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Home My WebLink AboutNC0031046_Wasteload Allocation_19880825NPDES DOCUMENT SCANNING COVER MEET NPDES Permit: NC0031046 Document Type: Permit Issuance Wasteload Allocation Authorization to Construct (AtC) Permit Modification Complete File - Historical Correspondence Speculative Limits Instream Assessment (67b) Environmental Assessment (EA) Permit History Document Date: August 25, 1988 "Man document is printed on reuse paper - ignore any content on the reYerse side DIVISION OF ENVIRONMENTAL MANAGEMENT August 25, 1988 MEMORANDUM TO: Arthur Mouberry THROUGH: Steve Tedder FROM: Trevor Clements :' SUBJECT: Comments regarding Colonial Pipeline Draft Permit Comments NPDES No. NC0031046, Guilford County I have reviewed the letter from Colonial Pipeline Company (8/1/88) requesting clarification of their proposed permit. My responses to their ques- tions and comments are as follows: 1. Pipe Number -- I concur that, if all other pipes are to be eliminated by the permit, the permitted outfall should be renumbered 001. 2. Flow Measurement -- Continuous flow recording should be required and the condition in Part III N regarding use of rain guages for flow measurement should be deleted from the permit. 3. Sampling -- Grab samples, as required in the permit, have been agreed to by the company. However, compliance with the phenols loading limit should probably not be based on the instantaneous flow at the time of the sample, since the discharge is quite variable in nature. It is recommended that either the daily average flow for that day be used to calculate loading (I prefer this alternative), or that average sample concentrations for the month be applied to average monthly flows to determine loading. Given the design of the pond and its retention time, I would expect that concentra- tions leaving the pond --except under extreme stormwater conditions -- would be fairly uniform. Therefore, applying grab samples to other than instanta- neous flows to obtain reliable loading estimates appears prudent. Discrete sampling for toxics is applied to reflect the intermittent or epi- sodic nature of the discharge. A discrete -event describes the period from the beginning to the end of the discharge. Samples must be collected during that time, and the BTX sample should be collected at the same time as the toxicity test sample to provide maximum correlation. Since we cannot pre- dict the frequency of these events, we are requiring simply that the first 5 be monitored. It should be noted that DEM recently revised the episodic toxicity testing requirement to include an annual test after the first 5 events have been monitored. 4. Phenols Limit -- Since the Colonial retention pond is below eight other permitted discharges with similar phenol limits (see attached map), I will propose that we give Colonial credit for all of these discharges. There- fore, the phenol limit corresponding to pipe 007 (in the current draft per- mit) could be changed to 0.009 lbs/day. This will still result in our objective of meeting the water quality standard of 1 ug/1 above High Point Lake under 7Q10 conditions. However, Colonial Pipeline must realize that they are fully responsible for meeting that limit. If the Company does not wish to incur that risk given the presence of the upstream discharges, then I recommend that the permit be revised to reflect each of the individual pipe discharges and that their 0.001 lbs/day portion of allowable loading be divided proportionately over all of the pipes. 5. The settleable solids and turbidity limitations are applied to all storm - water or retaining pond discharges. These limits reflect state standards and regulations intended to protect aquatic life instream. JTC CC: Please let me know iffurther clarification is required. Steve Mauney Ken Eagleson Central File v The following is a list of oil storage facilities whose dis- charge is upstream of the Colonial Pipeline Company (NC0031046). These discharges pass through Colonial's retention ponds before entering the East Fork Deep River (030608) . 