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Home My WebLink AboutDWQ-2024-000520 Page 1 of 4 Utah Division of Water Quality Statement of Basis ADDENDUM Wasteload Analysis and Antidegradation Level I Review Date: December 1, 2023 Prepared by: Christopher L. Shope Standards and Technical Services Facility: Springdale Wastewater Lagoons UPDES Permit No. UT-0025224 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: direct discharge to Virgin River at 0.29 MGD design flow. Receiving Water The effluent discharges directly into the Virgin River between Rockland, UT and Virgin, UT. Per UAC R317-2-13.4, the designated beneficial uses Virgin River and tributaries, from the Quail Creek diversion to headwaters, except as listed below are: 1C,2B,3C,4. • Class 1C – Protected for domestic purposes with prior treatment by treatment processes as required by the Utah Division of Drinking Water. • 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. • Class 4 - Protected for agricultural uses including irrigation of crops and stock watering. Utah Division of Water Quality Wasteload Analysis Springdale Wastewater Lagoons, UPDES Permit No. UT-0025224 Page 2 of 4 Flow Typically, the critical flow for the receiving water in a wasteload analysis is considered the lowest stream flow for seven consecutive days with a ten-year return frequency (7Q10). Daily in-stream flow records were analyzed from USGS 09406000: VIRGIN RIVER AT VIRGIN, UT monitoring location. The annual 7Q10 critical flow value for the Virgin River at this location is 71.86 ft3/s. Receiving water quality was characterized using data from DWQ Monitoring Station DWQ 4950850: VIRGIN R 1 MI E OF VIRGIN for the period 2000-2023. Both of the above monitoring stations are below the Springdale Wastewater Lagoons discharge location. However, review of available stations and associated data led to the conclusion that they are the most appropriate sites to characterize the receiving water. Upstream stations on the Virgin River are upstream of the confluence with major tributaries (East Fork of the Virgin River). Upstream water quality and discharge data were infrequently collected and have not been monitored for many years. Discharge data from Springdale Wastewater Lagoons indicate that they discharge on a very intermittent basis (on the order of 4 times per year). Additionally, the lagoon discharge rate (0.45 ft3/s) is very small compared to the receiving water flow (even at annual critical low flow of 71.86 ft3/s). Given these factors, it is unlikely that downstream data is significantly influenced by the lagoon discharge. Total Maximum Daily Load (TMDL) According to the Utah’s Final 2022 Integrated Report on Water Quality dated December 9, 2022, the receiving water for the discharge, “Virgin River and tributaries from North Creek confluence to North Fork Virgin River (Assessment Unit UT15010008-012_00)” was listed as “No Evidence of Impairment”. Furthermore, downstream Assessment Unit (UT15010008-011_00) “Virgin River and tributaries from Quail Creek Diversion to North Creek confluence” was listed as “Fully Supporting” Mixing Zone 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, per UAC R317-2-5. Water quality standards must be met at the end of the mixing zone. Individual mixing zones may be disallowed in consideration of site-specific factors. For the site location, biologically important areas such as fish spawning/nursery areas