Authority: IC 13-14-8-2; IC 13-14-8-3; IC 13-18-4-3

Affected: IC 13-11-2-258; IC 13-18-4; IC 13-30-2-1; IC 14-22-9

Sec. 8. (a) All surface water quality criteria in this section, except those provided in subsection (b)(1), are not applicable when the stream flows are less than the applicable stream design flow for the particular criterion as determined under 327 IAC 5-2-11.4.

(b) The following are minimum surface water quality conditions:

1. (1) All surface waters within the Great Lakes system, including waters within a mixing zone, must be free from substances, materials, floating debris, oil, or scum attributable to municipal, industrial, agricultural, and other land use practices, or other discharges that do any of the following:

   1. (A) Settle to form putrescent or otherwise objectionable deposits.
   2. (B) Occur in amounts sufficient to be unsightly or deleterious.

   3. (C) Produce:

      1. (i) color;
      2. (ii) visible oil sheen;
      3. (iii) odor; or
      4. (iv) other conditions;
   4. to an extent that creates a nuisance.

   5. (D) Occur in concentrations or combinations that will cause or contribute to the growth of aquatic plants or algae to a degree as to:

      1. (i) create a nuisance;
      2. (ii) be unsightly; or
      3. (iii) otherwise impair the designated uses of the surface waters.

   6. (E) Occur in amounts sufficient to be acutely toxic to, or to otherwise severely injure or kill, aquatic life, other animals, plants, or humans. To ensure protection of aquatic life, the surface waters must meet the following requirements:

      1. (i) Concentrations of toxic substances must not exceed the CMC or SMC outside the zone of initial dilution or the final acute value (FAV = 2 (CMC) or 2 (SMC)) in the undiluted discharge unless, for a discharge to a receiving stream or Lake Michigan, an alternate mixing zone demonstration is conducted and approved in accordance with 327 IAC 5-2-11.4(b)(4), in which case, the CMC or SMC must be met outside the applicable alternate mixing zone. The following apply where applicable:

         1. (AA) For certain substances, a CMC is specified in:

            1. (aa) subdivision (3), Table 8-1, which incorporates subdivision (4), Table 8-2; and
            2. (bb) subdivision (5).

         2. (BB) For substances for which a CMC is not specified in subdivision (3), Table 8-1, subdivision (4), Table 8-2, or subdivision (5):

            1. (aa) a CMC must be calculated by the commissioner using the procedures in section 11 of this rule; or
            2. (bb) if the minimum data requirements to calculate a CMC are not met, an SMC must be calculated using the procedures in section 12 of this rule.
         3. (CC) The CMC or SMC determined under subitem (AA) or (BB) may be modified on a site-specific basis to reflect local conditions in accordance with section 16 of this rule.
      2. (ii) A discharge must not cause acute toxicity, as measured by whole effluent toxicity tests, at any point in the waterbody. Compliance with this criterion is demonstrated if a discharge does not exceed one and zero-tenths (1.0) TUa in the undiluted discharge. For a discharge into a receiving stream or Lake Michigan, for which an alternate mixing zone demonstration is conducted and approved in accordance with 327 IAC 5-2-11.4(b)(4), compliance with this criterion is demonstrated if three-tenths (0.3) TUa is not exceeded outside the applicable alternate mixing zone.
   7. (F) Clause (E) does not apply to the chemical control of plants and animals when that control is performed in compliance with approval conditions specified by the Indiana department of natural resources as provided by IC 14-22-9.

2. (2) All surface waters outside of the applicable mixing zones determined in accordance with section 7 of this rule must be free of substances in concentrations that, on the basis of available scientific data, are believed to be sufficient to injure, be chronically toxic to, or be carcinogenic, mutagenic, or teratogenic to humans, animals, aquatic life, or plants. To ensure protection against the adverse effects identified in this subdivision, a toxic substance or pollutant must not be present in surface waters outside of the applicable mixing zones determined in accordance with section 7 of this rule in concentrations that exceed the most stringent of the following:

   1. (A) A CCC or SCC to protect aquatic life from chronic toxic effects, which is determined as follows:

      1. (i) For certain substances, a CCC is specified in:

         1. (AA) subdivision (3), Table 8-1, which incorporates subdivision (4), Table 8-2;
         2. (BB) subdivision (3), Table 8-1a; and
         3. (CC) subdivision (5).

      2. (ii) For substances for which a CCC is not specified in subdivision (3), Table 8-1, subdivision (3), Table 8-1a, subdivision (4), Table 8-2, or subdivision (5):

         1. (AA) a CCC must be calculated by the commissioner using the procedures in section 11 of this rule; or
         2. (BB) if the minimum data requirements to calculate a CCC are not met, an SCC must be calculated using the procedures in section 12 of this rule.
      3. (iii) The CCC or SCC determined under item (i)(AA), (i)(CC), or (ii) may be modified on a site-specific basis to reflect local conditions in accordance with section 16 of this rule.
      4. (iv) To ensure protection of aquatic life, a discharge must not cause chronic toxicity, as measured by whole effluent toxicity tests, outside of the applicable mixing zone. Compliance with this criterion is demonstrated if the waterbody does not exceed one and zero-tenths (1.0) TUc at the edge of the mixing zone.

   2. (B) An HNC or HNV to protect human health from adverse noncancer effects that may result from the consumption of aquatic organisms or drinking water from the waterbody, which is determined as follows:

      1. (i) For certain substances, an HNC is specified in subdivision (6), Table 8-3.

