NC0021156_SPECULATIVE LIMITS_19940408

NPDES DOCYNENT SCANNING COVER SHEET
NPDES Permit: NC0021156
Mount Holly WWTP
Document Type: Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Engineering Alternatives Analysis
201 Facilities Plan
Instream Assessment (67B)
Speculative Limits
Permit
History
Document Date: Aril 8, 1994
This dooumeat is printed oa rears paper-iSaore May
coateat oa the reverse side

State of North Carolina
Department of Environment,
Health and Natural Resources • •
Division of Environmental Management
James B. Hunt, Jr., Governor ��
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
April 8, 1994 ,,
Mr. C. Alexander Berkeley
WK Dickson
1924 Cleveland Avenue '
Charlotte, NC 28203
Subject: Potential Water Treatment Plant NPDES Permit 1!
City of Mt. Holly l;
Dear Mr. Berkeley:
The Permits and Engineering Unit has received your request for potential NPDES discharge
locations on behalf of the City of Mt. Holly. The NPDES discharge would consist of decant water from alum
sludge lagoons at the water treatment plant for the City.
Because Discharge Point No. 1 appears to be at an arm of Mountain Island Lake, optimal mixing
and assimilation may not occur. Discharge Point No. 2, as noted on the USGS map you submitted,
appears to be the most appropriate point. Please keep in mind that Discharge Point No. 2 appears to be at
an unnamed tributary to the Catawba River which has zero flow during design conditions (0.0 cfs 7010s).
Should limits for water treatment plants become more stringent in the future, location of the discharge to a
positive flow area(near the mouth of the tributary or most likely the Catawba River) may be beneficial.
Based on current policy, the following requirements would have to be met should an NPDES
permit be issued:
Parameter Monthly Avg/ Frequency Location
Daily Maximum
Flow monitor Weekly Effluent
(estimate)
TSS 30/45 mg/I Weekly Effluent
Settleable Solids 0.1/0.2 mVl Weekly Effluent
Turbidity Weekly Upstream,
Downstream
Iron monitor Weekly Effluent
Total Residual monitor Weekly Effluent
Chlorine
Aluminum monitor" Weekly Effluent
Chloride 250 mg/I (daily Weekly Effluent
maximum)
(Continued)
Pollution Prevention Pays
P.O. Box 29535,Raleigh,Nonh Carolina 27626-0535 Telephone [phone]
An Equal Opportunity Affirmative Action Employer

/ April 8, 1994
Mr. Alexander Berkeley
WK Dickson
The turbidity of the receiving water shall not exceed 50 NTU. If turbidity exceeds these levels due to
natural background conditions, the existing turbidity level cannot be increased.
All facilities that use alum flocculation.
The speculative limits provided here are for planning purposes only. If you have any questions
regarding this potential discharge, please call Susan A. Wilson at 919/733-5083.
Sincerely,
�s��/�WvgY • ���tir
��Coleen H. Sullins, Supervisor
U Permits and Engineering Unit
cc: Mooresville Regional Office
Instream Assessment-Unit;

State dt Norilh Carolina
j Department of Environment,
E Health and Natural Resources • •
? Division of Environmental Management r
James B. Hunt, Jr., Governor ���
Jonathan B. Howes, Secretary p E H N
A. Preston Howard, Jr., P.E., Director
February 15, 1994
Mr. Eddie Nichols
Public Works Director
Town of Mount Holly
PO. Box 406
Mount Holly, N.C. 28120
SUBJECT: Speculative Limits for Town of Mount Holly Expansion
NPDES Permit No. NCO021156
(WKD #94103.10 A)
Gaston County
Dear Mr. Nichols:
Your request for speculative effluent limits for the proposed expansion of the
Mount Holly WWTP to 6.0 MGD has been completed by the Technical Support Branch.
The speculative nature of this analysis must be emphasized because of its completion
without review or comments from the staff of our Mooresville Regional Office. In order to
receive final permit limits, a formal application will have to be submitted to the Division's
Permits and Engineering Unit.
It should also be noted that an expansion of more than 0.5 MGD for an existing
facility will require that an environmental document be prepared by the applicant. The
N.C. Environmental Policy Act and its associated rules require that an environmental
assessment (EA) and Fonsi (Finding of No Significant Impact) be prepared before the
permit for expansion is issued. If deemed appropriate, there is a possibility that an
environmental impact statement (EIS) might be necessary. Monica Swihart of the Water
Quality Planning Branch can provide further information regarding the EA requirement.
Based on available information, the tentative limits for conventional constituents
are:
Wasteflow (MGD) 6.0
BOD5 (mg/1) 15
NH3-N (mg/1) 4
DO(mg/1) 5
TSS (mg/1) 30
Fecal Coliform(#/100m1) 200
pH (SU) 6-9
Total Phosphorus (mg/1) 0.5
Total Nitrogen (mg/1) 4 (summer)
Total Nitrogen (mg/1) 8 (winter)
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/ 10%post-consumer paper