or segments with occurrences of federally listed threatened or endangered species may be present (R317-2-5.1.b.). According to US Fish and Wildlife Service (US FWS), endangered species downstream and possibly within this area include, Virgin River Chub (Gila seminuda) and Woundfin (Plagopterus argentissimus). Because the critical habitat of these species is potentially affected, authorized additional study may be required from agencies including but not limited to US EPA, US FWS, Utah Division of Wildlife Resources. In addition, early life species (ELS) are present at least January through August in this reach of Virgin River. Therefore, no mixing zone is granted for this effluent discharge point source. Water quality standards must be met at the end of pipe (EOP). Further special studies commissioned by the permittee would be required to support inclusion of a dilution credit through the addition of a mixing zone. Utah Division of Water Quality Wasteload Analysis Springdale Wastewater Lagoons, UPDES Permit No. UT-0025224 Page 3 of 4 Parameters of Concern The potential parameters of concern identified for the discharge/receiving water were 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. The potential parameters of concern for this facility include: Temperature, TDS, TSS, pH, dissolved oxygen, total ammonia, BOD, phosphorous, nitrogen, TRC, toxic organics, metals, and major ions. 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 for Outfall 001 for IC25 should be based on 0.9% effluent. Wasteload Allocation Methods Effluent limits were determined for conservative constituents using a simple mass balance mixing analysis (UDWQ 2021). The mass balance analysis is summarized in the Wasteload Addendum. The Utah Rivers Model was used to evaluate the DO sag and implications on nutrients and BOD. The analysis is summarized in the Wasteload Addendum. 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. To evaluate effluent discharge water quality, the Springdale Lagoons discharge monitoring report (DMR) was used. Background temperature and pH values from the Virgin River were used in the analysis. Models and supporting documentation are available for review upon request. 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 facility. The proposed permit is a is a renewal with no additional flow or concentration of pollutants over those authorized for the Virgin River. Documents: WLA Document: 231201-Springdale_Lagoon_WLA_2023.docx Wasteload Analysis and Addendums: 231201-Springdale_Lagoon_WLA_2023.xlsm References: Utah Division of Water Quality Wasteload Analysis Springdale Wastewater Lagoons, UPDES Permit No. UT-0025224 Page 4 of 4 Utah Division of Water Quality. 2022. Final 2022 Integrated Report on Water Quality. https://documents.deq.utah.gov/water-quality/monitoring-reporting/integrated-report/DWQ-2022-002386.pdf 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 Salt Lake City, Utah WASTELOAD ANALYSIS [WLA]= not included in the WLA 1-Dec-23 Addendum: Statement of Basis 4:00 PM Facilities: Springdale Lagoons UPDES No:UT-UT0025224 Discharging to:Virgin River THIS IS A DRAFT DOCUMENT I. Introduction 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 [R317-2-8, UAC]. Projected concen- trations are compared to numeric water quality standards to determine acceptability. The anti-degradation policy and procedures are also considered. The primary in-stream parameters of