1. Unocal - Gulf/BP Southeast Terminal (Union Oil) NC0026247 2. GNC Energy Corporation NC0074241 3. Shell ❑il Company 1\IC0073938 4. Amerada Hess •- Greensboro Terminal NC0069256 5. Chevron U.S.A. (Gulf OI1 Terminal) NC0068063 6. Plantation Pipeline Company NC0051161 7. Exxon - Greensboro NC0000795 8. Ashland Petroleum NC0065803 s. a i‘ r\ 71 Friendship.Ch ==. : . , • : ,.. ...i,1 .„r: ',,. • !i:,',. ..: .,..01 ,...:. • i . ., ••• ;• •S.., • .. .. , ndship -7 898 ;; 0, • 0 / • ... \ • \ • • piE. L.•1 \ • :900- '. N‘ ) ; s' C r- ‘1. ) \ IT s ....... .,! / \:,‘1. • .) ,,,,s..‘,,,:. \ c,) , • ' IP • I -Li' ---. .....- 8 c-11?8' -- iii/',/-..,, --.--°."4-.-_-..-7' •-"T;-1\- - .''..,\I, i.--- 90.5-.-- 1/ vA\\ , ,,,.........../ .. .. ,,,., 7 •:.... . .\\ ..; . , ...„, --- .11 \'-, /•,,,c . ,.. i-k',, . .. (,:' , • (.---/ee ,-1-v--: 4 • t X9/ Colonial Pipeline Company tENOX ll)WEW5 :1390 PIACHHiR(I ROAD :41 All•:Ni1. ,r;7,t, i irrt -4:.2, ;ni i4/l) A YAJ46Qf) )::r-,E{ August 1, 1988 Ms. Lula Harris Permits and Engineering Unit Division of Environmental Management P. 0. Box 27687 Raleigh, North Carolina 27611-7687 Re: Permit No. NC0031046 Greensboro Junction Dear Ms. Harris: Colonial Pipeline Company has received the draft reissuance of the above referenced permit and would like to take this opportunity to both make comments and obtain some clarifications about the permit. The permit only had one limitation page for outfall serial number 007. According to the past DEM Form MR-1 reporting, effluent location 007 is the point of compliance or final effluent from Colonial's property after all treatment. It is assumed the draft permit is referring to this same location and has established it as the only monitoring point for which Colonial is now responsible. It might be best to renumber this location 001 in the new permit. The next item which needs clarification is the contradiction between the limitation page and Part III N about flow monitoring requirements. Under Part III N, it states that flow may be calculated utilizing rain gauges. This type of procedure was outlined in the proposal submitted to you on May 3, 1988 (copy enclosed) incorporating actual daily rainfall data and stormwater runoff calculating methodologies. The limitation page, on the other hand, requires that a "Continuous Recording" or "Weekly Flow Totalizer" method of flow monitoring be used. Colonial would like to again petition for the use of the method outlined in the May 3 submission which it feels is representative and adequate. The variability of the flow leaving the facility would make other sophisticated and expensive means of flow monitoring no more accurate than the proposed method. If the above mentioned procedure is not acceptable, Colonial would propose to install a "primary flow device" at the final effluent location which was discussed earlier. The primary device would be some sort of weir, flume, or flow channel to be field determined at a later date. The sampling would in- volve obtaining an instantaneous grab sample, and reading the corresponding flow from the calibrated primary device. This rate will then be the representative flow to use in conjunction with the instantaneous grab sample to determine the phenols loading. However, it must be understood that upsets will occur due to large storm events which the primary device will not be able to handle. Not only will it be difficult to accurately handle all flows, a design range of flows will be hard to determine due to topography and lack of stream flow data. If this option is to be pursued, Colonial would like to receive any stream flow data for the unnamed tributary to the East Fork Deep River that the State might have on file. This data would be helpful for design purposes. f!,!