STATEMENT OF BASIS/TECHNICAL SUMMARYAND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION

DESCRIPTION OFAPPLICATION Applicant: Cooper Natural Resources Inc.; Texas Pollutant Discharge Elimination System (TPDES) Permit No. WQooo3642ooo (TX0112038) Regulated Activity: Industrial Wastewater Permit Type ofApplication: Major Amendmentwith Renewal Request:

Authority: Major Amendmentwith Renewal to reduce certain samplingfrequencies at all three outfalls
Federal Clean WaterAct §402; Texas Water Code §26.027; 30 Texas Administrative Code (TAC) Chapter 305, Subchapters C-F, Chapters 307 and 319; Commission policies; and Environmental ProtectionAgency (EPA) guidelines
EXECUTIVE DIRECTOR RECOMMENDATION
The Executive Director has made a preliminary decision that this permit, ifissued, meets all statutory and regulatory requirements. The draft permitincludes an expiration date ofDecember 1, 2019, following the requirements of30 TAC § 305.71, Basin Permitting.
REASON FOR PROJECT PROPOSED
The applicant has applied to the Texas Commission on Environmental Quality (TCEQ) for an amendment ofits existing permit. The proposed amendment would reduce certain sampling frequencies from once perweek to once peryear at all three outfalls.
PROJECT DESCRIPTIONAND LOCATION
The applicant currently operates the Cedar Lake Plant, a facility thatproduces sodium sulfate fi:om naturally occuringbrine deposits. The facility pumpsbrine from sediments beneath Cedar Lake, extracts the sodium sulfate from thebrine, and returns the spentbrine to Cedar Lake. The facility uses a simple recovery process that is based on the phase chemistryofsalts in solutionto preferentially extract the sodium sulfate from thebrine. No reagents orreactive chemicalprocesses are used. The brine is pumped from a series of54 productionwells, approximately 30 ofwhich are in use at any given time. The wells are approximately 100feet deep, are located throughout thelake, and are accessed along roads that extend into the lake. The wells drawbrine from the salty groundwater, which receives recharge from Cedar Lake. Portions ofthe access roads along the west shore ofCedar Lake form two salt-evaporator areas, each ofwhich is connectedto Cedar Lake via culverts. Brine withdrawn from the production wells is first pipedto a brine storage tank, then routed to the Chilling Plant. At the Chilling Plant, the field brine flows through chillers, where an ammonia coolant reduces the temperature ofthebrine to cause precipitation ofGlauber's Salt, the hydratedform of sodium sulfate. The spentbrineis cold, so itis used to cool the incoming field brine before being returned to Cedar Lake, thus enhancing plant efficiency. The Glauber's Salt is melted in its own waters ofhydration at the Swenson Evaporator Crystallizer (SEC) and subjected to further evaporation, resulting in precipitation ofanhydrous sodium sulfate. Steam condensate generated duringthe evaporation process is used throughout the plantfor many useful purposes, including salt reclamation. The sodium sulfate is further de-wateredby centrifuges in the Drying Plant and then sentSTATEMENT OF BASIS/ TECHNICAL SUMMARYAND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION TPDES Permit No. WQooo3642000 through a rotary dryer to remove anyremaining moisture. The final product, anhydrous sodium sulfate, is eitherbagged at the plantfor bulktruck orrail car shipment or transportedbytruckto a loading facility in Seagraves, Texas, where itis loaded intobulk rail cars for shipmentto customers. Any waste sodium sulfate generated during the production process is collected and placed in the Salt Reclamation Pond (SRP), which is in the southwestern corner ofthe southern salt-evaporator area. This saltis reprocessedby spraying it with water, pumping the resulting sodium sulfate solution to a brine storage tank, and then processing the solution in the same manner thatfield brine is processed. The water that is sprayed over the saltpile is a mix offresh water and steam condensate. Wastewaterfrom the facility is discharged via three different outfalls, as describedbelow. Outfall 001