concern may include metals (as a function of hardness), total dissolved solids (TDS), total residual chlorine (TRC), un-ionized ammonia (as a function of pH and temperature, measured and evaluated interms of total ammonia), and dissolved oxygen. Mathematical water quality modeling is employed to determine stream quality response to point source discharges. Models aid in the effort of anticipating stream quality at future effluent flows at critical environmental conditions (e.g., low stream flow, high temperature, high pH, etc). The numeric criteria in this wasteload analysis may always be modified by narrative criteria and other conditions determined by staff of the Division of Water Quality. II. Receiving Water and Stream Classification Virgin River:1C,2B,3C,4 Antidegradation Review:Level I review completed. Level II review is not required. III. Numeric Stream Standards for Protection of Aquatic Wildlife Total Ammonia (TNH3)Varies as a function of Temperature and pH Rebound. See Water Quality Standards Chronic Total Residual Chlorine (TRC)0.011 mg/l (4 Day Average) 0.019 mg/l (1 Hour Average) Chronic Dissolved Oxygen (DO) 5.0 mg/l (30 Day Average) N/A mg/l (7Day Average) 3.0 mg/l (1 Day Average) Maximum Total Dissolved Solids 1200.0 mg/l Acute and Chronic Heavy Metals (Dissolved) 4 Day Average (Chronic) Standard 1 Hour Average (Acute) Standard Parameter Concentration Load*Concentration Load* Aluminum 87.00 ug/l**0.210 lbs/day 750.00 ug/l 1.814 lbs/day Arsenic 150.00 ug/l 0.363 lbs/day 340.00 ug/l 0.822 lbs/day Cadmium 1.61 ug/l 0.004 lbs/day 4.55 ug/l 0.011 lbs/day Chromium III 178.88 ug/l 0.433 lbs/day 3742.56 ug/l 9.051 lbs/day ChromiumVI 11.00 ug/l 0.027 lbs/day 16.00 ug/l 0.039 lbs/day Copper 19.99 ug/l 0.048 lbs/day 32.43 ug/l 0.078 lbs/day Iron 1000.00 ug/l 2.418 lbs/day Lead 9.90 ug/l 0.024 lbs/day 254.04 ug/l 0.614 lbs/day Mercury 0.0120 ug/l 0.000 lbs/day 2.40 ug/l 0.006 lbs/day Nickel 110.91 ug/l 0.268 lbs/day 997.59 ug/l 2.413 lbs/day Selenium 4.60 ug/l 0.011 lbs/day 20.00 ug/l 0.048 lbs/day Silver N/A ug/l N/A lbs/day 17.54 ug/l 0.042 lbs/day Zinc 255.06 ug/l 0.617 lbs/day 255.06 ug/l 0.617 lbs/day Page 1 Utah Division of Water Quality Salt Lake City, Utah * Allowed below discharge **Chronic Aluminum standard applies only to waters with a pH < 7.0 and a Hardness < 50 mg/l as CaCO3 Metals Standards Based upon a Hardness of 243.93 mg/l as CaCO3 IV. Numeric Stream Standards for Protection of Agriculture 4 Day Average (Chronic) Standard 1 Hour Average (Acute) Standard Concentration Load*Concentration Load* Arsenic 100.0 ug/l lbs/day Boron 750.0 ug/l 0.91 lbs/day Cadmium 10.0 ug/l 0.01 lbs/day Chromium 100.0 ug/l lbs/day Copper 200.0 ug/l lbs/day Lead 100.0 ug/l lbs/day Selenium 50.0 ug/l lbs/day TDS, Summer 1200.0 mg/l 1.45 tons/day V. Numeric Stream Standards for Protection of Human Health (Class 1C Waters) 4 Day Average (Chronic) Standard 1 Hour Average (Acute) Standard Metals Concentration Load*Concentration Load* Arsenic 50.0 ug/l 13.976 lbs/day Barium 1000.0 ug/l 279.526 lbs/day Cadmium 10.0 ug/l 2.795 lbs/day Chromium 50.0 ug/l 13.976 lbs/day Lead 50.0 ug/l 13.976 lbs/day Mercury 2.0 ug/l 0.559 lbs/day Selenium 10.0 ug/l 2.795 lbs/day Silver 50.0 ug/l 13.976 lbs/day Fluoride (3)1.4 ug/l 0.391 lbs/day to 2.4 ug/l 0.671 lbs/day Nitrates as N 10.0 ug/l 2.795 lbs/day VI. Numeric Stream Standards the Protection of Human Health from Water & Fish Consumption [Toxics] Maximum