Letter to Eddie Nichols
- page 2 -
The BODS and NH3 limits were recommended using DEM's Best Professional
Judgment (BPJ) in an effort to help reduce the impact of point sources discharging directly
into the major lakes in the Catawba River Basin. With existing stages of eutrophication and
documented water quality problems in Lakes Wylie, Rhodhiss,Hickory and other tributary
arms above lakes, such as McDowell Creek, DEM does not recommend continuing with
the minimum level of wastewater treatment for direct discharges to lakes. Therefore, BPJ
limits will be applied to all new and expanding discharges to the Catawba chain lakes.
The effluent limits for Total Phosphorus (TP) and Total Nitrogen (TN) were
assigned based on recommendations from the Lake Wylie Management Plan. These
recommendations are needed to achieve necessary reductions in nutrients in the tributaries
to Lake Wylie and to ensure no future increase in nutrients. Upon expansion or major
modification, all existing discharges should be required to apply state-of-art nutrient
removal technology. A copy of the executive summary and recommendations from the
Lake Wylie report has been attached for your information.
In addition,under current Division of Environmental Management(DEM)
procedure, dechlorination and chlorine limits are now recommended for all new or
expanding dischargers proposing the use of chlorine for disinfection. An acceptable level
of chlorine in your effluent is 28 µgA to ensure protection against chronic toxicity. The
process of chlorination/dechlorination or an alternate form of disinfection, such as
ultraviolet radiation, should allow the facility to comply with the total residual chlorine
limit.
The instream waste concentration at 6.0 MGD is 9%. A chronic toxicity testing
requirement with quarterly monitoring will remain a condition of the NPDES permit A
complete evaluation of limits and monitoring requirements for metals and other toxicants
will have to be addressed at the time of formal NPDES application. Information
concerning these constituents is not readily available but the Town can assume that effluent
monitoring for cadmium, chromium, copper, nickel, lead, zinc, cyanide, phenols, chloride,
fluoride, and 1,1,2 trichloroethane will continue..
DEM is planning a basinwide water quality management initiative. Our schedule
for implementation in the Catawba River Basin is set for 1995. The plan will attempt to
address all sources of point and nonpoint pollutants where deemed necessary to protect or
restore water quality standards. In addressing interaction of sources, wasteload allocations
may be affected. Those facilities that already have committed to high levels of treatment
technology are least likely to be affected.

Letter to Eddie Nichols
- page 3 -
This information should provide some assistance in your planning endeavors. As
previously mentioned, final NPDES effluent limitations will be determined after a formal
permit application has been submitted to the Division. If there are any additional questions
concerning this matter,please feel free to contact Ruth Swanek or Jackie Nowell of my
staff at [phone].
S cerely,
k
Donald L. Sa4fb�r
Assistant Chilical Support
Attachment
DLS/JMW
cc: Steve Tedder
Rex Gleason
Coleen Sullins
M. L. Wolfe, WK Dickson
Central Files