- Spent brine, plant floor wash water, condensate from evaporation processes, and storm water flow through an oil/water separatorprior to discharge via Outfall 001. Outfall 002 -Decantedbrine water, washdown water from the pump house floor, condensate,
non-contact cooling water from the booster pump, and stormwaterfrom the SRP are discharged via Outfall 002 into the southern salt-evaporator area, which is part ofCedar Lake. The outfall is located at the decanttower ofthe SRP. Recovered sodium sulfate (from truckloading and other site activities) is routedto the SRP, where fresh water and steam condensate from the SEC is sprayed over the saltto bring itback into solution so it canbepumped to thebrine storage tank and processed as field brine. Outfall 003 Brine water, condensate, tankwashdown water, overflow from the evaporationpond (which includes condensate, cooling towerblowdown, and stormwater), and stormwater are discharged via Outfall 003. According to the permit application, domestic wastewater is routed to on-site septic tanks. The plant site is located adjacent to Cedar Lake, approximately 8 miles east ofthe intersection of Farm-to-Market Road 1066 and Farm-to-Market Road 303, southeast oftheTown ofLoop in Gaines County, Texas. Discharge Routes The effluentis discharged via Outfall 001 to a ditch; thence to Seco Draw; thence to Cedar Lake; via Outfall 002 to the Salt Reclamation Pond; thence to Cedar Lake; andvia Outfall 003 via culverts to Coyote Draw; thenceto Cedar Lake in SegmentNo. 1400 ofthe Colorado River. The unclassified receiving waters have minimal aquatic life use for the ditch, Seco Draw, Coyote Draw, and Cedar Lake. The effluent limits in the draft permit will maintain and protectthe existing instream uses. All determinations are preliminary and subject to additional review and revisions. Antidegradation Review In accordance with 30 TAC § 307.5 and the TCEQ implementation procedures (June 2010) for the Texas SurfaceWater Quality Standards, an antidegradation review ofthe receiving waters was performed. ATier 1 antidegradation review has preliminarily determined that existing water quality
uses will notbeimpairedbythis permit action. Numerical and narrative criteria to protect existing
uses will be maintained. ATier 2 review is not required since no exceptional, high, or intermediate aquatic life use waterbodies havebeen identified in the discharge route. Existing uses will be maintained and protected. The preliminarydetermination can be reexamined and maybe modified if
new information is received. EndangeredSpecies Review The discharge from this permit is not expected to have an effect on anyfederal endangered or threatened aquatic or aquatic-dependent species orproposed species or their critical habitat. This Page 2

### STATEMENT OF BASIS /TECHNICAL SUMMARY AND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION TPDES Permit No. WQooo3642000
determination is based on the United States Fish and Wildlife Service's (USFWS's) biological opinion
on the State ofTexas authorization oftheTPDES (September 14, 1998, and October 21, 1998 update). To make this determination for TPDES permits, TCEQ andthe EPA only considered aquatic or aquatic-dependent species occurring inwatersheds ofcritical concern or high priority as listed in Appendix A ofthe USFWS biological opinion. The determination is subjectto reevaluation due to subsequent updates or amendments to thebiological opinion. The permit does not require EPA review with respect to the presence ofendangered orthreatened species. ImpairedWaterBodies 

### None ofthewaterbodies in the discharge routes are currentlylisted onthe State's inventory of impaired andthreatened waters (the 2012 Clean Water Act Section 303(d) list).
SUMMARYOF EFFLUENT DATA


### The following is a quantitative description ofthe discharge described in the Monthly Effluent Report data for the period October 2009 through September 2014. The "Average ofDaily Avg" values presented in the following table are the average ofall daily average values for the reporting period for each parameter. The "Maximum ofDaily Max" values presented in the following table are the individual maximum values for the reporting period for each parameter. Flows are expressed in million gallons per day (MGD). pH values are expressed in standardunits (SU).
Flow 