•ri r"'i;. :UI)itrSS 1' (. BOX 114855 Ali A► 1:. CA 303:4;1.1855 Colonial Pipeline Company Ms. Lula Harris Page 2 August 1, 1988 Other items which warrant discussion include the twice per month sampling, the testing for settleable solids, and the meaning of discrete discharge events. Colonial has established a history of effluent quality, and maintaining com- pliance with the permit limits for all test parameters. Therefore, increasing the testing frequency to twice per month' would seem to not be justified at this time. Laboratory turn -around times will also create problems, since they cannot maintain a two -week schedule for providing results, and make it difficult to keep reporting deadlines. As for the discussion about settleable solids, Colonial would like a referenced method number for the defining and testing of this parameter. Another definition would also be needed for discrete discharge. Is it necessary for there to be a no flow condition between discharges or just a specified reduction? Please explain the intent behind the use of discrete in the description of the monitoring frequency for acute toxicity and BTX. The last topic for comments at this time is the testing for acute toxicity. In the body of the permit, a reference was made to an EPA document 600/4 - 85/013 which is to govern the toxicity testing protocol. Colonial would like to obtain a copy of that document since it is being made a part of the permit. In summary, Colonial maintains that only one outfall or point of compliance should be established for its NPDES permit. Limits should be set bearing in mind that the flow for the one outfall will be inclusive all influents from the facility and upstream. Hopefully, these comments will be carefully considered in the next drafting of the permit. If additional information is required, or if you have any questions, please contact me at the letterhead address or telephone number. Yours very truly, \Jr. D. V. Pearson Engineer njw Enclosure cc: Mr. T. W. Cervino Mr. W. C. Edwards Mr. J. E. Marder Mr. H. R. Melendy Mr. Trevor Clements - NC DNR & CD PERMIT NO.: NCOO (, FACILITY NAME- (2-o/b"'4 Pry l;. NPDES WASTE LOAD ALLOCATION ��Orya n f/ Facility Status: EXISTING PROPOSED (circle one) Permit Status: RENEWAL MODIFICATION UNPERM[ITED NEW (circle one) - f Major Minor, Pipe No• Design Capacity (MGD)• Domestic (% of Flow): Industrial (% of Flow)• Comments• RECEIVING STREAM: Class - Sub -Basin OJT Reference USGS Quad: , - (please attach) County: J Regional Office: As Fa Mo Ra Wa Wi WS (circle ems) Requested By: Date- "7 Prepared By: /� �T °v:'� Date• Reviewed By:__ 11 ��' Date. Modeler Date Rec. #/] I ' �j Salg 1 Drainage Area (mi ) (,UG: Avg. Streamflow (cfs)- 1.00 7Q10 (cfs) 0,i5- Winter 7Q10 (cfs) 0.20 30Q2 (cfs) o.Zo Toxicity Limits: IWC 95 % (circle one)Ccutte/ Chronic Ep i soAk Instream Monitoring: Parameters Upstream Location Downstream ` Location 13eenMali 2M ft ,eCTIuen4- o.,i�-v1 -rot *mow oI ,4' 3tea s:14It. .ble sdds, pktooeg, and }..rb.e►.HyReco.nn+c.J wwn:lkk' se� .roc b.enzene., An.L Xylen.t r ?e eto.ut. on +-LA. Sarfic ScL.4-1,4 a aS �il• +Ro✓ri�or n ({ 5 elisCre�e S��e�.or e tvtn+sl. K / r1 Effluent J Characteristics ��,,.th,j 4vSr D�;ly Pk\, Tu r b t d, j (Kit) Thy, dZxtar, Shull no Co.uac Wu. 4tAt b; d ashy c P rece;uio walcr +o exce.el So,rvu, 1-r 4u. 4ufbit:4-y cxcacti s 50N t.te 40 nab -veal back gco. 0or.1;t-ion4 `ink cl;xne,rgle tan not- ro.0y $[. an :nGrea.se ;,‘ fLt '4'uf\D ,ei c.),t -lu rece:Utnq ww! 9\-1- LSu) 6-I 6-4 U,( & Grease (1/i) 30 60 -Hite Solids try]) 0,1 o, z Pheao (5 (`bider) O. 00 I --i. lax;c_ Tes-I-tno Retlu;rcrric4 /4- eJ. nJ nnonilot.n� Lc it UoluMtS o� Wabkw l apply +,, i-l.. -C;r.0.1 cr°N, a collec-gvt I,.oliinq pond re-ce:wes 0r^ ( str&c,,`e ;scl�arge poin'i5, A r cora,r�c s4lott1,1 pticeJ 'n tL fir 4444- ko ollow for 1.'