The geomorphic condition of a stream system
can be used as both an indicator and predictor
of watershed health and function.
Stream Equilibrium & Stability
Boundary Condition
Channel Geometry
Watershed Input:
Sediment Load
Watershed Input:
Hydrologic Load
(Sediment LOAD) * (Sediment SIZE) ≈ (Stream SLOPE) * (Stream DISCHARGE)
[Lane’s Diagram (1955) from Rosgen 1996]
Deforestation – Snagging – Ditching – Settlements
Log Drives on the
White River
Roads – Railroads
Dams – Mill Works
Turning Slow Winders
Into Straight Channels
Major Floods
Post flood
channelization
results in major
alterations to
channel geometry
and the
destruction of
habitat features
Commercial
Gravel Mining
Encroachment - Urbanization - Stormwater
Leading to
Severe Channel Degradation and Aggradation
Temporal Scale of Fluvial Response
PreEquilibrium
condition
1800
Modification of watershed inputs, channels & floodplains
Pre-
1900
1927
Geomorphic
response
begins
Widening to
balance
energy with
boundary
conditions
1973
Developing
new flood
plain
2003
Equilibrium
condition
Recognize that:
 A significant percentage of VT
rivers are incised and have lost
access to historic floodplains;
 Incised rivers are currently
widening and aggrading;
 Historic channelization
practices have been maintained;
 Investments are now where
the river used to be;
 Conflict is economically and
ecologically unsustainable.
Up to 80% of stream miles in watersheds feeding Lake Champlain are
undergoing major adjustment due to historic channel modification.
Approximate location
of 1900 channel
Lewis
Creek
Channelized reach along
toe of valley wall
The Conflict:
Channel Adjustments v.s. Land Use Expectations
CEM and the Trick of Time
Widening, Aggradation & Planform Adjustments
Seen as Erosion
Not a Response to
Channel Incision
Five Major Floods - over $60 million to recover!
Channel management
necessary to protect
existing river corridor
development
Results in repeated:
Dredging
Berming
Armoring
How Do We Slow the Cycle??
Bank Erosion
and loss of
Riparian
Function
Floods and
Property Damage
Encroachment
Channel Incision
and loss of
Floodplain Function
Dredge, Berm
and Armor
Aggradation,
Widening,
and Planform
Adjustments
VT ANR Stream Geomorphic Assessment Program
The purpose of the
stream geomorphic
assessment protocols is
to provide a method for
gathering scientifically
sound information that
can be used for
watershed planning
and detailed
characterization of
riparian and instream
habitat, stream-related
erosion, and flood
hazards.
Stream Geomorphic
Assessments
Phase 1
Remote Sensing
Phase 2
Qualitative & Rapid Field Assessment
Quantitative Field Surveys
Phase 3
Vermont ANR Stream Geomorphic Assessment
Assessment Objectives
Identification of:
– stream condition as compared to a
reference stream of the same type
– adjustment process or physical change
currently underway in the channel
– sensitivity of valley, floodplain, and
channel to human or natural changes
Departure Analysis to Determine CEM Adjustment Process
Dimension
CEM Adj. Stream
Stage Proc. Type
I
Pattern
Degration
Floodplain
II
Terrace 1
Widening
(Headcutting)
F
River
Bed
Headcut
III
(Bank
Failure)
F/C
IV-V
Planform
Terrace 2
V
Cross-Section
Location
Red = Narrower Belt Width
Aggradation
& Planform
IV
I
II
G
III
Floodplain
Belt
Width
I
C/E
Profile
II
I
Degration
Aggradation
V
I
I
C/E
Terrace 1
Floodplain
III
