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HomeMy WebLinkAboutDWQ-2025-000354 Page 1 of 5 Utah Division of Water Quality Statement of Basis ADDENDUM Wasteload Analysis and Antidegradation Level I Review Date: December 9, 2024 Facility: Garland City Wastewater Treatment Facility UPDES No. UT-0026085 Receiving Water: Malad River (2B, 3C) This addendum summarizes the wasteload analysis that was performed to determine water quality based effluent limits (WQBEL) for this discharge. Wasteload analyses are performed to determine point source effluent limitations necessary to maintain designated beneficial uses by evaluating projected effects of discharge concentrations on in-stream water quality. The wasteload analysis also takes into account downstream designated uses (UAC R317-2-8). Projected concentrations are compared to numeric water quality standards to determine acceptability. The numeric criteria in this wasteload analysis may be modified by narrative criteria and other conditions determined by staff of the Division of Water Quality. Discharge Outfall 001: Discharge is into Malad River, which discharges into Bear River. The design capacity of the facility is 0.90 MGD, presumed to be the maximum daily design discharge. The maximum monthly average design discharge is 0.45 MGD. Receiving Water The receiving water for Outfall 001 is Malad River, which is tributary to Bear River, which drains to Bear River Bay of the Great Salt Lake. Per UAC R317-2-13.3.a, the designated beneficial uses for Malad River and tributaries, from confluence with Bear River to state line are 2B, 3C.  Class 2B - Protected for infrequent primary contact recreation. Also protected for secondary contact recreation where there is a low likelihood of ingestion of water or a low degree of bodily contact with the water. Examples include, but are not limited to, wading, hunting, and fishing.  Class 3C - Protected for nongame fish and other aquatic life, including the necessary aquatic organisms in their food chain. Per UAC R317-2-13.3.a, the designated beneficial uses for Bear River and tributaries, from Great Salt Lake to Utah-Idaho border, except as listed below are 2B,3B,3D,4.  Class 3B - Protected for warm water species of game fish and other warm water aquatic life, including the necessary aquatic organisms in their food chain. Utah Division of Water Quality Wasteload Analysis Garland City Wastewater Treatment Facility, UPDES No. UT0026034 Page 2 of 5  Class 3D – Protected for waterfowl, shore birds and other water-oriented wildlife not included in Classes 3A, 3B, or 3C, including the necessary aquatic organisms in their food chain.  Class 4 - Protected for agricultural uses including irrigation of crops and stock watering. Protection of Downstream Uses Per UAC R317-2-8, all actions to control waste discharges under these rules shall be modified as necessary to protect downstream designated uses. For this discharge, numeric aquatic life use criteria need to be met for both Malad River and Bear River. Receiving Water Critical Flow Typically, the critical flow for the wasteload analysis is considered the lowest stream flow for seven consecutive days with a ten-year return frequency (7Q10). Due to a lack of flow records for the source waters, the 20th percentile of flow measurements from water quality monitoring conducted by DWQ was calculated to estimate seasonal critical flow in the receiving water (Table 1). Measurements were collected from monitoring site DWQ 4902720 MALAD R AB TREMONTON WWTP. The average seasonal value was calculated for each constituent with available data in the