Conc., ug/l - Acute Standards Class 1C Class 3A, 3B Metals Antimony 14.0 ug/l 3.91 lbs/day Arsenic 50.0 ug/l 13.98 lbs/day 4300.00 ug/l 1201.96 lbs/day Asbestos 7.00E+06 ug/l 1.96E+06 lbs/day Beryllium Cadmium Chromium (III) Chromium (VI) Copper Cyanide 1.30E+03 ug/l 363.38 lbs/day 2.2E+05 ug/l 61495.66 lbs/day Lead 700.0 ug/l 195.67 lbs/day Mercury 0.15 ug/l 0.04 lbs/day Nickel 4600.00 ug/l 1285.82 lbs/day Selenium 0.1 ug/l 0.04 lbs/day Silver 610.0 ug/l 170.51 lbs/day Thallium 6.30 ug/l 1.76 lbs/day Zinc There are additional standards that apply to this receiving water, but were not considered in this modeling/waste load allocation analysis. VII. Mathematical Modeling of Stream Quality Model configuration was accomplished utilizing standard modeling procedures. Data points were plotted and coefficients adjusted as required to match observed data as closely as possible. Page 2 Utah Division of Water Quality Salt Lake City, Utah The modeling approach used in this analysis included one or a combination of the following models. (1) The Utah River Model, Utah Division of Water Quality, 1992. Based upon STREAMDO IV (Region VIII) and Supplemental Ammonia Toxicity Models; EPA Region VIII, Sept. 1990 and QUAL2E (EPA, Athens, GA). (2) Utah Ammonia/Chlorine Model, Utah Division of Water Quality, 1992. (3) AMMTOX Model, University of Colorado, Center of Limnology, and EPA Region 8 (4) Principles of Surface Water Quality Modeling and Control. Robert V. Thomann, et.al. Harper Collins Publisher, Inc. 1987, pp. 644. Coefficients used in the model were based, in part, upon the following references: (1) Rates, Constants, and Kinetics Formulations in Surface Water Quality Modeling. Environmen- tal Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Athens Georgia. EPA/600/3-85/040 June 1985. (2) Principles of Surface Water Quality Modeling and Control. Robert V. Thomann, et.al. Harper Collins Publisher, Inc. 1987, pp. 644. VIII. Modeling Information The required information for the model may include the following information for both the upstream conditions at low flow and the effluent conditions: Flow, Q, (cfs or MGD)D.O. mg/l Temperature, Deg. C.Total Residual Chlorine (TRC), mg/l pH Total NH3-N, mg/l BOD5, mg/l Total Dissolved Solids (TDS), mg/l Metals, ug/l Toxic Organics of Concern, ug/l Other Conditions In addition to the upstream and effluent conditions, the models require a variety of physical and biological coefficients and other technical information. In the process of actually establishing the permit limits for an effluent, values are used based upon the available data, model calibration, literature values, site visits and best professional judgement. 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. Current Upstream Information Stream Critical Low Flow Temp.pH T-NH3 BOD5 DO TRC TDS cfs Deg. C mg/l as N mg/l mg/l mg/l mg/l Summer (Irrig. Season)51.4 22.5 8.2 0.04 2.50 6.79 0.00 509.1 Fall 70.9 10.3 8.2 0.03 2.50 --- 0.00 504.5 Winter 103.7 7.8 8.2 0.03 2.50 --- 0.00 504.5 Spring 64.0 16.5 8.3 0.04 2.50 --- 0.00 504.5 Dissolved Al As Cd CrIII CrVI Copper Fe Pb Metals ug/l ug/l ug/l ug/l ug/l ug/l ug/l ug/l All Seasons 15.00 2.50 0.50 2.50 2.65*6.00 27.3 1.50 Page 3 Utah Division of Water Quality Salt Lake City, Utah Dissolved Hg Ni Se Ag Zn Boron Metals ug/l ug/l ug/l ug/l ug/l ug/l All Seasons 0.0000 2.50 0.69 1.00 15.00 10.0 * 1/2 MDL Projected Discharge Information Season Flow, MGD Temp.TDS mg/l TDS tons/day Summer 0.29000 23.8 1541.00 1.86316 Fall 0.29000 11.2 Winter 0.29000 18.6 Spring 0.29000 12.0 All model numerical inputs, intermediate calculations, outputs and graphs are available for discussion, inspection and copy at the Division of Water Quality. IX. 