VT ANR Stream Geomorphic Assessment Program
Phase 1
Assessment
Protocols
Getting Started….
• Assemble a team!
- ensure QA oversight
• Determine scope of assessment - how much can we do?
• Contact VTANR for protocol updates and reach
numbering start points
• Gather tools/materials – data sheets, software, measuring tools
• Gather data – maps & data layers: current/historic, paper/digital
• Conduct watershed orientation windshield survey
Orientation Windshield Survey
Understanding watershed boundaries
Mapping valley wall toes and changes
in valley setting
Observing land use and land cover
Mapping grade controls
Step 1 Watershed Delineation
Reach Breaks based on:
 Valley Width
 Valley Slope
 Geologic Materials
 Tributary Influence
Source
Watershed Zones
Transfer
Response
Reach Breaks based on Valley Width
Reach Break
Approximate toes of valley walls
Reach Breaks
based on Valley Slope
Percent Description Contour
Slope of slope
interval on
1:24,000 map
> 4%
Very Steep
<0.2 in.
2-4%
Steep
~0.2 - 0.5 in.
0.5-2%
Moderate
>0.5 in.
<0.5%
Gentle
>1 in.
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
0201000805-0001
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
Steps 1.1 Reach Description
1.2 Town
1.3 Latitude and Longitude
Steps 2.1 Upstream and
2.3 Valley Slope
Downstream Elevations 2.5 Channel Slope
Gentle Gradient
Check Box
Steps 2.2 Valley Length
2.4 Channel Length
2.6 Sinuosity
channel length (ft.)
valley length (ft.)
Step 2.7 Watershed Size
Step 2.8 Reference
Channel Width
W = 10.18(X)0.50
X = drainage area
in sq. mi.
Inner lines of reach sub-watersheds
Watershed Bounds
Vermont 2001 Regional Hydraulic
Geometry Curves (provisional)
10000.0
Qbkf (cfs)
Q = 17.69DA1.07
XS Area (sq.ft.)
Depth (ft.) / Width (ft.) / XS-Area (sq. ft.) / Discharge (cfs)
Measuring
Watershed Size
to estimate
Bankfull
Dimensions
R2 = 0.81
1000.0
Width (ft.)
A = 12.21DA0.75
Depth (ft.)
R2 = 0.85
100.0
W = 10.18DA0.50
R2 = 0.78
10.0
D = 1.22DA0.25
R2 = 0.59
1.0
1.0
10.0
100.0
Drainage Area (sq. mi.)
1000.0
Step 2.9 Valley Width
Valley
Width
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
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
Rosgen Stream Classifications
Step 3.1 Alluvial Fans
Step 3.2 Grade
Controls
Channel Spanning
Ledge
Dams
Step 3.3 Geologic Materials
Step 3.4 Valley Side Slopes
Step 3.5 Soil Characteristics
River Corridor in unconfined valleys = 8 x Channel Width
Centerline of Meander Belt Width
Appendix E
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.
Step 4.1 Watershed Land Cover / Land Use
Reach Watershed
Bounds
Impact Rating
based on:
 Urban
 Crop
Step 4.2 Corridor Land Cover / Land Use
River Corridor
Impact Rating
based on:
 Urban
 Crop
Step 4.3 Riparian Buffer Width
Percent
Buffer
Width
Cat.
LB
RB
0-25’
60
60
26-50’
10
0
51-100’
0
30
>100’
30
10
Impact Rating
Right
Bank
Left
Bank
Step 4.4 Groundwater and
Small Tributary Inputs
USGS Topo
VHD 1:5000
NWI 2003
Step 5.1 Flow Regulation
and Water
Withdrawals
Impact Rating
based on:
 Channel Geometry
 Depositional
Patterns
Step 5.2 Bridges
and Culverts
Impact Rating
based on:
 Channel Geometry
 Depositional
Patterns
Phase 1 Bridge & Culvert
Surveys and Database
F
C
D
C
A
B
Appendix G
G
E
E
Flow
At Grade
Cascade
Free fall
Step 5.3 Bank Armoring
or Revetments
rock rip-rap
revetments
cedar tree
revetments
Impact Rating
based on:
% Armoring or Revetments
along the reach
Step 5.4 Channel Modifications
Potential Channel Straightening
Impact Rating
based on:
% Channelization
of reach
Channel Straightening
Step 5.5 Dredging and Gravel Mining History
Impact Rating based on:
history, quantity, and
frequency of extraction
Step 6.1 Berms and Roads
Impact Rating
based on:
% roads and berms
along the length of
the corridor
Step 6.2 River Corridor Development
Corridor
Impact Rating
based on:
 % Corridor
 Belt Width
Width of the River Corridor
Road
Improved Path
Road along 30% of Left Corridor
Path along 50% of Right Corridor
High Impact
Step 6.3 Depositional Features
Unvegetated Point Bars
Impact Rating
based on:
 Quantity
 Size
 Vegetation
Step 6.4 Meander Migration / Channel Avulsion
Current
Channel
Impact Rating
based on:
 Frequency
 Extent
Old
Meander
Scars
1979 Location
1998 Location
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.
Step 6.5 Meander Width Ratio
For Unconfined Streams
Impact Rating
based on:
Departure from
regime conditions
Step 6.6 Wavelength Ratio
Wavelength
For Unconfined Streams
Cross over
Bendway apex
Impact Rating
based on:
Departure from
regime conditions
Meander Geometry
Wavelength
Belt
Width
Riffles
Pools
Appendix H
Step 7.1 Dominant Bed Form / Material
Cascade
Step-pool
Plane Bed
Riffle-pool
Dune-ripple
Braided
Appendix M
Bedrock
Boulder
Cobble
Gravel
Sand
Step 7.2 Bank Erosion – Relative Magnitude
Impact Rating
based on:
 Extent of reach
 Bank Height
Step 7.3 Debris / Ice Jam Potential
Impact Rating
based on:
 Channel geometry
 Infrastructure
 Historic evidence
Step 8 Impact Ratings
Total and Categorical Impact Ratings
Lewis Creek
30
Total Impact
25
20
A
B
15
C
E
10
5
0
1
3
5
7
9
11
13
15
17
19
21
Distance Upstream (miles)
23
25
27
29
31
33
Step 9.1 Channel Adjustment Process
Channel Evolution Model
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
Channel Degradation
In Response to Changes Imposed
In the Watershed or Within the Reach
Qs
Q
Realignment
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
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
Step 9.3 Reach Sensitivity
 Valley slope and confinement (Stream Type)
 Dominant sediment size and depositional features
 Watershed Hydrology
 Reach Condition (current adjustment processes)
 Upstream and downstream adjustment/condition
Step 10 Like Reach Evaluation
Phase 1 Quality Assurance Protocol
 Quality Assurance Team
 Training
 Watershed Orientation
 Reach Break Review
 Protocols and Database
 Tools Used to Collect Data
 Confidence Level
 Dates of Review and Updates