20221671 Ver 1_RSP - NCWRC Comment Response Letter - March 2023_20230303

NC Wildlife Resources Commission
Habitat Conservation Program
ATTN: Andrea Leslie, Mountain Region Coordinator
1721 Mail Service Center
Raleigh, NC 27699-1721
March 3, 2023
SUBJECT: RESPONSE TO RECOMMENDATIONS/REQUEST FOR ADDITIONAL INFORMATION
Woodfin Riverside Park & Wave
Dear Ms. Leslie,
On December 1, 2022, the Town of Woodfin (Town) submitted an application for an Individual Permit from the US
Army Corps of Engineers (USACE) for purposes of constructing an artificial whitewater wave in the French Broad River.
On January 4, 2023, the NC Wildlife Resources Commission (NCWRC) provided official recommendations and requests
for additional information on the application, which were shared with the Town via the USACE. Below, we provide an
official response to NCWRC recommendations in red text; standalone additional information requested by the NCWRC
and referenced in our responses is attached to this letter.
• The plans describe three different methods to isolate in -river work areas. It is unlikely that a sandbag
coffer dam will stay in place at high flows, and we recommend against using this method.
The sandbag detail has been removed from the EC drawing set. The project team appreciates this
comment and understands that water control is by far the most challenging part of most in -stream
projects. For this reason, construction is intended to be completed during the statistical low-water window
to avoid challenges associated with high water. The project team also understands that intense rain events
could produce high water conditions at any time and critical activities such as concrete placements will
need to be scheduled when there is high confidence in a clear weather forecast.
Super Sacks (preferred cofferdam method) have been used successfully in similar flow conditions on
other projects like the one proposed at Riverside Park. The most recent example of sand filled super sacks
used to dewater for construction of a wave feature similar to the one proposed is on the Catawba River in
South Carolina as part of the Great Falls -Dearborn Diversion project for Duke Energy. By securely
fastening the top of the sacks, the cofferdam was able to withstand overtopping flows without losing
material (photos can be sent if requested). With that said, the project team is very open to any suggested
alternative methods from NCWRC. The project team also intends to review the dewatering plan with the
selected contractor to ensure any concerns or suggestions for improvement are considered prior to the
start of construction.
It is possible to use gravel or cobble instead of sand to fill the super sacks, but it is our experience that
more water penetrates the cofferdam than with sand, which is able to be manipulated easier and fill
smaller voids.
Sheet piling was also considered and has been used successfully on other projects, however the presence
of shallow bedrock prevents the use of sheet piles.
• Contingency plans for high flow events should be developed. These should include cleaning up debris
from coffer dams and temporary roads in the channel. Any bags used for coffer dams should be filled
with clean material (e.g., sand) and not soil.

Agree with comment. This kind of plan is typically developed by the selected contractor. It would include
chain of command for notifying of high-water events and thresholds to enact high water contingency plan
as well as when crews can go back to work, equipment removal/storage procedure, material
removal/storage procedure and repair plan for any potential damage to water control infrastructure. A
general high-water plan has been developed and is attached.
• The weather forecast should be monitored closely; it is essential that concrete pours be done during low
flows and followed by several days of low flows to ensure dry conditions.
Agree with comment. Will add note to drawing set.
• Sump pits should be deep enough so that there is reasonable settling of suspended material.
Agree with comment. Will add note to drawing set.
• The plans do not include specifications on the in -river structures nor the manipulation of existing in -river
features, planting specifications, or specifications for river bank stabilization or river access sites. Please
provide these details.
Specifications are currently being developed and can be provided once complete.
• This project will involve an increase in impervious surface on the east side of the river. Please describe
the stormwater measures that will be use to minimize the hydrologic impacts of increased stormwater
from site development.
This project will reduce impervious surface from 119,449SF to 107,645SF as well as increase the overall
roughness of the site. In addition, 10 SCMs are designed to attenuate runoff further. Pre -development
peak flow for the lyr/24hr storm is 20.02cfs. Designed post -development peak flow off of the site for the
lyr./24hr storm is 4.95cfs. Pre -development peak flow for the 25yr/24hr storm is 49.13cfs. Designed
post -development peak flow off of the site for the lyr./24hr storm is 14.55cfs. This significant reduction
in runoff will provide opportunities for improved riparian health and rebound of buffer stabilization.
• Any erosion control matting used should be free of plastic or nylon mesh, as this type of mesh netting
frequently entangles wildlife and is slow to degrade, resulting in a hazard that may last for years.
The erosion control matting is specified to be a blend of straw and coconut fiber, designed to break down
within 12 months.
• Tree clearing should be accomplished outside of summer bat roosting season, during the period
recommended by the US Fish and Wildlife Service (USFWS).
Tree clearing will be conducted outside of the summer bat roosting and non-volant pup seasons per
USFWS recommendations.
• To compensate for the loss of habitat that will occur with the installation of the in -stream structures, we
recommend several habitat measures:
• Although a recent mussel survey did not find any rare mussels, survey work has demonstrated that the
riffle associated with the old railroad footprint provides some of the best bed habitat in the vicinity. It
is unclear if the removal of the railroad piers will destroy this habitat feature. We recommend
removing only the portion of the piers needed to ensure safety but maintaining that which will
preserve the riffle habitat, if at all possible.

