20200907 Ver 1_Email_20200817

Strickland, Bev
From: Homewood, Sue
Sent: Monday, August 17, 2020 9:02 AM
To: Jon Swaim
Cc: Leslie, Andrea J
Subject: FW: Wilkesboro WTP upgrades
Hi Jon,
Here are some additional comments regarding this project. Hopefully you can incorporate changes and/or answers into
your future submittal.
Also, I'm not sure if it was clear in our prior exchanges, but would you please send an email explicitly requesting to
withdraw the current application.
Thanks
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: Tarver, Fred <[e-mail]>
Sent: Friday, August 14, 2020 3:30 PM
To: Homewood, Sue <[e-mail]>; Leslie, Andrea J <[e-mail]>; Goudreau, Chris J.
<[e-mail]>
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?
1

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
Environmental Flows Program Consultant
Water Planning Section - Basin Planning Branch
Department of Environmental Quality
919-707-9029 office
fred.tarvera-ncdenr.gov
Division of Water Resources
1611 Mail Service Center
Raleigh NC 27699-1611
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