receiving water. Table 1: Malad River critical low flow from DWQ 4902720 MALAD R AB TREMONTON WWTP Season Flow (cfs) Summer 33.6 Fall 33.2 Winter 46.4 Spring 44.0 Total Maximum Daily Load (TMDL) According to the Utah’s Final 2024 Integrated Report on Water Quality dated April 30, 2024, the receiving water for the discharge, “Malad River and tributaries, from confluence with Bear River to state line (Assessment Unit Malad River-1, AU ID: UT16010204-006_00)” was listed as “Not Supporting” for Benthic Macroinvertebrates Bioassessments, E. coli, Thalium, and pH. A TMDL is needed, however, the priority is set to “Low”. There was an approved TMDL completed in 2002 for Total Phosphorous. The downstream reach “Bear River and tributaries, from Great Salt Lake to Utah-Idaho border, except as listed below (Assessment Unit Bear River-2-2, AU ID: UT16010204-008_02)” was listed as “Not Supporting” for Benthic Macroinvertebrates Bioassessments and Total Dissolved Solids. A TMDL is needed, however, the priority is set to “Low”. Mixing Zone Per UAC R317-2-5, the maximum allowable mixing zone is 15 minutes of travel time for acute conditions, not to exceed 50% of stream width, and 2,500 feet for chronic conditions. Water quality standards must be met at the end of the mixing zone. Utah Division of Water Quality Wasteload Analysis Garland City Wastewater Treatment Facility, UPDES No. UT0026034 Page 3 of 5 The actual length of the mixing zone was not delineated as part of this wasteload analysis; however, it was presumed to remain within the maximum allowable mixing zone dimensions. Acute limits were calculated using 50% of the annual critical low flow. Parameters of Concern The potential parameters of concern identified for the discharge/receiving water were total suspended solids (TSS), dissolved oxygen (DO), BOD5, total phosphorus (TP), total nitrogen (TN), total ammonia (TNH3), pH, and total dissolved solids (TDS), as determined in consultation with the UPDES Permit Writer, the Utah Water Quality Assessment Reports, and the industry SIC codes from https://www.osha.gov/data/sic-search. Water Quality Modeling A QUAL2Kw model of the Malad River downstream of the Tremonton WWTP was built and calibrated by DWQ to synoptic survey data collected by DWQ staff in August of 2011. The model extends 10.3 kilometers along Malad River downstream from the treatment facility outfall. The calibrated model was extended approximately 5.5 kilometers upstream from the Tremonton WWTP to the Garland WWTP and continues downstream approximately 4.8 kilometers from the Tremonton WWTP to the crossing at West 8800 North. The methods and results of the model calibration are summarized in the QUAL2Kw Calibration Report for the Malad River (DWQ 2019). Receiving water quality data was obtained from monitoring site DWQ 4902720 MALAD R AB TREMONTON WWTP. The average seasonal value was calculated for each constituent with available data in the receiving water for each of the parameters. Seasonal effluent flow and parameter concentrations were characterized using data from the Garland WWTP facility discharge monitoring report (DMR). Monitoring site DWQ 4902710 TREMONTON WWTP was also used as a downstream point source. No other tributary inflows or irrigation return flows were considered. The seasonal value was calculated for each constituent with available data in the effluent discharge using the 80th percentile for acute parameters and the average for chronic parameters. The QUAL2Kw model was used for determining the WQBELs for parameters related to eutrophication and in-stream DO criteria, as well as ammonia