railroad piers within the river channel need to be removed to ensure no metal debris or hazards are
present which could injure river users, however pier remnants near the banks may be left partially in
place if safe to do so. Additionally, the proposed bypass channel was designed in coordination with
GEI Consultants to maximize new habitat. It is composed of raised boulders to mimic natural riffle
habitat with several additional habitat boulder clusters proposed above and below the bypass in the
latest design drawing set (see attached Fish Passage Specifications Memo).
• If possible, plant native aquatic vegetation, such as Water Willow, to create a backwater refugium in
the shallow area on the west side of the river.
We will incorporate plantings of native aquatic vegetation on the west side of the river in the slack
water location just downstream of the fish bypass.
• Install educational kiosks that provide information on the native fauna of the river and the importance
of aquatic organism passage, riparian vegetation, and large woody debris.
We received approval from the Town of Woodfin for the development and installation of educational
signs. We will incorporate at least one sign to discuss the native fauna of the river and the importance
of aquatic organisms' passage, riparian vegetation, and woody debris.
• We recommend that the applicant meet with agency representatives to discuss concerns raised during
application review.
We would like to meet with agency representatives pursuant to this comment response, and will be
reaching out to coordinate schedules.
We appreciate your consideration of the above responses and attached information. Please do not
hesitate to contact me with any questions or further requests for information.
Sincerely,
D ttig.i'l eaA.Q,P1
Owen Carson, Botanist / Senior Ecologist
Equinox
37 Haywood Street, Suite 100
Asheville, NC 28801
[phone] extension 204

High Water Guidance for In -Stream Construction
Woodfin Wave at Riverside Park — Woodfin, North Carolina
This plan has been prepared to provide general guidance to the selected Contractor for use in determining
when it may be appropriate to enact a high-water contingency plan during construction of the Woodfin
Riverside Park in -stream scope. This document is intended to be a guide only and conditions must be
assessed in real-time using the best available data.
Proposed Construction Window
Hydrological analysis was completed using stream gauge data from USGS Station 03451500 at Asheville,
North Carolina. During the early design stages of the project this data was used for wave design and the
bypass channel and fish passage study. In addition, analysis was utilized to determine a preferred
construction window over the months with the statistically lowest average flow rates. The preferred
construction window was determined to be late July through October in a typical year. Average monthly
flows from historical gauge data are presented in the figure below.
3,000
2,500
2,000
v 1,500
0
1,000
500
French Broad River Monthly Mean Discharge
(USGS 03451500 AT ASHEVILLE, NC)
2 690
2,550
2,200
1,000
1,590
1y90 •55C 1,510
Jan Feb Mar Apr May Jun Jul Aug Sep
Figure 1 - Average Monthly Discharge (French Broad at Asheville)
318 McConnell Dr I Lyons I CO 180302
2,34C
Oct Nov Dec
1

Iig
Water Control
Erosion control plans have been produced and include a suggested water control configuration for
construction. These plans envision the use of multiple super sack cofferdams to dry out the work areas in
three different phases. Size, quantity and configuration of the super sacks shown in erosion control
drawings are conceptual only and will vary from actual site conditions. The selected contractor is
responsible for determining appropriate size, quantity and configuration of super sacks and/or other
means of water control to bypass flows around the work area and complete construction activities. Super
sack installation and layering may vary. Approximate flow depth at 1500cfs is 3-7ft depending on location
in the river (see Figure 4 below). The contractor shall maintain a minimum of 1ft of freeboard at all times
while construction is underway. The contractor shall adjust the installation as needed to maintain
freeboard during changing flow conditions or implement the High Water Contingency Plan to secure the
jobsite prior to inundation during high water events.
As part of the contractor selection process, other requested water control methods may be considered
based on contractor expertise and any requested changes to water control methods or configuration will
be submitted to regulatory agencies prior to construction.
Figure 2 - Example Phase of Water Control
Super sack cofferdams are anticipated to be 2 to 4 sacks high depending on location. The recommended
super sack row configuration is pyramidal (i.e. bottom row is 3 sacks wide, next row is 2 sacks wide, top
row is 1 sack wide) and example details can be found in the erosion control drawing set.
2
318 McConnell Dr I Lyons I CO 180302

