NC0032719_Email (Quarterly Report 4-19)_20190430

Strickland, Bev
From: Tawes, David
Sent: Tuesday, April 30, 2019 9:40 AM
To: Tankard, Robert; May, David; Sipe, Randy
Cc: Howard, Kevin B; Katie Hackney; Greg Churchill
Subject: Chowan County - SOC Quarterly Report
Attachments: 30-04-2019 SOC Qrtrly Report.pdf
Hi,
Well, it has been a year. We appreciate all the work you do for Chowan County citizens and its visitors.
Please see the attached report. If we need to discuss, just let us know.
Thank you,
David
David M. Tawes
Chowan Water
1608 Virginia Road
Edenton, NC 27932
Office [phone]
[e-mail]
Email correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties by an authorized
state official.

Uff-
DATER BEPT.
305 West Freemason Street
P.O. Box 1030
Edenton, NC 27932
[phone]
April 30, 2019
943 Washington Square Mall
Washington NC 27889
ATT: Mr. Robert Tankard
SUBJECT: County of Chowan Progress Report
Valhalla Water Treatment Plant
NPDES Permit No. NC 0032719
EMC SOC WQ S 16-003
Dear Mr. Tankard:
This is to inform you of the progress that we have been making as of this date to comply with the
SOC deadlines for the Chowan County Water Plant:
1. On January 23, 2019, the Chowan County Board of Commissioners granted permission to
Rivers to proceed with aerial survey preparation and production in advance of the arrival
of spring tree foliage.
2. On January 29, 2019, Chowan County mailed notifications to area property owners to
request approval for access to their properties to install control points/panels in
preparation for aerial survey work.
3. From February 6 - 13, 2019, Rivers' survey crew set points and fabric panels on the
ground for the aerial survey.
4. From February 14 — 28, 2019, Rivers' survey crew established control and surveyed the
aerial control points.
5. On February 5, 2019, Chowan County received additional comments via email from the
NPDES Unit relative to the previously submitted CORMIX dilution model. The NPDES
Unit performed a Reasonable Potential Analysis for chloride which predicted a maximum
chloride concentration of 9,016.8 mg/L at 95% probability and 95% confidence interval
based on DMR effluent concentrations from May, 2014 to November, 2018. The initial
dilution modelling was performed at a lower chloride concentration of 5,000 mg/L. The
NPDES Unit offered the County several options for proceeding forward. These included
(1) revise the dilution model for a higher chloride limit, (2) proceed with the current
chloride limit and request subsequent permit modification if desired, and (3) proceed with

current chloride limit and do not request subsequent permit modification. In either case,
if an exceedance of the limit is experienced, enforcement action may be taken.
6. On February 22, 2019, GMA submitted a final Groundwater Monitoring Report to
Chowan County with copies to NCDEQ, DWR, Water Quality Regional Operations.
7. On February 26, 2019, Spatial Data Consultants, Inc. flew and acquired aerial
photography of the project site to prepare for digital terrain modelling, planimetric and
topographic mapping.
8. On March 7, 2019, the Chowan County Board of Commissioners directed Rivers and
GMA to revise the dilution model to reflect a higher chloride limit.
9. On March 18, 2019, Rivers prepared a Reasonable Potential Analysis to confirm the
results obtained by the NPDES Unit.
10. On March 20, 2019, Chowan County received correspondence from NCDEQ, DWR,
Water Quality Regional Operations indicating concurrence with the conclusions and
recommendations presented in the final Groundwater Monitoring Report and a request that
Chowan County proceed with the proposed continued groundwater monitoring and the
completion of the Corrective Action Plan (CAP).
11.On March 20, 2019, hydrographic survey field work was conducted for the proposed
Chowan River discharge location by Geodynamics.
12.On March 28, 2019, topographic mapping of the project site was delivered to Rivers by
Spatial Data Consultants.
13. In April, 2019, GMA leased the CORMIX software and revised the dilution model based
on a chloride limit of 9,050 mg/L, and prepared Amendment No. 1 to the previously
submitted discharge mixing model. The Amendment was submitted to the NPDES Unit
for review on April, 22, 2019.
14. Additional sampling results will be submitted, as soon they are collected and analyzed.
Should you have any questions, please feel free to call.
Sincerely,
David Tawes,
Water Director
[phone]