### Average of Maximum of

Outfall Frequency Daily Avg, MGD Daily Max, MGD

001 Continuous 1.259 1.575 002 Intermittent No discharge reported 003 Intermittent 0.148 1.305
Effluent Characteristics



### Outfall Parameter

001 Total Dissolved Solids (TDS) Specific Gravity Chloride Sulfate as S04 

### Oil and Grease pH 002 _T;::cD=S-;--,;-----;:---:c------- Specific Gravity Average of Daily Avg, mg/L 179,697 1.141 (*1)

25,508

N/A 6.0 SU, min Maximum of Daily Max, mg/L 282,800 1.210 (*1) 166,000 435,001

22.8 8.8SU

Chloride Sulfate as S04 

### No discharge reported Oil and Grease

H 

### 003 TDS 150,115 326,000 Specific Gravity 1.117 (*1) 1.212 (*1) Chloride 66,857 211,000 Sulfate as S04 

### 40,717 178,000 OilandGrease N/A 11.6 pH 6.1 SU, min 8.8SU ("*1) This parameter has no units; it is dimensionless. Page3STATEMENT OF BASIS 

### j TECHNICAL SUMMARYAND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION TPDES Permit No. WQooo3642000

The facility reported a single violation ofits effluentlimits (daily maximum oil and grease at Outfall 001) duringthe period reviewed. No changes were made to the draft permitbased onthis single violation.
DRAFT PERMIT CONDITIONS
The draftpermit authorizes the discharge oftreatedprocess wastewater (plantfloor wash water and evaporation condensate), spentbrine, and stormwater at a daily average flow notto exceed 2.0 MGD via Outfall 001; decantedbrinewater, floor washdown water, condensate, non-contact cooling water, and stormwater on an intermittentandflow-variable basis via Outfall 002; andbrine water, condensate, tankwashdown water, stormwater, and overflowfrom the evaporationpond on an intermittent and flow-variable basis via Outfall 003.
Effluent limitations are established in the draftpermit as follows:

Outfall Pollutant DailyAverage, mg/L Daily Maximum, mg/L

001 Flow 2.oMGD 2.5MGD TDS Report Report Specific Gravity Report (''1) Report (*1) Chloride Report Report Sulfate Report Report Oil and Grease N/A 20 pH 6.0 SU,min g.oSU 002 Flow Report, MGD Report, MGD TDS Report Report Specific Gravity Report ('*1) Report (*1) Chloride Report Report Sulfate Report Report Oil and Grease N/A 20 pH 6.0 SU, min g.o SU 003 Flow Report,MGD Report, MGD TDS Report Report Specific Gravity Report (*1) Report (*1) Chloride Report Report Sulfate Report Report Oil and Grease N/A 20 pH 6.0 SU, min g.oSU (''1) This parameterhas no units; itis dimensionless. Technology-Based Effluent Limitations Regulations promulgated inTitle 40 ofthe Code ofFederal Regulations (40 CFR) require technologybasedlimitations to beplaced in wastewater discharge permits based on effluent limitations guidelines (ELGs), where applicable, or onbestprofessionaljudgment (BPJ) in the absence of guidelines. ELGs in 40 CFR Part436

