NC0076775_Permit (Modification)_20010126

NPDES DOCUMENT SCANNING COVER SHEET
NPDES Permit:
NC0076775
Falls Powerhouse
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Staff Report
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
January 26, 2001
This; document is printed on reuse paper - ignore any
content on the re-srerse side

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
Michael F. Easley, Governor
William G. Ross Jr., Secretary
Kerr T. Stevens, Director
January 26, 2001
Mr. William L. McCaskill
c / o Yadkin, Inc.
P.O. Box 576
Badin, North Carolina 28009
2./F
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
Subject: NPDES Permit Modification
Permit No. NC0076775
Falls Powerhouse
Stanly County
Dear Mr. McCaskill:
The Division issued NPDES permit NC0076775 to the Yadkin Inc. on May 30, 2000. The Division
has reviewed your request for permit modification at the subject facility. Specifically, you requested
removal of the limit for pH.
The basis for the request was that dam seepage through the walls of the powerhouse collected in.
the sump drain and that this water possessed elevated pH levels. The high pH in the dam seepage
water cannot be controlled by Yadkin Inc. and causes the effluent to exceed the limit. An attempt to
correct the problem, via steam cleaning the walls, has had no success, therefore Yadkin Inc. requested
that the pH limit be removed.
The general permit for hydroelectric facilities does allow a waiver of the pH limit for dam seepage
water. Therefore, In accordance with your permit modification request, the Division is forwarding
herewith a modification to the subject permit.
The revised page should be inserted into your permit. The old page may then be discarded. All
other terms and conditions contained in the original permit remain unchanged and in full effect. This
permit modification is issued under the requirements of North Carolina General Statutes 143-215.1 and
the Memorandum of Agreement between North Carolina and the U. S. Environmental Protection
Agency.
If any parts, measurement frequencies or sampling requirements contained in this permit
modification are unacceptable to you, you have the right to an adjudicatory hearing upon written
request within thirty (30) days following receipt of this letter. j
This request must be a written petition conforming to Chapter 150B of the North Carolina General
Statutes, filed with the Office of Administrative Hearings (6714 Mail Service Center, Raleigh, North
Carolina 27699-6714). Unless such demand is made, this decision shall be final and binding.
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer VISIT US ON THE INTERNET 4, http://h2o.enr.state.nc.us/NPDES

NPDES Permit: NC0076775
Page 2
If you have any questions concerning this permit modification, please contact Michael Myers at
[phone], extension 508.
Sincerely, � .
/-.4i c1/
err T. Stevens
cc: Central Files
Mooresville Regional Office, Water Quality Section
Point Source Compliance Enforcement Unit
NPDES Unit

A (2). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - FINAL
Permit No. NC0076775
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is authorized to discharge from outfall(s) serial number 007 — Sump
Drain. Such discharges shall be limited and monitored by the Permittee as specified below:
.' EFFLUENT CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING
Effluent Measurement
Frequency
REQUIREMENTS
Sample Type,,ft.
' fi '`
Sampleb.
- Location .-
Monthly Average
Weekly Average
Daily Maximum
Flow
Annual
Estimate
E
Oil and Grease'
15 mg/1
20 mg/1
Annual
Grab
E
pH2
_
Annual
Grab
E
NOTES:
* Sample Locations: E — Effluent or at the point closest to discharge where a representative sample of the discharge can feasibly be obtained.
1 The tailrace shall be visually inspected for oil sheen attributed to facility operations on a weekly basis in conjunction with inspections of the floor sump and rope skimmer.
Confirmation that a visual inspection was conducted shall be recorded in the operating log for the facility and provided to the Division upon request.
2. There is no limit for effluent pH, however annual monitoring shall be required.
Best Management Practices (BMPs) must be employed to ensure that excessive pollutants are not discharged to the surface water of the state. These practices
should include as a minimum, routine maintenance of the rope skimmer type oil/water separator and cleaning accumulated sediment in the bottom of the sump
annually.
Chemical wheel pit cleaning is permitted on a monthly basis. When wheel pit cleaning occurs, the tailrace shall be inspected visually for foam and oil. Cleaning shall be
conducted only with pre -approved solvents. Should the Permittee wish to change solvents, a written request should be made to the Division including the MSDS for the
proposed solvent.
Mechanical cleaning operations, which do not contribute any wastewater to the discharge are not limited by this permit. Non -discharging cleaning operations may be
conducted as often as necessary to ensure safety and proper facility operation.
The Permittee shall obtain authorization from the Division prior to the use of any chemical additive (i.e. biocides) in the discharge. The permittee shall notify the
Director in writing at least ninety (90) days prior to instituting the use of any additional additive in the discharge, which may be toxic to aquatic life (other than
additives previously approved by the division). Such notification shall include the completion of Biocide Worksheet Form 101 (if applicable), a copy of the MSDS
for the additive, and a map indicating the discharge point and receiving stream.
Monitoring results obtained during the calendar year shall be recorded and reported on a Discharge Monitoring Report (DMR) form and postmarked no later than January 30th
following the completed reporting period. The first DMR is due January. 30' 2001. Samples obtained for monitoring purposes may be collected anytime during the calendar
year.
There shall be no discharge of floating solids or visible foam (other than trace amounts) in the effluent, unless ambient river conditions prevent compliance.