      2. (ii) For substances for which an HNC is not specified in subdivision (6), Table 8-3:

         1. (AA) an HNC must be calculated by the commissioner using the procedures in section 14 of this rule; or
         2. (BB) if the minimum data requirements to calculate an HNC are not met, an HNV must be calculated using the procedures in section 14 of this rule.
      3. (iii) The HNC or HNV determined under item (i) or (ii) may be modified on a site-specific basis to reflect local conditions in accordance with section 16 of this rule.
      4. (iv) The HNC for nondrinking water or HNV for nondrinking water for a substance applies to all surface waters outside the applicable mixing zone for a discharge of that substance. The HNC for drinking water or HNV for drinking water for a substance applies at the point of the public water system intake.

   3. (C) For carcinogenic substances, an HCC or HCV to protect human health from unacceptable cancer risk of greater than one (1) additional occurrence of cancer per one hundred thousand (100,000) population, which is determined as follows:

      1. (i) For certain substances, an HCC is specified in subdivision (6), Table 8-3.

      2. (ii) For substances for which an HCC is not specified in subdivision (6), Table 8-3:

         1. (AA) an HCC must be calculated by the commissioner using the procedures in section 14 of this rule; or
         2. (BB) if the minimum data requirements to calculate an HCC are not met, an HCV must be calculated using the procedures in section 14 of this rule.
      3. (iii) The HCC or HCV determined under item (i) or (ii) may be modified on a site-specific basis to reflect local conditions in accordance with section 16 of this rule.
      4. (iv) The HCC for nondrinking water or HCV for nondrinking water for a substance applies to all surface waters outside the applicable mixing zone for a discharge of that substance. The HCC for drinking water or HCV for drinking water applies at the point of the public water system intake.

   4. (D) A WC to protect avian and mammalian wildlife populations from adverse effects that may result from the consumption of aquatic organisms or water from the waterbody, which is determined as follows:

      1. (i) For certain substances, a WC is specified in subdivision (7), Table 8-4.

      2. (ii) For substances for which a WC is not specified in subdivision (7), Table 8-4:

         1. (AA) a WC must be calculated by the commissioner using the procedures in section 15 of this rule; or
         2. (BB) if the minimum data requirements to calculate a WC are not met, a WV may be calculated using the procedures in section 15 of this rule.
      3. (iii) The WC or WV determined under item (i) or (ii) may be modified on a site-specific basis to reflect local conditions in accordance with section 16 of this rule.

3. (3) Surface water quality criteria for protection of aquatic life are as follows:

   1. (A) The surface water quality criteria for the protection of aquatic life for specific substances are as follows:

      Table 8-1
      Surface Water Quality Criteria for Protection of Aquatic Life
      CAS Number	Substances	Criterion Maximum Concentration (CMC) (Maximum) (μg/L)[1]	CMC Conversion Factors (CF)	Criterion Continuous Concentration (CCC) (4-Day Average) (μg/L)[1]	CCC Conversion Factors (CF)
      Metals (dissolved)[2][3]
      7440382	Arsenic	WER(340)(CF)	1.000	WER(150)(CF)	1.000
      7440439	Cadmium	WER (e(0.9789 [lnH] - 3.866))(CF)	1.136672 - [lnH] 0.041838	WER (e(0.7977[lnH] - 3.909))(CF)	1.101672 - [ln H]0.041838
      7440473	Chromium (III)	WER (e(0.819 [lnH] + 3.7256))(CF)	0.316	WER (e(0.819 [lnH] + 0.6848))(CF)	0.860
      7440473	Chromium (VI)	WER(16)(CF)	0.982	WER(11)(CF)	0.962
      7440508	Copper	WER (e(0.9422[lnH] - 1.700))(CF)	0.960	WER (e(0.8545[lnH] - 1.702))(CF)	0.960
      7439921	Lead	WER (e(1.273[lnH] - 1.460))(CF)	1.46203 -[lnH]0.145712	WER (e(1.273[lnH] - 4.705))(CF)	1.46203 -[lnH]0.145712
      7439976	Mercury	WER(1.694)(CF)	0.85	WER(0.9081)(CF)	0.85
      7440020	Nickel	WER (e(0.846 [lnH] + 2.255))(CF)	0.998	WER (e(0.846 [lnH] + 0.0584))(CF)	0.997
      7440666	Zinc	WER (e(0.8473 [lnH] + 0.884))(CF)	0.978	WER (e(0.8473 [lnH] + 0.884))(CF)	0.986
      Organics (Total)
      60571	Dieldrin	0.24	NA	0.056	NA
      72208	Endrin	0.086	NA	0.036	NA
      56382	Parathion	0.065	NA	0.013	NA
      87865	Pentachlorophenol[4]	e(1.005[pH] - 4.869)	NA	e(1.005[pH] - 5.134)	NA
      Other Substances
      	Chlorine (total residual)	19	NA	11	NA
      	Chlorine (intermittent, total residual)[5]	200	NA		NA
      57125	Cyanide (free)	22	NA	5.2	NA
      Selenium CCC are specified in clause (B)
      Chloride CMC and CCC are specified in subdivision (5)[1]
      [1]Aquatic organisms should not be affected unacceptably if the four (4) day average concentration specified in this table for a substance does not exceed the CCC more than once every three (3) years on the average and if the one (1) hour average concentration does not exceed the CMC more than once every three (3) years on the average, except possibly where a commercially or recreationally important species is very sensitive.
      [2]Aquatic life criteria for these metals are expressed as a dissolved concentration and are calculated using the water-effect ratio (WER) and the specified conversion factor (CF). The CMC and CCC for a dissolved metal are calculated by multiplying the WER by the criterion value or formula and then by the appropriate CF. A value of one (1) must be used for the WER unless an alternate value is established under section 16 of this rule. The dissolved CMC and CCC must be rounded to two (2) significant digits, except when the criteria are used as intermediate values in a calculation, such as in the calculation of water quality-based effluent limitations (WQBELs).
      [3]The hardness values used in the equations for these criteria must not be greater than 400 mg/l as calcium carbonate (CaCO3), and the criteria at a hardness of 400 mg/l as CaCO3 are used for a water hardness above 400 mg/l as CaCO3. The term "lnH" is the natural log of hardness.
      [4]A CMC and CCC calculated for pentachlorophenol using the equation in this table must be rounded to two (2) significant digits, except when the criteria are used as intermediate values in a calculation, such as in the calculation of WQBELs.
      [5] To be considered an intermittent discharge, total residual chlorine must not be detected in the discharge for a period of more than forty (40) minutes in duration, and these time periods must be separated by at least five (5) hours.

