Saxtons River Assessment Grafton Village, VT Prepared for the Town of Grafton

Saxtons River Assessment
Grafton Village, VT
Prepared for the Town of Grafton
By the Land Stewardship Program (LANDS), June 2014
2
Contents
Acknowledgements ......................................................................................................................... 4
About LANDS ................................................................................................................................ 5
Executive Summary ........................................................................................................................ 6
Introduction ..................................................................................................................................... 7
Site Description ........................................................................................................................... 7
Goals and Objectives .................................................................................................................. 8
Methods……………………………………………………………………………………………8
Results and Discussion ................................................................................................................... 9
Recommendations..………………………………………………………………………………10
Conclusions .................................................................................................................................. .11
Literature Cited ............................................................................................................................ .12
Glossary of Terms………………………………………………………………………………..13
Appendix…………………………………………………………………………………………14
Tables.……………………………………………………………………………………14
Figures……………………………………………………….…………………………...18
3
Acknowledgements
This report was compiled by the Land Stewardship Program (LANDS) summer 2014 intern
crew. The project was completed in Grafton Village, Vermont for the Windham Foundation.
LANDS would like to thank the Rubenstein School of Environment and Natural Resources
(RSENR) at the University of Vermont and the Student Conservation Association (SCA) for
establishing and supporting this internship program. In addition, we acknowledge the Aiken
Center at UVM for providing us with their valuable resources and work facility.
The undertaking of this particular project would not have been feasible without certain key
individuals working with us to make our rapid geomorphic assessment possible. Steve Libby of
the Vermont River Conservancy worked very closely with the LANDS Program Director, Emily
Brodsky to develop the scope of this project. Bob Allen, President of the Windham Foundation,
graciously welcomed us into Grafton and provided our crew with housing at the Palmer House
during our stay. His enthusiasm for our project was outstanding. Evan Fitzgerald, who completed
the previous assessment on the Saxtons River, trained us in the river assessment protocol. His
previous work in the area uniquely provided crucial data that allowed us a more complete
understanding of Hurricane Irene’s effects upon the Saxtons. Finally, Beth Roy gave us a
delightful tour of her neck of the Saxtons. As the local Nature Museum Director, her work along
the banks of the Saxtons with the youth of Grafton was inspiring. Bob Allen and Beth Roy also
helped organize and publicize a presentation of our work at the Grafton Inn.
4
About LANDS
The field of conservation is rapidly evolving to meet the growing demands of society. New ideas
and strategies are changing how we conserve and steward the land; The Land Stewardship
Program (LANDS) is one of these new ideas. During the Great Depression, the Conservation
Corps model was pioneered as a means to promote stewardship in the nation and provide jobs for
the unemployed. The idea has since been reinvented 116 times by local and state corps across the
United States. However, the general theme is the same: young people learning and growing
through service. LANDS is an innovative College Conservation Corps designed to train
tomorrow’s conservationist practitioners and leaders, and is a pilot partnership between the
University of Vermont and the Student Conservation Association in its eighth year of successful
programming.
Thanks to college level education and prior experience in environmental science fields, LANDS
interns are able to take on projects that are more technical than the work traditionally done by
conservation crews. LANDS interns draft management plans, map areas of interest using GPS
and GIS, inventory resources, survey for non-native species, survey soils, calculate carbon
stocks, and even find time to build trails. Municipalities, land trusts, state agencies, university
researchers, national forests and parks, and volunteer-managed conservation organizations all
benefit from LANDS’s high quality, affordable services. LANDS interns are advanced
undergraduates and recent graduates with natural resource experience from all over the world,
and they bring a wide range of skills and interests to the program. LANDS is a unique servicelearning model that addresses an ever-expanding list of conservation needs, while training
students as future environmental leaders.
Left to right: Courtney Webb, Lincoln Frasca, Jessica Mason, Emily Brodsky, Travis Hart, Laura
Yayac, Dustin Circe, Nate Ruby, Katherine Brainard, Gabriel Yarleque Ipanaque, Ben Henry.