III
II
Stream Equilibrium & Stability
Boundary Condition
Channel Geometry
Watershed Input:
Sediment Load
Watershed Input:
Hydrologic Load
(Sediment LOAD) * (Sediment SIZE) ≈ (Stream SLOPE) * (Stream DISCHARGE)
[Lane’s Diagram (1955) from Rosgen 1996]
Channel Form
as a function of
Watershed inputs
Landscape setting
Boundary Conditions
McCrae, 1991
Evaluating instability
due to watershed and
reach-scale changes
Hydrology
Sediment Load
Channel Geometry
Slope
Floodplain Access
Channel Degradation
In Response to Changes Imposed
In the Watershed or Within the Reach
Qs
Q
Degradation
Realignment
Aggradation
Q +
Qs S +
d50 -
Flow Increase
Sediment Load Decrease
Slope Increase
Sediment Size Decrease
Dredging /Mining
Berming
Watershed
Scale
Climate
(dry period)
Stormwater
Dams &
Diversions
Bridges &
Culverts
Reach or
Local Scale
Channel
Realignment
Dredging &
Mining
Berming
Bank
Armoring
Using geomorphic
data to for
assess
channel
stability in
Design Criteria
Trout
River
support of
protection,
management & restoration projects
Phase
I Reach
Bankfull Discharge - Q bkf
W idth - W bkf
M ean Depth - d bkf
Cross Sectional Area - A bkf
W idth/Depth Ratio - W /D
Entrenchment Ratio - ER
1750 ft 3/sec
70 ft
3. 54 ft
248 ft 2
19. 7
9. 3
M eander W idth Ratio - M WR
Radius of Curvature - R c
W avelength - L m
Belt W idth - B
W ater Surface Slope - S
Channel Sinuosity - K
H ydraulic Radius - R
Roughness Coefficient - n
M ean Velocity - u
Friction Factor - u/u *
Shear Velocity - u *
8. 8
230 ft
1, 000 ft
620 ft
0. 003
1. 58
3. 24 ft
0. 0292
6. 1 ft/sec
9. 77
0. 624 ft/s
Shear Stress - 
Stream Power - 
Threshold Grain Size
D50 Bed Particle Size
D84 Bed Particle Size
0. 6065 lbs. /ft. 2
3. 700 lbs. ft. /s
88. 2 mm
1. 52 in / 38. 6 mm
3. 00 in / 76. 2 mm
Parameters Assessed
 Valley Characteristics
 Stream & Floodplain Geomorphology
 Bed and Bank Erodibility
 Watershed & Riparian Corridor Land use/Land cover
 Instream Channel Modification
 Floodplain Modifications
 Flow Modifiers
 Stream & Riparian
Habitat Characteristics
Phase 1 - Remote Sensing
* Defining Stream Reaches
* Determine Stream Type
* Geology & Soils
* Factors Influencing Runoff
* Instream Channel
Modifications
* Floodplain Modifications
Step 1 Watershed Delineation
Reach Breaks based on:
 Valley Width
 Valley Slope
 Geologic Materials
 Tributary Influence
Reach
Numbering
Schemes
T1.6
T1.5
T1.3S1.5
T1.3S1.3
T1.3S1.4
T1.4S1.1
State
Geographic
T1.4S1.2
T1.3S1.4S1.1
T1.4
T1.3S1.4S1.1S1.1
0800000096-0001
T1.3
T1.3S1.2
T1.3S1.1
Reach Break
Hydrologic
T1.2
Watershed Bounds
M1T1.3S1.4S1.1S1.1
T1.1
Reach Number
M2
M1
Drainage Area
and Watershed
Location
Stream Typing
Flow Regime
Valley Slope &
Confinement
Sediment
Regime
Reference
Channel
Boundaries
Entrenchment
Existing
Width/depth
Sinuosity
Water Surface
Slope
D50
Sediment Size
D84
Sediment Size
Modified
Phase 1 Stream Typing
Sediment
Transport & Storage
Channel
Confinement & Slope
Steps 2.1 Upstream and
2.3 Valley Slope
Downstream Elevations 2.5 Channel Slope
Gentle Gradient
Check Box
Step 2.10 Confinement
Valley
Valley
Width/Channel
Confinement
Type
Width Ratio
1-NC
Narrowly
1 and < 2
Confined
1-SC
Semi-confined 2 and <4
2-NW
Narrow
4 and <6
3-BD
Broad
6 and <10
3-VB
Very Broad
10 -with abandoned
terraces on one or both
sides
Steps 2.2 Valley Length
2.4 Channel Length
2.6 Sinuosity
channel length (ft.)
valley length (ft.)