$ l$ ro io-e pi4`ed art ivX:camt1b stqoull �l . �0c,L j' rq;l ;1"s towe,:-Y �y Comments- eCOn'"°`e'c �l°^' ^ Request No.: 4598 ------------------- WAGTELOAD ALLOCATION APPROVAL FORM - ------------------ Facility Name n NPDES No.: Type of Waste: Status: Receiving Streamo Class ifiCat icon : Gubbasin: County: Regional Office: Requestor: Date of Request: Quad: Wasteflow (mgd): Oil & Grease (mg/l): Settleable Solids (ml/l): Phenols (lb/day): pH (SU): Turbidity (NTU): COLONIAL PIPELINE COMPANY NC0031046 INDUGTRIAL EXISTING UT TO EAST FORK DEEP RIVER WSIII 030608 Drainage area: GUILFORD Summer 7Q10: WINSTON-SALEM Winter 7Q10: LULA HARRIG Average flowx 4/11/88 3002: C19SW 1.000 sq mi 0.15 cfs 0.20 cfs 1.00 cfs 0.20 cfs RECOMMENDED EFFLUENT LIMITS -------------------------- Mo Avg Daily Max 0.0099 30 0.1 60 0.2 0^001 6-9 The discharge shall not cause the turbidity of the receiving waters to exceed 50NTU. If the turbidity exceeds these levels due to natural background cond- itions, the discharge can not cause any increase in the turbidity of the receiving water. Toxicity Testing Req.: ��k50~0^«� ' � - ---------------------------- MONITORING �� `^ ^ � h0t )mr"^'~ Ak�x��~ w»p� ----------------------------- COMMENT8 Recommend flow monitoring for all volumes of wastewater leaving the facility. Recommend 2/month monitoring for oil & grease, settleable solids, pH, phenols, and turbidity. Recommend monitoring for benzene, toulene, and xylene be done on the same schedule as toxicity monitoring (1st 5 discrete discharge events). A reopener clause should be placed in the permit to allow for limits to be placed on toxicants should the facility fail its whole -effluent toxicity test. Location: Locationo , Recommended by. - Reviewed by Tech Support Supervisor,. - Regional Gupervisor: Permits & Engineering: RETURN TO TECHNICAL SERVICES BY: Date: Z —Oak Da _____________ Date: __ __ __ -__ Request No.: 4598 8�� .mx»xn � " m�� ------------------- WASTELOAD ALLOCATION APPROVAL FORM -----��-�-�-�=`----- Facility Name Co`ontc j Com F co Permit# IVGOa3/oqd ACUTE TOXICITY TESTING REQUIREMENT Daphnid 48 hr - Monitoring for Episodic Events The permittee shall conduct FIVE acute toxicity tests using protocols defined in E.P.A. Document 600/4-85/013 entitled "The Acute Toxicity of Effluents to Freshwater and Marine Organisms". The monitoring shall be performed as a Daphnia pulex, or Ceriodaphnia 48 hour static test, using effluent collected as a single grab sample. Effluent samples for self -monitoring purposes must be obtained below all waste treatment. Sampling and subsequent testing will occur during the first five discrete discharge events after the effective date of this permit. The parameter code for this test if using Daphnia pulex is TAA3D. The parameter code for this test if using Ceriodaphnia is TAA3B. AlItoxicity testing results required as part of this permit condition will be entered on the Effluent Discharge Form (MR-1) for the month in which it was performed, using the appropriate parameter code. Addutonally, DEM Form AT-1(original) is to be sent to the following address: :�... . Attention:. Technical. Services Branch North Carolina:Division of Environmental Management P.O. Box 27687 Raleigh, N.C.. 27611 Test data shall be complete and accurate and include all supporting chemical/physical measurements performed in association with the toxicity tests, as well as all se data:: Total residual chlorine of the effluent toxicity sample must be measured and • . if chlorine is employed for disinfection of the waste stream. • . . Should any test data from either these monitoring i .. ,ta n.. • _ • .. inmme.or tests paiomned.b�tho-Natrth. Carolina Division of Environmental Management ' 8e potential to.the • • � stn p� may and moded to include alternate monitoring • . -8 roquu+einents-oz NOTE: Failure to achieve test conditions as specified in the cited ::i:: •. document, such as• minimum. control organism suvival and appropriate environmental controls, shall llconstituta an invandtest: Failure to submit suitable test results will constitute a failure of permit condition. 7Q10 0 , + S- cfs Permitted Flow , oogq MOD IWC% 9 , 3 Basin & Sub -Basin 0 3060 8 Receiving Stream ur to Gas+ Fork Deer %or. Count G;(�� _ , . - .1, . '�«� - • .. Y �o rDate s /'t(Sg **Acute Toxicity(Daphnid 48 hr) Monitoring, EPISODIC, See Part 3 , Condition G . larti ex( . tt ; co"-, Gt Lir l o asf' Fork. Ddc Dee L\rve Des i. !1 Ca tirc o_o q_ ,o1S3 ces 7Qtos— �5. o1S3 . IS 4-_ o153 , o l S 3 c-C-5 . 1653 tfs . Dq 26 q.2.