5
Executive Summary
This report was prepared in June 2014 by the UVM - SCA LANDS program. It presents
information collected during a Rapid Geomorphic Assessment of the Saxtons River in Grafton
Village, VT, and includes a map of significant features along surveyed sections. The purpose of
the assessment is to update previous records made in the 2010 Saxtons River Corridor Plan by
Fitzgerald Environmental Associates, LLC (FEA) and compare data from before and after Irene.
This information was used to evaluate the environmental consequences of the storm and to
provide short- and long-term recommendations to mitigate future storm damage and to protect
the Saxtons’ River stream ecology.
The LANDS crew surveyed five cross-sections of the river in order to assess its current condition
and to identify problematic trend in the river’s changing geological and biological
characteristics. Features such as erosion, mass failure, armoring, side bars, point bars, mid bars,
large woody debris, and buffer zones were recorded and mapped. Geomorphic profiles of crosssections were created in order to determine entrenchment ratio, incision ratio and width-to-depth
ratio. Other information documented includes vegetation surveys along the river banks and
pebble counts in the active channel.
Results from the assessment show that the cross-sections surveyed deviate from reference, or
natural conditions. Most prominently there has been an overall increase in incision ratio post
hurricane Irene, indicating that the river is becoming increasingly deep and narrow. The
assessment also showed frequent occurrence of erosion along the bank, numerous mass failures
where large sections of bank have slid into the river, and long stretches of bank armoring, which
can increase erosion. Changes in the riverbed composition indicates a increased presence of
coarse gravel possibly due to deposition from flooding events. Many buffer zones were small or
nonexistent, rendering much of the river vulnerable to polluted runoff and erosion. Many large
patches of the invasive Japanese Knotweed also occur along the river.
Further geomorphic assessments are recommended periodically to continue tracking changes in
stream geomorphology and vegetation. Long term solutions for maintaining the health of the
river, preventing harmful erosion, and controlling damage during floods should be oriented
toward preventing development near river banks or in areas prone to erosion and flooding.
Continuous monitoring and removal of Japanese knotweed is essential to maintaining the few
existing natural buffers along the stream and its overall health. Planting native species in buffer
zones will help prevent knotweed from gaining footholds.
6
Introduction
The LANDS crews surveyed five reach locations that FEA had assessed in 2010, all of which
were located in or near Grafton Village. Reaches M13 through M15 are sections along the main
stem of the Saxtons running through the center of town and T601.A and T601.B are part of the
south branch of the river. The team measured geomorphic features, tallied large woody debris,
surveyed vegetation, and mapped features such as erosion, mass failure, and bank armoring.
In 2010, an assessment was completed for the Saxtons River watershed by Fitzgerald
Environmental Associates, LLC (FEA). Hurricane Irene caused significant flood damage to the
town of Grafton in 2011, from which the town and its residents are still recovering. With the
2010 assessment done a year prior to the hurricane, a comparison could be done between pre-and
post- Irene. Part of the 2010 assessment was to complete a rapid geomorphic assessment, which
evaluates degradation, aggradation, widening, and determines the stage of channel evolution.
The project is sponsored by the Windham Foundation, a non-profit located in Grafton, VT whose
mission is to promote the vitality of Grafton and Vermont’s rural communities through its
philanthropic and educational programs and its subsidiaries whose operations contribute to these
endeavors (Windham Foundation 2012). The foundation is dedicated to helping the town recover
from Hurricane Irene, and graciously housed the LANDS crew in the Palmer House. With this
assistance, the team could easily access the reaches and perform the highest quality work
possible. The team worked over the course of four days in Grafton, VT.
Site Description and Land Use History
The Saxtons River watershed is a 77.9 square mile tributary of the Connecticut River.
The main stem flows in an easterly direction along Route 121, and the watershed runs though the
towns of Windham, Grafton, Rockingham Westminster, and Athens (Fitzgerald 2010).
Historically deforestation and grazing (primarily from sheep farms) resulted in a loss of roughly
80% of tree cover in the watershed (Albers 2000). In the early 1800’s, farmers began to move
out west in search of more productive farmlands. In this time, the forest began to regenerate and
is now 90% forested with a small percentage of agriculture throughout.