EXECUTIVE SUMMARY
In response to public concerns about the proliferation of waste water discharges to Lake
Wylie and perceived threats to use of the lake for recreation and as a drinking water supply,
North Carolina and South Carolina entered into a joint study to evaluate water quality in
Lake Wylie. The objectives of this study were to evaluate the assimilative capacity of the
lake, identify nutrient loading patterns in the watershed, and to determine what control
strategies would be most effective in protecting the lake as a water resource. The study
consisted of an analysis of physical, chemical, and biological data collected in 1989 and
1990 as well as a modeling analysis of eutrophication response.
Results of the physical and chemical survey of Lake Wylie indicate that the lake is
threatened by eutrophic conditions, especially in the embayments. The tributary arms and
embayments consistently demonstrate problematic biological response to nutrient loading.
The South Fork Catawba River is the major source of nutrient loading to Lake Wylie and is
high in nutrients and solids. The Catawba Creek arm of the lake, in particular, consistently
exhibits eutrophic conditions. Both Catawba Creek and Crowders Creek have experienced
elevated nutrient concentrations, algal blooms, and violations of the North Carolina
chlorophyll-a water quality standard.
Allison Creek has also shown signs of eutrophication, yet not to the extent as the South
Fork Catawba River, Catawba Creek, or Crowders Creek. However, chlorophyll-a values
as high as 40 ugA were measured, and elevated phytoplankton communities were
i
documented. i
Results of the modeling analysis indicate that control of both point and non-point
sources will be required to control nutrient loading to Lake Wylie. The eutrophic arms of
Lake Wylie are presently nitrogen limited during the algal growing season due to existing
phosphorus loads from point and non-point sources. Point sources are the dominant
source of nutrients in the Catawba Creek and Crowders Creek watersheds. Point and non-
point sources are both important sources of nutrient loading to the South Fork Catawba
River. j
Although numerous point sources discharge into the Catawba River basin upstream of
Lake Wylie, nutrient entrapment in upstream reservoirs prevent a large influx of nutrients
from the Catawba River. However, inputs from the South Fork Catawba River, Catawba
Creek, and Crowders Creek result in a high concentration of nutrients in Lake Wylie.
Phytoplankton populations reached levels of concern in response to nutrient availability
during both wet (1989) and dry (1990) years. Direct discharge of treated wastewater to the
mainstem without nutrient controls was predicted to raise chlorophyll-a concentrations in
iii

the lake. However, model results suggest that with state of the art nutrient removal, a
significant amount of wastewater could be added without causing chlorophyll-a violations
if phosphorus loadings are minimized through the use of best available technologies.
From the results of this study management recommendations were developed. These
recommendations were designed to reduce nutrient loading to the eutrophic arms of Lake
Wylie and prevent further eutrophication of the lake mainstem.
iv

• I
RECOMMENDATIONS
In order to control nutrient loading in Lake Wylie and its major tributaries, both point
and non-point source controls should be implemented. The following recommendations
are needed to achieve necessary reductions in nutrients in the nutrient rich tributaries to
Lake Wylie and to ensure no future increase in nutrients to Lake Wylie.
Point Sources
i
To prevent further nutrient enrichment of Lake Wylie the following recommendations
are made for point source discharges to Lake Wylie and its tributaries including the
Catawba River and its tributaries below Mountain Island Dam and the South Fork Catawba .
River below its confluence with Long Creek:
i
• No new discharges should be allowed to the lake mainstem or its tributaries,
unless an evaluation of engineering alternatives shows that it is the most
environmentally sound alternative. Any new discharges that meet this
requirement should be required to apply state-of-art nutrient removal
technology. At present, this would mean meeting limits of 0.5 mg/I total
phosphorus and 4 mg/1 summer, 8 mg/l winter total nitrogen.
• Existing discharges to the lake mainstem and tributaries should be encouraged
to be removed when alternatives become available. Programs such as the
CMUD sewer line extension project should continue to be supported.
• Upon expansion or major modification, all existing discharges should be
required to apply state-of-art nutrient removal technology. In addition, no
expansion should be allowed that increases the total nutrient load from the
facility, unless an evaluation of engineering alternatives shows that it is the
most environmentally sound alternative.
To reduce nutrient enrichment in the three eutrophic arms of Lake Wylie, additional
recommendations are made for point source discharges to the Catawba Creek and
Crowders Creek watershed as well as the South Fork Catawba watershed below its
confluence with Long Creek.
• All existing surface water discharges in these watersheds with a permitted
design flow of>0.05 MGD should be required to apply state-of-art nutrient
removal technology. Existing facilities should be allowed a five year time
frame with which to come into compliance.
• Incentives should be established to encourage the privately owned facilities to
be on to larger municipal WWTPs which have a greater resource base to draw
on in order to consistently operate the state-of-art treatment facilities required to
protect water quality in the above listed sensitive areas.
v