� MDS Skigk MM 47 Gasoline u/M y. 73',ks Are a • Mekr Du/ Area Gaso/i, e T n,F rank line s//i /ers NL.11 llll 11 ll.11 fir V,x}1 nT, M ;%T. iF j rid J APR _ -1 . . Spray rr'rigo ti on mac= :te J 1 1 1 ct CTank 60No 0 /77 !va /er drain sy5fcrn Apr ,0; wakr Scpara /or c7 Farm Area S'RnPr" Lt/AT 4000 BBL. Ho/ding Tank API %i/wafcr Scpara for Pvn'p . fkcraled Lagoon AP: o/$y separakr A u/dind e tram_ (Tr)I I I-4O Hwy Dike Drains tx OW : . ria r S • l AP? of /wa/er 1-JJ Scp2ra fan 9n1( boffom Gila/cr drain $y5/cen 1?e/cn/ion c No/e; A// ponds d /a,(:s have uncle/Wow out//c/s, cr ga5v e0,6.1 Asz of DEE P. city A,� v C aC P L^ Al A /A/A Pi A NI) L//13/,71. Colonitn,� I: b P.pjrn... Cof,r1 (AT --; Est FarK "6°0 Si 0146 ►pc coo I 0;i 0" Geeasc &VI )— - 30 60 Sealc%ble__Soitc.S (!J/'t)-- - 0,1 0.7. FN (su) r�,�r�-� _ Jew ?e�l�! _nol s (( s/jw'() o MMAftiS 6-9 7O os e0,1:n.4.1 ,- iors unatys;s Y ReCCovIA 1 -f L,J Plani-1-o1.; 1_ -GEol� -`col e-,b,s�cwak (e av( 3 4'vA a4 (r f/ ?2COMmtn2 Vv,an4Y, ',onr4-a1;Aq tote v u ( a r-c''SG,y SLTT.ie5cb(4. CO (I4 {___9 � ) p�u/i0'S d✓I � T� r rdt ccoM/VK/1i Ma/Ir lJI/ y rOf S�ny¢n.c -�Q�I j a✓� Z)/I 1(- [___done 'falcici fy /+10n,FC/lln�1�r5 'VrSCPc — 01L Svc n tv). -SVtOtAd �{ I.NGC�------ �" ptrM[� �'}'O 0.10W _tox;coid.s 51,10ui`fV=—fucc`i,7L j 4.1 ifs w(no(e — e i} 44- 'Iokic�-� 7(5-vf5. MDS Hlz0Y • Co`0✓1«( UT EcsFor c, f,6v�r 1nJG - ror +oX(cjy -Fesfc47 7Qto 5 C ooa� r1 GD .0IS3 c�s .0(S cf 7Qtc) cnL•LIC . 0151 cfss '" .0153 ce5,.., c"tL hu' r^ t stteow WA (e r, r 7a + S �a�� v�S��✓q�r NG rcQtt:c�C.s - #% Danhncd 9fi hr — Km:4`cezj ��r EpiSoJt'c Evcn�S. I 1` i� r+ �a. S 'r�.Y, W--.S 2 e v.,n., . U we, Stu c,Q - ail we C ( ci t v e r+ '% ,r e e-k. ' c �n,�. maa Le_ A,s a VLwct,flide-- 14, cA (S S c.) W e •• c iSvGt(C,r +V)((CTI ±54IL c3 a ev 0 Facility Name: Existing Proposed 1 1 011 /0'7 =,44"Ag--2 NPDES WASTE LOAD ALLOCATION / �fJ Date- _ /(` / 7 I\.) L0 0 - k Pipe Permit No.: No.: C O"( County: () c,<-`' Design Capacity (MGD): LO VA Industrial (% of Flow): i C)C)io Domestic (% of Flow): U Receiving Stream: Zo -- Class: /1-IC Sub -Basin: 0 -0(-0 Reference USGS Quad: C - I9 S`"" (Please attach) Requestor• �� a1 Office (Guideline limitations, if applicable, are to be listed on the back of this form.) Design Temp.: Drainage Area: Avg. Streamflow: 7Q10: Winter 7Q10• 30Q2• nCU Location of D.O.minimum (miles below outfall): Slope:_• 0 N as cs OS Velocity (fps): K1 (base e, per day, 20°C): K2 (base e, per day, 20°C)• Effluent Characteristics Monthly Average Comments Phl- -.6`i5 t50 30(001d, 1 %1 PAknol 01id6{ /0 d y�Jj /s1 dabay 4,1 Original Allocation Revised Allocation Prepared By: n Date(s) of Revision(s) (Please attach previous allocation) Reviewed By: REQUEST NO. ********************* WASTELOAD ALLOCATION APPROVAL FORM ********************:: FACILITY NAME TYPE OF WASTE COUNTY REGIONAL OFFICE RECEIVING STREAM 7Q10 : 0 CFS DRAINAGE AREA 4 Co/onlu.5 Pike/ire CO . OIL STORAGE GUILFORD WINSTON-SALEM REQUESTOR : DAVE ALDKINS : EAST FORK DEEP R SUBBASIN : 03-06-Og W7Q10 : CFS 30Q2 : CFS SQ.MI. STREAM CLASS :AII ************************ RECOMMENDED EFFLUENT LIMSITS ************************ WASTEFLOW(S) BOD-5 NH3-N D.O. PH FECAL COLIFORM TSS PHENOL (MGD) : 0.005 (MG/L) (MG/L) : (MG/L) : (SU) (/100ML): (MG/L) : LBS/D : 0.0012 6-8.5 • OIL AND GREASE: 10 MC/L DAILY AVG 15 MG/L DAILY MAX PLEASE SEE THE ATTACHED MEiiO FOR A DISCUSSION OF THE PHENOL LIMITAIONS. *******************************************************************:************0 FACILITY IS : PROPOSED ( ) EXISTING (✓S NEW ( ) LIMITS ARE : REVISION (�) CONFIRMATION ( ) OF THOSE PREVIOUSLY ISSUED REVIEWED AND RECOMMENDED BY: MODELER SUPERVISOR,MODELING GROUP REGIONAL SUPERVISOR PERMITS MANAGER APPROVED BY : DIVISION DIRECTOR DATE : _�_ �;,` DATE :(fr2h7-3 al. DATE �D__ II � d . DATE «_VQS5_ -- +11.70/AATE ;#r Colonial Pipeline Company GREENSBORO JUNCTION NPDES PERMIT NO. NC0031046 RENEWAL MODIFICATION Colonial Pipeline Company's Greensboro Junction is a breakout tank farm for the pipeline distribution and scheduling of refined petroleum products. The facility is approximately 288 acres of which 193 acres