The surficial geology of the watershed was ruled by glacial activity. About 12,000 years
ago, the glaciers began to retreat northwards. This movement deposited glacial till in the
depressions and dug out the landscape to its current state. The resultant soils are therefore
primarily glacial till, which are coarsely graded, heterogeneous sediments left from glacial
retreats.
7
Goals and Objectives
The goal of this project is to update part of the Rapid Geomorphic Assessments made in
the by FEA and to map significant features along the Saxtons River. To map river features, the
LANDS crew walked stretches of the Saxtons River near the town of Grafton and recorded any
signs of environmental degradation or human disturbance. The Fitzgerald assessment was made
prior to Tropical Storm Irene in 2011, and the town of Grafton received particularly severe storm
flooding and damage. This project therefore aims to compare data on the Saxtons River from
before and after Irene, offering insight onto the environmental consequences of the storm.
Methods
The LANDS team conducted a rapid geomorphic stream assessment for five segments of
the Saxton’s river in the town of Grafton, VT. In addition to this assessment we also conducted
large woody debris (LWD) surveys, and mapped significant features along the aforementioned
segments.
The rapid geomorphological assessment was completed at five cross sections (Reaches
M13, M14, M15, T6.01.A, and T6.01.B). Locations were determined based on the 2010
assessment performed by Evan Fitzgerald (Fitzgerald, 2010). GPS units were used to locate these
cross sections. Once located, we used pins, string, a line level, and a measuring tape to measure
the bankfull width across the segments of the river. This leveled line was used as a reference
point to measure the depth of the stream, thalweg, height and distance to flood plain, and
floodprone width. All measurements were taken from the left to right in reference to the leveled
line. All distances before the left pin were noted as negative whereas distance after the right pin
were positive. All measurements taken above the line were negative and below the line were
positive.
Depth measurements were taken at intervals determined by dividing bankfull width by 10 as
each segment required at least 10 measurements. In addition to the intervals, left and right edges
of water and thalweg were recorded using a measuring rod. The same rods were used to measure
the height and distance to the closest available floodplain on either side of the left and right pins.
Floodplain was determined by the top of banks on either side of the segment. The final
measurement was the floodprone width. This was determined by doubling the thalweg, and
extending this height horizontally outward from the stream until land of equal height was
reached. These measurements were then used to calculate mean depth, entrenchment ratio,
incision ratio, and width to depth ratio. These formulas are listed below:



Entrenchment ratio = Floodprone width/Bankfull width
Incision ratio = (Thalweg+Height from bankfull width to flood plain)/Thalweg
Width to depth ratio = Bankfull width/Mean depth
8
The next portion of the assessment was the pebble count. This was conducted by walking in
the stream from bank to bank diagonally. With every step, stones were picked up where the toe
of the counter landed. One hundred samples were taken and recorded by size class to determine
bed substrate composition. Size classes include:






Sand or smaller: <0.08’’ or smaller than a peppercorn
Fine gravel: 0.08’’ - 0.63’’ or between a peppercorn and a marble
Coarse Gravel: 0.63’’ – 2.5’’ or between marble and a tennis ball
Cobble: 2.5’’- 10.1’’ or between tennis ball and basketball
Boulder: 10.1’’ – 160’’ or between basketball and VW bug
Bedrock: >160’’ or bigger than a VW bug
The crew evaluated vegetation condition using the 2010 data collection sheet. Canopy,
shrub/sapling, and herbaceous layers were looked at independently for each side of the stream,
and each side was further broken down into near bank vegetation and buffer vegetation.
A large woody debris tally was performed for each segment. Large woody debris was
defined as any woody debris greater than six inches in diameter that was in the width of the
channel. This was done by both walking in and along the stream while recording on a tally sheet.
In addition, GPS coordinates and pictures with bearings were taken to create photo points of
significant features and mapped in ArcGIS 10.2. Locations were recorded for erosion, mass
failure, buffers less than 25 feet, bank armoring, dredging/berming, and any new development
along the river corridor. Features were observed by walking along the stream bank. All data
collected was gathered and analyzed to perform a paired t-test in comparison to Fitzgerald
(2010).