- Mineral Mining and Processing, Subpart L- Salines from Brine Lakes, have been previously applied to the withdrawal ofbrine from Cedar Lake and subsequent processing ofsodium sulfate. According to regulations in 40 CFR § 436.122(a) for bestpracticable control technology currently available (BPT): "there shallbe no discharge ofprocess waste water pollutants into navigable waters." Historically, the ELGs in 40 CFR § 436.122(b), which apply the limitations in 40 CFR § 436.122(a) [no discharge] on a netbasis when "the source ofthe applicant's water supply is the samebodyofwaterinto which the discharge is made," were usedto establish Page4STATEMENT OF BASIS/ TECHNICAL SUMMARYAND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION TPDES Permit No. WQooo3642000
Other Requirement No.3 in the original permit (issuedJuly 5, 1994). Other Requirement No.3 prohibits any net increase ofTDS, chloride, and sulfate in the combined discharges from Outfalls 001, 002, and 003 and specifies that sulfate mustbe used as the indicator parameter. With this application, the permittee submitted an "Approved Jurisdictional Determination Form" completedbythe U.S. Army Corps ofEngineers onApril2, 2010. According to this determination form, Cedar Lake is "an intrastate, non-navigable isolated water (salt playa lake) and is not subject to Section 404jurisdictionunder 33 CFR 328.3(a)(3)." The prohibition on discharging in 40 CFR § 436.122(a) and the application ofthatprohibition on a netbasis in 40 CFR §436.122(b) therefore do not apply; however, the permittee did not request removal ofOther Requirement No.3 from the permit. The review performed during the original permit action determinedthat TDS, chloride, and sulfate were appropriate indicator parameters for the wastewaterbeing discharged, and monitoring and reporting requirements for these parameters were included in the original permit. Monitoring and reporting requirements for specific gravity were also included in the original permitin order to determine whether a correlation couldbe established with TDS concentration, butitis unclear whether such an analysis was ever performed. Monitoring and reporting requirements for TDS, chloride, sulfate, and specific gravity are therefore carriedforward in the draft permit based on EPA anti-backsliding requirements at 40 CFR §122-44(1). The permittee did request thatthe monitoring frequencies for TDS, chloride, sulfate, and specific gravity be reduced from once per week to once per year. The requested frequency is consistentwith the existing monitoring and reporting frequency for oil and grease, and the requested changes havebeen made. The oil and grease and pH limits, which were originally establishedbased on BPJ, are continued in the draftpermitbased on EPA antibacksliding requirements at 40 CFR §122-44(1).


### Water Quality-BasedEffluent Limitations Calculations ofwater quality-based effluent limitations for the protection ofaquatic life are presented inAppendixA. Aquatic life criteria established inTable 1of30 TAC Chapter 307 are incorporatedinto the calculations, as are recommendations in the Water Quality AssessmentTeam memorandum dated January 6, 2015. TCEQ practice for determining significantpotential is to compare the reported analytical data from thefacility against percentages ofthe calculated daily average water qualitybased effluent limitation. Permitlimitations are required when analytical data reported in the application exceeds 85 percent ofthe calculated daily average water quality-based effluent limitation. Monitoring and reporting is required when analytical data reported inthe application exceeds 70 percent ofthe calculated daily average water quality-based effluent limitation. Effluent data was submitted with the application for Outfalls 001 and 003; there was no discharge via Outfall 002 during the previous permitterm. OtherRequirement No.9 hasbeen added to the draft permitrequiring submittal ofeffluent testing for Outfall 002 within 90 days ofa discharge. Effluent data for total aluminum at Outfall 003 andhexavalent chromium, total selenium, and total silver at both Outfalls 001 and 003 exhibited a wide range ofnon-detectlevels (5

- 500 11g/L) thatwere all greater than the required minimum analytical levels (MALs) in the permit application. Given the extremely high TDS concentrations in the effluent, it appears likely that effluent test results were affected bymatrix interference and that achievement ofthe TCEQ MALs for these parameters may not bepossible. Forthis reason, Other Requirement No. 11 was added to require a studyto establish effluent-specific MALs for these pollutants. The study is to be completed and submitted to the TCEQ within oneyear ofthe date ofpermit issuance andwith the nextpermit application. 

### TDS, Chloride, and Sulfate Screening Cedar Lake, which receives the discharges from thisfacility, does not have criteria established for TDS, chloride, or sulfate in 30 TAC Chapter 307; therefore, no screening was performed. PagespH Screening 

### STATEMENT OF BASIS/ TECHNICAL SUMMARYAND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION TPDES Permit No. WQooo3642000

The existing permit includes limits onpHof6.0

- 9.0 SU at Outfalls 001, 002, and 003, which discharge into unclassified waterbodies. Consistent with the procedures for pH screening thatwere submittedto EPA with a letter dated May 28, 2014, and approvedby EPA in a letter dated June 2, 2014, requiring these discharges to unclassified water bodies to meet pH limits of6.0

- 9.0 standard units reasonably ensures instream compliance withTexas Surface Water Quality Standards pH criteria.
Whole Effluent ToxicityTesting (Biomonitoring) 

### Biomonitoring requirements are not included in the draft permit.
SUMMARYOF CHANGES FROMAPPLICATION


### The following change has been made to the draft permit that makes it more stringent:

1. 