comprise one watershed and one discharge from the property. The other 84 acres are either unused having no potential for contamination and drain through sheet overland flow, or bermed regions with no outlets and designed for total infiltration. The following discussion/proposal for modification of the renewal for NPDES Permit No. NC0031046 consists of an extensive watershed analysis. The methodologies used in this proposal are from the U. S. Department of Agriculture, Soil Conservation Services' National Engineering Handbook, Section 4: Hydrology. This handbook has been an acceptable reference in design, for use in predicting future runoff from urbanizing areas. The Soil Survey of Guilford County, North Carolina, was also used to determine hydrologic soil groups. The Technical Release No. 55 is a summary of NEH-4 and demonstrates the procedures used in examples. The Greensboro facility is in an area where there are a lot of industrial discharges into the tributary of the East Fork of the Deep River. The Colonial tank farm is built such that the stream runs through the facility. Two main lakes have been constructed for retention purposes of the stream. Also contained with the facility are six secondary ponds which feed the two lakes. (See Drawing No. 7-GR-32.) However, the final effluent containing all treated discharges leaves the property through one location. This point of compliance is labeled number eight on the Greensboro Water Drainage Schematic. The numbers on this sketch denote the sampling and monitoring points of the present permit. This proposal is a request to reduce these sampling points to just the influent, Point No. 1, and effluent, Point No. 8. The present discharge reporting units for phenols is in pounds per day. If these units are to be maintained, it is necessary to obtain both discharge quality and quantity. The quality with respect to Colonial's loading can be determined by computing the difference between monthly concentration results obtained from the influent and effluent; hence, the concentration originating from Colonial's facility. Then, by combining that monthly concentration result with the estimated runoff quantity from the facility, a pounds per day loading rate can be determined specific to Colonial's Greensboro Junction. This procedure will allow monitoring personnel to focus on one point of compliance when obtaining samples, which will insure better quality control and monthly representation. The quantity of runoff contributing to the discharge from Colonial's facility can be quite accurately estimated through a watershed analysis. The following breakdown is the step-by-step procedure used to evaluate the runoff (volume) characteristics of Greensboro Junction. The first step in the analysis is the determination of the different hydrologic soil groups. These groups are then related to land use and total area. The combination of hydrologic soil groups, land use, and treatment class is used to determine the hydrologic soil -cover complex. The effect of the complex is represented by the runoff curve number, referred to as CN. Colonial Pipeline Company I. Soil Survey Types on Facility Hydrologic Group 1. CfB: Cecil -Urban land complex, 2 - 10% slopes B 2. CeC2: Cecil sandy loam, 6 - 10% slopes, eroded B 3. EoC2: Enon clay loam, 6 - 10% slopes, eroded C 4. Ch: Chewacla sandy loam C 5. CeB2: Cecil sandy clay loam, 2 - 6% slopes, eroded B 6. MuB: Mecklenburg -Urban land complex, 2 - 10% slopes C 7. CcB: Cecil sandy loam, 2 - 6% slopes B II. Land Use 1. CfB: This soil is found in the gasoline tank dikes, manifold switchgear, storage area, landfarm, control building, parking lot, and some grassed pasture areas. 2. CeC2, CeB2: These soils are found in manifold and wooded areas. 3. MuB: This soil is only found in the fuel oil tank dike region. 4. EoC2: This soil is found in both wooded and meadow areas. 5. Ch: This soil is confined to meadow areas. 