Results and Discussion
Geomorphic Assessments
The measurements taken during the 2014 LANDS assessment included bankfull width
(BKF), mean depth, width-to-depth ratio, entrenchment ratio, and incision ratio for crosssections at five reaches within Grafton Village. Table 1 presents these data alongside data from
the 2010 Fitzgerald Environmental Associates survey and reference values. Table 2 presents the
difference in these measurements between 2010 and 2014, and the difference between 2014
measurements and reference values. Since the FEA survey was conducted pre-Irene, changes in
geomorphic characteristics displayed in Table 2 may reflect changes due to Irene. The only
consistent post-Irene trend is an increase in incision ratio, indicating possible deepening of
riverbeds due to floodwaters. In addition, each cross-section shows substantial post-Irene change
to most or all geomorphic characteristics. Reference values reflect ideal or expected conditions
for type C streams, and all cross-sections showed appreciable deviation from reference
conditions. Bankfull width, width-to-depth ratio, and incision ratio for all cross-sections deviated
from reference values.
9
Pebble Counts
Random samples of 100 pebbles at each cross-section yielded the percent composition of
substrate classes (Figure 1). Coarse gravel and cobble were generally most prevalent, and no silt
or bedrock was found. Figures 2-6 compare substrate composition between the 2014 and 2010
surveys at each site. During the four years interceding between surveys, the proportion of cobble
decreased at all sites. The proportion of boulders increased at all sites, and the proportion of
coarse gravel increased at all but the M14 site. At all but the M13 site, the proportion of sand and
fine gravel increased slightly.
These changes may be attributed to deposition from floods, such as Irene, or to increased
sediment load from river straightening in some areas. One possibility is that smaller particles like
coarse gravel, fine gravel, and sand have been eroded upstream and deposited over the past years
in these reaches, which would account for the decrease in proportion of cobble.
Vegetation Surveys
Vegetation data was collected at each cross-section to detect any changes between the
FEA survey in 2010 and our survey in the summer of 2014 (Tables 3-7). It is notable that midchannel canopy cover did not change at any site between the surveys. Although a variety of
changes have taken place over the last four years, there are no apparent trends in regard to
vegetative succession. However, during the most recent survey, we recorded 7 buffer widths
between 0-25 feet, compared to 2 such buffers found in 2010. This may be due to discrepancies
between the methodologies used to determine buffer extent, but more likely indicates a trend of
reduction in buffer size.
Recommendations
In order to understand trends in the Saxtons River’s geomorphology and the impact of
future flood events, we recommend continued geomorphic assessments every few years. Every
subsequent assessment of the cross-sections that FEA and LANDS surveyed will add to our
running understanding of how the Saxtons River is changing, and how rapidly it is doing so.
A frequent bank feature encountered by our survey was bank armoring in the form of
riprap. Armoring prevents natural meandering and consequently increases the velocity and
eroding power of the river. Such armoring and straightening is likely responsible for the increase
in incision ratios between 2010 and 2014, which indicates a positive feedback loop whereby
incision prevents floodwaters from escaping the main channel and further accelerates erosion.
The increase in power can result in mass bank failure, of which our survey recorded numerous
occurrences. The long stretch of armoring where the Saxtons runs through the center of Grafton,
for instance, likely contributed to an extremely large mass failure that occurs downstream at the
next major bend in the river. For this reason, bank armoring is not a permanent solution to bank
failure, as it only increases the likelihood of failures downstream. Instead, a more long-term
10
solution restricts building near river banks, especially large curves that are prone to heavy
erosion and mass failure during floods. In addition, buildings that are currently near the river and
at high risk of damage due to bank failure should be identified and property owners notified.
Within the five cross-sections studied, the 2010 survey recorded only 2 buffer zones that
fell in the 0-25 feet range. The present survey recorded 7 such buffers, which suggests a trend of
decrease in buffer size and vitality. We recommend close monitoring of buffer conditions to
track any future decline. For areas with little or no buffer, such as the residential areas near the
center of Grafton, we strongly support programs that encourage private involvement.
