Authority: IC 13-14-8; IC 13-14-9; IC 13-15-1-2; IC 13-15-2-1; IC 13-18-3

Affected: IC 13-11-2; IC 13-18-4

Sec. 11.5. (a) If the commissioner determines that a pollutant or pollutant parameter (either conventional, nonconventional, a toxic substance, or whole effluent toxicity (WET)) is or may be discharged into the Great Lakes system at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above any applicable narrative criterion or numeric water quality criterion or value under 327 IAC 2-1.5, the commissioner shall incorporate water quality-based effluent limitations (WQBELs) in an NPDES permit that will ensure compliance with the criterion or value. The commissioner shall exercise best professional judgment, taking into account the:

1. (1) source and nature of the discharge;
2. (2) existing controls on point and nonpoint sources of pollution;
3. (3) variability of the pollutant or pollutant parameter in the effluent; and
4. (4) where appropriate, dilution of the effluent in the receiving water.

In all cases, the commissioner shall use any valid, relevant, representative information pertaining to the discharge of the pollutant.

(b) If the commissioner determines that a substance is or may be discharged into the Great Lakes system at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above any numeric criterion for a toxic substance contained in 327 IAC 2-1.5-8(b)(3), Table 8-1, 327 IAC 2-1.5-8(b)(5), 327 IAC 2-1.5-8(b)(6), Table 8-3, 327 IAC 2-1.5-8(b)(7), Table 8-4, 327 IAC 2-1.5-16(g), Table 16-1, a criterion for ammonia contained under 327 IAC 2-1.5-8(c)(5), a criterion for chloride, sulfate, total dissolved solids, fluoride, or dissolved iron under 327 IAC 2-1.5-8(j), or a Tier I criterion or Tier II value established under 327 IAC 2-1.5-11 through 327 IAC 2-1.5-16, the commissioner shall incorporate WQBELs in an NPDES permit for the discharge of that pollutant, and in all cases, the commissioner shall use any valid, relevant, representative information pertaining to the discharge of the substance as follows:

1. (1) When facility-specific effluent monitoring data for a substance are available, the commissioner may take into account the source and nature of the discharge, existing controls on point and nonpoint sources of pollution, the variability of the pollutant or pollutant parameter in the effluent, and, where appropriate, the dilution of the effluent in the receiving water in making the determination whether to develop preliminary effluent limitations (PELs) and comparing those effluent limitations to the projected effluent quality (PEQ) of the discharge in accordance with the following procedures:

   1. (A) The commissioner shall develop PELs for the discharge of a pollutant from a point source using the following procedures:

      1. (i) The commissioner shall develop preliminary WLAs for the discharge of the pollutant from the point source to protect human health, wildlife, acute aquatic life, and chronic aquatic life, based upon the following:

         1. (AA) Any existing numeric criterion for a toxic substance contained in 327 IAC 2-1.5-8(b)(3), Table 8-1, 327 IAC 2-1.5-8(b)(5), 327 IAC 2-1.5-8(b)(6), Table 8-3, 327 IAC 2-1.5-8(b)(7), Table 8-4, 327 IAC 2-1.5-16(g), Table 16-1, or 327 IAC 2-1.5-8(c)(5) or a site-specific modification to an existing numeric criterion established under 327 IAC 2-1.5-16.
         2. (BB) Where there is no existing numeric criterion, the commissioner shall calculate a Tier I criterion for such substance for the protection of human health, wildlife, and aquatic life using the methodologies under 327 IAC 2-1.5-11 (aquatic life), 327 IAC 2-1.5-14 (human health), 327 IAC 2-1.5-15 (wildlife), and 327 IAC 2-1.5-16 (site-specific modifications).
         3. (CC) Where there is insufficient data to calculate a Tier I criterion, the commissioner shall calculate a Tier II value for such substance for the protection of human health and aquatic life using the methodologies under 327 IAC 2-1.5-12 (aquatic life), 327 IAC 2-1.5-14 (human health), and 327 IAC 2-1.5-16 (site-specific modifications).
         4. (DD) Where there is insufficient data to calculate a Tier II value, the commissioner shall apply the procedure in subdivision (3) to determine whether data must be generated to calculate a Tier II value.
      2. (ii) The commissioner shall develop a preliminary WLA for the discharge of chloride, sulfate, total dissolved solids, fluoride, or dissolved iron, in addition to the preliminary WLAs developed for the parameter under item (i), based on the numeric criterion for the substance under 327 IAC 2-1.5-8(j) when applicable.
      3. (iii) Section 11.4(c) of this rule shall be used as the basis for determining preliminary WLAs in accordance with items (i) and (ii).
      4. (iv) The commissioner shall use the preliminary WLAs developed under items (i) through (iii) to develop monthly and daily PELs in accordance with the procedure for converting WLAs into WQBELs under section 11.6(c) of this rule.

   2. (B) The commissioner shall determine the PEQ as follows:

      1. (i) When monthly average data are available, calculated using at least two (2) data points over the period of a month, the monthly PEQ shall be determined as follows:

         1. (AA) The commissioner shall identify the number of monthly averages of the effluent data and the coefficient of variation of the monthly averages of the effluent data.
         2. (BB) The commissioner shall obtain the appropriate multiplying factor from subsection (h) based on the information obtained in subitem (AA).
         3. (CC) The maximum of the monthly average values shall be multiplied by the multiplying factor determined under subitem (BB) to determine the monthly PEQ.
      2. (ii) When monthly average data are not available, the monthly PEQ shall be identical to the daily PEQ determined under item (iii). An alternate method of calculating monthly averages may be used if the applicant demonstrates that this alternate method results in monthly averages representative of actual conditions at the facility. Monthly averages calculated under this item shall be used to determine the monthly PEQ using the procedure in item (i).