Mq
Figure 3 - Super Sacks
Figure 4 - Water Depths at 1500cfs +/-
High Water Planning
As flows increase to 3500cfs, modeling shows the approximate depths around the construction site
increase to 4-9ft which is likely the upper threshold for in -stream work unless the contractor has proposed
an alternative method of water control and design from a supplier. The point at which this upper threshold
3
318 McConnell Dr I Lyons I CO 180302

is reached, the selected contractor would need to have their contingency plan executed (i.e. equipment
and materials out of the work area by the time the river reaches this level).
Based on historical data, it is likely that 3500cfs WILL BE exceeded at some point in the construction
window during large rain events, and the selected contractor will be expected to develop a High Water
Contingency Plan prior to starting construction. This plan will need to outline how the contractor will
efficiently secure the job site including removal of personnel, materials and equipment from the river in
the event that water levels begin increasing or if significant precipitation is forecasted. Additionally, the
plan will need to include a method of monitoring the meteorological forecast and a chain of command
and notification system to execute the contingency plan.
A general rule of thumb would be for construction crews to be on alert if 0.5" or more precipitation is
forecasted in the next 24hrs and that the jobsite be secured if 1.0" or more of precipitation is forecasted
in the next 24hrs. In addition, long term forecasts should be consulted regularly, and jobsites left secure
at the end of each work day in case of an unexpected rise in water levels overnight. For critical tasks such
as concrete placements, work should not begin unless the 3-day forecast is clear with little to no
precipitation expected. As stated above, the final plan details will need to be proposed by the selected
contractor and reviewed by the town and engineer. S20 will support the contractor with hydrological data
and modeling results as needed.
4
318 McConnell Dr I Lyons I CO 180302

Consulting
Engineers and
Scientists
Memo
To: Dane Palmer and Riley Adams, S2o Design and Engineering
From: Ashley Ficke and Chris Craft, GEI Consultants
Cc: Scott Shipley, S2o Design and Engineering
Date: March 3, 2023
Re: Fish Passage Specifications for Woodfin Wave Whitewater Park
GL I Consultants
INTRODUCTION
The French Broad River supports a highly diverse aquatic community. The fish assemblage
currently contains approximately 31 species from seven families, but 35 additional species
are either present in upstream stream reaches or tributaries or were historically present and/or
are being reintroduced to the system. The French Broad River also supports two mussels of
conservation concern: the Federally Endangered Appalachian Elktoe (Alasmidonta
raveneliana) and Creeper (Strophitus undulatus), a North Carolina State Species of Special
Concern. All mussels have parasitic larvae and rely on fish hosts to complete their life cycles.
Appalachian Elktoe targets specific fish species as hosts, whereas Creeper are generalists.
An increased interest in river systems in urban areas has led to a subsequent increase in
riverfront revitalization projects. Many of these projects include whitewater parks (WWPs).
Whitewater parks have the potential to disrupt fish movements, although they are not
typically as problematic as dams and grade control structures. Consideration of fish passage
needs during the design process can often alleviate the potential for whitewater parks or
specific features within these parks to function as barriers to fish passage. GEI was retained
by S2o Design and Engineering to develop specifications for the fish bypass in the Woodfin
Wave WWP, to allow upstream passage of the diverse resident fish assemblage.
METHODS
The best opportunity biologists have to provide design specifications for whitewater parks
lies in searching and synthesizing the abundant literature on fish swimming performances. To
maximize the probability of successful fish passage, the resident fish assemblage can be
categorized into swimming "guilds." These guilds consist of groups of species that have
similar swimming performances and behaviors, and therefore similar requirements for fish
passage. Once the guilds are developed, specifications for hydraulic characteristics such as
depth, velocity, and turbulence can be tailored for the guild with the most exacting
specifications for each characteristic. For example, a "big river fishes" guild containing
species that avoid shallow water can be used to set minimum depths at low flows, and a
"small -bodied fishes" guild can be used to develop recommendations for shallow, wetted
margins that would allow them to move upstream. In a situation where the fish assemblage is
species -rich, each guild may incorporate large numbers of species. Alternatively, a guild
might represent a single species in depauperate headwater systems.
Memo Page 1
GEI Consultants, Inc.
4601 DTC Boulevard, Suite 900, Denver, CO 80237
303.662.0100 fax: [phone]
www.geiconsultants.com

