20191577 Ver 1_More Info Email 1 1-6-20_20200106

Moore, Andrew W
From:
Sent:
To:
Cc:
Clement Riddle <[e-mail]>
Monday, January 6, 2020 12:17 PM
Amanda Jones (amanda [e-mail])
Moore, Andrew W; Anna Priest
Subject: [External] RE: Project Ranger - PCN Comments -Action ID 2019-01867
Attachments: Draft River Safety Plan 12.31.19.pdf, Permit Drawing_Biltmore French Broad Bridge 5A
12.30.19.pdf, 1-6-20 Impact Map 5-0 Project Ranger.pdf
External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
[e-mail]
Amanda,
We are submitting this email response to US Army Corps OF Engineers comments dated December 4, 2019 for project
Ranger. In addition to our responses below, there have been several changes to the bridge design which more than
doubles the length of the center span over the river as well as reduce the overall permanent impact and duration of the
temporary impacts.
The proposed bridge design has changed from approximately 550 feet long with five concrete spans of 110 ft and three
bents in the river to an approximately 610 foot long continuous steel girder type bridge with a center span of 240 feet
and two bents in the river (see attached revised permit Figures 5.0 and 5A. For an estimated 12 month period,
temporary rock causeway footprints will extend 114 ft in the direction of flow and 80 ft and 70 ft out in the river from
the west and east banks, respectively, such that less than 50% of the river is blocked at one time. The centermost,
approx. 100 ft, of this girder span will be installed last. In order for cranes to reach out and hang this last 100 ft steel
beam, both temporary rock causeways will have to be extended an additional 24 ft downstream and an additional 40 ft
out into the river for a short period of time estimated at 1 month. This will result in an additional 0.327-acre temporary
impact. Temporary disturbance in the French Broad River for both Phases of the temporary causeways is expected to be
reduced from an estimated 19 months to an estimated 12 months. As a result, the proposed jurisdictional impacts are
now:
• Impact S1- 25 If. of stream impact in the French Broad River for the bridge footings, 5 piers per bent and piers
are 5 foot diameter. Total of 10 piers for the bridge. Piers are 20 sq. ft per pier and total 0.005 ac of impact
• Impact S2 — The temporary causeways impact will have two phases. Phase 1 of the temporary causeway will
include 114 If. of stream impact and the causeway size is reduced to 0.170 acre each (east and west causeway
). Phase 1 impact is approximately 0.34 acre. Phase 1 impacts are expected to remain for approximately
12months. Phase 2 temporary causeway impact will increase each causeway for approximately 1 month to 138
If. of stream impact and the causeway size will increase by an additional 0.166 ac (west) and 0.161 acre
(east). Total Phase 2 impacts are approximately 0.327 ac.
• Impacts S3 —114 linear feet of permanent stream impact (0.031 ac) for bank stabilization on each side of the
French Broad River which will consist of class II riprap (24-inch thick) keyed into the riverbank
• Impact S4 — wetland W1— 0.067 acres of wetland impact (2,898 sq. ft).
Reduction in Tree -clearing, Limits of Disturbance and Excavation
There will be approximately 80.0 of tree clearing for Project Ranger. An additional 3.0 acres will be graded
within the limits of disturbance that are not forested.
The changes in the bridge design will result in further reduction of tree clearing at the bridge location. Tree -
clearing in the vicinity of the bridge will total approximately 3.0 ac to accommodate excavation and bridge

construction. On the west side of the river, clearing will be reduced from approximately 500 to 270 linear feet
along river or from 1.7 to 1.3 acres. On the east side of the river, clearing will be reduced from approximately
400 to 260 linear feet along river or from 2.0 to 1.7 acres. Not including the bridge construction site, tree -clearing
limits will extend no closer than 400 ft. from the French Broad River for the manufacturing facility. On the west
bank of the river, there is currently a gap in the canopy that spans approximately 200 ft., located south of the
proposed bridge at Bent Creek River Park. A 230-ft. (approximate) canopy gap occurs on the east side of the river
where transmission lines cut across, with a corresponding gap of 270 ft. on the west side. The remaining
riverbanks are forested within the Action Area. Design revisions will also reduce excavation in the vicinity of
the bridge from 3.7 to 0.6 acres.