6. CcB: This soil is mostly in wooded and grassed areas but does not contribute to effluent discharge. The above information is now used in the computation of the weighted CN which will represent the entire Greensboro Junction facility. Land Use Soil Type Hydrologic Soil Groups B C % CN Product X CN Product Gasoline dike areas (28% impervious) CfB 19 86 1634 Manifold Gravel areas CfB 16 85 1360 Landfarm Cultivated area CfB 3 71 213 Parking Lots & Building Roofs CfB 3 98 294 Grassed Pasture areas CfB 7 65 455 Oil Dike areas (46% impervious) MuB - - - 30 92 2760 Manifold Gravel areas CeC2 CeB2 5 85 425 Wooded area CeC2 CeB2 10 55 550 - - - Meadow area ch - - - 2 71 142 Wooded area EoC2 - - - 2 77 154 Meadow area EoC2 - - - 3 71 213 63 4931 37 3269 Weighted CN = 4931 + 3269 = 82 100 2 Colonial pipeline Company ANTECEDENT MOISTURE CONDITIONS (Preceding 5-day Period of Storm) I II III CN = 66 82 92 The AMC are the conditions of the soil at the outset of a storm event. Condition II is considered average, I is the lower limit or very high absorption capabilities, and III is the condition of saturation or the upper limit of moisture holding capacity. The preceding five days' rainfall is totaled and entered into Figure 4.9 to determine which curve on the Greensboro Junction Storm Runoff vs. Rainfall graph should be used for that particular storm. Season changes have been divided at November 1 and March 1. Once the antecedent moisture condition has been established, the storm's rainfall is used with the appropriate AMC on the Runoff vs. Rainfall graph, to determine the storm's resulting runoff for the entire watershed contributing to the effluent at Colonial's point of compliance. These storm runoffs will then be totaled for the month, computed to units of million gallons per day and combined with concentration results for the loading rate in pounds per day. Field Procedures 1. Call daily to Airport for report on actual precipitation. 2. Check effluent pipe after each rainfall event for a discharge, take monthly samples if not already obtained. 3. Fill out Greensboro Junction Precipitation Log with the daily rainfall. Total the antecedent rainfall and determine the AMC as described above. Then by using the Runoff vs. Rainfall graph, log in the runoff. If successive days constitute one storm, accumulate each day's runoff in the "by storm" column. Use the comments column for any observations such as whether .or not the storm event produced discharge. If not, that storm's runoff will not be included in month's total. Use comments column to note the day samples were taken. 4. At the end of the month, total the runoff and calculate the month's average daily volume in gallons per day. Volume s month's total runoff (in.) X 193 ac X ft X 43,562 ft2 X 7.481 gal 1 ac f t . 3 Volume m M.T.R. (in.) X 5,241,354 GPD = M.T.R. (in.) X 5,241,354 no. of days/mo 5. Calculate loading by the following: Loading = Concentration (ppb) X 8.34 lbs. X GPD 1 X 109 g on 6. Report on the State DEM MR-1 form; phenols loading and other required results. The above procedures should be adequate in provididng realistic number for the quantity of flow discharged from Colonial's point of compliance at Greensboro Junction. One practice that will reduce the amount of discharge is the operation of 3 Colonial Pipeline Company the drains that contain the water in the tank dikes. These dike drains are always kept closed except when intense rainfall occurs. This procedure is a safeguard for containing spills. However, in the event of extreme rainfall, the drains must be opened to prevent the possible floating of a tank. Therefore, evaporation, infil- tration, and ponding in the dikes will prevent all storm events from producing discharge. These events will not be totaled in the month's runoff. The pond and lake levels also play a role in whether or not a storm event creates discharge. If the levels are low, for whatever reasons, the storage capacities must first be replenished before the level is sufficient to begin a discharge. All these proce- dures and methods, if managed correctly, can supply a quantity of flow representa- tive of the watershed for Greensboro Junction. However, if unrealistic numbers are being produced, the method will need to be further scrutinized and updated. One last consideration must be incorporated when setting the limitation on the loading for phenols. Past estimates were inclusive of only 82.6 acres of the facility. This updated estimate includes 193 acres to be discharged through the one confluence or point of compliance (see Greensboro Water Drainage Plan - attached.) 