### Other Requirement No. 11 

### has been added to require the permittee to conduct a studyto establish effluent-specific MALs for total aluminum, hexavalent chromium, total selenium, and total silver. Effluent testing submitted during the application process for these pollutants exhibited a wide range ofnon-detectlevels (5

- 500 f.lg/L). Given the extremely high TDS concentrations in the effluent, it appears likely that effluent testresults were being affected by matrixinterference and that achievement ofthe TCEQ MALs for these parameters may notbe possible. The study is to be completed and submittedto the TCEQ within one year ofthe date of permit issuance andwith the next permit application.
SUMMARYOF CHANGES FROM EXISTINGPERMIT


### The permittee requested the following change in its amendment request that the Executive Director (ED) has recommended granting.

1. 

### Reduce samplingfrequencies for TDS, chloride, sulfate, and specific gravity from once perweek to once peryear at all three outfalls. Based on information providedinthe application, Cedar Lake is not considered to be a navigable waterbody, and the ELGs in40 CFR § 

### 436.122 no longer apply. The monitoring andreporting requirements for TDS, chloride, sulfate, and specific gravitywere originally included in the permitbased on the ELGs. The permittee has not requested that these requirementsbe removed frotn the permit, butthe ED agrees there is no reason to require weekly monitoring. The monitoring frequencies for these pollutants have been reduced to once peryear as requested. The following additional changes have been madeto the draft permit.

1. 

### "Salt Cake Reclamation Pond" has been changed to "Salt Reclamation Pond" in the discharge route for Outfall 002, consistentwith the information provided in the permit application. 2. Other Requirement No. 1has been updated with current language usedto prohibit discharge of domestic wastewater. 3· Other Requirement No. 3, which deals with the no net increase ofTDS, chloride, and sulfate, has been revised for clarity andto change the frequency ofupdating records from monthlyto yearly, consistent with the change in monitoring and reporting frequencies on pages 2-2b. 4· Other Requirement No. 5 has been revised to specify that the mixing zone definition applies to all three outfalls. 5· Other Requirement No.6, which deals with the disposal ofcooling tower blowdown into an evaporation pond, has been revised for clarity. Page6

### STATEMENT OF BASIS/ TECHNICAL SUMMARYAND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION TPDES Permit No. WQooo3642000

6. Other Requirement No. 8 has been revised to remove the instructions for submitting data for pollutants that are monitored twice peryear and four times peryear because the draftpermit does not include either ofthese monitoring frequencies. 7. Existing Other Requirement No.9, dealing with intensive water quality surveys, hasbeen removed because it is no longer applicable. 8. Existing Other Requirement No. 10 has been removed because it is no longer applicable. 9. New Other Requirement No. 9 has been added to require effluent samplingfor Outfall 002 upon discharge. Effluent testing tables have been added as AttachmentA. 10. New Other Requirement No. 10 has been added to specify requirements for any new ponds constructed after this permit is issued.
BASIS FORDRAFfPERMIT


### The following items were considered in developing the draft permit: 1. Application received on October 14, 2014, and additional information received on November 12, December 1, and December 3, 2014, and on March 13, 2015 2. Existing permits: TPDES PermitNo. WQooo3642000 issued onApri113, 2010 3. TCEQ Rules 4. Texas Surface Water Quality Standards- 30 TAC §§307.1-307.10, effective March 6, 2014, as approvedbyEPA Region 6 5· Texas SurfaceWater Quality Standards- 30 TAC §§307.1-307.10, eflective July 22, 2010, as approvedbyEPA Region 6, for portions ofthe 2014 Standards not approved by EPA Region 6 6. Texas Surface Water Quality Standards