Landowners should be made aware that planting a buffer on their property protects their land
from encroachment by river erosion, protects their land from flooding, and moreover protects the
river from harmful runoff. In particular, properties owned by the Windham Foundation lacked
adequate buffer areas, and we recommend that the foundation consider planting buffers.
Our survey encountered numerous large patches of Japanese knotweed along with
smaller instances of various other non-native invasive plants. Given that knotweed presents an
ecological threat to native species and acts as a poor buffer, we strongly recommend that the
town continue to monitor and control knotweed. Such events as the Nature Center’s field days
with the local elementary school uprooting knotweed and laying down carpets are excellent
contributors. Again, the interest and involvement of private landowners may be a crucial
resource for effectively dealing with knotweed. Patches of knotweed can encroach upon lawns or
gardens, and may eventually cause bank damage on private land by outcompeting the native
species that act as more effective buffers.
We would like to urge Windham Foundation and the town of Grafton to continue its
partnership with the LANDS program for future projects. LANDS hires a crew of collegeeducated interns each summer, and will be available to carry out any and all of the
recommendations made by the present assessment.
Conclusion
The FEA survey in 2010 allowed us a brilliant chance to better understand the dramatic effects of
Hurricane Irene. The powerful storm deeply affected the geomorphology of the Saxtons and
resulted in substantial areas of mass failure along its banks, not to mention the damage to
property and livelihood of the inhabitants of Grafton. The flooding resulting from Irene
drastically changed much of the landscape and destroyed habitats of a wide range of flora and
fauna.
Yet nothing upon or within our incredibly complex planet stays the same forever. Rivers are no
exception. We need to be aware of their workings and their complexity. Rivers naturally change;
some would say you can’t step in the same one twice. Respect and appreciation for that change
are important to foster within human communities, like Grafton’s, that sit upon the banks of a
11
river. By increasing knowledge, appreciation, and understanding of the Saxtons the citizens of
Grafton may long be able to abide in its cool and flowing waters.
Literature Cited
Albers, J., 2000, Hands on the Land: A History of the Vermont Landscape, MIT Press,
Cambridge, MA.
Fitzgerald Environmental Associates, 2010. River Corridor Plan for the Saxtons River
Watershed Windham Country, Vermont. Fitzgerald Environmental Associates, LLC.
Colchester, VT.
Windham Foundation. (2012). History. Retrieved July 30, 2014, from http://www.windhamfoundation.org/about-us.html
12
Glossary of Terms:
Armoring: The installation of concrete walls, gabions, stone riprap, and other large erosion
resistant material along stream banks.
Bankfull width: The width of a river or stream channel between the highest banks on either side
of a stream.
Berms: Mounds of dirt, earth, gravel, or other fill built parallel to the stream banks designed to
keep flood flows from entering the adjacent floodplain.
Buffer: A barrier of permanent vegetation, either forest or other vegetation, between waterways
and land uses such as agriculture or urban development.
Dredging: Removing material (usually sediments) from wetlands or waterways, usually to make
them deeper or wider.
Erosion: Wearing away of rock or soil by the gradual detachment of soil or rock fragments by
water, wind, ice, and other mechanical, chemical, or biological forces.
Floodplain: Land built of fine particulate organic matter and small substrate that is regularly
covered with water as a result of the flooding of a nearby stream.
Floodprone width: In the instance of a high water event, the area of land that is likely to flood.
Determined by doubling the Thalweg, and extending this height horizontally outward from
stream until a land formation of equal height was reached.
Mass failure: Large scale erosion where a portion of the bank has completely given way.
Thalweg: The middle, chief, or deepest part of a navigable part of a water way.
