not nearly enough?
More than enough?
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Washington Salomon Recovery Conference 2019
A need for policy protecting habitat Flood inundation
hazards (FEMA FIRMs)
Erosion hazards (State CMZ delineations)
Ecological Corridor: space to accommodate & sustain habitat forming processes
Current corridors are opportunistic
corr
idor
deve
lopm
ent
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Washington Salomon Recovery Conference 2019
Ecological Corridor Definition:The minimum space needed to accommodate the fluvial processes and habitat structural elements that create and sustain the site’s natural habitat diversity.
small valley - EC could be entire valley bottom. large valley – EC could be a fraction of the valley
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Washington Salomon Recovery Conference 2019
historical conditions: large floodplain
Habi
tat D
iver
sity
Percent of valley width managed as fluvial corridor
Cost
of R
iver
Man
agem
ent
Straightened, leveed channel
Complete valley restoration
Ecol
ogic
al C
orrid
or
High habitat diversity
No habitat diversity
High cost
Low cost
S
Ecological Corridor Basics
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Washington Salomon Recovery Conference 2019
large floodplainHa
bita
t Div
ersi
ty (D
)
Percent of valley width managed as fluvial corridor
Straightened, leveed channel
Complete valley
restoration
Ecol
ogic
al C
orrid
or
High habitat diversity
No habitat diversity 100%
S
Large River
Small Stream
Small floodplain
Ecol
ogic
al C
orrid
or
Ecological Corridor Basics
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Constraints on a river vary within its basin.
Valley width Existing river
corridor
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Washington Salomon Recovery Conference 201912
An EC depends on understanding pre-disturbance conditions
what habitat existed?what formed it?
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Washington Salomon Recovery Conference 2019
Habitat Diversity, Quantity, Quality = f(space)
13
8
Alluvial valley
Confined valley
Structural elements
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Washington Salomon Recovery Conference 2019
Habitat Formation Depends on Structural Elements
Big trees directly influence habitat complexity
A loss of big trees leads to a simplification
Willamette 1854 Willamette 1967
Riparian forests, geology and human structures (roads, levees, bridges) influence formative processes over variable spatial and temporal scales
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Wood influences vertical and horizontal scales
cm kmsubstrate & cover
Sub-reachBedforms & gradients
Reachplanform & floodplain
992
994
996
998
1000
1002
1004
0 25 50 75 100 125 150 175 200 225 250
Distance (m)
Rela
tive
Elev
atio
n (m
)
Alta Creek Floodplain, Queets Basin, WA
Wood dominated floodplain
Chart1
0
10
25
33
35
36
39.5
41.5
43.5
44.5
45.3
45.4
45.9
46.1
46.9
50.9
51.8
53.8
56.8
60.8
61.7
64.7
65.7
68.7
70.7
72.7
82.7
92.7
102.7
104.7
106.7
108.7
110.7
112.7
114.7
115.2
117.2
119.2
121.2
122.4
125.4
126.4
127.4
128.4
131.4
132.4
134.4
136.4
136.9
137.9
142.4
143.4
144.4
147.4
148.4
151.4
165.4
170.4
174.4
177.4
188.4
192.4
193.4
198.4
199.4
202.4
206.4
207.4
209.4
212.4
216.4
218.4
220.4
222.4
223.4
228.4
233.4
245.4
251.4
Distance (m)
Relative Elevation (m)
999
997.9
998
997.9
997.9
998.8
999
999.1
999.15
999.2
996.4
996.2
996.2
996.1
996.1
995.8
998.1
998.4
998.45
998.5
998.4
998.4
997
997.2
997.4
997.5
997.61
997.4
997.55
997.52
997.46
997.3
996.9
997.1
997.3
999.8
999.8
999.85
999.8
999.8
999.8
1000.8
1001.1
1001
1000.9
1000.85
1000.85
1000.7
1000
999.54
999.55
999.4
994.1
994.3
994.8
994.9
994.8
994.3
994.4
999.1
998.8
998.5
997.5
997.5
998.7
998.8
998.7
995.6
995.7
996.6
996.7
996.4
996
996
1001.4
1001.5
1001.5
1001.4
1001.6
Sheet1
relative
Staelevation
0999
10997.9
25998
33997.9
35997.9
36998.8
39.5999
41.5999.1
43.5999.15
44.5999.2
45.3996.4
45.4996.2
45.9996.2
46.1996.1
46.9996.1
50.9995.8
51.8998.1
53.8998.4
56.8998.45
60.8998.5
61.7998.4
64.7998.4
Figure 3B65.7997
68.7997.2
70.7997.4
72.7997.5
82.7997.61
92.7997.4
102.7997.55
104.7997.52
106.7997.46
108.7997.3
110.7996.9
112.7997.1
114.7997.3
115.2999.8
117.2999.8
119.2999.85
121.2999.8
122.4999.8
125.4999.8
126.41000.8
127.41001.1
128.41001
131.41000.9
132.41000.85
134.41000.85
