NC0026000_Speculative Limits_19950712

NPDES DOCUMENT SCANNING COVER SHEET
NC0026000
Tabor City WWTP
NPDES Permit:
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Owner Name Change
Instream Assessment (67b)
Speculative Limits`i
Environmental Assessment (EA)
Document Date:
July 12, 1995
This documezit is prizited ooni reuse paper - igziore any
contest ozz the reirerse 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
Al J. Leonard, Jr.
Post Office Box 655
Tabor City, North Carolina 28463
Subject:
July 12, 1995
Tabor City Waste Water Treatment Plant
NC0026000 Subbasin: 03-07-57
Columbus County
Dear Mr. Leonard:
L7EHNf=1.
I am writing in response to your letter of June 9, 1995 requesting speculative limits for a proposed
relocation of the Tabor City wastewater treatment plant to "approximately 1,100 feet to the east for
direct discharge to Grissett Swamp". The recommendations made in this letter reflect
management strategies outlined in the Lumber River Basinwide Water Quality Management Plan
as well as estimates made about the low flow statistics for the proposed relocation site.
The Lumber River management strategy recommends limits of 5.0 mg/I BOD5 and 2.0 mg/I NH3N,
(summer limits) for new discharges and existing loading for expansions. Since your facility is
already limited at levels of 5.0 mg/I BOD5 and 2.0 mg/I NH3N, (summer limits), no changes would
be recommended with this relocation.
Another aspect of this proposed relocation was the possible change in 7Q10 statistics. This
discharge is located in a hydrologic area that makes flows difficult to ascertain. The USGS has
prepared an open report, (90-399) with which to make flow determinations following specific
protocol. Upon review of this document, it was determined that the low flow statistics in Grissett
Swamp will remain at s7Q10 = 0 cfs. Therefore, the instream waste concentration from this
discharge would still dominate the stream and the Whole Effluent Toxicity Test will remain at 90%.
Finally, current ratings for Grissett Swamp indicate a support -threaten condition. Benthic
rnacroinvertebrate data collected downstream from the Tabor City discharge indicated poor water
quality, while fish community ratings indicate good water quality. The mechanism(s) for
determining these ratings are under review for swamp waters, therefore the rating could change in
the future. It should be noted that the current discharge location to Town Canal is also classified
as swamp waters.
In light of the above discussion, the relocation of the effluent pipe for this discharge would have
rao effect on the current limits and thus, in our opinion, relocation would serve no beneficial
purpose. If there are any additional questions concerning this matter, please feel free td
contact Farrell Keough (ext. 510) or me (ext. 519) at [phone].
ncerely,
onald
Assistant
Water Quality Section
cc: Dave Goodrich, NPDES Permits Group
Steven West, Wilmington Regional Office
Central Files
hnical Support
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