13
Appendix
Tables:
FES 2010 Assessment
Mean
W/D
EntrenchDepth
Ratio
ment
(ft)
Site
BKF
(ft)
M13
65.4
3.1
20.8
M14
49.7
2.4
M15
44.3
T6.01A
T6.01B
Mean
LANDS 2014 Assessment
Mean
W/D
EntrenchDepth
Ratio
ment
(ft)
Inciion
BKF
(ft)
2.1
1.8
79
3.39
20
20.9
2.8
1.3
25.1
1.37
2.3
19
5.5
1.4
39.3
56
2.6
21.5
4
1.3
42
3.3
13.1
1.5
51.48
2.74
19.06
3.18
Reference Conditions
Mean
W/D
EntrenchDepth
Ratio
ment
(ft)
Incision
BKF
(ft)
1.86
2.15
65.70
N/A
>12
>2.2
1.00
18.31
4.04
1.5
42.10
N/A
>12
>2.2
1.00
2.05
19.1
1.23
2.22
39.10
N/A
>12
>2.2
1.00
60.7
2.83
21.4
3.54
2.74
49.00
N/A
>12
>2.2
1.00
2.2
36.5
1.53
23.92
1.12
5.26
49.00
N/A
>12
>2.2
1.00
1.6
48.12
2.234
20.55
2.358
2.774
48.98
N/A
>12
>2.2
1.00
Table 1. Geomorphic characteristics of 5 cross-sections measured in 2010 and 2014.
Difference 2010 to 2014
Mean
W/D
EntrenchDepth
Ratio
ment
(ft)
Site
BKF
(ft)
M13
13.60
0.85
-0.80
M14
-24.6
-1.03
M15
-5.00
T6.01A
T6.01B
Difference 2014 to Reference
Mean
W/D
EntrenchDepth
Incision
Ratio
ment
(ft)
Incision
BKF
(ft)
-0.23
0.35
13.3
N/A
Yes
No
0.8
-2.59
1.24
0.23
-17
N/A
Yes
Yes
-0.3
-0.25
0.10
-4.27
0.82
5.2
N/A
Yes
No
1.2
4.70
0.23
-0.09
-0.46
1.44
7
N/A
Yes
Yes
1.7
-5.50
-1.77
10.82
-0.38
3.06
-7
N/A
Yes
No
4.3
Table 2. Changes in geomorphic characteristics for 5 cross-sections. Differences are show between the 2010 and 2014 surveys, and
between the 2014 survey and the stream-type reference condition. Positive values indicate greater measurements in 2014; negative
values indicate lower measurement.
Incision
M13
Near Bank Vegetation
Dominant
Sub-dominant
Bank Canopy Cover
2010 FEA Survey
Left Bank
Right Bank
2014 LANDS Survey
Left Bank
Right Bank
Invasives
Deciduous
Invasives
Deciduous
Shrubs/Saplings
Invasives
Deciduous
Shrubs/Saplings
26%-50%
51%-75%
1%-25%
Mid-Channel Canopy
Buffer Vegetation
Dominant
Sub-dominant
Buffer Width (ft)
51%-75%
Open
Open
Mixed Trees
Mixed Trees
Shrubs/Saplings
Conifers
Invasives
Deciduous
Deciduous
Deciduous
26-50
>100
0-25
>100
Table 3. A comparison of changes in vegetation on the near bank and in the buffer area in M13 as measured in 2010 and in 2014.
M14
Near Bank
Vegetation
Dominant
Sub-dominant
Bank Canopy
2010 FEA Survey
Left Bank
Right Bank
2014 LANDS Survey
Left Bank
Right Bank
Invasives
Deciduous
26-50
Deciduous
Saplings
1-25
Mid-Channel Canopy
Buffer Vegetation
Dominant
Sub-dominant
Buffer Width (ft)
Invasives
Deciduous
26-50
Open
NA
NA
1-25
Open
Shrubs/saplings
Invasives
Deciduous
NA
Invasives
Herbaceous
Shrubs/saplings
NA
>100
26-50
51-100
0-25
Table 4. A comparison of changes in vegetation on the near bank and in the buffer area in cross section M14 as measured in 2010 and
in 2014.
15
M15
2010 FEA Survey
2014 LANDS Survey
Left Bank
Right Bank
Left Bank
Right Bank
Near Bank Vegetation
Dominant
Invasives
Invasives
Herbs
Herbs
Sub-dominant
Deciduous
Deciduous
Conifer
Shrubs/Saplings
Bank Canopy
51-75
26-50
51-75
Mid-Channel Canopy
Buffer Vegetation
Dominant
Open
76-100
Open
Mixed trees
Mixed trees
Herbs
Herbs
Sub-dominant
Invasives
Invasives
Conifer
Shrubs/Saplings
Buffer Width
26-50
>100
0-25
>100
Table 5. A comparison of changes in vegetation on the near bank and in the buffer area in cross section along M15 as measured in
2010 and in 2014.