toxicity. Effluent concentrations were adjusted so that water quality standards were not exceeded in the receiving water. Where WQBELs exceeded secondary standards or technology based effluent limits (TBEL), the concentration in the model was set at the secondary standard or TBEL. Fish early life stages (ELS) are assumed absent. The QUAL2Kw model was also used to determine the limits for ammonia. The water quality standard for chronic ammonia toxicity is dependent on temperature and pH, and the water quality standard for acute ammonia toxicity is dependent on pH. QUAL2Kw rates, input and output for DO and eutrophication related constituents are summarized in Appendix A. Utah Division of Water Quality Wasteload Analysis Garland City Wastewater Treatment Facility, UPDES No. UT0026034 Page 4 of 5 A mass balance mixing analysis was conducted for conservative constituents such as dissolved metals. The WQBELs for conservative constituents are summarized in Appendix B. The decay of chlorine from the treatment plant to the outfall at the river was estimated based on a first-order decay equation. The analysis for total residual chlorine (TRC) is summarized in Appendix C. The calibration and wasteload models are available for review by request. Whole Effluent Toxicity (WET) Limits The percent of effluent in the receiving water in a fully mixed condition, and acute and chronic dilution in a not fully mixed condition are calculated in the WLA in order to generate WET limits. The LC50 (lethal concentration, 50%) percent effluent for acute toxicity and the IC25 (inhibition concentration, 25%) percent effluent for chronic toxicity, as determined by the WET test, needs to be below the WET limits, as determined by the WLA. The WET limit for LC50 is typically 100% effluent and does not need to be determined by the WLA. WET limits are provided in Table 2. Table 2: WET Limits for IC25 Season Percent Effluent Summer 2% Fall 2% Winter 1% Spring 2% Effluent Limits Eutrophication and dissolved oxygen in the receiving water were evaluated using the QUAL2Kw model. A DO sag was not observed downstream in the Malad River. Algal growth appeared to be light limited likely as a result of the high TSS. However, the DO concentration was not predicted to exceed water quality criteria within the model extents. Therefore, limits beyond secondary standards are not required for DO and BOD5. The complete list of WQBELs is listed in Appendices A, B, and C. However, all WQBELs greater than the current effluent limits listed in the Permit, revert to the previous limits. Antidegradation Level I Review The objective of the Level I ADR is to ensure the protection of existing uses, defined as the beneficial uses attained in the receiving water on or after November 28, 1975. No evidence is known that the existing uses deviate from the designated beneficial uses for the receiving water. Therefore, the beneficial uses will be protected if the discharge remains below the WQBELs presented in this wasteload. A Level II Antidegradation Review (ADR) is not required for this discharge, as pollutant concentration and load are not proposed to increase beyond the design capacity of the facility under this permit renewal. Utah Division of Water Quality Wasteload Analysis Garland City Wastewater Treatment Facility, UPDES No. UT0026034 Page 5 of 5 Prepared by: Christopher L. Shope, PhD Standards and Technical Services Section Documents WLA Document: 241209-Garland_WWTP_Q2Kw_WLA_2024.docx QUAL2Kw Calibration Model: garland_q2kw_cal_2019.xlsm QUAL2Kw Wasteload Model: 241209-Garland_WWTP_Q2Kw_WLA_2024.xlsm References: Neilson, B.T., A.J. Hobson, N. von Stackelberg, M. Shupryt, and J.D. Ostermiller. 