sr
Non point sources
All tributaries to Lake Wylie should be targeted by the Division of Soil and Water for
cost share funds for use in implementation of best management practices (BMPs). When
possible, resources should be targeted toward implementation of BMPs in the Catawba .
Creek, Crowders Creek, and the South Fork Catawba River watersheds since a significant
amount of the nutrients reaching these streams is from non-point sources. Since the South
Fork Catawba River provides by far the largest nutrient load of any tributary to Lake
Wylie, the South Fork should be considered the highest priority for implementation of best
management practices.
vi

i
WK
DICKSON
November 15, 1993
C
N. C. Department of Environment, fi
Health and Natural Resources
Engineers Management Division of Environmental Managt
J
Planners P. O. Box 29535
Surveyors Raleigh, North Carolina 27626-0535 / $�9 7 1993
Attention: Mr. Donald L. Safrit, P.E. ��5
Environmental Supervisor l 0
Water Quality Section i 4i
Re: City of Mount Holly, Gaston County -O���ct leF cv fD mt, �I�
Permit # NC0021156 Jf JG le
WKD #94103.10 A d CC
roF baLk rD, a A)h2le Well
Gentlemen: reL1551 Yl
5 a�-J', 121,30
We are requesting "speculative" effluent limits for the subject'permit to enable
evaluation of the wastewater treatment plant for expansion. The current
discharge point is into the Catawba River at a point about 1 .8 miles upstream
of the Interstate-85 crossing of the Catawba River (see enclosed map). The
latitude-longitude of the discharge is N35-16-54 x E81-00-34. We would like to
know what limits might apply for a discharge of 6.0 MGD at this location.
Sincerely,
W. K. DICKSON & CO., INC.
M. L. offe
MW/dm
Enclosure
1924 Cleveland Avenue Other Offices:
Charlotte,North Carolina 28203 Asheville,NC
704 334-5348 Raleigh,NC
FAX [phone] Columbia,SC

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MOUNT HOLLY, N. C.
QUADRANGLE LOCATION SE/4 GASTONIA 15' QUADRANGLE
N3515—W8100/7.5
1970
AMS 4754 1 SE—SERIES V842 '

02/05/94 ver 3 . 1 T 0 X I C S R
Facility: MT . HOLLY WWTP
NPDES Permit No . : NC0021156
Status (E, P, or M) : M
Permitted Flow: 6 . 0 mgd
Actual Average Flow: 2 . 7 mgd
Subbasin : 1030833
Receiving Stream: CATAWBA RIVER I ---------PRETREATMENT DATA
Stream Classification: WS-III I ACTUAL
7Q10 : 95 . 0 cfs I Ind. +
IWC: 8 . 92 % Domestic PERMIT
Stn' d / Bkg I Removal Domestic Act . Ind. Total Indust
Pollutant AL Conc. I Eff. Load Load Load Loa
(ug/1) (ug/1) I % (#/d) (#/d) (#/d) (#/d
--------- -- -------- -------- -------- -------- -------- -------- ------
Cadmium S 2 . 0 0%
Chromium S 50 . 0 I 0%
Copper AL 7 . 0 I 0%
Nickel S 25 . 0 I 0%
Lead S 25 . 0 i 0%
Zinc AL 50 . 0 I 0%
Cyanide S 5 . 0 0%
Mercury S 0 . 012 0%
Silver AL 0 . 06 0%
Selenium S 5 . 00 0%
Arsenic S 50 . 00 0%
Phenols S 1 . 0 0 . 0
NH3-N C 0%
T .R.Chlor .AL 17 . 0 0%
I
I
I
I --------------- ALLOWABLE PRDCT' D PRDCT' D PRDCT' D -------
I Effluent Effluent Effluent Instream
I Conc. using using Conc. Based
I Allowable CHRONIC ACTUAL PERMIT using ACTU
Pollutant I Load Criteria Influent Influent OBSERVED Influ
I (#/d) (ug/1) (ug/1) (ug/1) (ug/1) Loadi
--------- -- --------- -------- --------- -------- -------- -----
Cadmium S 1 . 07 22 . 430 0 . 000 0 . 000 0 . 00
Chromium S I 26 . 71 560 . 753 0 . 000 0 . 000 3 .57
Copper AL I 3 . 74 78 . 505 0 . 000 0 . 000 2 . 67
Nickel S I 13 . 36 280 . 376 0 . 000 0 . 000 4 . 46
Lead S I 13 . 36 280 . 376 0 . 000 0 . 000 0 . 00
Zinc AL I 26. 71 560 . 753 0 . 000 0 . 000 13 . 46
Cyanide S I 2 . 67 56. 075 0 . 000 0 . 000 0 . 00
Mercury S I 0 . 01 0 . 135 0 . 000 0 . 000 0 . 00
Silver AL I 0 . 03 0 . 673 0 . 000 0 . 000 0 . 00
Selenium S 2 . 67 56 . 075 0 . 000 0 . 000 0 . 00
Arsenic S 26 . 71 560 . 753 0 . 000 0 . 000 0 . 00
Phenols S 0 . 53 11 . 215 0 . 000 0 . 000 17 . 83
NH3-N C I 0 . 000 0 . 00
T .R.Chlor.AL I 190 . 656 0 . 00
I
I
I