   2. (B) The surface water quality criterion for the protection of aquatic life for selenium is as follows:

      Table 8-1a
      Surface Water Quality Aquatic Life Criterion for Selenium (CAS # 7782492)
      Criterion Continuous Concentration (CCC)
      Media Type	Fish Tissue[1]		Water Column[5][7]
      Criterion Element	Egg/Ovary[2]	Fish Whole-Body or Muscle[3]	Monthly Average Exposure	Intermittent Exposure[6]
      Magnitude	15.1 mg/kg dw	8.5 mg/kg dw whole-body or 11.3 mg/kg dw muscle (skinless, boneless filet)	1.5 μg/l in lentic aquatic systems3.1 μg/l in lotic aquatic systems
      Duration	Instantaneous measurement[4]	Instantaneous measurement[4]	Thirty (30) days	Number of days per month with an elevated concentration
      Frequency	Not to be exceeded	Not to be exceeded	Not more than once in three (3) years on average	Not more than once in three (3) years on average

^[1]Fish tissue elements are expressed as steady-state; the aquatic system should not be experiencing new or increasing inputs of selenium. ^[2]Egg or ovary supersedes any whole-body, muscle, or water column element when fish egg or ovary concentrations are measured. Any proposal to sample egg or ovary fish tissue must be submitted to the department for review and approval prior to initiation of sampling, and the department will evaluate all representative egg or ovary fish tissue data to determine compliance with this criterion element. ^[3]Fish whole-body or muscle tissue supersedes the water column element when both fish tissue and water concentrations are measured. Any proposal to sample fish whole-body or muscle tissue must be submitted to the department for review and approval prior to initiation of sampling, and the department will evaluate all representative fish whole-body or muscle tissue data to determine compliance with this criterion element. ^[4]Fish tissue data provide instantaneous point measurements that reflect integrative accumulation of selenium over time and space in fish populations at a given site. ^[5]Water column values are the applicable criterion element in the absence of steady-state condition fish tissue data and for fishless waters. Water column values are based on dissolved total selenium in water and are derived from fish tissue values via bioaccumulation modeling. Instead of the requirement in 327 IAC 5-2-11.4(b)(3)(A)(i)(CC), the thirty (30) day, ten (10) year stream design flow (Q_30,10) must be used for deriving total maximum daily loads (TMDLs), waste load allocations (WLAs) in the absence of TMDLs, and preliminary WLAs for tributaries of the Great Lakes system that exhibit appreciable flows relative to their volumes for the CCC water column criterion element applicable to lotic aquatic systems unless data exist to demonstrate that an alternate stream design flow is appropriate for stream-specific and pollutant-specific conditions. ^[6]Intermittent Exposure Equation variables mean the following:

WQC_int is the water column intermittent element.

WQC_30-day is the water column monthly element for either lentic or lotic waters.

C_bkgrnd is the average background selenium concentration.

f_int is the fraction of any 30-day period during which elevated selenium concentrations occur, with f_int assigned a value >0.033 (corresponding to one (1) day).

^[7]The water column criterion element may be modified on a site-specific basis in accordance with clause (C).

(C) Modification of the selenium water column criterion element must be achieved according to the following: (i) Site-specific water column criterion elements must be derived using either the empirical bioaccumulation factor (BAF) or mechanistic modeling method provided in Aquatic Life Ambient Water Quality Criterion for Selenium – Freshwater, EPA-822-R-16-006, Appendix K: Translation of a Selenium Fish Tissue Criterion Element to a Site-Specific Water Column Value (June 2016)*. (ii) Any proposal to derive a site-specific water column criterion element must be submitted to the department for review and approval of the methodology and sampling plan prior to initiation of sampling. The department shall evaluate and approve the applicability of and use of all representative data used to derive a site-specific water column criterion element. (iii) Any proposal to derive a site-specific water column criterion element must be protective of downstream designated uses for aquatic life and human health. (iv) Upon receipt of an application for a site-specific water column criterion element, the department shall do the following: (AA) Publish on the department's website all pertinent information about the proposed site-specific modification. (BB) Provide notice and request comment on the application. (v) Upon approval of a site-specific water column criterion element, the department shall do the following: (AA) Publish a notice in the Indiana Register. (BB) Place on the department's website all pertinent information about the approved site-specific modification. (CC) Submit the site-specific modification to U.S. EPA for approval. (DD) If approved by U.S. EPA, incorporate the site-specific modification into the water quality standards during the next revision of the water quality standards. (vi) Site-specific modifications of this criterion must not be incorporated into a final NPDES permit or used for other Clean Water Act purposes until approved by U.S. EPA.