till Memo 1 Page 2 March 3, 2023
S2o Design and Engineering
The following fishes were chosen as representative species for each swimming guild.
Selection of these species was based on availability of swimming performance data, presence
in the French Broad River, and ecological significance of the species. The species list
provided by the State of North Carolina and the guilds that were developed for them are
included in an attachment at the end of this document.
Small -bodied fishes: The swimming abilities of 16 common North American fishes from
seven families were used to develop representative specifications for small -bodied fishes.
The slowest of these species were Stonecat (Noturus flavus) and Johnny Darter (Etheostoma
nigrum), both of which were capable of sprinting at approximately 2 ft/s (Ficke 2015).
Mottled Sculpin (Cottus bairdii) was also considered during development of specifications.
This species is not known to be present in the project area, but it is a host for Appalachian
Elktoe (NCWC 2021), so providing for passage of this species was essential. This species
can sprint for extremely short distances at nearly 3 ft/s (Aedo et al. 2009), but its sustained
swimming ability is limited by large fins, which produce substantial drag (e.g., Webb 1998).
Mottled Sculpin are benthic and can use several station -holding techniques to rest when
challenged by high water velocities (Aedo et al. 2009).
The available data on swimming performance for small -bodied species that are surface -
oriented suggest that their swimming and sprinting abilities are similar to those of other
small -bodied species that have different water column preferences. For example, Inland
Silverside (Menidia menidia) can swim at approximately 10 body lengths/second
(approximately 1 ft/s) for prolonged periods (i.e., up to 25 minutes, Arnott et al. 2006).
Western Mosquitofish (Gambusia affinis) can swim at similar relative speeds; their
swimming ability is somewhat lower than other tested species (sprinting speeds of
approximately 1 ft/s, Li et al. 2017) because of their small sizes. The swimming abilities of
these two species are comparable to those of other small -bodied species with documented
prolonged swimming and sprinting performances (e.g., Ficke 2015, Prenosil et al. 2016).
Studies involving multiple small -bodied fishes tested under the same conditions indicate no
substantial difference between the swimming performance of small -bodied species with
different preferences for water column position. Therefore, top -water specialists such as
Western Mosquitofish and Inland Silverside were included in the guild with the remainder of
the small -bodied species.
Fortunately, most small -bodied fishes will utilize shallow, low -velocity water on channel
margins if main channel velocities are challenging (e.g., Schwartz and Herricks 2005).
Continuous pathways with water velocities between 0 and 2 ft/s within the fish bypass will
allow fish passage for this guild.
Anguilliform swimmers: Lamprey are anguilliform or "eel -like" swimmers; this mode of
swimming is less efficient. Pacific Lamprey (Entosphenus tridentatus) was used as a
surrogate species in absence of available swimming data for the three native lampreys
1 Although adult Western Mosquitofish are smaller (and thus slower) than adults of many other species native to
the French Broad River, they should still be able to utilize the slow, shallow margins of the fishway, where
depth -averaged velocities range from 0 — 2 ft/sec.

kel Memo l Page 3 March 3, 2023
S2o Design and Engineering
currently and historically present in the watershed. A 200 mm Pacific Lamprey2 can swim at
2 ft/s for an average of 38 seconds (DiRocco and Gervais 2021; Katopodis and Gervais
2016). Because of their eel -like shape, these fishes would be able to use the same shallow,
low -velocity water to ascend the fishway as the small -bodied fishes.
Sunfishes: Smallmouth Bass (Micropterus dolomieu). The swimming ability of this sought-
after native game fish has been well -documented. This species is also ecologically significant
because it serves as a host for multiple mussel species. The remaining sunfishes in the project
area were included in the small -bodied fishes guild because of their smaller size and limited
swimming abilities (e.g., Jones et al. 2011). Smallmouth bass in voluntary studies involving a
large raceway (over 150 ft. in length) showed that upstream passage success and the
probability that fish would try to move upstream decreased dramatically as water velocities
exceeded 4 ft/s (Peake and Farrell 2005). Therefore, availability of water depths of 1 ft or
more (to provide sufficient depth for large individuals) and velocities of 4 ft/s or less will
allow passage for this species.
Fusiform river fishes: Because its swimming ability is well -studied, White Sucker
(Catostomus commersonii) was used to develop specifications for larger, fusiform (i.e.,
streamlined) river fishes, such as suckers and large minnows. Adults can sprint for
approximately 60 s at 10 body lengths per second (BL/s, Castro -Santos 2005). This indicates
that adult White Sucker can negotiate the bypass if water velocities are less than 6 ft/s over a
distance of 40 ft. Therefore, if bypass specifications for Smallmouth Bass are met, White
Sucker will also be able to utilize the bypass.
This guild also includes a number of redhorse species (Genus Moxostoma). The swimming
performance of these species is poorly studied, but one study of intraspecific comparisons
was available. The slowest of the three species, Silver Redhorse (M. anisurum) was able to
swim at 2 — 3 body lengths per second for an approximate median of 100 s (Hatrey et al.
2014). Thus, an adult Silver Redhorse that was 300 mm long should be able to swim at
velocities of approximately 2 ft/s. However, the tests used in this study probably also
underestimated swimming ability, because all three redhorse species have been able to
successfully ascend a vertical slot fishway, which generally requires short periods of
negotiating high water velocities.3 Nevertheless, if fishway water velocities of 0 — 2 ft/s at
depths of 1 ft should allow passage of the redhorses present in the French Broad River.
Redhorses are also benthic, or bottom -oriented species, so they would likely be able to
negotiate depth averaged velocities greater than 2 ft/s, because water velocities tend to be
lower near the substrate, particularly in hydraulically rough channels (e.g., Knighton 1988).
Big River Fishes: Specifications for big river fishes were developed using studies of
sturgeon in prototype fishways. Lake Sturgeon (Acipenser fulvescens) are present in the
project area, and reintroduction of Paddlefish (Polydon spathula) has begun in the watershed.
Therefore, specifications that allow passage of this species are critical to project success.
Adult Shovelnose Sturgeon (Scaphirhynchus platorhynchus) in U.S. Bureau of Reclamation
2 While adults of this species attain lengths of nearly 900 mm, adults of the species in the Broad French River
do not usually exceed 200 mm in length (MDFW 2022; NDEC 2022; Williams and Williams 2005).
3 The primary goal of the study was to compare swimming ability between Moxostoma species, not numerically
estimate them.