Request #
Facility Name: Tabor City Waste Water Treatment Plant
NPDES No.: NC0026000
Type of Waste: 100 % Domestic
Facility Status: proposed relocation
Permit Status: existing Stream Characteristic;
Receiving Stream: Town Canal [ ut Grissett Swamp ] USGS #
Stream Classification: C - Swamp Date:
Subbasin: 03-07-57 Drainage Area (mi2): 1.0 11.55
County: Columbus Summer 7Q10 (cfs): 0.0 refer below
Regional Office: Wilmington Winter 7Q10 (cfs): 0.0 n/a
Requestor: Average Flow (cfs): 1.0 n/a
Date of Request: 9 June, 1995 letter 30Q2 (cfs): 0.0 n/a
Topo Quad: K23NE IWC (%): 100 % 88.6 %
Notes for Proposed Relocation
Flows
A drainage area was established by USGS upstream of this discharge, (02.1097.5700) but unfortunately we have no record of
any flows which might have accompanied it. To facilitate this lack of information, we, (Steve Bevington and I) were able to
determine an approximation for the s7Q10 and whether any change in IWC would take place with this relocation.
To determine the highest possible s7Q10 we used the chart on Plate 1 of the USGS Open Report. The proposed discharge is
in an Hydrologic Area 41 and the minimum required drainage area for a positive s7Q10 is 35 mi2; therefore this proposed site
is only 1/3 of the minimum required area. Unfortunately, the language on this report is not definitive, saying that "generally"
drainage areas less than this are zero flow. To substantiate this better, we used the conversion factors to determine what the
possible s7Q10 might be.
We chose to use the "maximum" conversion factor, (0.019) to compare whether this relocation would make any difference in
the IWC for this facility - the management strategy would require that the Tabor WWTP would remain limited at 5 / 2, therefore
the only possible change in limits would be the toxicity test percentage -
Thus, the new drainage area, 11.55 mi2 would be multiplied times the conversion factor of 0.019 yielding a "maximum" s7Q10
of 0.21945 cfs. Using this flow and a discharge of 1,1 mgd, an IWC of 88.6% was determined. Since the previous toxicity test
was at 90%, (i.e. 100% IWC) this proposed relocation would not substantially decrease the percentage of effluent tested.
Therefore no changes in limits would be implemented by this proposed relocation.
It should be noted that using the "maximum" conversion factor for determining a flow is not standard USGS procedure and
was used for comparison purposes only !
Lake Tabor (upstream) has nutrient problems 4.6.3
Grissett Swamp at SR 1141 had fish tissue sample in April, 1992: NCIBI rating was GOOD (52). Metals sampling of one fish
species with all results lower than FDA criteria.
Grissett Swamp offers another example of the difficulty of assessing the ecological integrity of a swamp environment. Swamp
waters are being assessed using techniques applied to Piedmont and mountain streams. Grissett Swamp received a Poor
biological index rating in 1991, but that rating was discounted because of the low stream flow conditions in the swamp. In
1992, a Good fish community rating was determined. The stream received an overall use support rating of support -threatened
(not impaired). The problems of applying the biotic index used in other fresh waters to swamp waters has been under review
by DEM for the past two years. Once this study has been completed, use of a macrobenthic sampling index that has been
fine-tuned to swamp conditions should provide more appropriate and useful information when evaluating swamps in the future.
6.2.1 (p 6 - 4 )
Waccamaw River Watershed - subbasins 03-07-56 throuoh 03-07-58
Expansions: Increased flows allowed; waste loads to be maintained at existing permitted levels (mass basis).
New Facilities: All facilities recommended to receive 5 mg/I BOD5 and 2 mg/I NH3N.

Subbasin 03-07-57 (Lower Waccamaw River - Waccamaw River Watershed)
This drainage area delineates the lower Waccamaw River watershed excluding the White Marsh drainage area. There are five
discharges in this subbasin: one municipality, one resort, and three schools. No clusters of discharges exist in this subbasin, and there
would seem to be no chance of regionalization in the near future because of the somewhat isolated location of the non -municipal
discharges.
Tabor City WWTP discharges to Town Canal which is a tributary to Grissett Swamp. Benthic macroinvertebrate data collected
downstream from this discharge indicated poor water quality. However, it is unlikely that Tabor City is contributing to significant
degradation to the water quality at this site given that these results are less reliable in swampy areas, and the diffusive nature of the
receiving stream should buffer effects from this point source. Nevertheless, future WLA analyses for the Town of Tabor City should
concentrate on toxicants in the discharge. This subbasin will also benefit from the results of the study DEM is conducting on discharges
to swampy systems.