MT. HOLLY WWTP
Residual Chlorine Ammonia as NH3
(summer)
7Q10(CFS) 95 7010(CFS) 95
DESIGN FLOW(MGD) 6 DESIGN FLOW(MGD) 6
DESIGN FLOW(CFS) 9.3 DESIGN FLOW(CFS) 9.3
STREAM STD(UG/L) 17.0 STREAM STD(MG/L) 2.0
UPS BACKGROUND LEVEL(UG/L) 0 UPS BACKGROUND LEVEL(MG/L) 0.22
IWC (/) 8.92 IWC(%) 8.92
Allowable Concentration (ug/I) 190.66 Allowable Concentration(mgll) 20.18
Ammonia as NH3
(winter)
7010(CFS) 95
Fecal Limit 200/100m1 DESIGN FLOW(MGD) 6
Ratio of 10.2:1 DESIGN FLOW(CFS) 9.3
STREAM STD(MG/L) 4.0
UPS BACKGROUND LEVEL(MG/L) 0.22
IWC(%) 8.92
Allowable Concentration(mg/1) 42.61
NC0021156 2/4/94

S,• State of North Carolina
Department of Environment,
Health and Natural Resources IT •
Division of Environmental Management 4
A& rr
James B. Hunt, Jr., Governor ±gmg
Jonathan B. Howes, Secretary p E H N F 1
A. Preston Howard, Jr., P.E., Director
February 15, 1994 f
Mr. Eddie Nichols
Public Works Director
Town of Mount Holly
PO. Box 406
Mount Holly, N.C. 28120 .- t�4
SUBJECT: Speculative Limits for Town of Mount Holly Expansion ?,;
NPDES Permit No. NCO021156
(WKD #94103.10 A) �'•�
Gaston County R 3 r '
0
Dear Mr. Nichols:
Your request for speculative effluent limits for the proposed expansion of the
Mount Holly WWTP to 6.0 MGD has been completed by the Technical Support Branch.
The speculative nature of this analysis must be emphasized because of its completion
without review or comments from the staff of our Mooresville Regional Office. In order to
receive final pemvt limits, a formal application will have to be submitted to the Division's
Permits and Engineering Unit.
It should also be noted that an expansion of more than 0.5 MGD for an existing
facility will require that an environmental document be prepared by the applicant. The
N.C. Environmental Policy Act and its associated rules require that an environmental
assessment (EA) and Fonsi(Finding of No Significant Impact) be prepared before the
permit for expansion is issued. If deemed appropriate,there is a possibility that an
environmental impact statement (EIS) might be necessary. Monica Swihart of the Water
Quality Planning Branch can provide further information regarding the EA requirement.
Based on available information, the tentative limits for conventional constituents
are:
Wasteflow (MGD) 6.0
BOD5 (mg/1) 15
NH3-N (mg/1) 4
DO(mg/1) 5
TSS (mg/1) 30
Fecal Coliform (#/100ml) 200
pH_(SU) 6-9
Total Phosphorus (mg/1) 0.5
Total Nitrogen (mg/1) 4 (summer)
Total Nitrogen (mg/1) 8 (winter)
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50%recycled/ 10%post-consumer paper