Step 2.11 Reference Stream Type
Stream Type
1. Confinement
(Valley Type)
2. Valley
Slope*
Dominant Bed
Material (Step 7)
Bed Form
(Step 7)
A / Cascade
Narrowly
confined (NC)
Very Steep
> 6.5 %
BedrockBoulder
Tumbling jet
and wake flow
A / Step-pool
Confined
(NC)
Very Steep
4.0 - 6.5 %
Boulder-cobble
Steps and
channel
spanning pools
B / Step-pool
Confined or
Semi-confined
(NC, SC)
Steep
3.0 - 4.0 %
Boulder-cobble
Steps and
channel
spanning pools
B / Plane bed
Confined or
Semi-confined or
Narrow
(NC, SC, NW)
Mod.- Steep
2.0 – 3.0 %
Cobble-bouldergravel or finer
Run, riffle,
and rapid
C or E /
Riffle-Pool
or
Dune-ripple
Unconfined
(NW, BD, VB)
Mod.- Gentle
< 2.0 %
Gravel-cobblesand or finer
Undulating
D / Braided
Channel
Unconfined
(NW, BD, VB)
Mod.- Gentle
< 2.0 %
Gravel or finercobble-boulder
Braided
Watershed Zones and Stream & Valley Types
Source
A
Confined
B
Transfer
D
Semi-confined
C
Response
E
Unconfined
D
Step 3.1 Alluvial Fans
Phase 1 River Corridor
Parameters evaluated
1) Soils and Geology
2) Land Use and Land Cover
3) Riparian Vegetation
4) Berms, Roads & Paths
5) Development
River Corridor Delineation
Based on:
1. Belt Width to achieve
slope requirements to
satisfy sediment storage
and transport processes
2. Streambank Stability
with woody vegetation
3. Runoff Characteristics
related to near stream
land uses
River
Corridor
delineation
Using soils maps to draw the toes of valley walls
Original valley toes drawn
based only on contour lines.
Corrected valley toe based on soils map, showing
alluvial material beyond change in slope contours.
Approximate valley wall
Soils Data and
approximate
Valley Wall Lines
Corridor where
soils reviewed
Step 4.2 Corridor Land Cover / Land Use
River Corridor
Impact Rating
based on:
 Urban
 Crop
Channel
Straightening
Floodplain
Modifications
Channel
Modifications
Topographic Map (1917) Explains Channelization
Width of the River Corridor
Road
Improved Path
Road along 30% of Left Corridor
Path along 50% of Right Corridor
High Impact
Topographic map of M3 in 1900
Orthophoto of M3 in 1942
Approximate
location of 1900
channel
Topographic map of M3 in 2001
Orthophoto of M3 in 1992
Road intersection is common point of reference in all photos.
Meander Geometry
Wavelength
Belt
Width
Riffles
Pools
Appendix H
Using Regime
Relations
to estimate
Planform
Geometry
Step 7.1 Dominant Bed Form / Material
Cascade
Step-pool
Plane Bed
Riffle-pool
Dune-ripple
Braided
Appendix M
Bedrock
Boulder
Cobble
Gravel
Sand
Reach
Number
Stream
Type
M19
C
Step 6
Step 7
Step 5
Step 4
Total
Floodplain
Windshield
Instream
Land Use
impact
Survey
Modification Modification
Impact
Impact
(out of 32)
Impact
Impact
(out of 6) (out of 10)
(out of 12)
(out of 4)
14
3
4
5
2
Watershed
Size
Confinement
18.21
3-VB
Types of Impacts seen along stream reach:
1)
2)
3)
4)
5)
6)
7)
Active Agriculture in corridor (crop) {Step 4}
Little to no Riparian vegetation {Step 4}
Channel modification (straightening) {Step 5}
Bank Armoring (Rock rip-rap) {Step 5}
Mid-channel bars {Step 6}
Planform changes (meander migration & avulsions) {Step 6}
Erosion {Step 7}
Step 9.2 Reach Condition
Phase 1
Provisional
Adjustment
Scores
Impact
Degradation
Aggradation
Widening
Planform
Condition
8
4
7
5
1
Fair
10
5
6
7
10
Poor
10
6
4
5
8