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 coincide with the environmental conditions expected at low stream flows. Effluent Limitation for Flow based upon Water Quality Standards In-stream criteria of downstream segments will be met with an effluent flow maximum value as follows: Season Daily Average Summer 0.290 MGD 0.449 cfs Fall 0.290 MGD 0.449 cfs Winter 0.290 MGD 0.449 cfs Spring 0.290 MGD 0.449 cfs Flow Requirement or Loading Requirement The calculations in this wasteload analysis utilize the maximum effluent discharge flow of 0.29 MGD. If the discharger is allowed to have a flow greater than 0.29 MGD during 7Q10 conditions, and effluent limit concentrations as indicated, then water quality standards will be violated. In order to prevent this from occuring, the permit writers must include the discharge flow limititation as indicated above; or, include loading effluent limits in the permit. Effluent Limitation for Whole Effluent Toxicity (WET) based upon WET Policy Effluent Toxicity will not occur in downstream segements if the values below are met. WET Requirements LC50 >2.9%Effluent [Acute] IC25 >0.9%Effluent [Chronic] Season Receiving Water Flow (cfs) Effluent Flow (MGD) Effluent Flow (cfs) Combined Flow (cfs) Totally Mixed Chronic IC25 % Effluent Acute LC50 % Effluent Summer 51.41 0.3 0.4 51.9 NO 0.9%0.1% Fall 70.86 0.3 0.4 71.3 NO 0.6%0.0% Winter 103.71 0.3 0.4 104.2 NO 0.4%0.0% Spring 64.00 0.3 0.4 64.4 NO 0.7%0.0% Effluent Limitation for Biological Oxygen Demand (BOD) based upon Water Quality Standards or Regulations Page 4 Utah Division of Water Quality Salt Lake City, Utah In-stream criteria of downstream segments for Dissolved Oxygen will be met with an effluent BOD limitation as follows: Season Concentration Summer 35.0 mg/l as BOD5 84.6 lbs/day Fall 35.0 mg/l as BOD5 84.6 lbs/day Winter 35.0 mg/l as BOD5 84.6 lbs/day Spring 35.0 mg/l as BOD5 84.6 lbs/day Effluent Limitation for Dissolved Oxygen (DO) based upon Water Quality Standards In-stream criteria of downstream segments for Dissolved Oxygen will be met with an effluent D.O. limitation as follows: Season Concentration Summer 4.00 Fall 4.00 Winter 4.00 Spring 4.00 Effluent Limitation for Total Ammonia based upon Water Quality Standards In-stream criteria of downstream segments for Total Ammonia will be met with an effluent limitation (expressed as Total Ammonia as N) as follows: Season Concentration Load Summer 4 Day Avg. - Chronic 104.9 mg/l as N 253.7 lbs/day 1 Hour Avg. - Acute 222.1 mg/l as N 537.1 lbs/day Fall 4 Day Avg. - Chronic 138.5 mg/l as N 334.9 lbs/day 1 Hour Avg. - Acute 309.2 mg/l as N 747.7 lbs/day Winter 4 Day Avg. - Chronic 238.9 mg/l as N 577.7 lbs/day 1 Hour Avg. - Acute 519.9 mg/l as N 1,257.3 lbs/day Spring 4 Day Avg. - Chronic 153.0 mg/l as N 370.0 lbs/day 1 Hour Avg. - Acute 340.5 mg/l as N 823.4 lbs/day Acute limit calculated with an Acute Zone of Initial Dilution (ZID) to be equal to 50.