T6.01A
Near Bank Vegetation
Dominant
Sub-dominant
Bank Canopy
Mid-Channel Canopy
Buffer Vegetation
Dominant
Sub-dominant
Buffer Width
2010 FEA Survey
Left Bank
Right Bank
2014 LANDS Survey
Left Bank
Right Bank
Herbacious
Deciduous
26-50
Deciduous
Shrubs/Saplings
51-75
Open
Herbacious
Deciduous
26-50
Mixed Trees
Shrubs/Saplings
26-50
Herbacious
Deciduous
0-25
Herbacious
Deciduous
0-25
Herbacious
26-50
Open
Herbacious
Deciduous
0-25
Table 6. A comparison of changes in vegetation on the near bank and in the buffer area in cross section T6.01A as measured in 2010
and in 2014
16
T6.01B
2010 FEA Survey
Left Bank
Right Bank
2014 LANDS Survey
Left Bank
Right Bank
Invasives
Shrubs/Saps
26-50
Near Bank Vegetation
Dominant
Sub-dominant
Bank Canopy
Mid-Channel Canopy
Coniferous
Deciduous
Shrub/Saplings Shurbs/Saplings
76-100
26-50
Closed
Herbacious
Deciduous
51-75
Buffer Vegetation
Dominant
Sub-dominant
Buffer Width
Coniferous
Shrub/Saplings
>100
Herbacious
Shrubs/Saps
0-25
Herbacious
Deciduous
0-25
Closed
None
None
0-25
Table 7. A comparison of changes in vegetation on the near bank and in the buffer area in cross section T6.01B as measured in 2010
and in 2014.
17
Figures
50
45
M13
40
M14
Percent Composition (%)
35
M15
30
T6.01A
25
T6.01B
20
15
10
5
0
Silt
Sand
Fine Gravel
Coarse Gravel
Cobble
Boulder
Bedrock
Substrate Class
Figure 1. Pebble composition for five cross-section sites. Composition was determined from a
count of 100 randomly sampled pebbles at each cross-section.
50
Percent Composition
45
40
35
30
25
LANDS 2014
20
FEA 2010
15
10
5
0
Silt
Sand
Fine
Gravel
Coarse
Gravel
Cobble
Boulder
Bedrock
Substrate Class
Figure 2. Pebble composition at site M13 during the 2010 and 2014 surveys, from random
samples of 100 pebbles.
Percent Composition
60
50
40
30
20
LANDS 2014
10
FEA 2010
0
Silt
Sand
Fine
Coarse Cobble Boulder Bedrock
Gravel Gravel
Substrate Class
Percent Composition
Figure 3. Pebble composition at site M14 during the 2010 and 2014 surveys, from random
samples of 100 pebbles.
80
70
60
50
40
30
20
10
0
LANDS 2014
FEA 2010
Silt
Sand
Fine
Coarse Cobble Boulder Bedrock
Gravel Gravel
Substrate Class
Percent Composition
Figure 4. Pebble composition at site M15 during the 2010 and 2014 surveys, from random
samples of 100 pebbles.
60
50
40
30
20
10
0
LANDS 2014
FEA 2010
Silt
Sand
Fine
Coarse Cobble Boulder Bedrock
Gravel Gravel
Substrate Class
Figure 5. Pebble composition at site T6.01A during the 2010 and 2014 surveys, from random
samples of 100 pebbles.
19
Percent Composition
50
45
40
35
30
25
20
15
10
5
0
LANDS 2014
FEA 2010
Silt
Sand
Fine
Coarse
Cobble
Gravel
Gravel
Substrate Class
Boulder
Bedrock
Figure 6. Pebble composition at site T6.01B during the 2010 and 2014 surveys, from random
samples of 100 pebbles.
20