2012. Using QUAL2K Modeling to Support Nutrient Criteria Development and Wasteload Analyses in Utah. 2012. https://documents.deq.utah.gov/legacy/programs/water-quality/standards-technical- services/docs/2012/12Dec/UtahQ2kModelingDataGuidance-Final_12-12-12.pdf Utah Division of Water Quality. 2002. Lower Bear River Watershed Restoration Action Strategy. Utah Division of Water Quality. 2012. Field Data Collection for QUAL2Kw Model Build and Calibration Standard Operating Procedures Version 1.0. https://documents.deq.utah.gov/legacy/programs/water-quality/standards-technical- services/docs/2012/05May/SOP_QUAL2Kw_Data_Collection_V1_2012-05-30.pdf Utah Division of Water Quality. 2019. QUAL2Kw Calibration Report for the Malad River. Utah Division of Water Quality. 2021. Utah Wasteload Analysis Procedures Version 2.0. https://documents.deq.utah.gov/water-quality/standards-technical-services/DWQ-2021-000684.pdf Utah Division of Water Quality. 2024. Final 2024 Integrated Report on Water Quality. https://lf- public.deq.utah.gov/WebLink/DocView.aspx?id=87957&repo=Public&searchid=fcd9ea4c-51e1-4227-aa29- fb1921c2cc19&cr=1 Utah Division of Water Quality WASTELOAD ANALYSIS [WLA]Date: 1/8/2025 Appendix A: QUAL2Kw Analysis for Eutrophication Discharging Facility: Garland WWTP UPDES No: UT-0026034 Permit Flow [MGD]: 0.5 Maximum Monthly Flow 0.9 Maximum Daily Flow Receiving Water: Malad River Stream Classification: 2B,3C Stream Flows [cfs]: 33.6 Summer (July-Sept) Critical Low Flow 33.2 Fall (Oct-Dec) 46.4 Winter (Jan-Mar) 44.0 Spring (Apr-June) Fully Mixed: NO Acute River Width: 50% Chronic River Width: 100% Modeling Information A QUAL2Kw model was used to determine these effluent limits. Model Inputs The following is upstream and discharge information that was utilized as inputs for the analysis. Dry washes are considered to have an upstream flow equal to the flow of the discharge. Headwater Inputs Summer Fall Winter Spring Flow (cfs)33.6 33.2 46.4 44.0 Temperature (deg C)18.8 8.0 4.7 14.3 Specific Conductance (µmhos)4586 4565 3793 4528 Inorganic Suspended Solids (mg/L)158.9 65.1 92.6 107.7 Dissolved Oxygen (mg/L)8.1 9.4 10.1 8.2 CBOD5 (mg/L)4.1 2.2 2.0 3.5 Organic Nitrogen (mg/L)2.863 1.270 1.290 1.808 NH4-Nitrogen (mg/L)0.077 0.078 0.102 0.073 NO3-Nitrogen (mg/L)2.387 1.308 0.671 1.275 Organic Phosphorus (mg/L)0.049 0.000 0.000 0.074 Inorganic Ortho-Phosphorus (mg/L)0.094 0.077 0.146 0.085 Phytoplankton (µg/L)0.0 0.0 0.0 0.0 Detritus [POM] (mg/L)17.2 2.9 8.4 14.2 Alkalinity (mg/L)356 351 352 366 pH 8.1 8.0 8.1 8.1 Discharge Inputs Summer Fall Winter Spring Flow (cfs)0.5 0.5 0.5 0.5 Temperature (deg C)17.7 12.6 9.4 13.7 Specific Conductance (µmhos)1565 1589 1535 1492 Inorganic Suspended Solids (mg/L)1.3 1.3 5.3 4.9 Dissolved Oxygen (mg/L)5.0 5.0 5.0 5.0 CBOD5 (mg/L)25.0 25.0 25.0 25.0 Organic Nitrogen (mg/L)10.277 5.600 11.960 11.960 NH4-Nitrogen (mg/L)1.000 2.500 15.000 15.000 NO3-Nitrogen (mg/L)2.542 0.301 2.499 3.138 Organic Phosphorus (mg/L)0.000 0.000 0.000 0.000 Inorganic Ortho-Phosphorus (mg/L)1.000 1.000 1.000 1.000 Phytoplankton (µg/L)0.000 0.000 0.000 0.000 Detritus [POM] (mg/L)0.000 0.000 0.000 0.000 Alkalinity (mg/L)387 377 412 399 pH 3.6 2.6 5.3 7.9 Page A-1 Utah Division of Water Quality Little Spring Creek Inputs Summer Fall Winter Spring Flow (cfs)1.7 1.1 1.1 1.2 Temperature (deg C)17.7 12.6 9.4 13.7 Specific Conductance (µmhos)1565 1589 1535 1492 Inorganic Suspended Solids (mg/L)9.1 5.0 8.3 2.6 Dissolved Oxygen (mg/L)6.4 7.0 7.3 7.0 CBOD5 (mg/L)19.3 14.9 27.1 18.1 Organic Nitrogen (mg/L)1.153 1.604 4.000 0.958 NH4-Nitrogen (mg/L)1.237 2.771 3.256 2.184 NO3-Nitrogen (mg/L)2.398 4.689 2.137 1.567 Organic Phosphorus (mg/L)0.481 1.748 0.000 1.257 Inorganic Ortho-Phosphorus (mg/L)2.157 2.350 4.763 1.917 Phytoplankton (µg/L)0.0 0.0 0.0 0.0 Detritus [POM] (mg/L)0.0 0.0 0.0 0.0 Alkalinity (mg/L)375 375 375 375 pH 7.8 7.7 7.7 7.8 Big Spring Creek Inputs Summer Fall Winter Spring Flow (cfs)0.0 0.0 0.0 0.0 Temperature (deg C)0.0 0.0 0.0 0.0 Specific Conductance (µmhos)0 0 0 0 Inorganic Suspended Solids (mg/L)0.0 0.0 0.0 0.0 Dissolved Oxygen (mg/L)0.0 0.0 0.0 0.0 CBOD5 (mg/L)0.0 0.0 0.0 0.0 Organic Nitrogen (mg/L)0.000 0.000 0.000 0.000 NH4-Nitrogen (mg/L)0.000 0.000 0.000 0.000 NO3-Nitrogen (mg/L)0.000 0.000 0.000 0.000 Organic Phosphorus (mg/L)0.000 0.000 0.000 0.000 Inorganic Ortho-Phosphorus (mg/L)0.000 0.000 0.000 0.000 Phytoplankton (µg/L)0.0 0.0 0.0 0.0 Detritus [POM] (mg/L)0.0 0.0 0.0 0.0 Alkalinity (mg/L)0 0 0 0 pH 0.0 0.0 0.0 0.0 All model numerical inputs, intermediate calculations, outputs and graphs are available for discussion, inspection and copy at the Division of Water Quality. Page A-2 Utah Division of Water Quality Effluent Limitations Current State water quality standards are required to be met under a variety of conditions including in-stream flows targeted to the 7-day, 10-year low flow (R317-2-9). Other conditions used in the modeling effort reflect the environmental conditions expected at low stream flows. Effluent Limitations based upon Water Quality Standards for DO and Ammonia Toxicity In-stream criteria of downstream segments for Dissolved Oxygen will be met with an effluent limitation as follows: Chronic Standard Summer Fall Winter Spring Flow (MGD) N/A 0.5 0.5 0.5 0.5 NH4-Nitrogen (mg/L)Varies 1.0 2.5 15.0 15.0 CBOD5 (mg/L)N/A 25.0 25.0 25.0 25.0 Dissolved Oxygen [30-day Ave] (mg/L) 5.5 5.0 5.0 5.0 5.0 Acute Standard Summer Fall Winter Spring Flow (cfs) N/A 0.9 0.9 0.9 0.9 NH4-Nitrogen (mg/L)Varies 12.0 17.0 25.0 30.0 CBOD5 (mg/L)N/A 35.0 35.0 35.0 35.0 Dissolved Oxygen [Minimum] (mg/L) 5.0 5.0 5.0 5.0 5.0 Summary Comments The mathematical modeling and best professional judgement indicate that violations of receiving water beneficial uses with their associated water quality standards, including important down- stream segments, will not occur for the evaluated parameters of concern as discussed above if the effluent limitations indicated above are met. Page A-3 Utah Division of Water Quality Coefficients and Other Model Information Parameter Value Units Stoichiometry: Carbon 40 gC Nitrogen 7.2 gN Phosphorus 1 gP Dry weight 100 gD Chlorophyll 1 gA Inorganic suspended solids: Settling velocity 0.001 m/d Oxygen: Reaeration model Churchill Temp correction 1.024 Reaeration wind effect None O2 for carbon oxidation 2.69 gO2/gC O2 for NH4 nitrification 4.57 gO2/gN Oxygen inhib model CBOD oxidation Exponential Oxygen inhib parameter CBOD oxidation 0.60 L/mgO2 Oxygen inhib model nitrification Exponential Oxygen inhib parameter nitrification 0.60 L/mgO2 Oxygen enhance model denitrification Exponential Oxygen enhance parameter denitrification 0.60 L/mgO2 Oxygen inhib model phyto resp Exponential Oxygen inhib parameter phyto resp 0.60 L/mgO2 Oxygen enhance model bot alg resp Exponential Oxygen enhance parameter bot alg resp 0.60 L/mgO2 Slow CBOD: Hydrolysis rate 0 /d Temp correction 1.047 Oxidation rate 0.103 /d Temp correction 1.047 Fast CBOD: Oxidation rate 10 /d Temp correction 1.047 Organic N: Hydrolysis 0.2903475 /d Temp correction 1.07 Settling velocity 0.242158 m/d Ammonium: Nitrification 0.2693435 /d Temp correction 1.07 Nitrate: Denitrification 1.6900865 /d Temp correction 1.07 Sed denitrification transfer coeff 0.21487 m/d Temp correction 1.07 Organic P: Hydrolysis 0.228215 /d Temp correction 1.07 Settling velocity 0.05548 m/d Inorganic P: Settling velocity 0.85204 m/d Sed P oxygen attenuation half sat constant 1.98778 mgO2/L Page A-4 Utah Division of Water Quality Phytoplankton: Max Growth rate 2.8944 /d Temp correction 1.07 Respiration rate 0.480803 /d Temp correction 1.07 Death rate 0.86518 /d Temp correction 1 Nitrogen half sat constant 15 ugN/L Phosphorus half sat constant 2 ugP/L Inorganic carbon half sat constant 1.30E-05 moles/L Phytoplankton use HCO3- as substrate Yes Light model Smith Light constant 57.6 langleys/d Ammonia preference 25.4151 ugN/L Settling velocity 0.468545 m/d Bottom Plants: Growth model Zero-order Max Growth rate 72.858765 gD/m2/d or /d Temp correction 1.07 First-order model carrying capacity 100 gD/m2 Basal respiration rate 0.1996688 /d Photo-respiration rate parameter 0.01 unitless Temp correction 1.07 Excretion rate 0.225035 /d Temp correction 1.07 Death rate 1.1864 /d Temp correction 1.07 External nitrogen half sat constant 424.656 ugN/L External phosphorus half sat constant 63.89725 ugP/L Inorganic carbon half sat constant 3.89E-05 moles/L Bottom algae use HCO3- as substrate Yes Light model Smith Light constant 93.4186 mgO^2/L Ammonia preference 19.602 ugN/L Subsistence quota for nitrogen 0.3791592 mgN/gD Subsistence quota for phosphorus 0.1186205 mgP/gD Maximum uptake rate for nitrogen 1474.3665 mgN/gD/d Maximum uptake rate for phosphorus 111.866 mgP/gD/d Internal nitrogen half sat ratio 3.167674 Internal phosphorus half sat ratio 2.9784295 Nitrogen uptake water column fraction 1 Phosphorus uptake water column fraction 1 Detritus (POM): Dissolution rate 0.168998 /d Temp correction 1.07 Settling velocity 0.206573 m/d pH: Partial pressure of carbon dioxide 370 ppm Atmospheric Inputs:Summer Fall Winter Spring Min. Air Temperature, F 52.3 26.2 19.4 41.7 Max. Air Temperature, F 85.5 49.4 39.7 69.8 Dew Point, Temp., F 53.6 31.0 25.1 45.4 Wind, ft./sec. @ 21 ft. 4.9 3.6 3.6 5.8 Cloud Cover, % 18% 44% 46% 26% Other Inputs: Bottom Algae Coverage 10% Bottom SOD Coverage 100% Prescribed SOD, gO2/m^2/day 0 Page A-5 Utah Division of Water Quality WASTELOAD ANALYSIS [WLA]Date: 1/8/2025 Appendix B: Mass Balance Mixing Analysis for Conservative Constituents Discharging Facility: Garland WWTP UPDES No: UT-0026034 Permit Flow [MGD]: 0.5 Maximum Monthly Flow 0.9 Maximum Daily Flow Receiving Water: Malad River Stream Classification: 2B,3C Stream Flows [cfs]: 33.6 Summer (July-Sept) Critical Low Flow 33.2 Fall (Oct-Dec) 46.4 Winter (Jan-Mar) 44.0 Spring (Apr-June) Fully Mixed: NO Acute River Width: 50% Chronic River Width: 100% Acute Combined Flow [cfs] 18.17 Chronic Combined Flow [cfs] 34.26 Modeling Information A simple mixing analysis was used to determine these effluent limits. Model Inputs The following is upstream and discharge information that was utilized as inputs for the analysis. Dry washes are considered to have an upstream flow equal to the flow of the discharge. Headwater/Upstream Information DWQ 4902720 MALAD R AB TREMONTON WWTP DWQ 4902710 TREMONTON WWTP cfs cfs Summer 33.6 1.7 Fall 33.2 1.1 Winter 46.4 1.1 Spring 44.0 1.2 Discharge Information Flow MGD Maximum Daily 0.9 Maximum Monthly 0.5 All model numerical inputs, intermediate calculations, outputs and graphs are available for discussion, inspection and copy at the Division of Water Quality. Page B-1 Utah Division of Water Quality Effluent Limitations Current State water quality standards are required