(4) The dissolved CMC and CCC for certain metals at selected hardness values calculated from the equations and conversion factors in subdivision (3), Table 8-1 with a value of one (1) used for the WER are as follows:                       Table 8-2  Metals Concentrations in Micrograms Per Liter; Hardness in Milligrams Per Liter CaCO₃^[1]    Arsenic  Cadmium  Chromium (III)  Chromium (VI)  Copper  Hardness  CMC  CCC  CMC  CCC  CMC  CCC  CMC  CCC  CMC  CCC  50  340  150  0.94  0.43  320  42  16  11  7.0  5.0  100  340  150  1.8  0.72  570  74  16  11  13  9.0  150  340  150  2.6  0.97  790  100  16  11  20  13  200  340  150  3.4  1.2  1,000  130  16  11  26  16  250  340  150  4.2  1.4  1,200  160  16  11  32  20  300  340  150  5.0  1.6  1,400  180  16  11  38  23  350  340  150  5.8  1.8  1,600  210  16  11  44  26  400  340  150  6.5  2.0  1,800  230  16  11  50  29                                                                      Lead  Mercury  Nickel    Zinc  Hardness  CMC  CCC  CMC  CCC  CMC  CCC      CMC  CCC  50  30  1.2  1.4  0.77  260  29      65  66  100  65  2.5  1.4  0.77  470  52      120  120  150  100  3.9  1.4  0.77  660  73      170  170  200  140  5.3  1.4  0.77  840  93      210  210  250  170  6.7  1.4  0.77  1,000  110      250  260  300  210  8.1  1.4  0.77  1,200  130      300  300  350  240  9.5  1.4  0.77  1,400  150      340  340  400  280  11  1.4  0.77  1,500  170      380  380                                              ^[1] The dissolved metals criteria in this table have been rounded to two (2) significant digits in accordance with subdivision (3), Table 8-1. The equations and conversion factors in subdivision (3), Table 8-1 must be used instead of the criteria in this table when these criteria are used as intermediate values in a calculation, such as in the calculation of WQBELs.

(5) Surface water quality criteria for chloride for protection of aquatic life are as follows: (A) The CMC for chloride as a function of hardness (in mg/l as CaCO₃) and sulfate (in mg/l) in surface waters is calculated using the following formula: C = 287.8 (hardness)^0.205797 (sulfate)^-0.07452 Where: C = chloride CMC (maximum) in mg/l. (B) The CCC for chloride as a function of hardness (in mg/l as CaCO₃) and sulfate (in mg/l) in surface waters is calculated using the following formula: C = 177.87 (hardness)^0.205797 (sulfate)^-0.07452 Where: C = chloride CCC (4-Day Average) in mg/l. (C) The CMC and CCC for chloride calculated from the equations in this subdivision must be rounded to the nearest whole numbers, except when the criteria are used as intermediate values in a calculation, such as in the calculation of WQBELs. (D) The CMC for chloride in mg/l at selected concentrations of hardness (in mg/l as CaCO₃) and sulfate is as follows:                       Table 8-2a^[1]  Hardness (mg/l)  Sulfate (mg/l)  50  100  150  200  250  300  350  400  450  500  15  526  607  660  700  733  761  785  807  827  845  20  515  594  646  685  717  745  769  790  809  827  25  506  584  635  674  705  732  756  777  796  813  50  481  555  603  640  670  695  718  738  756  773  100  457  527  573  608  636  660  682  701  718  734  150  443  511  556  589  617  641  661  680  697  712  200  434  500  544  577  604  627  647  665  682  697  250  427  492  535  567  594  617  637  654  671  685  300  421  485  528  560  586  609  628  646  661  676  350  416  480  522  553  579  602  621  638  654  668  400  412  475  516  548  574  596  615  632  647  662  450  408  471  512  543  569  590  609  626  642  656  500  405  467  508  539  564  586  605  622  637  651  ^[1] The equation in clause (A) must be used instead of the criteria in this table when chloride criteria are used as intermediate values in a calculation, such as in the calculation of WQBELs.  (E) The CCC for chloride in mg/l at selected concentrations of hardness (in mg/l as CaCO₃) and sulfate is as follows:                       Table 8-2b^[1]  Hardness (mg/l)  Sulfate (mg/l)  50  100  150  200  250  300  350  400  450  500  15  325  375  408  433  453  470  485  499  511  522  20  318  367  399  423  443  460  475  488  500  511  25  313  361  392  416  436  453  467  480  492  503  50  297  343  373  395  414  430  444  456  467  477  100  282  326  354  375  393  408  421  433  444  453  150  274  316  343  364  381  396  409  420  430  440  200  268  309  336  357  373  388  400  411  421  431  250  264  304  331  351  367  381  394  404  414  423  300  260  300  326  346  362  376  388  399  409  418  350  257  297  322  342  358  372  384  394  404  413  400  255  294  319  339  355  368  380  391  400  409  450  252  291  316  336  351  365  377  387  397  405  500  250  289  314  333  349  362  374  384  394  402  ^[1] The equation in clause (B) must be used instead of the criteria in this table when chloride criteria are used as intermediate values in a calculation, such as in the calculation of WQBELs.

(6) Surface water quality criteria for protection of human health are as follows:               Table 8-3  Surface Water Quality Criteria for Protection of Human Health^[1]        Human Noncancer Criteria (HNC)  Human Cancer Criteria (HCC)  CAS Number  Substances  Drinking Water (μg/l)  Nondrinking Water (μg/l)  Drinking Water (μg/l)  Nondrinking Water (μg/l)    Metals (total recoverable)  7439976    Mercury (including methylmercury)  0.0018  0.0018        Organics (total)  71432    Benzene  19  510  12  310  57749    Chlordane  0.0014  0.0014  0.00025  0.00025  108907    Chlorobenzene  470  3,200      50293    DDT  0.002  0.002  0.00015  0.00015  60571    Dieldrin  0.00041  0.00041  6.5 × 10^-6  6.5 × 10^-6  105679    2,4-dimethylphenol  450  8,700      51285    2,4-dinitrophenol  55  2,800      118741    Hexachlorobenzene  0.046  0.046  0.00045  0.00045  67721    Hexachloroethane  6  7.6  5.3  6.7  58899    Lindane  0.47  0.5      75092    Methylene chloride  1,600  90,000  47  2600  1336363    PCBs (class)      6.8 × 10^-6  6.8 × 10^-6  1746016    2,3,7,8-TCDD (dioxin)  6.7 × 10^-8  6.7 × 10^-8  8.6 × 10^-9  8.6 × 10^-9  108883    Toluene  5,600  51,000      8001352    Toxaphene      6.8 × 10^-5  6.8 × 10^-5  79016    Trichloroethylene      29  370    Other Substances  57125    Cyanide (total)  600  48,000      ^[1]The HNC and HCC are thirty (30) day average criteria.