%. Effluent Limitation for Total Residual Chlorine based upon Water Quality Standards In-stream criteria of downstream segments for Total Residual Chlorine will be met with an effluent limitation as follows: Season Concentration Load Summer 4 Day Avg. - Chronic 1.157 mg/l 2.80 lbs/day 1 Hour Avg. - Acute 1.050 mg/l 2.54 lbs/day Fall 4 Day Avg. - Chronic 1.590 mg/l 3.85 lbs/day 1 Hour Avg. - Acute 1.440 mg/l 3.48 lbs/day Winter 4 Day Avg. - Chronic 2.323 mg/l 5.62 lbs/day 1 Hour Avg. - Acute 2.099 mg/l 5.08 lbs/day Spring 4 Day Avg. - Chronic 1.437 mg/l 3.48 lbs/day 1 Hour Avg. - Acute 1.303 mg/l 3.15 lbs/day Page 5 Utah Division of Water Quality Salt Lake City, Utah Effluent Limitations for Total Dissolved Solids based upon Water Quality Standards Season Concentration Load Summer Maximum, Acute 80372.7 mg/l 97.18 tons/day Fall Maximum, Acute 80900.0 mg/l 97.81 tons/day Winter Maximum, Acute 82035.7 mg/l 99.19 tons/day Spring 4 Day Avg. - Chronic 86478.5 mg/l 104.56 tons/day Colorado Salinity Forum Limits Determined by Permitting Section Effluent Limitations for Total Recoverable Metals based upon Water Quality Standards In-stream criteria of downstream segments for Dissolved Metals will be met with an effluent limitation as follows (based upon a hardness of 243.93 mg/l): 4 Day Average 1 Hour Average Concentration Load Concentration Load Aluminum N/A N/A 42,864.2 ug/l 103.7 lbs/day Arsenic 17,052.98 ug/l 26.7 lbs/day 19,678.2 ug/l 47.6 lbs/day Cadmium 128.74 ug/l 0.2 lbs/day 236.5 ug/l 0.6 lbs/day Chromium III 20,391.67 ug/l 31.9 lbs/day 218,041.6 ug/l 527.3 lbs/day Chromium VI 816.04 ug/l 1.3 lbs/day 705.0 ug/l 1.7 lbs/day Copper 1,622.82 ug/l 2.5 lbs/day 1,546.9 ug/l 3.7 lbs/day Iron N/A N/A 56,731.7 ug/l 137.2 lbs/day Lead 972.48 ug/l 1.5 lbs/day 14,724.3 ug/l 35.6 lbs/day Mercury 1.39 ug/l 0.0 lbs/day 139.9 ug/l 0.3 lbs/day Nickel 12,534.63 ug/l 19.6 lbs/day 58,014.5 ug/l 140.3 lbs/day Selenium 452.21 ug/l 0.7 lbs/day 1,126.2 ug/l 2.7 lbs/day Silver N/A ug/l N/A lbs/day 965.4 ug/l 2.3 lbs/day Zinc 27,764.80 ug/l 43.4 lbs/day 14,009.9 ug/l 33.9 lbs/day Cyanide (free)601.10 ug/l 0.9 lbs/day 1,282.6 ug/l 3.1 lbs/day Effluent Limitations for Heat/Temperature based upon Water Quality Standards Summer 100.0 Deg. C.212.0 Deg. F Fall 100.0 Deg. C.212.0 Deg. F Winter 100.0 Deg. C.212.0 Deg. F Spring 100.0 Deg. C.212.0 Deg. F Effluent Limitations for Organics [Pesticides] Based upon Water Quality Standards In-stream criteria of downstream segments for Organics [Pesticides] will be met with an effluent limit as follows: 4 Day Average 1 Hour Average Concentration Load Concentration Load Aldrin 1.5E+00 ug/l 5.61E-03 lbs/day Chlordane 4.30E-03 ug/l 1.04E-02 lbs/day 1.2E+00 ug/l 4.49E-03 lbs/day DDT, DDE 1.00E-03 ug/l 2.42E-03 lbs/day 5.5E-01 ug/l 2.06E-03 lbs/day Dieldrin 1.90E-03 ug/l 4.59E-03 lbs/day 1.3E+00 ug/l 4.68E-03 lbs/day Endosulfan 5.60E-02 ug/l 1.35E-01 lbs/day 1.1E-01 ug/l 4.12E-04 lbs/day Endrin 2.30E-03 ug/l 5.56E-03 lbs/day 9.0E-02 ug/l 3.37E-04 lbs/day Page 6 Utah Division of Water Quality Salt Lake City, Utah Guthion 0.00E+00 ug/l 0.00E+00 lbs/day 1.0E-02 ug/l 3.74E-05 lbs/day Heptachlor 3.80E-03 ug/l 9.19E-03 lbs/day 2.6E-01 ug/l 9.73E-04 lbs/day Lindane 8.00E-02 ug/l 1.93E-01 lbs/day 1.0E+00 ug/l 3.74E-03 lbs/day Methoxychlor 0.00E+00 ug/l 0.00E+00 lbs/day 3.0E-02 ug/l 1.12E-04 lbs/day Mirex 0.00E+00 ug/l 0.00E+00 lbs/day 1.0E-02 ug/l 3.74E-05 lbs/day Parathion 0.00E+00 ug/l 0.00E+00 lbs/day 4.0E-02 ug/l 1.50E-04 lbs/day PCB's 1.40E-02 ug/l 3.39E-02 lbs/day 2.0E+00 ug/l 7.48E-03 lbs/day Pentachlorophenol 1.30E+01 ug/l 3.14E+01 lbs/day 2.0E+01 ug/l 7.48E-02 lbs/day Toxephene 2.00E-04 ug/l 