to be met under a variety of conditions including in-stream flows targeted to the 7-day, 10-year low flow (R317-2-9). Other conditions used in the modeling effort reflect the environmental conditions expected at low stream flows. Effluent Limitations for Protection of Recreation (Class 2B Waters) Physical Parameter Maximum Concentration pH Minimum 6.5 pH Maximum 9.0 Bacteriological E. coli (30 Day Geometric Mean) 206 (#/100 mL) E. coli (Maximum) 668 (#/100 mL) Effluent Limitations for Protection of Aquatic Wildlife (Class 3D Waters) Inorganics Chronic Standard (4 Day Average) Acute Standard (1 Hour Average) Parameter Standard Standard Phenol (mg/L) 0.010 Hydrogen Sulfide (Undissociated) [mg/L] 0.002 Total Recoverable Metals Chronic Standard (4 Day Average)1 Acute Standard (1 Hour Average)1 Parameter Standard Background Limit Standard Background2 Limit Aluminum (µg/L)N/A3 20.6 N/A 750 69.0 8957 Arsenic (µg/L) 150 0.9 7335 340 0.9 4426 Cadmium (µg/L) 0.6 0.1 26.8 7.7 0.1 99.8 Chromium VI (µg/L) 11.0 1.9 449.7 16.0 1.9 185.9 Chromium III (µg/L) 231 1.9 11259 1,773 1.9 23122 Copper (µg/L) 29.3 2.0 1344.4 49.6 2.0 623.5 Cyanide (µg/L)2 5.2 3.5 87.9 22.0 3.5 245.2 Iron (µg/L) 1,000 30.0 12690 Lead (µg/L) 10.9 0.7 504.8 281 0.7 3657 Mercury (µg/L)2 0.012 0.008 0.203 2.4 0.0 31.2 Nickel (µg/L) 168 4.6 8047 1,513 4.6 19691 Selenium (µg/L) 4.6 1.0 178.1 18.4 1.0 228.1 Silver (µg/L) 34.9 0.5 449.6 Tributylin (µg/L)2 0.072 0.048 1.217 0.46 0.048 5.423 Zinc (µg/L) 382 9.3 18369 379 9.3 4839 1: Based upon a Hardness of 400 mg/l as CaCO3. 2: Background concentration assumed 67% of chronic standard. 3: Where the pH is equal to or greater than 7.0 and the hardness is equal to or greater than 50 ppm as CaC03 in the receiving water after mixing, the 87 ug/L chronic criterion (expressed as total recoverable) will not apply, and aluminum will be regulated based on compliance with the 750 ug/L acute aluminum criterion (expressed as total recoverable). Page B-2 Utah Division of Water Quality Organics [Pesticides] Chronic Standard (4 Day Average) Acute Standard (1 Hour Average) Parameter Standard Background1 Limit Standard Background1 Limit Aldrin (µg/L) 1.5 1.0 7.5 Chlordane (µg/L) 0.0043 0.0029 0.0727 1.2 0.0 15.6 DDT, DDE (µg/L) 0.001 0.001 0.017 0.55 0.00 7.17 Diazinon (µg/L) 0.17 0.11 2.87 0.17 0.11 0.85 Dieldrin (µg/L) 0.0056 0.0038 0.0947 0.24 0.00 3.09 Endosulfan, a & b (µg/L) 0.056 0.038 0.947 0.11 0.04 0.98 Endrin (µg/L) 0.036 0.024 0.609 0.086 0.024 0.832 Heptachlor & H. epoxide (µg/L) 0.0038 0.0025 0.0643 0.26 0.00 3.36 Lindane (µg/L) 0.08 0.05 1.35 1.0 0.1 12.4 Methoxychlor (µg/L) 0.03 0.02 0.15 Mirex (µg/L) 0.001 0.001 0.005 Nonylphenol (µg/L) 6.6 4.4 111.6 28.0 4.4 312.2 Parathion (µg/L) 0.0130 0.0087 0.2198 0.066 0.009 0.756 PCB's (µg/L) 0.014 0.009 0.237 Pentachlorophenol (µg/L) 15.0 10.1 253.63 19.0 10.1 126.9 Toxephene (µg/L) 0.0002 0.0001 0.0034 0.73 0.00 9.53 1: Background concentration assumed 67% of chronic standard Radiological Maximum Concentration Parameter Standard Background1 Limit Gross Alpha (pCi/L) 15 10.1 253.63 1: Background concentration assumed 67% of chronic standard. Effluent Limitation for Protection of Agriculture (Class 4 Waters) Maximum Concentration Parameter Standard Background1 Limit Total Dissolved Solids (mg/L) 1,200 808 20098 Boron (µg/L) 75.0 99.8 -1120.6 Arsenic (µg/L) 100 0.9 4875.1 Cadmium (µg/L) 10.0 6.7 169.1 Chromium (µg/L) 100 1.9 4829.2 Copper (µg/L) 200 2.0 9745.2 Lead (µg/L) 100 0.7 4887.1 Selenium (µg/L) 50.0 1.0 2412.2 Gross Alpha (pCi/L)1 15.0 10.1 253.6 1: Background concentration assumed 67% of chronic standard. Page B-3