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
June 13, 1995
Mr. Charles W. Davis, EIT
Hobbs, Upchurch & Associates, P.A.
P.O. Box 1737
Southern Pines, NC 28388
Subject: Request for Speculative Limits
Town of Tabor City
NPDES No. NC0026000
Dear Mr. Davis:
ArVA
1:-.)EHNFl
The Technical Support Branch received your request for speculative limits for the Tabor
City WWTP on June 13. The project has been assigned to Farrell Keough for review. It
normally takes approximately thirty days for the modeler to review the available water
quality information and draft a response.
If you have any questions or comments, please contact Farrell (ext. 510) or me (ext 503) at
[phone].
Sincerely,
2a±L c &cuedt
Ruth C. Swanek, Supervisor
Instream Assessment Unit
cc: Wilmington Regional Office
AL J. LWAJA12-8 Je •
Pont 05fic box 655
-Trilm Ur', NC- 7-E463
Oil) 653- 695w
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

• L04-. -) CupoiRec "rl/!/�Iia 'r oa3nr5 •6• 3
1 pa,EL, i%`iZ NGI81 : Good CS2) MG-h b 6**v Is
P ' CO6L) n tc �oLj (� +644 ; o
A p
G2�t�

Hobbs, Upchurch & Associates, P.A.
Consulting Engineers
290 S.W. Broad Street • Post Office Box 1737 • Southern Pines, NC 28388
June 9, 1995
Ms. Ruth Swanek
Division of Environmental Management
Water Quality Section
P_O. Box 2.9535
Raleigh, NC 27626-0535
RE: Tabor City Wastewater Treatment Plant Improvements
HUA No. TC9403
Dear Ms. Swanek:
:SUN 1 2
e.
jolt 6%
'Q\G-v\ W�9,VL
DJ-
V- b—
Our firm is designing a facility upgrade for the Tabor City wastewater treatment plant. The
Town currently discharges to a canal which ultimately discharges to Grissett Swamp. We
want to determine if the effluent limitations would change by relocating the discharge point
approximately 1,100 feet to the east for direct discharge to Grissett Swamp. Please see the
enclosed quadrangle sheet showing the proposed discharge location.
I would appreciate it if you would provide me with speculative limits for the upgraded plant
according to the information listed below.
D3- 3 r"5 t
1. NPDES Permit No. NC0026000 Ta�^��3A!
2. Flow will remain at 1.0 MGD.
3. Tertiary filtration is being considered.
ckle2iU0.4,v1 Mc-•Iat021NOION 3GivJ1t(
4. Either dechlorination or U.V. disinfection shall be added. L� ��.o ,,i/o
If you need any additional information, please contact me at our Southern Pines office.
Sincerely,
HOBBS, UPCHURCH & ASSOCIATES, P.A.
Charles W. Davis, E.I.T.
Southern Pines, NC
Winston-Salem, NC
Myrtle Beach, SC
Telephone [phone]
Telephone [phone]
Telephone [phone]
Fax [phone]
Fax [phone]
Fax [phone]

•
02
•
TAit
Field
410/0
I
++ 7 ` /l
a SVpz,109� S�OV GR•t56ETr50ugMP
z \ US fi,604(04,4 ioI $ fo,9 mil
1l
2/3O'" 2 04::30 FEET (N. C.) 698
Mapped, edite:. and published by the Geological Survey
�ontr.l by USGS -d USC&GS
lanirnetry by pho:=grammetric methods frog, aerial photographs
aken 1951. To:cgraphy by planetable surveys 1961 and 1962
olyccnic projecticr. 1927 North American datum
10,C00-foot grids :ased on North Carolina c-Dordinate system and
South Carolina cc:-dinate system, north zore
t00C-meter Uni,;•;al Trars.erse Mercator _•id ticks,
one _7, sho..n it clue
ine •ed das-ed -es indica:e selected fence and field lines where
ene•_ity vis'zie c- aerial photographs. Th s information is unchecked
— "t-- —
SANDY PLAIN 5 Mf•
FIREWAY 14 AN.
UTM GRID AND 1962 MAGNETIC NORTH
DECLINATION AT CENTER OF SHEET
//•
//
,t
1l,
"�irfirs
1
50' 700
S, ^
FI
C65-D
75•
-
1000 0
1
T'A8o2 c rry /T
QviNpe._&4ErCs3
7