4.84E-04 lbs/day 7.3E-01 ug/l 2.73E-03 lbs/day Effluent Targets for Pollution Indicators Based upon Water Quality Standards In-stream criteria of downstream segments for Pollution Indicators will be met with an effluent limit as follows: 1 Hour Average Concentration Loading Gross Beta (pCi/l)50.0 pCi/L BOD (mg/l)5.0 mg/l 12.1 lbs/day Nitrates as N 4.0 mg/l 9.7 lbs/day Total Phosphorus as P 0.05 mg/l 0.1 lbs/day Total Suspended Solids 90.0 mg/l 217.7 lbs/day Note: Pollution indicator targets are for information purposes only. Effluent Limitations for Protection of Human Health [Toxics Rule] Based upon Water Quality Standards (Most stringent of 1C or 3A & 3B as appropriate.) In-stream criteria of downstream segments for Protection of Human Health [Toxics] will be met with an effluent limit as follows: Maximum Concentration Concentration Load Metals Antimony 1618.35 ug/l 3.91 lbs/day Arsenic 5493.33 ug/l 13.28 lbs/day Asbestos 8.09E+08 ug/l 1.96E+06 lbs/day Beryllium Cadmium Chromium (III) Chromium (VI) Copper 150275.45 ug/l 363.38 lbs/day Cyanide 80917.55 ug/l 195.67 lbs/day Lead 0.00 0.00 Mercury 16.18 ug/l 0.04 lbs/day Nickel 70513.87 ug/l 170.51 lbs/day Selenium 0.00 0.00 Silver 0.00 0.00 Thallium 196.51 ug/l 0.48 lbs/day Zinc Metals Effluent Limitations for Protection of All Beneficial Uses Based upon Water Quality Standards and Toxics Rule Class 4 Acute Agricultural Class 3 Acute Aquatic Wildlife Acute Toxics Drinking Water Source Acute Toxics Wildlife 1C Acute Health Criteria Acute Most Stringent Class 3 Chronic Aquatic Wildlife Page 7 Utah Division of Water Quality Salt Lake City, Utah ug/l ug/l ug/l ug/l ug/l ug/l ug/l Aluminum 42864.2 42864.2 N/A Antimony 1618.4 497065.0 1618.4 Arsenic 11559.7 19678.2 5493.3 0.0 5493.3 17053.0 Asbestos 8.09E+08 8.09E+08 Barium 115596.5 115596.5 Beryllium 0.0 Cadmium 1098.7 236.5 0.0 236.5 128.7 Chromium (III)218041.6 0.0 218041.6 20391.7 Chromium (VI)11273.2 705.0 0.0 705.01 816.04 Copper 22431.7 1546.9 150275.5 1546.9 1622.8 Cyanide 1282.6 25431230.4 1282.6 601.1 Iron 56731.7 56731.7 Lead 11387.8 14724.3 0.0 11387.8 972.5 Mercury 139.92 16.2 17.34 0.0 16.18 1.386 Nickel 58014.5 70513.9 531743.9 58014.5 12534.6 Selenium 5700.3 1126.2 0.0 1126.2 452.2 Silver 965.4 0.0 965.4 Thallium 196.5 728.3 196.5 Zinc 14009.9 14009.9 27764.8 Boron 77639.7 77639.7 Summary Effluent Limitations for Metals [Wasteload Allocation, TMDL] [If Acute is more stringent than Chronic, then the Chronic takes on the Acute value.] WLA Acute WLA Chronic ug/l ug/l Aluminum 42864.2 N/A Antimony 1618.35 Arsenic 5493.3 17053.0 Acute Controls Asbestos 8.09E+08 Barium Beryllium Cadmium 236.5 128.7 Chromium (III)218041.6 20392 Chromium (VI)705.0 816.0 Acute Controls Copper 1546.9 1622.8 Acute Controls Cyanide 1282.6 601.1 Iron 56731.7 Lead 11387.8 972.5 Mercury 16.182 1.386 Nickel 58014.5 12535 Selenium 1126.2 452.2 Silver 965.4 N/A Thallium 196.5 Zinc 14009.9 27764.8 Acute Controls Boron 77639.67 Other Effluent Limitations are based upon R317-1. E. coli 126.0 organisms per 100 ml X. Antidegradation Considerations The Utah Antidegradation Policy allows for degradation of existing quality where it is determined that such lowering of water quality is necessary to accommodate important economic or social development in the area in which the waters are protected [R317-2-3]. It has been determined that certain chemical parameters introduced by this discharge will cause an increase of the