20200907 Ver 1_Staff Comments_20200814

Strickland, Bev
From:
Tarver, Fred
Sent:
Friday, August 14, 2020 3:30 PM
To:
Homewood, Sue; Leslie, Andrea J; Goudreau, Chris J.
Subject:
RE: Wilkesboro WTP upgrades
Sue
A few observations on the proposed Wilkesboro Intake in the Yadkin River below W. Kerr Scott Dam.
• The schematic shows a calculated minimum depth of 3' 10". Is it known what flow that elevation corresponds
to? 125 cfs?
• The schematic shows a calculated minimum depth required of 4' 6". Is it known what flow that elevation
corresponds to?
• Will there be enough draft and area to allow passage of recreational boaters over and around the installed
structures?
As Chris states below: 16 mgd (24.7 cfs) is 19.8% of the 125 cfs min flow value; so, that looks fine (akin to being less
than 20% of 7Q10).
The 7Q10 (02112000 - YADKIN RIVER AT WILKESBORO, NC; Analysis Period: 01/01/1983 to 01/07/2020, Climatic Year)
is —182 cfs. Given the altered hydrology, the 125 cfs should be the benchmark rather than the 7Q10.
• The town of North Wilkesboro has expressed an interest in putting a surface water w/d in the Yadkin River as
well. It would be downstream of Wilkesboro's intake. The w/d capacity mentioned was 6 mgd.
• The City of Winston-Salem has a 401 Condition to maintain 554 cfs below Idols Dam (12-08-1999)(WQC Project #
910386).
• At some point in the future, when Wilkesboro gets a permitted capacity of 16 mgd to match the intake and
North Wilkesboro gets its 6 mgd intake and the associated 6 mgd-permitted capacity WTP, then the water
withdrawers of Yadkin River flow will need to plan how to partition the 20% 125 cfs. Or, perhaps increase the
low flow from 125 cfs to meet increasing demand. And, still meet Winston-Salem's 401-required target.
From Local Water Supply Plan (LWSP) on DWR website:
Wilkesboro:
Water Treatment Plant Permitted Capacity: 10mgd
Present supply: Yadkin River, W Kerr Scott Reservoir, Avg. Day w/d: 4.7936 mgd, Max. Day: 0.0000 mgd, Available
supply: 16.0000 (20% ISF).
North Wilkesboro:
North Wilkesboro Water Plant Permitted Capacity: 4.32 mgd.
Present supply: Reddies River, Avg. Day w/d: 2.6570 mgd, Max. day w/d: 3.7830 cfs, Available Supply: 15.0000 mgd
(safe yield 50).
Fred
Fred R Tarver III
1

Environmental Flows Program Consultant
Water Planning Section - Basin Planning Branch
Department of Environmental Quality
919-707-9029 office
fred.tarver(cDncdenr.aov
Division of Water Resources
1611 Mail Service Center
Raleigh NC 27699-1611
Email correspondence to & from this address is subject to the N.C. Public Records Law & may be disclosed to third
parties!
From: Homewood, Sue
Sent: Monday, August 10, 2020 11:36 AM
To: Tarver, Fred <[e-mail]>
Subject: FW: Wilkesboro WTP upgrades
Hey Fred,
I had assumed (maybe mistakenly) that you would be looped in through the PWS process of approving the upgraded
intake. Is that correct? If not then I'll make a note to myself to get your input on any 401 applications for water supply
intakes. If that's correct, then I'll continue on as usual.
Sorry, still learning who does what after 24 years with DWR... geez.
Sue Homewood
Division of Water Resources, Winston Salem Regional Office
Department of Environmental Quality
336 776 9693 office
336 813 1863 mobile
Sue. [e-mail]
450 W. Hanes Mill Rd, Suite 300
Winston Salem NC 27105
From: Leslie, Andrea J <[e-mail]>
Sent: Monday, August 10, 2020 11:33 AM
To: Tarver, Fred <[e-mail]>
Cc: Goudreau, Chris J.<[e-mail]>; Homewood, Sue <[e-mail]>
Subject: FW: Wilkesboro WTP upgrades

Fred -
I talked with Sue Homewood just now, and I mentioned we wanted to make sure you were aware of the
Wilkesboro upgrades. Any input? See Chris' discussion points below.
Andrea
Andrea Leslie
Mountain Habitat Conservation Coordinator
NC Wildlife Resources Commission
645 Fish Hatchery Rd., Building B
Marion, NC 28752
828-803-6054 (office)
828-400-4223 (cell)
www.ncwildlife.org
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From: Goudreau, Chris J. <[e-mail]>
Sent: Friday, August 07, 2020 10:20 AM
To: Leslie, Andrea J <[e-mail]>
Cc: Russ, W. Thomas <[e-mail]>; Hodges, Kinnon B <[e-mail]>
Subject: RE: Wilkesboro WTP upgrades
Here are my comments:
1. They're using passing intake screens installed on river bottom. Good, no dam involved.
2. Intake velocity design 0.5 fps. Meets WRC guidelines.
3. Intake screen openings — not specified. WRC guidelines call for openings no larger than 0.4 inch (1 cm). They'll
have to adjust the overall size of the intake to meet their target of 16 mgd withdrawal.
4. Construction to be done in dry by installing dewatering dikes upstream and downstream of work area. Not clear
if they will just block off the near part of the river to do this or dig a temporary stream through the opposite
riverbank. No indication of how big the bypass channel length would be. Need details.
5. Back in 2009 Catena did aquatic fauna surveys for licensing of WKS hydro (see attached). Catena's site 3 is just
upstream of the Wilkesboro WTP. They found Eastern Elliptio and Carolina lance. Also said that brook floater
and creeper are known from further downstream, but not found at site under less than ideal survey
conditions. Also 3 crayfish species and 2 salamanders. Fish species rather limited. TR — Do you have more
recent records for this area?
6. Regardless of how the work area is created, they need to survey the area for mussels and move them
upstream. The survey area should include 100 feet upstream and downstream of the extent of the work area.
7. They rely on releases from WKS (about 3.2 miles upstream) to maintain adequate flows for withdrawal. The
Corps min flow release is 125 cfs under drought conditions (based on lake level drawdown exceeding 6
feet). Under normal conditions the min release is 300-400 cfs. 16 mgd (24.7 cfs) is 19.8% of the 125 cfs min
flow value; so, that looks fine (akin to being less than 20% of 7Q10). Even so, it is not clear from this application
if the 16 mgd design is already permitted by DWR. Probably need to check with Fred Tarver.
3

Let me know if you have questions.
Chris
From: Leslie, Andrea J <[e-mail]>
Sent: Thursday, August 06, 2020 5:30 PM
To: Goudreau, Chris J. <[e-mail]>
Subject: Wilkesboro WTP upgrades
Hi Chris -
Can you take a look at the permit application, attached, for upgrades to the Wilkesboro WTP? They didn't
include construction drawings, so I'm waiting on those and will forward when I get them. For now, this is a
heads up - we may need to ask for additional info once we get the construction drawings.
Andrea
Andrea Leslie
Mountain Habitat Conservation Coordinator
NC Wildlife Resources Commission
645 Fish Hatchery Rd., Building B
Marion, NC 28752
828-803-6054 (office)
828-400-4223 (cell)
www.ncwildlife.org
Get NC Wildlife Update delivered to your inbox from the N.C. Wildlife Resources Commission.
Email correspondence to and from this sender is subject to the N.C. Public Records Law and may be disclosed to third parties.