Alcoa Inc.
2000 November 16
N. C. Departm : of Environment
Division of ater Quality
P. O. B p • 29535
Ral •h. N. C. 27626-0535
Attention: T. Kerr Stevens
RE: PROPOSED PERMIT MODIFICA
and Natural Resources
CERTIFIED MAIL
RETURN RECEIPT
0214 5914
TION — FALLS POWERHOUSE
NPDES PERMIT # NC 0076775
Gentlemen:
ALCOA
'114?
DiV! OF
D OR, EQUAL/TY
REQUESTED FF�'E
As a follow-up to recent coilve;cations w 4iehaeyer3 regarding the rc:ccntly
renewed NPDES permit for the referenced facility, Alcoa is submitting a request on
behalf of Yadkin, Inc. for the Division of Water Quality to consider modifying the
referenced permit to address a permit condition related to the pH limits for Outfall 007.
During the initial round of monitoring under the recently renewed permit, it was
discovered that the pH in the sump discharge (Outfall 007) was above the permitted limit
of 9.0 pH units. Further investigation has revealed that the alkalinity of the water is being
elevated as it seeps through the walls of the Powerhouse as a result of contact with lime
& calcium in the concrete.. Yadkin has made an attempt to wash down the troughs that
collect the seepage water and convey it to the sump, but proved unsuccessful in altering
the pH of the seepage water since it already has an elevated pH when it enters the
powerhouse through the cracks in the walls. Yadkin would like to request that the
Division of Water Quality consider alternative permitting requirements for this discharge
to allow the water to be discharged outside of the standard 6.0 — 9.0 limits in the current
permit.
We believe it is appropriate to allow a different upper pH limit for the discharge
containing this seepage water. The. Fact Sheet for North Carolina General Permit
NCG500000 acknowledged that water seeping through a dam should be treated
differently than other water discharged at such a facility. The Fact Sheet states at the end
of Item 6:
NOTE: Effluent Limitations and Monitoring Requirements do not apply to
exempt stormwater and dam seepage, as these are naturally occurring waters
not subject to control by the permittee. These two classes of wastewater do not
appear on the Effluent Limitations and Monitoring Requirements pages in the
General Permit.
P.O. Box 576 Badin, North Carolina 28009 USA

The water quality standard regulations found at Title 15A, Chapter 2, Subchapter 2B,
Section .0200, state the following:
.0211 FRESH SURFACE WATER QUALITY STANDARDS FOR CLASS C WATERS
(3) Quality standards applicable to all fresh surface waters:
(g) pH: shall be normal for the waters in the area, which generally shall range between 6.0 and 9.0
except that swamp waters may have a pH as low as 4.3 if it is the result of natural conditions;
As was described above, we believe that the "normal" pH of the seepage water into the
powerhouse can be higher than 9.0, due to the material it must flow through. This
condition of water seeping into the powerhouse will exist until the dam and powerhouse
are removed. As with dam seepage, there is no way to stop seepage into the powerhouse,
and this should be considered a "naturally occurring water" at a dam just as dam seepage
is under the general permit.
If you should have questions or comments regarding these matters, please don't hesitate
to contact me.
Very truly yours,
William L. McCaskill
Senior Environmental Specialist
Alcoa — Badin Works
Cc:email
B. A. Cox
G. J. Ott
B. J. Polk
S. H. Myers
J. A. Lease — PGH NAEHS
J. D. Morton — PGH NAEHS
M. A. Ross — PGH Legal
K. G. Hunsucker
2
P:IWINWORDIENVIRONIWATERIYADKINIFALLS PERMIT MOD REQUEST.DOC