-----Original Message -----
From: Fuemmeler, Amanda J CIV (US) <[e-mail]>
Sent: Wednesday, December 4, 2019 5:15 PM
To: Clement Riddle <clement(@cwenv.com>
Cc: Lee Thomason <[e-mail]>
Subject: Project Ranger - PCN Comments
Clement,
We have received the application for NWP 14 and 25 and a Section 10 permit request for the Project Ranger site dated
November 12, 2019. We have since forwarded the application to the NC State Historic Preservation Office, appropriate
Tribes, and US Fish & Wildlife Service to begin the corresponding consultation processes under Section 106 of the
Historic Preservation Act and Section 7 of the Endangered Species Act. As noted in the application, investigations/final
reports for potential impacts to cultural resources and T/E species are still pending and will be forwarded under separate
cover once completed. In the meantime, I am providing additional information requested from our office to continue
the review of this application as it relates to construction plans/details, avoidance & minimization efforts, and
considerations for recreational users and their safety on the French Broad River.
1) Based on the information submitted, proposed bridge clearance will be 20-30 feet above normal water surface
elevation. We have concerns that this height may be too low to safely pass recreational boaters especially during higher
flow conditions on the river. Please provide information on the vertical clearance of other existing bridges upstream and
downstream of the River in this general vicinity. Also please provide details on what the expected clearance would be
during various flood stages.
Requested data on the proposed bridge as well as up and downstream existing bridges is shown in the two tables
below. As shown, the clearance of the proposed bridge meets or exceeds the clearance of all up & downstream
bridges. The 1-26 bridges (going under construction early 2020) are the only area bridges that provide the clearance
being proposed. It should be noted that, based on our analysis, the clearance of the 1-26 bridges was a result of
topographic constraints and would not have been as high just for clearance considerations. The proposed bridge for
Project Ranger should provide recreational boaters with ample clearance to navigate the river.
Clearance Range over Normal Water Surface (NWS)
footprint
Glenn
1-26 Bridges
Bridge Rd
NC-146
Proposed
(under
Biltmore Estate
Bridge #46
Bridge #53
Bridge
construction)
Bridge
5 miles
3 miles
Project
0.9 miles
5.7 miles
Distance Away:
upstream
upstream
Location
downstream
downstream
Clearance to
13'
18' to 24'
20' to 30'
24' to 26'
8' to 10'
NWS Elev

Clearance to
Completely
10yr WS Elev
5' to 6'
7' to 13'
9' to 19'
10' to 12'
Submerged
(Overtops)
Clearance to
Completely
50yr WS Elev
1' to 2'
2' to 9'
4' to 14'
6' to 8'
Submerged
(Overtops)
Clearance to
Completely
100yr WS Elev
0' to 0.5'
0' to 7'
2' to 12'
4' to 6'
Submerged
(Overtops)
Average Clearance over Normal Water Surface (NWS) footprint
Glenn
1-26 Bridges
Bridge Rd
NC-146
Proposed
(under
Biltmore Estate
Bridge #46
Bridge #53
Bridge
construction)
Bridge
Distance Away:
5 miles
3 miles
Project
0.9 miles
5.7 miles
upstream
upstream
Location
downstream
downstream
Avg Clearance to
13'
21'
25'
25'
9'
NWS Elev
Avg Clearance to
Completely
10yr WS Elev
5'
10,
14'
11'
Submerged
(Overtops)
Avg Clearance to
Completely
50yr WS Elev
2'
6'
9'
7'
Submerged
(Overtops)
Avg Clearance to
Completely
100yr WS Elev
0.3'
4'
7'
S'
Submerged
(Overtops)
2) The plans note that there will be 3 piers/bents in the river (along with 3 on the river banks/uplands). We have concerns
that the number and spacing of these piers/bents will obstruct navigation for recreational boaters and create a safety
hazard. Please provide information on how the number/location of these structures were determined and could an
alternative design be evaluated that called for less bents/wider spacing. This information should also include the number
of bents and horizontal spacing on bridges upstream and downstream in this area. Also, we recommend that a survey of
the river bottom and thalweg in the project area in addition to upstream/downstream of the project area be completed
in order to better predict the natural course of the river and path that recreational boaters would be using in this area so
that we can determine if any bridge piers/bents will impede navigation.