- 30 TAC §§307.1-307.10, effective August 17, 2000, and Appendix E, effective February 27, 2002, for portions ofthe 2010 Standards not approvedby EPA Region 6 7· Procedures to Implement the Texas Surface Water Quality Standards (IP), Texas Commission
on Environmental Quality, June 2010, as approved by EPA Region 6 8. Procedures to Implement the Texas Surface Water Quality Standards, Texas Commission on Environmental Quality, January 2003, for portions ofthe 2010 IP not approved byEPA Region 6 9· Memos from theWater Quality Standards Implementation Team and the Water Quality Assessment Team ofthe Water Quality Assessment Section ofthe TCEQ 10. "Guidance Document for Establishing Monitoring Frequencies for Domestic and Industrial Wastewater Discharge Permits," TCEQ Document No. 98-oo1.ooo-OWR-WQ, May 1998

11. 

### EPA Effluent Guidelines: N/A 12. Consistencywith the Coastal Management Plan: N/A 13. Letter dated May 28, 2014, from L'Oreal W. Stepney, P.E., Deputy Director, Office ofWater, TCEQ, to Bill Honker, Director, Water Quality Protection Division, EPA (TCEQ proposed development strategyfor pH evaluation procedures) 14. Letter dated June 2, 2014, from William K. 

### Honker, P.E., Director, Water Quality Protection Division, EPA, to L'Oreal W. Stepney, P.E., Deputy Director, Office ofWater, TCEQ (Approval of TCEQ proposed development strategyfor pH evaluation procedures)
Page7STATEMENT OF BASIS/ TECHNICAL SUMMARYAND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION TPDES Permit No. 

### WQooos642ooo

PROCEDURES FOR FINAL DECISION
When an application is declared administratively complete, the Chief Clerk sends a lettertothe applicant advising the applicantto publishtheNotice ofReceipt ofApplication and Intentto Obtain Permit inthe newspaper. In addition, the ChiefClerk instructs the applicant to place a copy ofthe applicationin a public place for reviewing and copying inthe countywhere the facility is orwill be located. This application will be in a publicplace throughoutthe comment period. The ChiefClerk also mails this notice to any interested persons and, ifrequired, tolandowners identifiedinthe permit application. This notice informs the public aboutthe application andprovides that an interestedperson may file comments onthe application or request a contested case hearing or a public meeting. Once a draftpermitis completed, it is sent, along with the Executive Director'spreliminarydecision, as containedinthe technical summaryorfact sheet, tothe ChiefClerk. At thattime, the Notice of Application and Preliminary Decision will bemailedto the samepeople andpublished in the same newspaper as the priornotice. This notice sets a deadline for maldng public comments. The applicant mustplace a copy ofthe Executive Director's preliminary decision and draft permitinthe publicplace withthe application. This notice sets a deadline for public comment. Any interested person may request a public meeting onthe application until the deadline for filing public comments. Apublic meeting is intendedfor thetaking ofpublic comment and is nota contested
case proceeding. After the public comment deadline, the Executive Director prepares a response to all significantpublic comments onthe application orthe draft permit raised during the public commentperiod. The Chief Clerkthen mails the Executive Director's response tocomments andfinal decision to people who have filed comments, requested a contested case hearing, orrequested tobe onthe mailing list. This notice provides thatifa person is not satisfied with the Executive Director's response and decision, they can request a contested case hearing orfile a request to reconsider the Executive Director's decision within 30 days after the notice is mailed. The Executive Director will issue the permit unless a writtenhearingrequest or requestfor reconsiderationis filed within 30 days after the Executive Director's response to comments andfinal decision is mailed. Ifa hearingrequest or requestfor reconsideration is filed, the Executive Director will notissue the permit andwill forward the application andrequesttothe TCEQ Commissioners for their consideration at a scheduled Commission meeting. Ifa contested case hearing is held, it will be a legal proceeding similarto a civil trial in state district court. Ifthe Executive Director calls a public meeting orthe Commission grants a contested case hearing as described above, the Commission will give notice ofthe date, time, andplace ofthe meeting or hearing. Ifa hearingrequest orrequestfor reconsideration is made, the Commission will consider all public comments in making its decision and shall either adopt the Executive Director's response to comments orprepare its own response. For additional information aboutthis application, contact Karen Halligan at (512) 239-4589.