titil Memo 1 Page 4 March 3, 2023
S2o Design and Engineering
prototype fishways could negotiate water velocities of 6 ft/s for 40 ft. with a 47% success
rate, and field studies of habitat preferences indicated that adults of this species will utilize
habitats with velocities of up to 6 ft/s (White and Mefford 2002). A 2007 study of fish
passage also indicated that White Sturgeon (A. transmontanus) could sprint faster than 6 ft/s
for short distances (Webber et al. 2007). No swimming performance data are available for
adult Paddlefish.
Sturgeon and Paddlefish should be able ascend the fishway if velocities between 4 and 6 ft/s
are available in the low -flow channel. However, the big river fishes guild also includes a
number of deeper -bodied fishes, such as Quillback and River Carpsucker, which may have
reduced swimming performance compared to more fusiform species. A 1982 study of
Missouri River fishes indicated that aerobic swimming velocities of Bigmouth Buffalo
(Ictiobus cyprinellus) and River Carpsucker (Carpoides carpio) were approximately 2 ft/s
(Schmulback et al. 1982). While no sprinting performance data are available for these
species, it is likely that their swimming abilities are underestimated, as commonly occurs
with studies conducted using swimming flumes (e.g., Peake and Farrell 2006). For example,
the aerobic swimming ability of Shovelnose Sturgeon was documented to be 2.5 ft/s in the
Schmulback et al. study, but volitional trials indicate that this species can negotiate much
higher water velocities for significant distances (see following section for details). Successful
passage of the deeper -bodied fishes in this guild was assumed if velocities of 2 — 3 ft/s
occurred at depths of 1 ft or more.
The recommendations for each guild described above were compared against 2D
hydrodynamic model output provided by S2o Design and Engineering to determine if
fishway specifications for all guilds were met for the proposed design. When specifications
were not met, GEI discussed with S2o, and the fish bypass design was revised accordingly by
S2o. This iterative process was used to develop the 60% design. The 60% design was
modified in response to comments received from the North Carolina Wildlife Resources
Commission using the same process and with updated fish passage specifications.
RESULTS:
FISH PASSAGE AT LOW FLOWS
Examination of current model output indicates that all specifications have been met for
passage of the fish guilds present in the project area (Table 1). The velocities shown below
(Figure 1) were modeled at a cross section that was midway between the top and bottom of
the fishway. This location was chosen because velocities are highest and depths lowest at this
location.
Small -bodied fishes and anguilliform swimmers: This cross section contains multiple
locations where water depths are between 0.5 and 1 ft and water velocities are less than 2 ft/s
(Figure 1a; Figure lb). This should allow passage of small -bodied fishes and anguilliform
swimmers.
Sunfish and fusiform fishes:
Water velocities less than 4 ft/s at depths of 1 ft or more are predicted to be present on the
margins of the low -flow notch of the bypass (Figure 1 a; Figure lb). The side slopes of the
bypass were decreased during a design revision so that the cross -sectional shape was more

pi Memo 1 Page 5 March 3, 2023
S2o Design and Engineering
trapezoidal than rectangular; this created a larger area of low -velocity water on each side of
the low -flow notch. Smallmouth Bass and fusiform river fishes should be able to utilize the
margins of the bypass to ascend it.
Big -river fishes: Sturgeon and paddlefishes should be able to utilize the fish bypass, even if
they are large enough to be restricted to the center of the low -flow notch. Water velocities
throughout the fish bypass do not exceed 6 ft/s at a flow of 1,000 cfs (Figure la; Figure lb).
To the extent possible, boulder clusters will be placed near the side slopes of the low -flow
notch to allow fish that prefer deeper water and slower water velocities. These will be placed
in a manner that allows fish to rest periodically while ascending the fishway, so they will not
become exhausted. For example, because sturgeon are known to move distances of 40 ft
against water velocities of 6 ft/s, boulder clusters will be installed every 20-30 ft to permit
frequent resting.
Table 1.—Predicted fish passage success for species representing the swimming guilds
develoued for the French Broad River.
Species
Guild
Successful Passage?
Stonecat, Johnny
Darter, Mottled
Sculpin
Small -bodied fishes
Yes — based on availability of water with velocities
between 0 and 2 ft/s on shallow margins of bypass
Pacific Lamprey
Anguilliform swimmers
Yes — based on availability of water with velocities
between 0 and 2 ft/s on shallow margins of bypass.
Adult Smallmouth
Sunfishes
Yes — based on availability of water with velocities
< 4 ft/s on bypass benches and on margins of low -
flow notch.
Bass
White Sucker
Fusiform fishes
Yes —based on availability of water with velocities
< 4 ft/s on bypass benches and on margins of low -
flow notch.
Lake Sturgeon
Big -river fishes
Yes — based on availability of water with velocities
< 6 ft/s in low -flow notch.