I
Letter to Eddie Nichols
- page 2 -
The BOD5 and NH3 limits were recommended using DEM's Best Professional
Judgment (BPJ) in an effort to help reduce the impact of point sources discharging directly
into the major lakes in the Catawba River Basin. With existing stages of eutrophication and
documented water quality problems in Lakes Wylie, Rhodhiss,Hickory and other tributary
arms above lakes, such as McDowell Creek,DEM does not recommend continuing with
the minimum level of wastewater treatment for direct discharges to lakes. Therefore, BPJ
limits will be applied to all new and expanding discharges to the Catawba chain lakes.
The effluent limits for Total Phosphorus ('17P) and Total Nitrogen (TN) were
assigned based on recommendations from the Lake Wylie Management Plan. These
recommendations are needed to achieve necessary reductions in nutrients in the tributaries
to Lake Wylie and to ensure no future increase in nutrients. Upon expansion or major
modification, all existing discharges should be required to apply state-of-art nutrient
removal technology. A copy of the executive summary and recommendations from the
Lake Wylie report has been attached for your information.
In addition, under current Division of Environmental Management (DEM)
procedure,dechlorination and chlorine limits are now recommended for all new or
expanding dischargers proposing the use of chlorine for disinfection. An acceptable level
of chlorine in your effluent is 28 µg/l to ensure protection against chronic toxicity. The
process of chlorination/dechlorination or an alternate form of disinfection, such as
ultraviolet radiation, should allow the facility to comply with the total residual chlorine
limit.
The instream waste concentration at 6.0 MGD is 9%. A chronic toxicity testing
requirement with quarterly monitoring will remain a condition of the NPDES permit. A
complete evaluation of limits and monitoring requirements for metals and other toxicants
will have to be addressed at the time of formal NPDES application. Information
concerning these constituents is not readily available but the Town can assume that effluent
monitoring for cadmium, chromium, copper, nickel, lead, zinc, cyanide,phenols, chloride,
fluoride, and 1,1,2 trichloroethane will continue..
DEM is planning a basinwide water quality management initiative. Our schedule
for implementation in the Catawba River Basin is set for 1995. The plan will attempt to
address all sources of point and nonpoint pollutants where deemed necessary to protect or
restore water quality standards. In addressing interaction of sources, wasteload allocations
may be affected. Those facilities that already have committed to high levels of treatment
technology are least likely to be affected.

,
Letter to Eddie Nichols
- page 3 -
This information should provide some assistance in your planning endeavors. As
previously mentioned, final NPDES effluent limitations will be determined after a formal
permit application has been submitted to the Division. If there are any additional questions
concerning this matter,please feel free to contact Ruth Swanek or Jackie Nowell of my
staff at [phone].
acc
rely,
d L. Safrit, P. .
Assistant Chief for Tec ical Support
Attachment
DLS/JMN
cc: Steve Tedder
Rex Gleason
CColeen Su1Gns--2
M. L. Wolfe, WK Dickson
Central Files
�r
:v c.=
z
y