Alcoa Inc.
2000 October 20
J
HONYb8 308110S 1NI0d
A1nYn0 831t'M - 21N30
1111 5Z 100 —1r
JU
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
919 North Main Street
Mooresville, North Carolina 28115
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
0214 6362
Attention: D. Rex Gleason, P.E.
RE. VIOLATION OF pII LIMIT - YADKIN FALLS DAM - NPDES PERMIT NO. NC0076775
Gentlemen:
ALCOA
As a follow-up to my phone conversation with Mr. Mike Parker of the Mooresville Regional Office on 2000
October 19, on behalf of Yadkin, Inc, Alcoa is providing the Division of Water Quality with this letter to
report a violation of the pH limit for Outfall 007. The problem was discovered during the initial round of
NPDES monitoring which was being conducted under the recently renewed Yadkin Falls NPDES permit
which became effective 7/1/00. At 9:23 on 10/19/00, a pH measurement of 9.4 pH units was recorded for
Outfall 007. The subsequent investigation has revealed that the source of the problem is attributable to water
seepage from the walls inside the Powerhouse which are leaching lime and calcium from the concrete and
mortar used in the construction of the walls of the building. The wall seepage is collected throughout the
Powerhouse in a system of small floor troughs which carry the low volume of alkaline seepage water to the
basement sump which then discharges the water through Outfall 007. In an effort to attempt to correct the
problem, Yadkin is planning on powerwashing the system of troughs and the sump to attempt to remove as
much of the calcium and lime residue as possible. Once this is completed, we will take additional pH
measurements to verify what effect this has on the situation. At this point, based on this new discovery
during the initial round of monitoring, and the fact that we are not sure how this approach will effect the
long term nature of the problem, we would ask that the agency realize that the nature of the problem may
require further discussion regarding this recently issued permit to assist us in determining what other
alternatives there may be for addressing the situation which currently exists.
Very Truly Yours,
L�c.�,145, -- (//V6 3 3-
William L. McCaskill
Senior Environmental Specialist
Alcoa - Badin Works
e:mail
B. A. Cox
S. H. Myers
B. J. Polk
J. D. Morton - PGH 19AB
K.G. Hunsucker
G. J. Ott
J. A. Lease
cc: Dave Goodrich — DWQ Raleigh
\\BAD—SERVICES\MCCASWL$\WINWORD\ENVIRON\WATER\N.C.DIVISION OF WATER QUALITY\FALLS PH
VIOLATION.DOC
P.O. Box 576 Badin, North Carolina 28009 USA

2000 November 16
N. C. Department of Environment and Natural Resources
Division of Water Quality
P. O. Box 29535
Raleigh, N. C. 27626-0535 CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Attention: T. Kerr Stevens 0214 5914
RE: PROPOSED PERMIT MODIFICATION - FALLS POWERHOUSE
NPDES PERMIT # NC 0076775
Gentlemen:
As a follow-up to recent conversations with Michael Myers regarding the recently
renewed NPDES permit for the referenced facility, Alcoa is submitting a request on
behalf of Yadkin, Inc. for the Division of Water Quality to consider modifying the
referenced permit to address a permit condition related to the pH limits for Outfall 007.
During the initial round of monitoring under the recently renewed permit, it was
discovered that the pH in the sump discharge (Outfall 007) was above the permitted limit
of 9.0 pH units. Further investigation has revealed that the alkalinity of the water is being
elevated as it seeps through the walls of the Powerhouse as a result of contact with lime
& calcium in the concrete.. Yadkin has made an attempt to wash down the troughs that
collect the seepage water and convey it to the sump, but proved unsuccessful in altering
the pH of the seepage water since it already has an elevated pH when it enters the
powerhouse through the cracks in the walls. Yadkin would like to request that the
Division of Water Quality consider alternative permitting requirements for this discharge
to allow the water to be discharged outside of the standard 6.0 — 9.0 limits in the current
permit.
We believe it is appropriate to allow a different upper pH limit for the discharge
containing this seepage water. The Fact Sheet for North Carolina General Permit
NCG500000 acknowledged that water seeping through a dam should be treated
differently than other water discharged at such a facility. The Fact Sheet states at the end
of Item 6:
NOTE: Effluent Limitations and Monitoring Requirements do not apply to
exempt stormwater and dam seepage, as these are naturally occurring waters
not subject to control by the permittee. These two classes of wastewater do not
appear on the Effluent Limitations and Monitoring Requirements pages in the
General Permit.

The water quality standard regulations found at Title 15A, Chapter 2, Subchapter 2B,
Section .0200, state the following:
.0211 FRESH SURFACE WATER QUALITY STANDARDS FOR CLASS C WATERS
(3) Quality standards applicable to all fresh surface waters:
(g) pH: shall be normal for the waters in the area, which generally shall range between 6.0 and 9.0
except that swamp waters may have a pH as low as 4.3 if it is the result of natural conditions;
As was described above, we believe that the "normal" pH of the seepage water into the
powerhouse can be higher than 9.0, due to the material it must flow through. This
condition of water seeping into the powerhouse will exist until the dam and powerhouse
are removed. As with dam seepage, there is no way to stop seepage into the powerhouse,
and this should be considered a "naturally occurring water" at a dam just as dam seepage
is under the general permit.
If you should have questions or comments regarding these matters, please don't hesitate
to contact me.
Very truly yours,
William L. McCaskill
Senior Environmental Specialist
Alcoa — Badin Works
�Cc:email
B. A. Cox
G. J. Ott
B. J. Polk
S. H. Myers
J. A. Lease — PGH NAEHS
J. D. Morton — PGH NAEHS
M. A. Ross — PGH Legal •
K. G. Hunsucker
2
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INTERNET FILES\CONTENT.OUTLOOK\INA1H4OM\FALLS PERMIT MOD REQUEST.DOC
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