a, Memo Page 6
193S-
1934
1933
1932
193!
1930
1929
!0 l5 20 00
March 3, 2023
S2o Design and Engineering
— ;34)pll1-9EV9'19]042o22P1:_AM
A�
-- 24230111p3h02 ,W Fsflpas4c ?' n -
6a
4.0
20
30 15 +0 a 58
Sla3on 99Q
70 73 90 *0
Figure la. —Modeled velocities at a representative cross section of the proposed fish bypass at
1,000 cfs.
veledly oe'Elyptlf 33- Middle'
6-
5-
— reKKety'161PN20
C 5 10 •5 20 25 30 35 40 a5 50 55 60 65 70 75 ac 00
Sb9o, IPo
Figure 2b.—Modeled velocities at a representative cross section of the proposed fish bypass at
1,000 cfs.
FISH PASSAGE AT HIGHER FLOWS
95
SS

Memo Page 7 March 3, 2023
S2o Design and Engineering
The preceding fish passage predictions were based on examination of predicted conditions at
1,000 cfs. This flow is common throughout much of the year, including during much of the
spring spawning season, when directed migrations are more common. Further, discussions
with S2o staff suggest that velocity changes with an increase in flow to 1,200 or 1,400 cfs
would not have a substantial effect on water velocity. Thus, fish passage should occur over
most of the observed flow range in the project area.
At flows of 2,250 cfs, which are similar to expected median flows in the high flow months of
March and April, fish passage specifications were met for larger fishes, but they would have
had to use the shallower areas outside of the low -flow notch to ascend the fishway (Figure
2a; Figure 2b). Passage of small -bodied fishes and anguilliform swimmers would have been
limited to the margins of the areas outside of the low -flow notch. The reduced predicted
passage success at the structure at flows of 2,250 cfs led to structural modifications as
described in the following section.
Wacky against Tarraln lcolon1 on'6ygsa XS • MOdr'
1935-
,934-
1930-
1929 -
—J
—20230111-RES9'1614N2022023(Z00'
—'2023011 I_Ashierraln_FcMOSSageREW Grol
20 25 30 35 w 45 - i5 50 55 i0 75 BO BS 90 95
Figure 2a.—Modeled velocities at a representative cross section of the proposed fish bypass at
2,250 cfs.

a, Memo Page 8
Velocity on'Bypass x5 - Middle'
Suoon rill
March 3, 2023
S2o Design and Engineering
Figure 2b.—Modeled velocities at a representative cross section of the proposed fish bypass at
2,250 cfs.
MODIFICATIONS BASED ON FEEDBACK FROM NORTH CAROLINA WILDLIFE
RESOURCES COMMISSION
The original 60% design has been modified based on comments received from the North
Carolina Wildlife Resources Commission. Primarily, a different range of flows was
examined to ensure that fish passage was possible during a larger and more biologically
relevant range of flows. The new analysis focused on a flow of 2,250 cfs, which is similar to
the median flow during the months of March and April; additional flows were not modeled
because according to the 2D hydrodynamic models, fish passage efficiency was likely to
decrease as flows increase (due to higher velocities).
To improve fish passage efficiency at higher flows, the slope of the shallow areas outside of
the low flow notch was reduced from 3.5% to 1.75%, and the slope of the low flow notch
was reduced to 0.5% (Figure 3). Although water velocities remain high in the low flow notch
of the fishway, the increased depth in the shallow areas will allow its use by some fishes with
preferences for deeper water (Figure 4). For example, volitional fish passage trials indicate
that water depths of 1.5 ft are sufficient to facilitate passage of Shovelnose Sturgeon (White
and Mefford 2002).
The North Carolina Wildlife Resources Commission also requested that large roughness
elements/resting areas in the fishway imitate local geomorphology; specifically, it was
requested that rock ledges or shelves that protrude from the streambed be mimicked in the
fishway design. Thus, boulder rows were included in the fishway (Figure 5), as these are
analogous to rock ledges but do not create a rise in 100-year flood elevations or cause
unusual flow conditions in the fishway.

Memo I Page 9
March 3, 2023
S2o Design and Engineering
Figure 3. — Slopes of the low flow notch and the shallow areas in the revised bypass
design.
NEXT STEPS
The bypass would be constructed with boulders that were grouted to 50% of their height,
with the remainder of the void filled with native substrate. The presence of native substrate
and interstitial spaces would help increase the probability of successful passage for benthic
(i.e., bottom -oriented) species such as darters, Mottled Sculpin, and larger species such as
redhorses. However, the fishway will contain larger "roughness elements" such as boulder
rows and/or boulder clusters to facilitate passage at higher flows (Figure 5). These features
will provide resting opportunities, particularly for fish utilizing the deeper, higher -velocity
water in the low -flow notch. The type and placement of the roughness elements will be based
on a combination of hydraulic laboratory studies and field studies that provide information
on how to increase passage success.

Memo I Page 10
March 3, 2023
S2o Design and Engineering
Figure 4a.—Modeled velocities on the fish bypass, with boulder clusters, at 2,250 cfs.
1935-
1994 -
1933-
1930-
1929 -
10 15 2C
Velocity .y.in.t Tm.in kolonl an 'Bypass MS. Middle
50 55 60 B5
51211011 RI
75
202301 I 1-RE 1/13' 15188203 92:30120.
—WM111 A5h1main_E111'a161494BEV$' hole
BO 85
Figure 4b.—Modeled velocities at a representative cross section of the proposed fish bypass,
with boulder clusters, at 2,250 cfs.