136.41000.7
136.91000
137.9999.54
142.4999.55
143.4999.4
144.4994.1
147.4994.3
148.4994.8
151.4994.9
165.4994.8
170.4994.3
174.4994.4
177.4999.1
188.4998.8
192.4998.5
193.4997.5
198.4997.5
199.4998.7
202.4998.8
206.4998.7
207.4995.6
209.4995.7
212.4996.6
216.4996.7
218.4996.4
220.4996
222.4996
223.41001.4
228.41001.5
233.41001.5
245.41001.4
251.41001.6
Sheet1
Distance (m)
Relative Elevation (m)
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Washington Salomon Recovery Conference 2019
Wood can change channel morphology
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Washington Salomon Recovery Conference 2019
Unconstrained
Abbe 2016
Increased morphologic complexity occupies more space
Constrained levee reach
White River, King County
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Washington Salomon Recovery Conference 2019
Ecological Corridor AtlasProtocol completed for Skookumchuck Watershed
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Washington Salomon Recovery Conference 2019
Ecological Corridor AtlasSkookumchuck Watershed
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Washington Salomon Recovery Conference 2019
Ecological Corridor AtlasSkookumchuck Watershed
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Washington Salomon Recovery Conference 2019
Current conditions
Skookumchuck
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Washington Salomon Recovery Conference 2019
Relative Elevation Mapping (REM)
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Washington Salomon Recovery Conference 2019
4 ft
4 ft
Historic Channel Incision
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Washington Salomon Recovery Conference 2019
Detail Next Slide
Centralia
Historic Conditions: GLO Mapping
Distance alongSection Line1 chain = 66 feet
Traverse from E to W
Primary Channel
Slough Channel
Another Slough
Plat Map Field Notes
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Washington Salomon Recovery Conference 2019
Current conditions
Skookumchuck
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Washington Salomon Recovery Conference 2019
“Enter Skookumchuck bottom”
“Intersect Left Bankof the Skookumchuck,100 links (66 ft) wide,Course S 30° W”
“Enter a Slough, Course SE”1 chain (66 ft) wide
“Slough,100 links (66 ft) wideCourse N & S”
“Leave Skookumchuck bottomand enter prairie”
Field notes document primary channel plus two additional slough channels of equal width. Not shown in plat maps… Evidence of anabranching channel pattern
Historic Conditions: GLO Mapping
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Washington Salomon Recovery Conference 2019
“Enter Skookumchuck bottom”
“Intersect Left Bankof the Skookumchuck,100 links (66 ft) wide,Course S 30° W”
“Enter a Slough, Course SE”1 chain (66 ft) wide
“Slough,100 links (66 ft) wideCourse N & S”
“Leave Skookumchuck bottomand enter prairie”
Old channel covered in fill
Remnant of slough
Overlaying historic on current REM
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Washington Salomon Recovery Conference 2019
“Enter a Slough, Course SE”1 chain (66 ft) wide
Historic reconstruction
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Washington Salomon Recovery Conference 2019
Delineated EC
Acknowledgements: Office of Chehalis Basin Aquatic Species Restoration Plan
Defining ecological corridors �(a tool for salmon recovery assessment, planning, and process-based restoration design)Sufficient space is essential to accommodate natural processesHow much space does a river need?Slide Number 4Leveed Ditch – Hanaford Creek, Chehalis BasinSlide Number 6Slide Number 7A need for policy protecting habitatEcological Corridor Definition:��The minimum space needed to accommodate the fluvial processes and habitat structural elements that create and sustain the site’s natural habitat diversity.Slide Number 10Slide Number 11Slide Number 12Slide Number 13Habitat Diversity, Quantity, Quality = f(space)Habitat Formation Depends on Structural ElementsSlide Number 16Wood can change channel morphologySlide Number 18Ecological Corridor Atlas�Protocol completed for Skookumchuck WatershedEcological Corridor Atlas�Skookumchuck WatershedEcological Corridor Atlas�Skookumchuck WatershedCurrent conditionsSlide Number 23Slide Number 24Slide Number 25Slide Number 26Slide Number 27Slide Number 28Slide Number 29Slide Number 30