March 31, 2015 Karen Halligan Date

PageS

### STATEMENT OF BASIS/TECHNICAL SUMMARYAND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION AppendixA CalculatedWater Quality-Based EffluentLimits

TEXTOX MENU #1- INTERMITTENT STREAM

The water quality-based effluent limitations developed below are calculated using:

Table 1, 2014 Texas Surface Water Quality Standards (30 TAC 307) for Freshwater Aquatic Life "Procedures to Implement the Texas Surface Water Quality Standards," TCEQ June 2010

PERMIT INFORMATION Permittee Name: TPDES Permit No: Outfall No: Prepared By: Date:

DISCHARGE INFORMATION Intermittent Receiving Waterbody: Segment No: Cooper Natural Resources Inc. WQ0003642000 001,002,003 Karen Halligan January 30, 2015

ditch, Seco Draw, Coyote Draw, Cedar Draw 1400 TSS (mg/L): 16 (Value from Segment No. 1412) pH (Standard Units): 7.6 (Value from Segment No. 1412) Hardness (mg/L as CaC03 ): 31D (Value from Segment No. 1412) Chloride (mg/L): 1635 (Value from Segment No. 1412) Effluent Flow for Aquatic Life (MGD): not needed- results not dependent on flow Critical Low Flow [7Q2) (cis): 0 %Effluent for Acute Aquatic Life: ____:1c"O::.O

____________ _

CALCULATE DISSOLVED FRACTION (AND ENTER WATER EFFECT RATIO IF APPLICABLE): Partftlon Dissolved Water Intercept Slope Coefficient Fraction Effect Ratio Stream/RiverMetal (b) (m) {Kp} {Cd/Ct) {WER) Aluminum N/A N/A N/A 1.00 Assumed 1 Assumed Arsenic 5.68 -0.73 63240.08 0.50 1 Assumed Cadmium 6.60 -1.13 173517.95 0.26 1 Assumed Chromium (Total) 6.52 -0.93 251286.07 0.20 1 Assumed Chromium (+3) 6.52 -0.93 251286.07 0.20 1 Assumed Chromium (+6) N/A N/A N/A 1.00 Assumed 1 Assumed Copper 5.02 -0.74 134570.92 0.32 1 Assumed Lead 6.45 -0.80 306593.11 0.17 1 Assumed Mercury N/A N/A N/A 1.00 Assumed 1 Assumed Nickel 5.69 -0.57 100844.36 0.38 1 Assumed Selenium N/A N/A N/A 1.00 Assumed 1 Assumed Silver 6.38 -1.03 137951.03 0.31 1 Assumed Zinc 6.10 -0.70 180765.59 0.26 1 Assumed



### Page9

### STATEMENT OF BASIS/ TECHNICAL SUMMARY AND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION TPDES Permit No. WQ0003642000