(7) Surface water quality criteria for protection of wildlife are as follows:         Table 8-4  Surface Water Quality Criteria for Protection of Wildlife^[1]  CAS Number  Substances  Wildlife Criteria (μg/l)    Metals (total recoverable)    7439976    Mercury (including methylmercury)  0.0013    Organics (total)    50293    DDT and metabolites  1.1 × 10^-5  1336363    PCBs (class)  1.2 × 10^-4  1746016    2, 3, 7, 8-TCDD (dioxin)  3.1 × 10^{-9  [1]}The WC are thirty (30) day average criteria.

(c) In addition to subsection (b), the following minimum conditions are applicable in the surface waters outside of the applicable mixing zone, as determined in accordance with section 7 of this rule, to ensure conditions necessary for the maintenance of a well-balanced aquatic community:

1. (1) There must be no substance that:

   1. (A) imparts unpalatable flavor to food fish; or
   2. (B) results in offensive odors in the vicinity of the water.

2. (2) No pH values below six (6.0) or above nine (9.0) are permitted, except daily fluctuations that:

   1. (A) exceed pH nine (9.0); and
   2. (B) are correlated with photosynthetic activity.

3. (3) Concentrations of dissolved oxygen must:

   1. (A) average at least five (5.0) milligrams per liter per calendar day; and
   2. (B) not be less than four (4.0) milligrams per liter at any time.

4. (4) Conditions for temperature are as follows:

   1. (A) Abnormal temperature changes that may adversely affect aquatic life are prohibited unless caused by natural conditions.
   2. (B) The normal daily and seasonal temperature fluctuations that existed before the addition of heat due to other than natural causes must be maintained.

   3. (C) Water temperatures must not exceed the maximum limits in the following table:

      1. (i) during more than one percent (1%) of the hours in the twelve (12) month period ending with any month; and

      2. (ii) by more than three (3) degrees Fahrenheit (one and seven-tenths (1.7) degrees Celsius):

         Table 8-5
         Maximum Instream Water Temperatures
         Month	St. Joseph River Tributary to LakeMichigan Upstream of the Twin Branch Dam °F(°C)	All Other Indiana Streams in the Great Lakes System °F(°C)
         January	50 (10)	50 (10)
         February	50 (10)	50 (10)
         March	55 (12.8)	60 (15.6)
         April	65 (18.3)	70 (21.1)
         May	75 (23.9)	80 (26.7)
         June	85 (29.4)	90 (32.2)
         July	85 (29.4)	90 (32.2)
         August	85 (29.4)	90 (32.2)
         September	84 (29.4)	90 (32.2)
         October	70 (21.1)	78 (25.5)
         November	60 (15.6)	70 (21.1)
         December	50 (10)	57 (14.0)

   4. (D) The following temperature criteria apply to Lake Michigan:

      1. (i) In all receiving waters, the points of measurement normally must be in the first meter below the surface at depths necessary to avoid thin layer surface warming due to extreme ambient air temperatures, but, where required to determine the true distribution of heated wastes and natural variations in water temperatures, measurements must be at a greater depth and at several depths as a thermal profile.

      2. (ii) Abnormal temperature changes injurious to fish, wildlife, or other aquatic life, or the growth or propagation thereof, are prohibited. In addition, plume interaction with the bottom must:

         1. (AA) be minimized; and
         2. (BB) not injuriously affect fish, shellfish, and wildlife spawning or nursery areas.
      3. (iii) The normal daily and seasonal temperature fluctuations that existed before the addition of heat must be maintained.

      4. (iv) At any time and at a maximum distance of a one thousand (1,000) foot arc inscribed from a fixed point adjacent to the discharge or as agreed upon by the commissioner and federal regulatory agencies, the following apply:

         1. (AA) The receiving water temperature must not be more than three (3) degrees Fahrenheit (one and seven-tenths (1.7) degrees Celsius) above the existing natural water temperature.

         2. (BB) Thermal discharges to Lake Michigan must comply with the following maximum temperature requirements:

            1. (aa) Thermal discharges to Lake Michigan must not raise the maximum temperature in the receiving water above those listed in the following table, except to the extent the permittee adequately demonstrates that the exceedance is caused by the water temperature of the intake water:

               	Table 8-6
               	Maximum Water Temperatures
               	Month	°F(°C)
               	January	45 (7)
               	February	45 (7)
               	March	45 (7)
               	April	55 (13)
               	May	60 (16)
               	June	70 (21)
               	July	80 (27)
               	August	80 (27)
               	September	80 (27)
               	October	65 (18)
               	November	60 (16)
               	December	50 (10)

            2. (bb) If the permittee demonstrates that the intake water temperature is within three (3) degrees Fahrenheit below an applicable maximum temperature under subitem (aa), Table 8-6, then not more than a three (3) degree Fahrenheit exceedance of the maximum water temperature is permitted.

      5. (v) The following facilities that discharge into the open waters of Lake Michigan are limited to the amount essential for blowdown in the operation of a closed cycle cooling facility:

         1. (AA) All facilities that have new waste heat discharges exceeding a daily average of five-tenths (0.5) billion British thermal units (Btu) per hour. As used in this item, "new waste heat discharge" means any discharge that had not begun operations as of February 11, 1972.
         2. (BB) All facilities with existing waste heat discharges that increase the quantity of waste heat discharged by more than a daily average of five-tenths (0.5) billion Btu per hour.