concentration of said parameters in the receiving waters. Under no conditions will the increase in concentration be allowed to interfere with existing instream water uses. Page 8 Utah Division of Water Quality Salt Lake City, Utah The antidegradation rules and procedures allow for modification of effluent limits less than those based strictly upon mass balance equations utilizing 100% of the assimilative capacity of the receiving water. Additional factors include considerations for "Blue-ribbon" fisheries, special recreational areas, threatened and endangered species, and drinking water sources. An Antidegradation Level I Review was conducted on this discharge and its effect on the receiving water. Based upon that review, it has been determined that an Antidegradation Level II Review is required because it is a new discharge. XI. Colorado River Salinity Forum Considerations Discharges in the Colorado River Basin are required to have their discharge at a TDS loading of less than 1.00 tons/day unless certain exemptions apply. Refer to the Forum's Guidelines for additional information allowing for an exceedence of this value. This doesn’t apply to facilities that do not discharge to the Colorado River Basin. XII. 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. XIII. Notice of UPDES Requirement This Addendum to the Statement of Basis does not authorize any entity or party to discharge to the waters of the State of Utah. That authority is granted through a UPDES permit issued by the Utah Division of Water Quality. The numbers presented here may be changed as a function of other factors. Dischargers are strongly urged to contact the Permits Section for further information. Permit writers may utilize other information to adjust these limits and/or to determine other limits based upon best available technology and other considerations provided that the values in this wasteload analysis [TMDL] are not compromised. See special provisions in Utah Water Quality Standards for adjustments in the Total Dissolved Solids values based upon background concentration. THIS IS A DRAFT DOCUMENT Utah Division of Water Quality 801-538-6052 File Name: 231201-Springdale Lagoon_WLA_2023.xlsm APPENDIX - Coefficients and Other Model Information CBOD CBOD CBOD REAER.REAER.REAER.NBOD NBOD Coeff.Coeff.Coeff.Coeff.Coeff.Coeff.Coeff.Coeff. (Kd)20 FORCED (Ka)T (Ka)20 FORCED (Ka)T (Kn)20 (Kn)T 1/day (Kd)/day 1/day (Ka)/day 1/day 1/day 1/day 1/day 1.000 0.000 1.122 19.956 0.000 21.175 0.400 0.485 Open Open NH3 NH3 NO2+NO3 NO2+NO3 TRC TRC Coeff.Coeff.LOSS LOSS Decay (K4)20 (K4)T (K5)20 (K5)T (K6)20 (K6)T K(Cl)20 K(Cl)(T) 1/day 1/day 1/day 1/day 1/day 1/day 1/day 1/day 0.000 0.000 4.000 4.486 0.000 0.000 32.000 37.014 BENTHIC BENTHIC DEMAND DEMAND (SOD)20 (SOD)T gm/m2/day gm/m2/day 1.000 1.170 Page 9 Utah Division of Water Quality Salt Lake City, Utah K1 K2 K3 K4 K5 K6 K(Cl)S CBOD Reaer. NH3 Open NH3 Loss NO2+3 TRC Benthic {theta} {theta} {theta} {theta} {theta} {theta}{theta} {theta} 1.0 1.0 1.1 1.0 1.0 1.0 1.1 1.1 Antidegredation Review An antidegradation review (ADR) was conducted to determine whether the proposed activity complies with the applicable antidegradation requirements for receiving waters that may be affected. The Level I ADR evaluated the criteria of R317-2-3.5(b) and determined that a Level II antidegradation Review is not required because this is a permit renewal with no change in discharge. Page 10