AQUATIC LIFE CAlCUlATE DAllY AVERAGE AND DAllY MAXIMUM EFFlUENT LIMITATIONS: FWAcute Daily Daily Criterion Avg. Max. Parameter (ug/L} WLAa LTAa (ug/L} (ug/L} Aldrin 3.0 3.0 1.72 2.53 5.35 Aluminum 991 991 568 835 1766 Arsenic 340 684 392 576 1219 Cadmium 25.7 97.2 55.7 81.9 173 Carbaryl 2.0 2.0 1.15 1.68 3.56 Chlordane 2.4 2.4 1.38 2.02 4.28 Chlorpyrifos 0.083 0.083 0.048 0.070 0.148 Chromium (+3) 1439 7226 4140 6086 12876 Chromium (+6) 15.7 15.7 9.00 13.2 28.0 Copper 41.2 130 74.5 110 232 Cyanide (free) 45.8 45.8 26.2 38.6 81.6 4,4'-DDT 1.1 1.1 0.630 0.927 1.96 Demeton N/A N/A N/A N/A N/A Diazlnon 0.17 0.17 0.097 0.143 0.303 DicofoJ 59.3 59.3 34.0 49.9 106 Dieldrin 0.24 0.24 0.138 0.202 0.428 Diu ron 210 210 120 177 374 Endosulfan I (alpha) 0.22 0.22 0.126 0.185 0.392 Endosulfan II (beta) 0.22 0.22 0.126 0.185 0.392 Endosulfan sulfate 0.22 0.22 0.126 0.185 0.392 Endrin 0.086 0.086 0.049 0.072 0.153 Guthion N/A N/A N/A N/A N/A Heptachlor 0.52 0.52 0.298 0.438 0.927 Hexachlorocyclohexane (Lindane) 1.126 1.126 0.645 0.948 2.01 Lead 216 1275 731 1074 2272 Malathion N/A N/A N/A N/A N/A Mercury 2.4 2.4 1.38 2.02 4.28 Methoxychlor N/A N/A N/A N/A N/A Mirex N/A N/A N/A N/A N/A Nickel 1219 3187 1826 2684 5679 Nonylphenol 28 28 16.0 23.6 49.9 Parathion (ethyl) 0.065 0.065 0.037 0.055 0.116 Pentachlorophenol 15.9 15.9 9.14 13.4 28.4 Phenanthrene 30 30 17.2 25.3 53.5 Polychlorinated Biphenyls (PCBs) 2.0 2.0 1.15 1.68 3.56 Selenium 20 20 11.5 16.8 35.6 Silver 0.8 28.6 16.4 24.1 50.9 Toxaphene 0.78 0.78 0.447 0.657 1.39 Trlbutyltin (TBT) 0.13 0.13 0.074 0.110 0.232 2,4,5 Trichlorophenol 136 136 77.9 115 242 Zinc 306 1190 682 1002 2120



### Page 10

### STATEMENT OF BASIS/ TECHNICAL SUMMARY AND EXECUTIVE DIRECTOR'S PRELIMINARY DECISION TPDESPermit No. WQooo3642000

CALCULATE 70% AND 85% OF DAILY AVERAGE EFFLUENT LIMITATIONS:

Aquatic Life Parameter 70% 85% Aldrin. 1.77 2.15 Aluminum 584 710 Arsenic 403 490 Cadmium 57.3 69.6 Carbaryl 1.18 1.43 Chlordane 1.42 1.72 Chlorpyrifos 0.049 0.059 Chromium (+3) 4260 5173 Chromium (+6) 9.26 11.2 Copper 76.7 93.1 Cyanide (free) 27.0 32.8 4,4'-DDT 0.649 0.788 Demeton N/A N/A Diazinon 0.100 0.122 Dicofol 35.0 42.5 Dieldrin 0.142 0.172 Diu ron 124 150 Endosulfan I (alpha) 0.130 0.158 Endosulfan II (beta) 0.130 0.158 Endosulfan sulfate 0.130 0.158 Endrin 0.051 0.062 Guthion N/A N/A Heptachlor 0.307 0.372 Hexachlorocyclohexane (Lindane) 0.664 0.806 Lead 752 913 Malathion N/A N/A Mercury 1.42 1.72 Methoxychlor N/A N/A Mirex N/A N/A Nickel 1879 2282 Nonylphenol 16.5 20.0 Parathion (ethyl) 0.038 0.047 Pentachlorophenol 9.40 11.4 Phenanthrene 17.7 21.5 Polychlorinated Biphenyls (PCBs) 1.18 1.43 Selenium 11.8 14.3 Silver 16.8 20.5 Toxaphene 0.460 0.558 Tributyltin (TBT) 0.077 0.093 2,4,5 Trichlorophenol 80.2 97.4 Zinc 701 852



### Page 11