      6. (vi) Water intakes must be designed and located to minimize entrainment and damage to desirable organisms. Requirements may vary depending upon local conditions, but, in general, intakes must:

         1. (AA) have minimum water velocity; and
         2. (BB) not be located in spawning or nursery areas of important fishes.
      7. Water velocity at screens and other exclusion devices must be at a minimum.
      8. (vii) Discharges other than those in existence on or before February 11, 1972, must not have thermal plumes that overlap or intersect.

      9. (viii) Facilities discharging more than a daily average of five-tenths (0.5) billion Btu of waste heat must:

         1. (AA) continuously record intake and discharge temperature and flow; and
         2. (BB) make those records available to the public or regulatory agencies upon request.

5. (5) The following criteria must be used to regulate ammonia:

   1. (A) Concentrations of total ammonia (as N) must not exceed the CMC outside the zone of initial dilution or the final acute value (FAV = 2 (CMC)) in the undiluted discharge unless, for a discharge to a receiving stream or Lake Michigan, an alternate mixing zone demonstration is conducted and approved in accordance with 327 IAC 5-2-11.4(b)(4), in which case, the CMC must be met outside the applicable alternate mixing zone. The CMC of total ammonia (as N) is determined using the following equation:

      Where:	FT	=	100.03(20-T)
      	FPH	=	1; when: 8 < pH < 9; or
      			1 + 10(7.4 - pH)	; when: 6.5 < pH < 8
      			1.25
      	pKa	=	0.09018 +	2729
      	T + 273.2
      	T	=	Temperature in °C

   2. (B) The CCC of total ammonia (as N) is determined using the following equation:

      Where:	FT	=	100.03(20-T)
      	FPH	=	1; when: 8 < pH < 9; or
      			1 + 10(7.4 -pH)		; when 6.5<pH<8
      			1.25
      	RATIO	=	13.5; when: 7.7 < pH < 9; or
      			(20)(10(7.7 -pH))		; when 6.5<pH<7.7
      			1 + 10(7.4 - pH)
      	pKa	=	0.09018 +	2729
      	T + 273.2
      	T	=	Temperature in °C

   3. (C) The use of the equations in clause (A) results in the following CMCs for total ammonia (as N) at different temperatures and pHs:

      Table 8-7
      Criterion Maximum Concentrations for Total Ammonia (as N) Temperature (°C)
      pH	0	5	10	15	20	25	30
      6.5	28.48	26.61	25.23	24.26	23.64	23.32	23.29
      6.6	27.68	25.87	24.53	23.59	22.98	22.68	22.65
      6.7	26.74	24.99	23.69	22.78	22.20	21.92	21.90
      6.8	25.64	23.96	22.72	21.85	21.30	21.03	21.01
      6.9	24.37	22.78	21.60	20.78	20.26	20.01	20.00
      7.0	22.95	21.45	20.35	19.58	19.09	18.86	18.86
      7.1	21.38	19.98	18.96	18.24	17.80	17.59	17.60
      7.2	19.68	18.40	17.46	16.81	16.40	16.22	16.24
      7.3	17.90	16.73	15.88	15.29	14.93	14.78	14.81
      7.4	16.06	15.02	14.26	13.74	13.42	13.30	13.35
      7.5	14.23	13.31	12.64	12.19	11.92	11.81	11.88
      7.6	12.44	11.65	11.07	10.67	10.45	10.37	10.45
      7.7	10.75	10.06	9.569	9.238	9.052	9.003	9.088
      7.8	9.177	8.597	8.181	7.907	7.760	7.734	7.830
      7.9	7.753	7.268	6.924	6.701	6.589	6.584	6.689
      8.0	6.496	6.095	5.813	5.636	5.555	5.569	5.683
      8.1	5.171	4.857	4.639	4.508	4.457	4.486	4.602
      8.2	4.119	3.873	3.707	3.612	3.584	3.625	3.743
      8.3	3.283	3.092	2.967	2.900	2.891	2.942	3.061
      8.4	2.618	2.472	2.379	2.335	2.340	2.399	2.519
      8.5	2.091	1.979	1.911	1.886	1.903	1.968	2.089
      8.6	1.672	1.588	1.540	1.529	1.555	1.625	1.747
      8.7	1.339	1.277	1.246	1.246	1.279	1.353	1.475
      8.8	1.075	1.030	1.011	1.021	1.060	1.137	1.260
      8.9	0.8647	0.8336	0.8254	0.8418	0.8862	0.9650	1.088
      9.0	0.6979	0.6777	0.6777	0.6998	0.7479	0.8286	0.9521

   4. (D) The use of the equations in clause (B) results in the following CCCs for total ammonia (as N) at different temperatures and pHs:

      Table 8-8
      Criterion Continuous Concentrations for Total Ammonia (as N) Temperature (°C)
      pH	0	5	10	15	20	25	30
      6.5	2.473	2.310	2.191	2.106	2.052	2.025	2.022
      6.6	2.473	2.311	2.191	2.107	2.053	2.026	2.023
      6.7	2.473	2.311	2.191	2.107	2.054	2.027	2.025
      6.8	2.473	2.311	2.192	2.108	2.055	2.028	2.027
      6.9	2.474	2.312	2.193	2.109	2.056	2.030	2.030
      7.0	2.474	2.312	2.193	2.110	2.058	2.033	2.033
      7.1	2.475	2.313	2.195	2.112	2.060	2.036	2.037
      7.2	2.475	2.314	2.196	2.114	2.063	2.040	2.043
      7.3	2.476	2.315	2.198	2.116	2.066	2.044	2.050
      7.4	2.477	2.317	2.200	2.119	2.070	2.050	2.058
      7.5	2.478	2.319	2.202	2.123	2.075	2.058	2.069
      7.6	2.480	2.321	2.206	2.128	2.082	2.067	2.082
      7.7	2.450	2.294	2.181	2.106	2.063	2.052	2.071
      7.8	2.092	1.959	1.865	1.802	1.769	1.763	1.785
      7.9	1.767	1.657	1.578	1.527	1.502	1.501	1.525
      8.0	1.481	1.389	1.325	1.285	1.266	1.269	1.295
      8.1	1.179	1.107	1.057	1.027	1.016	1.022	1.049
      8.2	0.9387	0.8828	0.8450	0.8232	0.8169	0.8263	0.8531
      8.3	0.7481	0.7048	0.6762	0.6610	0.6589	0.6705	0.6976
      8.4	0.5968	0.5634	0.5421	0.5321	0.5334	0.5468	0.5741
      8.5	0.4766	0.4511	0.4357	0.4298	0.4337	0.4485	0.4760
      8.6	0.3811	0.3619	0.3511	0.3485	0.3545	0.3704	0.3981
      8.7	0.3052	0.2910	0.2839	0.2839	0.2916	0.3083	0.3362
      8.8	0.2450	0.2347	0.2305	0.2326	0.2417	0.2591	0.2871
      8.9	0.1971	0.1900	0.1881	0.1919	0.2020	0.2199	0.2480
      9.0	0.1591	0.1545	0.1545	0.1595	0.1705	0.1889	0.2170