5/2/88 DVP:njw o Drainage from 6 b ui #C PI a h r s I-40 Hay. • 4101, 47 6aso/;ne /f•/ T i,ks doso/,,C Ta,k Mani,'o Id 7bn& fine Sfinyers V...1.,. .. • O.. Spray lrrrier oh' on 1111 SOe • fLmp Area fa /w eje r' SCCara TO r p4%/wa-L - Saco.rn4o r 1)i‘jt4/24 6o/f � 0 wa fer drai/7 system API Oiwafcr Separa /or 5 �para for S, ado BBL. Holding Tank APl of//wa/er Pconp i Os t sk;n,n"t pit ii r t• vok Dike Drains • 2S c / 0i/ Td4 s Di/ rank man; f a /d Tgkli,e S/inS'e? 1 U APT of $Fafcr u Sepera for 7"8nk boffoin a'a/cr drain Syslit en ct Aerated "4--C Oily Wa sfe Land Farm Area Lagoon Meter In Area API o4y separaioi 8e/cn fi on La,E e J'o/e; A// ponds d /9,4cs have undee/loin ocn'/cfs, *POINT OG �tetPLIAPaCf REs y /v../83 ove R RE v cREENS8ORo WATER I RA/ NA GE PL N. I. j" 15 3 SS 0 1 Mde r— L_ _ 4 000 11)00 ,.000 I 000 Scale -1: 20000 5000 Feel Nov. 1 - FEL3. ZS jAomk. 1 — OCT . 31 • ikkr •\ .•il•.!.• %►►1/w�\w • tom. ''�',••�.•: 2 3 TOTAL 5—DAY ANTECEDENT RAINFALL IN INCHES Figure l.9..-Graph for esti- mating antecedent moisture. condition. • i • it y ,• . • 4 O. • it • • .. • t:'•• • • Vp� 20 X 20 TO THE INCH • 1 x ID INLIILS 11 KEUFFEL & ESSER CO. M+I.r: U. U S A i 46 1240 1 5 z F✓ c 4.0 LL U. 0 30 CC 2.0 1.0 • . •-i GFE 5' ' Yao.14..:...._:. ' Tz4 flt! vlst P.A1P $•Q•' M'jFi, P A". i :II, i1 IIII I' 1 ! i i ! Ii.iitiI f 1 ''i iI ' ! , 1 I ` ! '1 f1 I "it,' 1 i 1 Ili. Ill-,--. (' j II ,.: !III 11 1 I ' r ! 1 !i. ' 1 I ( , 1 Ii 1 1 1' 1 1 1 r ('f i !Il, i I ,I�• I It I 'I 1 i !ii: I ,. ! "•••tr- i i ' I , 1 .1 r ! '! :1 .. ;. •}i ii rr-r • i 11 h f 1 :1 • • 'I' II i I :1 1 !, t� t, }il 1 ; is Iii1 tit. i 'tit -rr,. .1, • G- • I ;;I •i ..i :i!I :I •i 1.r it t•1 MC. TIT i; 1 CU 11.0 S,-) R t►T N r A 1 1 (I,ic1 3' too 7 c•7 10 4 GREEINISIBC)RC) JUNCTION PRECIPITATION LOG MONTH n YEAR u STORM ANTECEDENT RAINFALL RAINFALL DAY (in) (in.) 2 «d jrrI 9 1.0 .1..1. .M� 3.4 1.::,; .6 1. 7 :1.8 19 20 21 22 23 24 25 26 27 28 29 :3I_) 3 MMMMMMMMMM MM MM MM..M...... MM .Mr MM MM. MMMMMM MMMM.....MMM............MMMMMM MMMMMM AMC MMMMM Mmmmm .MM .MM .MM MM MM MMMMM MM..MMMMMMM MMMMM MMMMM MMMM M...MMMM.MM...M. MMMMM MMMMM MMMMMMMMMMMMM ESTIMATED RUNOFF BY DAY BY STORM (in.) (in.) COMMENTS .M.. MM. MM M.. M«. M.M.M....... .MM MM MM. MM MM Mw M.M M... MM x.M MM MM. MM. MM. M.N MM MMMMMMMM MM. M... jMM MM. MM. MM M.M MM MM MM MM. MM ..M .M. mmmmmMMm ..M. MM MM MM MM MM MM MM MM MM. MM MM. MM .M. MMMMMMMM MMMMMMMM MMMMMMMM.MM.M. MM. MM ..M .MM MM..MM MMMMMMMM...M.MM .MM .MM.MM ...M MM MM.MM MM .MM MM. MM MM MM MM. MM MM MMMMMMMMMMMMMMMM .M,MMMMMMMMMMMMMMMMMM MMMMMMMMM MMMM MMMMMMMM MM MM. MM MM M.. MM M MM MM MM MM MM MM MM MM MM MM MM. MM..MM MN. MM .MM mmmmmm .M..MM M...NM.M..MM .MM MM MM MM MM m MM. MM...M MM MM..M. M...MM MM. M... MM MM .MM MM M.. M.. MM MM. MM M...MM.M..M..MM MM .MM MM .M. MM..M. MM ..M MM..M..MM MM..M. M.. MM .MM m MM MM «M .MM MM M.M MM MM. MM. MM MM m• MM Mb me Me MM _ .M. .Mee .MM MM M.M me Me .MMMMM..MMMM MMMMMM MM.. M... MM ..M..MM .M. MM MM. MM M.....M M....M.. MM MM. M.....M MM. MM .MM MM .MM MM ..M M.M MM MM MM I.x..w ..«. MM..M. MM. MM. uM .M...M.. ...« .M.. MM MM....M M.. MM M.M M.M ..M. MM MM......M.....M MM MM ..... M....«M ............M...........MM..... ...M............... M«. M....M..M.. M... M.. M.M.M...M MM...M M... ..M ..,........... M... M.....M........... .MM..M..M...MM MM..M.MM M.. »M..M....M...... M... MM...M. MMMMMM MMMMMM MMMMMM MMMmMM MMMMMM MONTH ' S TOTAL RUNOFF % ( ONLY DAYS CAUSING DISCHARGE ) VOLUME = M.T.R. (in.) X 5,241,354 / NO. OF DAYS I N MONTH 5,241,354 «. VOLUME MM' CIF'D LOADING = CONC. (ppb) X 8.34 l bs„ X (F'D 1 X .I. 0''"` % gallons M« X 8.34 X :1. O''''MM9 X LOADING = POUNDS/DAY deees