A topographic survey of the riverbed has been performed which extends 430 ft & 350 ft, up & downstream, respectively,
of the proposed crossing. Contours (as well as existing ground profile) from this survey are shown on the included
Permit Drawing. Analysis of data indicates no discernable, continuous thalweg in this area. The width of the river bed is
generally 280 ft to 320 ft wide in this area.
As discussed above in more detail, the proposed bridge layout has been revised to reduce the number of bents in the
water from three to two and increase the length of the span over the center of the river from 110 ft to 240
ft. Requested data on the proposed bridge as well as up & downstream bridges is shown in table below. As shown, the
number of proposed bents in the water is less than or equal to up/downstream bridges and the proposed span length
3

over the river is somewhat larger than up/downstream bridges, which should provide recreational boaters with ample
room to navigate the river.
Number of Bents and Horizontal Spacing
Glenn
NC-146
1-26 Bridges
Bridge Rd
Bridge
Parkway
Proposed
(under
Biltmore Estate
Bridge #46
#53
Bridge
Bridge
construction)
Bridge
5 miles
3 miles
0.2 miles
0.9 miles
5.7 miles
Distance Away:
upstream
upstream
upstream
Project Location
downstream
downstream
Number of
3
3
9
2
2
2
Bents:
Number of
(existing
2(
Bents in NWS
3
2
3
2
4+)
2
footprint:
120',
All100'
Horizontal
,
151, ,
Spacing:
4 @ 75'
118',
over
165', 240', 205'
143'
86', 88', 86'
118', 45'
water
Main Span
Length in middle
75'
118'
100,
240'
170'
88'
of River:
3) The application notes that work in the river associated with investigative drilling, construction drilling and
construction/use of causeways will take approximately 22 months. Due to the prolonged length of time that construction
will be occurring in the river and the high volume of recreational boaters using this section of river, we will require the
following:
The applicant expects the investigative drilling, pier construction, and use both phases of the temporary
causeways to take approximately 12 months.
a) Coordinate with the recreational boating outfitters in the area to develop and provide signage alerting users
to this project/construction and recommended put in/pull out areas. Also, please address if there will be any
additional/new put in/out areas provided for river users. We recommend that you coordinate with NCDOT on this
effort to avoid any public confusion since it has been done for the 1-26 Bridge Construction downstream. NCDOT
contact is Luke Middleton - [e-mail]
No new public river put-in/pull-out areas will be added. Should the river need to be closed to boaters for a
limited duration during construction, the closest pull-out area is Bent Creek River Park and the closest put -in is
Hominy Creek River Park. Biltmore Farms has retained a Public Relations firm to coordinate communication
with affected recreational river users and NCDOT as recommended.
b) Develop a River Safety Plan that addresses lighting requirements during construction, contractor
training/requirements in the event of a distressed boater, placement of in -stream navigational aids marking a
safe passage lane, and efforts to prevent construction material from falling on river users during bridge
construction. The attached River Safety Plan was developed by NCDOT as part of the permit requirements
associated with the 1-26 Bridge Construction over the French Broad River and is being provided as a guide to
assist you in this request.
The River Safety Plan prepared for Project Ranger is attached for your review.

4) Please provide information on how you plan to manage high water flows during drilling and while temporary
causeways are in the river. This should include any proposed measures to avoid or minimize adverse effects from the
causeways to upstream and downstream areas. Adverse effects include things such as bank erosion, scour, flooding, etc.
This documentation should include details concerning monitoring of conditions preconstruction, during construction, and
post construction. This documentation should also include a plan to address remediation measures for any streambank
instability as soon as possible after a high water event, or in the case of a destabilizing issue that arises for some other
reason related to the causeways - e.g., debris caught on the causeways, etc. Plans to ensure that equipment and supplies
are not placed in locations that will flood in the event of high water should also be detailed.
In the area of the proposed crossing, the river resembles a typical healthy mountain river in this region of the Blue Ridge
Mountains with boulders, cobbles, pebbles and sand of varying depth over bedrock throughout the channel bottom and
with stream banks lined with thick vegetative cover. No stream incisions, scour or bank erosion were observed in the
vicinity of the proposed crossing.