i
I
EXECUTIVE SUMMARY
In response to public concerns about the proliferation of waste water discharges to Lake
Wylie and perceived threats to use of the lake for recreation and as a drinking water supply,
North Carolina and South Carolina entered into a joint study to evaluate water quality in
Lake Wylie. The objectives of this study were to evaluate the assimilative capacity of the
lake, identify nutrient loading patterns in the watershed, and to determine what control
strategies would be most effective in protecting the lake as a water resource. The study
consisted of an analysis of physical, chemical, and biological data collected in 1989 and
1990 as well as a modeling analysis of eutrophication response.
Results of the physical and chemical survey of Lake Wylie indicate that the lake is
threatened by eurrophic conditions, especially in the embayments. The tributary arms and
embayments consistently demonstrate problematic biological response to nutrient loading.
The South Fork Catawba River is the major source of nutrient loading to Lake Wylie and is
high in nutrients and solids. The Catawba Creek arm of the lake, in particular, consistently
exhibits eutrophic conditions. Both Catawba Creek and Crowders Creek have experienced
elevated nutrient concentrations, algal blooms, and violations of the North Carolina
chlorophyll-a water quality standard.
Allison Creek has also shown signs of eutrophication, yet not to the extent as the South
Fork Catawba River, Catawba Creek, or Crowders Creek. However, chlorophyll-a values
as high as 40 ug/ were measured, and elevated phytoplankton communities were
documented.
Results of the modeling analysis indicate that control of both point and non-point
sources will be required to control nutrient loading to Lake Wylie. The eutrophic arms of
Lake Wylie are presently nitrogen limited during the algal growing season due to existing
phosphorus loads from point and non-point sources. Point sources are the dominant
source of nutrients in the Catawba Creek and Crowders Creek watersheds. Point and non-
point sources are both important sources of nutrient loading to the South Fork Catawba
River.
Although numerous point sources discharge into the Catawba River basin upstream of
Lake Wylie, nutrient entrapment in upstream reservoirs prevent a large influx of nutrients
from the Catawba River. However, inputs from the South Fork Catawba River, Catawba
Creek, and Crowders Creek result in a high concentration of nutrients in Lake Wylie.
Phytoplankton populations reached levels of concern in response to nutrient availability
during both wet (1989) and dry (1990) years. Direct discharge of treated wastewater to the
mainstem without nutrient controls was predicted to raise chlorophyll-a concentrations in
iii

the lake. However, model results suggest that with state of the art nutrient removal, a
significant amount of wastewater could be added without causing chlorophyll-a violations
if phosphorus loadings are minimized through the use of best available technologies.
From the results of this study management recommendations were developed. These
recommendations were designed to reduce nutrient loading to the eutrophic arms of Lake
Wylie and prevent further eutrophication of the lake mainstem.
iv

RECOMMENDATIONS
In order to control nutrient loading in Lake Wylie and its major tributaries, both point
and non-point source controls should be implemented. The following recommendations
are needed to achieve necessary reductions in nutrients in the nutrient rich tributaries to
Lake Wylie and to ensure no future increase in nutrients to Lake Wylie.
Point Sources
To prevent further nutrient enrichment of Lake Wylie the following recommendations
are made for point source discharges to Lake Wylie and its tributaries including the
Catawba River and its tributaries below Mountain Island Dam and the South Fork Catawba
River below its confluence with Long Creek:
• No new discharges should be allowed to the lake mainstem or its tributaries,
unless an evaluation of engineering alternatives shows that it is the most
environmentally sound alternative. Any new discharges that meet this
requirement should be required to apply state-of-art nutrient removal
technology. At present, this would mean meeting limits of 0.5 mg/1 total
phosphorus and 4 mg/l summer, 8 mg/1 winter total nitrogen.
• Existing discharges to the lake mainstem and tributaries should be encouraged
to be removed when alternatives become available. Programs such as the
CMUD sewer line extension project should continue to be supported.
• Upon expansion or major modification, all existing discharges should be
required to apply state-of-art nutrient removal technology. In addition, no
expansion should be allowed that increases the total nutrient load from the
facility, unless an evaluation of engineering alternatives shows that it is the
most environmentally sound alternative.
To reduce nutrient enrichment in the three eutrophic arms of Lake Wylie, additional
recommendations are made for point source discharges to the Catawba Creek and
Crowders Creek watershed as well as the South Fork Catawba watershed below its
confluence with Long Creek.
• All existing surface water discharges in these watersheds with a permitted
design flow of> 0.05 MGD should be required to apply state-of-art nutrient
removal technology. Existing facilities should be allowed a five year time
frame with which to come into compliance.
• Incentives should be established to encourage the privately owned facilities to
tie on to larger municipal WWTPs which have a greater resource base to draw
on in order to consistently operate the state-of-art treatment facilities required to
protect water quality in the above listed sensitive areas.
v

� Y
N n point Sources
All tributaries to Lake Wylie should be targeted by the Division of Soil and Water for
cost share funds for use in implementation of best management practices (BMPs). When -
possible, resources should be targeted toward implementation of BMPs in the Catawba
Creek, Crowders Creek, and the South Fork Catawba River watersheds since a significant
amount of the nutrients reaching these streams is from non-point sources. Since the South
Fork Catawba River provides by far the largest nutrient load of any tributary to Lake
Wylie, the South Fork should be considered the highest priority for implementation of best
management practices.
vi