Memo Page 11
March 3, 2023
S2o Design and Engineering
Raised Boulder
Fences 12"-18"
Protrusion
Figure 5. — Boulder "rows" added to the fishway to mimic local geomorphic conditions and
facilitate passage.

a Memo Page 12 March 3, 2023
S2o Design and Engineering
REFERENCES
Aedo, J., M. Belk, and R. Hotchkiss. 2009. Morphology and swimming performance of Utah
fishes: critical information for culvert design in Utah stream. Utah Department of
Transportation, Research Division, UT-09.12. Salt Lake City, UT.
Arnott, S. A., S. Chiba, and D. O. Conover. 2006. Evolution of intrinsic growth rate:
metabolic costs drive trade-offs between growth and swimming performance in Menidia
menidia. Evolution 60(6):1269-1278.
Castro -Santos, T. 2005. Optimal swim speeds for traversing velocity barriers: an analysis of
volitional high-speed swimming behavior of migratory fishes. Journal of Experimental
Biology 208:421-432.
Di Rocco, R, and R. Gervais. 2021. SPOT: Swim Performance Online Tools. Available
from http://www.fishprotectiontools.ca/.
Ficke, A. 2015. Mitigation measures for barriers to Great Plains fish migration. PhD
Dissertation. Department of Fish, Wildlife, and Conservation Biology, Colorado State
University, Fort Collins, CO.
Hatry, C., J. D. Thiem, T. R. Binder, D. Hatin, P. Dumont, K. M. Stamplecoskie, J. M.
Molina, K. E. Smokorowski, and S. J. Cooke. 2014. Comparative physiology and relative
swimming performance of three redhorse (Moxostoma spp.) species: associations with
fishway passage success. Physiological and Biochemical Zoology 87(1):148-159.
Jones, E. A., A. S. Jong, and D. J. Ellerby. 2008. The effects of acute temperature change on
swimming performance in bluegill sunfish Lepomis macrochirus. Journal of Experimental
Biology 211(9):1386-1393.
Katopodis, C, and R Gervais. 2016. Fish Swimming Performance Database and Analyses.
DFO Can. Sci. Advis. Sec. Res. Doc. 2016/002., 550. Available from http://www.dfo-
mpo. gc. ca/csas-sccs/Publications/ResDocs-DocRech/2016/2016_002-eng.html.
Knighton, D. 1998. Fluvial Forms and Processes: a new perspective. Hodder Education
Group, London. 400p.
Li, J., X. Lin, Z. Xu, and J. Sun. 2017. Differences in swimming ability and its response to
starvation among male and female Gambusia affinis. Biology Open 6:625-632.
MDFW. 2022. American Brook Lamprey Lethenteron appendix. Massachusetts Division of
Fisheries and Wildlife Natural Heritage & Endangered Species Program. Available online:
mass.gov/doc/american-brook-lamprey/download.
Michigan Natural Features Inventory (MNFI) 2004. Lampsilis fasciola fact sheet. Michigan
State University Board of Trustees.
https://mnfi.anr.msu.edu/abstracts/zoology/Lampsilis_fasciola.pdf. Accessed 10/21.
NDEC. 2022. Mountain Brook Lamprey. New York Department of Environmental
Conservation Species Assessment. Available online:
https://www.dec.ny.gov/animals/26031.html.

Et Memo Page 13
March 3, 2023
S2o Design and Engineering
Peake, S. J. and A. P. Farrell. 2005. Postexercise physiology and repeat performance
behaviour of free-swimming smallmouth bass in an experimental raceway. Physiological and
Biochemical Zoology 78(5):801-807.
Schmulbach, J. C., D. H. Tunink, and A. E. Zittell. 1982. Swimming performance of fishes
endemic to the Missouri River in South Dakota. Biological Services Program. U.S. Fish and
Wildl. Serv., Kearneysville, WV 107 pp.
Schwartz, J. S. and E. E. Herricks. 2005. Fish use of stage -specific fluvial habitats as refuge
patches during a flood in a low -gradient Illinois stream. Canadian Journal of Fisheries and
Aquatic Sciences 62:1540-1552.
Webb, P. W. 1998. Swimming. Pages 3-14 in Evans, D. H. (ed). The Physiology of Fishes,
2nd ed. CRC Press, Boca Raton, FL.
Webber, J. D., S. N. Chun, T. R. MacColl, L. T. Mirise, A. Kawabata, E. K. Anderson, T. S.
Cheong, L. Kavvas, M. McGee Rotondo, K. L. Hochgraf, R. Churchwell, and J. J. Cech Jr.
2007. Upstream swimming performance of adult white sturgeon: effects of partial baffles and
a ramp. Transactions of the American Fisheries Society 136:402-408.
White, R. G. and B. Mefford. 2002. Assessment of behavior and swimming ability of
Yellowstone River Sturgeon for design of fish passage devices. U.S. Bureau of Reclamation
Science and Technology Program.
Williams, M. G. and L. R. Williams. 2005. Conservation Assessment: Ohio Lamprey. USDA
Forest Service, Eastern Region. Available online:
http s ://www.fs.usda.gov/Internet/F SE DOCUMENTS/fsm91 _0543 81.pdf