Based on field reconnaissance, review of historical records including Bridge Maintenance Reports of existing nearby
structures and interviews with Bridge Maintenance personnel familiar with nearby crossings, measurable scour is not
anticipated at the proposed crossing due to either temporary or permanent proposed conditions. This is further
supported by review of geotechnical borings at the 1-26 bridges indicating crystalline rock at 0 to 3 feet below the
streambed elevation. Similar conditions are anticipated at the proposed location.
Channel velocities and maximum shear stresses were analyzed for both existing and proposed conditions as well as
temporary conditions while causeways are in place under high (100yr event) flow conditions. All scenarios considered
resulted in velocities of less than 7 ft/sec and max shear stresses of less than 2 psf in the vicinity of the crossing, which
would not be expected to cause erosion to naturally vegetated river banks or river banks underneath the bridge which
are proposed to be stabilized with Class II Rip Rap. As shown by these results, velocity increases due to causeways
outside the bridge footprint are negligible.
Channel Velocities (feet/second)
Distance
upstream of
100-YR Flood Event Discharge
proposed
crossing (miles)
Existing
Proposed
12 Month
1 Month
Permanent
Causeway
Causeway
-0.03
6.1
6.1
6.1
6.1
downstream
toe of bridge
5.9
6.1
6.1
6.3
downstream
face of bridge
N/A
6.1
6.5
6.9
upstream face
of bridge
N/A
6.1
6.6
6.9
upstream toe
of bridge
1 6.0
1 6.2
1 6.2
1 6.3
0.10
6.3
6.3
6.3
6.3
We propose to add the following commitments to further address concerns:
• Following high water events, any debris observed to be caught on temporary causeways will be removed.
• Following high water events, river banks will be inspected for signs of erosion and, if found, will be stabilized.

• Any equipment that is placed on the causeways will be removed any time throughout a work day when the
water level rises or is expected to rise overnight.
• Prior to construction, a limited qualitative evaluation will be made of the river banks immediately upstream and
downstream of the proposed project to establish a baseline in the event future erosion is caused by this
project. Periodic visual inspection to confirm river banks are stable and that no measurable scour is present will
be made from the start of construction until the bridge is conveyed to NCDOT.
5) Please provide information on the water surface elevation (WSE) upstream during different storm events and how it
would affect structures in the floodplain. The summary and/or plan should include information that details how the
causeways and any other temporary structure(s) will not cause or exacerbate any upstream flooding under both normal
and high flow conditions.
Water surface elevations have been analyzed for both existing and proposed conditions as well as temporary conditions
while causeways are in place under both normal (2050 cfs) and high (100yr, 50000 cfs) flow conditions. The high flow
portion of this analysis is explained in more detail in a CLOMR request submitted to FEMA on 12/19/2019.
• Existing to proposed permanent conditions result in increases of less than 0.1 feet upstream of the proposed
crossing for 100yr flow conditions and no increases under normal flow conditions.
• Existing to primary temporary causeway phase (conservatively estimated as 12 month duration) result in a max
WSE increase of 0.2 feet which dissipates to a less than 0.1 foot increase 0.2 miles upstream of the proposed
crossing for the normal flow conditions. Similarly, for 100yr flow conditions, a max increase of 0.1 feet
dissipates to less than 0.1 feet at 0.4 miles upstream.
• Existing to short term temporary causeway phase (estimated as 1 month duration) result in a max WSE increase
of 0.8 feet which dissipates to a less than 0.1 foot increase 0.3 miles upstream of the proposed crossing for the
normal flow conditions. Similarly, for 100yr flow conditions, a max increase of 0.2 feet dissipates to less than 0.1
feet at 0.9 miles upstream.
Based on HEC-RAS modeling results and field verification, there are no insurable structures within the limits of the
project that have an increase in 100yr WSE of 0.1 feet or greater from either existing to temporary or existing to
proposed conditions. Based on this analysis, increases in water surface elevation due to both temporary and permanent
proposed conditions result in negligible increases in water surface elevations. Once FEMA's technical review of the
CLOMR request is complete, the local floodplain administrators will send out notifications to all property owners
informing them of proposed changes to WSEs and the floodway on their property.
Please contact me with any questions, thanks.
Amanda Jones
Regulatory Specialist
U.S. Army Corps of Engineers
Asheville Regulatory Field Office
151 Patton Avenue, Room 208
Asheville, NC 28801-5006
828-271-7980 ext. 4225