W� United States Department of the. Interior NAWCA= .
° GEOLOGICAL SURVEY
_ y ■
WATER RESOURCES DIVISION -
Post Office Box 30728
Raleigh, North Carolina 27622
February 2, 1993
Mr. J. Paige Straley
Corporate Environmental Manager
Sandoz chemicals Corporation
P.O. Box 669246
Charlotte, North Carolina 28266
Dear Mr. Straley: .
In response to your September 8, 1992, request for low-flow data for the Catawba River
at North Carolina Highway 27, I have enclosed an estimate of the 30-day, 2-year low
flow computed from the Duke Power Company Mountain Island Lake discharge data (1977-
1992) which you provided with your letter of December 7, 1992 . The estimate is adjusted
for intervening drainage.
In addition to the normal variations caused by weather, the estimation of low flows on
regulated streams is highly dependent on regulatory patterns and reservoir operations.
The enclosed estimate is developed from the most recent 16 years of discharge data and
reflects reservoir operations from that period. No level of accuracy is assigned to the
computed statistic.
The U.S. Geological Survey provides timely water-resources information and data through
a variety of scientific and technical publications and data reports. For many years,
the Survey also has processed special requests for water-resources information free of
charge. Because of the increase in volume of special requests along with budget
reductions imposed by the Gramm-Rudman-Hollings Budget Deficit Reduction Act, the
Survey will no longer be able to process special requests free of charge.
A charge for accessing and processing information has been assessed to partially offset
these costs. Your requested data and an invoice covering processing costs for these
data are attached. Please forward the original bill with your check to the U.S.
Geological Survey, MS 271, 12201 Sunrise Valley Drive; Reston, Virginia 22092.
-212

data are preliminary and subject to revision pending approval for
• ication by the Director of the U.S. Geological Survey, and are made
.1able._through_:our ..cooperative program of water resources, investigations
,ith the North Carolina Department of Environment, Health, andNatural -
Resources'.
If you have any questions regarding this information, please contact us.
Sincerely,
aob ert R. Mason, Jr.
Hydrologist
Enclosures
Copies to: Mr. John N. Morris, Director
Division of Water Resources
North Carolina Department of
Environment, Health, and
Natural Resources ,
Raleigh, NC
Mr. Steve Bevington
Division of Environmental Management
North Carolina Department of
Environment, Health, and
Natural Resources
Raleigh, NC
A.E. Fogleman, WRD
Raleigh, NC

J i
• QUEST-INDUSTRYS SITE NO: 1ACTION: EXISTING2/ 9/93
SOURCE:
STATION NUMBER: 0214280800 TYPE STATION: 20
STATION NAME: CATAWBA R AT NC 27 AT MT HOLLY, NC
i LOCATION: AT NC 27 AND 0 . 6 MI E OF MT HOLLY, NC
LATITUDE: 351752 LONGITUDE: 810014
QUADRANGLE NUMBER: F14SE
COUNTY CODE: 071 STATE CODE: 37 DISTRICT CODE: 37
HYDROLOGIC UNIT CODE: 03050101 NRCD BASIN CODE: 030633
DRAINAGE AREA: 2003.00 SQ" MI
AVERAGE FLOW: [ ]
7Q10 MIN FLOW: [ ]
(SUMMER)
30Q2 MIN FLOW: 716. [A]
7Q10 MIN FLOW: [ ]
(WINTER)
7Q2 MIN FLOW: [ ]
NOTES:
[A] Estimate is based on records collected at or near the site.
[B] Estimate is based entirely on runoff observed at nearby streams .
[C] Estimate based on procedures given in Open-File Report 90-399
"Low-Flow Characteristics of Streams. In North Carolina"
[D] Estimate based on procedures given in Open-File Report 90-399 and
in conjuction with records collected at or near the site.
***** These data are provisional pending approval by the Director,USGS ******
REMARKS:
f REQUESTOR--SANDOZ CHEMICAL CORPORATION
Entered by: AF
Fee charged: 125
I