E. Memo Page 14 March 3, 2023
S2o Design and Engineering
ATTACHMENT 1: FISH SWIMMING GUILDS, FRENCH BROAD RIVER

Consulting
Engineers and
Scientists
GEL..
Species
Family
Guild
Status
American Brook Lamprey
Petromyzontidae
Anguilliform
1
Ohio Lamprey
Petromyzontidae
Anguilliform
1
Lake Sturgeon
Acipenseridae
Big river
1
Quillback
Catostomidae
Big River
1
River Carpsucker
Catostomidae
Big River
1
Flathead Catfish
Ictaluridae
Big river
1
Paddlefish
Polyodontidae
Big river
1
Black Redhorse
Catostomidae
Fusiform River
1
Golden Redhorse
Catostomidae
Fusiform River
1
River Redhorse
Catostomidae
Fusiform River
1
Silver Redhorse
Catostomidae
Fusiform River
1
Smallmouth Buffalo
Catostomidae
Fusiform River
1
Smallmouth Redhorse
Catostomidae
Fusiform River
1
White Sucker
Catostomidae
Fusiform River
1
Smallmouth Bass
Centrarchidae
Fusiform River
1
Common Carp
Cyprinidae
Fusiform River
1
Creek Chub
Cyprinidae
Fusiform River
1
Grass Carp
Cyprinidae
Fusiform River
1
Chain Pickerel
Esocidae
Fusiform River
1
Muskellunge
Esocidae
Fusiform River
1
Channel Catfish
Ictaluridae
Fusiform River
1
White Catfish
Ictaluridae
Fusiform River
1
Brown Trout
Salmonidae
Fusiform River
1
Rainbow Trout
Salmonidae
Fusiform River
1
Northern Hogsucker
Catostomidae
Small -bodied
2
Green Sunfish
Centrarchidae
Small -bodied
2
Redbreast Sunfish
Centrarchidae
Small -bodied
2
Mottled Sculpin
Cottidae
Small -bodied
2
Bigeye Chub
Cyprinidae
Small -bodied
1
Blacknose Dace
Cyprinidae
Small -bodied
1
Blotched Chub
Cyprinidae
Small -bodied
1
Central Stoneroller
Cyprinidae
Small -bodied
1
Fatlips Minnow
Cyprinidae
Small -bodied
1
Golden Shiner
Cyprinidae
Small -bodied
2
Highland Shiner
Cyprinidae
Small -bodied
2
Longnose Dace
Cyprinidae
Small -bodied
2
Mimic Shiner
Cyprinidae
Small -bodied
2
Mirror Shiner
Cyprinidae
Small -bodied
2
1 = currently present in project area, 2 = present in vicinity of project area, 3 = not currently present
but reintroductions are planned or in discussion
Memo I Page 15
GEI Consultants, Inc.
4601 DTC Boulevard, Suite 900, Denver, CO 80237
303.662.0100 fax: [phone]
www.geiconsultants.com

Memo I Page 16
March 3, 2023
S2o Design and Engineering
Species
Family
Guild
Status
River Chub
Cyprinidae
Small -bodied
3
Saffron Shiner
Cyprinidae
Small -bodied
3
Silver Shiner
Cyprinidae
Small -bodied
3
Spotfin Chub
Cyprinidae
Small -bodied
3
Telescope Shiner
Cyprinidae
Small -bodied
3
Tennessee Shiner
Cyprinidae
Small -bodied
3
Warpaint Shiner
Cyprinidae
Small -bodied
3
Whitetail Shiner
Cyprinidae
Small -bodied
3
Brown Bullhead
Ictaluridae
Small -bodied
3
Flat Bullhead
Ictaluridae
Small -bodied
3
Banded Darter
Percidae
Small -bodied
1
Blotchside Logperch
Percidae
Small -bodied
1
Fantail Darter
Percidae
Small -bodied
1
Gilt Darter
Percidae
Small -bodied
2
Greenfin Darter
Percidae
Small -bodied
2
Greenside Darter
Percidae
Small -bodied
2
Logperch
Percidae
Small -bodied
2
Olive Darter
Percidae
Small -bodied
2
Redline Darter
Percidae
Small -bodied
2
Sickle Darter
Percidae
Small -bodied
3
Swannanoa Darter
Percidae
Small -bodied
3
Tangerine Darter
Percidae
Small -bodied
3
Wounded Darter
Percidae
Small -bodied
3
Mountain Brook Lamprey
Petromyzontidae
Small -bodied
2
Black Crappie
Centrarchidae
Sunfish
3
Bluegill
Centrarchidae
Sunfish
3
Largemouth Bass
Centrarchidae
Sunfish
3
Rock Bass
Centrarchidae
Sunfish
3
White Crappie
Centrarchidae
Sunfish
3
1 = currently present in project area, 2 = present in vicinity of project area, 3 = not currently present
but reintroductions are planned or in discussion