Fair
10
2
2
2
6
Good
8
6
4
5
8
Fair
8
2
2
2
6
Good
10
9
4
3
8
Fair
11
4
6
5
8
Fair
10
5
6
5
7
Fair
12
7
5
5
5
Fair
14
6
9
7
8
Poor
8
2
3
0
2
Good
Lewis Creek Mainstem Reaches
Phase 1
Results
Total Impact
30
25
A
20
B
14
15
9
10
11
10
9
6
5
3
7
9
8
6
4
11
5
6
6
9
C
10
7
6
6
E
6
2
1
0
2
0
0
M1
M4
M7
M12
M14
M16
M18
M21
M23
Reach Numbers
 Reference stream type for each reach
 Total Impact rating for each reach
 Likely adjustment process determined for each reach
 Eight standardized database reports to help determine
like reaches and to prioritize field assessments
Phase 2 - Rapid Field Assessment
 Field verification of Phase 1 data
 Collecting data using the Field-Note Form
Rapid Assessments Protocols
 Identifying stream type, adjustment process
and condition of reaches and reach segments
Phase 2 - Channel and Floodplain Measurements
Stream Type and Condition
RGA
Evaluate
Indicators of
Adjustment
Stages of
Channel
Evolution
Floodplain 1
New floodplain
Floodplain 1
Stream Geomorphic Condition as an Assessment Tool
• In Regime – reference and good condition
• In Adjustment – fair condition
• Active Adjustment and
Stream Type Departure – poor condition
(from Rosgen 1996)
Sensitivity Ratings
Geomorphic
Existing Geomorphic
Stream Type
Stream Type*
Group
Reference or
Good Condition
Fair-Poor Condition Poor Condition and
in Major
represents a Stream
Adjustment
Type Departure
1
A1, A2, B1, B2,
Very Low
Very Low
Low
2
C1, C2
Very Low
Low
Moderate
3
G1,G2, F1, F2
Low
Moderate
High
4
B3
Low
Moderate
High
5
B4, B5
Moderate
High
High
6
C3, E3
Moderate
High
High
7
C4, C5, E4, E5
High
Very High
Very High
8
A3, A4, A5,
G4, G5
High
Very High
Extreme
9
F3, F4, F5
Very High
Very High
Extreme
10
D3, D4, D5
Extreme
Extreme
Extreme
G3,
Rapid Habitat
Assessment
Protocols
Substrates
Depth / Velocity
Riparian
Phase 3 - Survey Level Assessment
Reference Reach
Phase 3 Survey
Measured
Width
Depth
X-Area
Velocity
Discharge
91.5 ft
3.2 ft
291 ft 2
5.7 ft/s
1652 cfs
VT-HGC
82.4 ft
3.4 ft
293 ft 2
5.6 ft/s
1643 cfs
Phase 3 Assessment
Empirical Data
Planform information
from aerial photos
Rc
Lm
Trout River Longitudinal Profile
20
Relative Elevation (ft.)
18
16
14
12
10
As Built Profile
8
6
Existing Profile
4
Bankful Elevation
2
0
0
200
400
600
W belt
800
Station Location (ft.)
1000
1200
1400
1600
Data Management and Quality Assurance
Training
Data Review
Data Management
GEOMORPHIC APPLICATIONS IN VERMONT
Stream Alteration
Permit Program
Silvicultural AMPs need to address suitability of
land to support bare ground harvesting.
Hydrograph before and after
conversion from overland flow
and infiltration to channel flow.
after
Stream
Flow
before
Time
Understanding
Sediment-related
Impairments
Flood Plain Management – State & Local
NFIP
&
CEM
State Floodway Policy
Flood Hazard Mitigation - FEMA
Pre-disaster Hazard Assessment and Mapping
Transportation Planning & Highway Design
Bridges
and
Culverts
State and Regional
Land Use Planning and Regulatory Review
Education of Local Planning and Zoning Officials
Habitat Restoration
Habitat
Protection and
Restoration
State & COE
Dam Removal
Task Group
Implement Alternatives at the Watershed Scale
Long-term Solutions
 Passive Geomorphic
 Active Geomorphic
Short-term Solutions
 Channelization
 Do-nothing