(d) Waters designated by the Indiana department of natural resources for put-and-take trout fishing and listed in section 5(a)(3) of this rule are designated as salmonid waters and must be protected for cold-water fish. In addition to subsections (b) and (c), the following criteria are applicable outside of a mixing zone, as determined in accordance with section 7 of this rule, in the surface waters designated as salmonid waters to ensure conditions necessary for the maintenance of a well-balanced, cold-water fish community:

1. (1) Dissolved oxygen concentrations must not be less than:

   1. (A) six (6.0) milligrams per liter at any time; and
   2. (B) seven (7.0) milligrams per liter in areas where spawning occurs during the spawning season and in areas used for imprinting during the time salmonids are being imprinted.
2. Dissolved oxygen concentrations in the open waters of Lake Michigan must not be less than seven (7.0) milligrams per liter at any time.

3. (2) The maximum temperature rise above natural must not exceed two (2) degrees Fahrenheit (one and one-tenth (1.1) degrees Celsius) at any time or place and, unless due to natural causes, the temperature must not exceed the following:

   1. (A) Seventy (70) degrees Fahrenheit (twenty-one and one-tenth (21.1) degrees Celsius) at any time.
   2. (B) Sixty-five (65) degrees Fahrenheit (eighteen and three-tenths (18.3) degrees Celsius) during spawning or imprinting periods.

(e) Bacteriological quality for recreational uses during the recreational season is as follows:

1. (1) The recreational season is defined as the months of April through October, inclusive.

2. (2) In addition to subsection (b), the criteria in this subsection are to be used to do the following:

   1. (A) Evaluate waters for full body contact recreational uses.
   2. (B) Establish wastewater treatment requirements.
   3. (C) Establish effluent limits during the recreational season.

3. (3) For full body contact recreational uses, E. coli bacteria must not exceed the following:

   1. (A) One hundred twenty-five (125) colony forming units (cfu) or most probable number (MPN) per one hundred (100) milliliters as a geometric mean based on not less than five (5) samples equally spaced over a thirty (30) day period.

   2. (B) Two hundred thirty-five (235) cfu or MPN per one hundred (100) milliliters in any one (1) sample in a thirty (30) day period, except that, in cases where there are at least ten (10) samples at a given site, up to ten percent (10%) of the samples may exceed two hundred thirty-five (235) cfu or MPN per one hundred (100) milliliters where the:

      1. (i) E. coli exceedances are incidental and attributable solely to E. coli resulting from the discharge of treated wastewater from a wastewater treatment plant as defined at IC 13-11-2-258; and
      2. (ii) criterion in clause (A) is met.
   3. However, a single sample is used for making beach notification and closure decisions.
4. If a geometric mean cannot be calculated because five (5) equally spaced samples are not available, then the criterion stated in clause (B) must be met.

5. (4) For demonstrating compliance with wastewater treatment requirements, sanitary wastewater dischargers shall ensure the following:

   1. (A) The concentration of E. coli in the undiluted discharge does not exceed one hundred twenty-five (125) cfu or MPN per one hundred (100) milliliters as a geometric mean of the effluent samples taken in a calendar month.
   2. (B) Not more than ten percent (10%) of all samples when not less than ten (10) samples are taken and analyzed for E. coli in a calendar month exceed two hundred thirty-five (235) cfu or MPN per one hundred (100) milliliters as a daily maximum. Under this clause, the calculation of ten percent (10%) of the samples taken must be limited to the lowest whole number result.

6. (5) Effluent limits to implement the criteria in subdivision (3) during the recreational season must be established in NPDES permits by incorporating the following that are to be applied to the undiluted discharge:

   1. (A) The concentration of E. coli in the undiluted discharge must not exceed one hundred twenty-five (125) cfu or MPN per one hundred (100) milliliters as a geometric mean of the effluent samples taken in a calendar month.
   2. (B) Not more than ten percent (10%) of all samples in a calendar month exceed two hundred thirty-five (235) cfu or MPN per one hundred (100) milliliters as a daily maximum. Under this clause, the calculation of ten percent (10%) of the samples taken must be limited to the lowest whole number result.

(f) In addition to subsection (b), the criteria to protect the surface water quality at the point at which water is withdrawn for treatment for public water supply are as follows:

1. (1) The coliform bacteria group must not exceed the following:

   1. (A) Five thousand (5,000) cfu or MPN per one hundred (100) milliliters as a monthly average value (either MPN or membrane filter (MF) count).
   2. (B) Five thousand (5,000) cfu or MPN per one hundred (100) milliliters in more than twenty percent (20%) of the samples examined during any month.
   3. (C) Twenty thousand (20,000) cfu or MPN per one hundred (100) milliliters in more than five percent (5%) of the samples examined during any month.

2. (2) Taste and odor producing substances, other than those naturally occurring, must not interfere with the production of a finished water by conventional treatment consisting of the following:

   1. (A) Coagulation.
   2. (B) Sedimentation.
   3. (C) Filtration.
   4. (D) Disinfection.
3. (3) The concentrations of either chloride or sulfate must not exceed two hundred fifty (250) milligrams per liter unless due to naturally occurring sources.
4. (4) The concentration of dissolved solids must not exceed seven hundred fifty (750) milligrams per liter unless due to naturally occurring sources. A specific conductance of one thousand two hundred (1,200) micromhos per centimeter (at twenty-five (25) degrees Celsius) may be considered equivalent to a dissolved solids concentration of seven hundred fifty (750) milligrams per liter.
5. (5) Surface waters are acceptable for public water supply if radium-226 and strontium-90 are present in amounts not exceeding three (3) and ten (10) picocuries per liter, respectively. In the known absence of strontium-90 and alpha emitters, the water supply is acceptable when the gross beta concentrations do not exceed one thousand (1,000) picocuries per liter.

6. (6) The:

   1. (A) combined concentration of nitrate-N and nitrite-N must not exceed ten (10) milligrams per liter; and
   2. (B) concentration of nitrite-N must not exceed one (1) milligram per liter.
7. (7) Chemical constituents in the waters must not be present at levels that prevent, after conventional treatment, meeting the drinking water standards contained in 327 IAC 8-2, due to other than natural causes.

(g) In addition to subsection (b), dissolved solids must not exceed seven hundred fifty (750) milligrams per liter at any time, other than from naturally occurring sources, to ensure protection of water quality at the point at which surface water is withdrawn for use, either with or without treatment, for industrial cooling and processing. A specific conductance of one thousand two hundred (1,200) micromhos per centimeter (at twenty-five (25) degrees Celsius) may be considered equivalent to a dissolved solids concentration of seven hundred fifty (750) milligrams per liter.

(h) The criteria to ensure surface water quality conditions necessary for agricultural use are the same as those in subsection (b).

(i) The quality of surface waters designated for limited uses under section 19(a) of this rule must, at a minimum, meet the criteria contained in subsections (b), (e), and (g), and be aerobic at all times. However, the water must meet the criteria that are applicable to the higher use water at the point where a limited use water:

1. (1) becomes physically or chemically capable of supporting a higher use; or
2. (2) interfaces with a higher use water segment.

(j) Additional requirements for the open waters of Lake Michigan are as follows:

1. (1) In addition to complying with all other applicable subsections, open waters in Lake Michigan must meet the following criteria:

   Table 8-9
   Additional Criteria for Lake Michigan
   Parameters	Criteria
   Dissolved oxygen	Dissolved oxygen concentrations must not be less than seven (7.0) milligrams per liter outside the applicable mixing zone.
   pH	No pH values below six (6.0) or above nine (9.0) are permitted, except daily fluctuations that exceed pH 9.0 and are correlated with photosynthetic activity.
   Chloride	250 mg/l[1]
   Phenols	The criteria in subsection (c)(1)
   Sulfate	250 mg/l[1]
   Total phosphorus	The requirements in 327 IAC 5-10-2
   Total dissolved solids	750 mg/l[1]
   Fluoride	1.0 mg/l[1]
   Dissolved iron	300 μg/l[1]
   [1] This criterion minimizes or prevents increased levels of this substance in Lake Michigan. For the purposes of establishing water quality-based effluent limitations (WQBEL) based on this criterion, it must be treated as a four (4) day average criterion.

2. (2) During each triennial review of the water quality standards, prior to preliminary adoption of revised rules, the following must occur:

   1. (A) The department shall prepare a report for the board on the monitoring data for the parameters in Table 8-10, as measured at the drinking water intakes in Lake Michigan.

   2. (B) If the monitoring data in clause (A) indicate that the levels of the parameters are either increasing or exceed the levels in Table 8-10, the report for the board must provide available information on the known and potential causes of the increased levels of these parameters, the known and potential impacts on aquatic life, wildlife, and human health, and any recommended revisions of the criteria.

      	Table 8-10
      	Parameters		Levels
      	pH		7.5-8.5 s.u.
      	Chloride
      		Monthly average	15 mg/l
      		Daily maximum	20 mg/l
      	Sulfate
      		Monthly average	26 mg/l
      		Daily maximum	50 mg/l
      	Total phosphorus
      		Monthly average	0.03 mg/l
      		Daily maximum	0.04 mg/l
      	Total dissolved solids
      		Monthly average	172 mg/l
      		Daily maximum	200 mg/l

*This document is incorporated by reference. Copies may be obtained from the U.S. EPA National Service Center for Environmental Publications (www.epa.gov/nscep), or are available for review at the Indiana Department of Environmental Management, Office of Legal Counsel, Indiana Government Center North, Thirteenth Floor, 100 North Senate Avenue, Indianapolis, Indiana 46204.

(Water Pollution Control Division; 327 IAC 2-1.5-8; filed Jan 14, 1997, 12:00 p.m.: 20 IR 1370; errata filed Aug 11, 1997, 4:15 p.m.: 20 IR 3376; filed Feb 14, 2005, 10:05 a.m.: 28 IR 2074; errata filed Apr 6, 2006, 2:48 p.m.: 29 IR 2546; filed Mar 18, 2008, 2:26 p.m.: 20080416-IR-327060573FRA; filed Jul 9, 2012, 2:54 p.m.: 20120808-IR-327110320FRA; filed Nov 5, 2021, 12:56 p.m.: 20211201-IR-327140058FRA; readopted filed Oct 18, 2024, 1:57 p.m.: 20241113-IR-327230810RFA)