      3. (iii) The daily PEQ shall be determined as follows:

         1. (AA) The commissioner shall identify the number of daily effluent samples and the coefficient of variation of the daily effluent samples.
         2. (BB) The commissioner shall obtain the appropriate multiplying factor from subsection (h) based on the information obtained in subitem (AA).
         3. (CC) The maximum of the daily effluent samples shall be multiplied by the multiplying factor determined under subitem (BB) to determine the daily PEQ.
      4. (iv) The coefficient of variation shall be calculated as the ratio of the standard deviation of the daily or monthly effluent data divided by the arithmetic average of the effluent data, except that where there are fewer than ten (10) data points the coefficient of variation shall be specified as six-tenths (0.6).

      5. (v) In lieu of the procedures under items (i) through (iv), the commissioner shall allow the use of an alternate procedure for the determination of the PEQ if the applicant demonstrates that the alternate statistical procedure meets the following:

         1. (AA) Is a scientifically defensible statistical method.
         2. (BB) Specifies the daily PEQ as the ninety-fifth percentile of the distribution of the projected population of daily values of the facility-specific effluent monitoring data.
         3. (CC) Specifies the monthly PEQ as the ninety-fifth percentile of the distribution of the projected population of monthly average values of the facility-specific effluent monitoring data.
         4. (DD) Accounts for and captures the long term daily and monthly variability of the effluent quality.
         5. (EE) Accounts for limitations associated with sparse data sets.
         6. (FF) Assumes a lognormal distribution of the facility-specific effluent data unless otherwise shown by the effluent data set.

   3. (C) The commissioner shall establish WQBELs in the NPDES permit for each substance that:

      1. (i) the monthly PEQ developed under clause (B) exceeds the monthly PEL developed under clause (A); or
      2. (ii) the daily PEQ developed under clause (B) exceeds the daily PEL developed under clause (A).

   4. (D) If facility-specific effluent monitoring data for a metal are available in the form of dissolved metal and the PELs for the metal developed under clause (A) are based on an acute or chronic aquatic life water quality criterion or value expressed in the form of dissolved metal, the commissioner shall make the determination under clause (C) using PEQs and PELs in the form of dissolved metal if the following conditions are satisfied:

      1. (i) The discharger provides an acceptable site-specific study that shows that the metal in the effluent does not become more dissolved in the receiving waterbody outside the mixing zone.
      2. (ii) Representative data are available from the receiving waterbody to calculate the background concentration of the metal in accordance with section 11.4(a)(8) of this rule and, if applicable, the hardness of the receiving waterbody in accordance with section 11.4(a)(13) of this rule.
      3. (iii) The facility-specific effluent monitoring data in the form of dissolved metal are representative of the magnitude and variability of the metal in the effluent.
      4. (iv) The PEQs in the form of dissolved metal are determined under clause (B) using the effluent monitoring data in item (iii).

      5. (v) The PELs in the form of dissolved metal are developed as follows:

         1. (AA) Preliminary WLAs in the form of dissolved metal are developed consistent with section 11.4(c) of this rule and using the receiving waterbody data in item (ii) to protect acute and chronic aquatic life.
         2. (BB) The preliminary WLAs in subitem (AA) are used to develop monthly and daily PELs in accordance with section 11.6(c) of this rule.

      6. (vi) A determination under clause (C) using PEQs and PELs developed under this item in the form of total recoverable metal shows that the commissioner is not required to establish WQBELs in the NPDES permit for the metal. The PEQs and PELs shall be developed as follows:

         1. (AA) PEQs in the form of total recoverable metal shall be determined under clause (B) using facility-specific effluent monitoring data in the form of total recoverable metal that is comparable to the data in item (iii).
         2. (BB) Monthly and daily PELs in the form of total recoverable metal shall be developed using preliminary WLAs developed under section 11.4(c) of this rule for all the applicable criteria and values for the metal that are expressed in the form of total recoverable metal and in accordance with section 11.6(c) of this rule. The preliminary WLAs shall be calculated using the receiving waterbody data in item (ii).

2. (2) When facility-specific effluent monitoring data for a substance are not available, the commissioner shall exercise best professional judgment, taking into account the source and nature of the discharge, existing controls on point and nonpoint sources of pollution, and, where appropriate, the dilution of the effluent in the receiving water:

   1. (A) for a new Great Lakes discharger, to develop an estimated monthly and daily PEQ necessary to make a determination under this subsection; or
   2. (B) for an existing Great Lakes discharger, to determine whether it is necessary to require the applicant to collect the data required to make a determination under this subsection.

3. (3) The commissioner shall develop the necessary data to calculate Tier II values where such data does not currently exist as follows:

   1. (A) Except as provided in clauses (B) and (D) or subdivision (4), for each toxic substance that a permittee reports as known or believed to be present in its effluent, or that the commissioner reasonably believes may be present in the effluent, and for which pollutant data sufficient to calculate Tier II values for noncancer human health, acute aquatic life, or chronic aquatic life do not exist, the commissioner shall take the following actions:

      1. (i) For those effects (noncancer human health, acute aquatic life, or chronic aquatic life) for which sufficient data do not exist, the commissioner shall use all available, relevant information, including QSAR information and other relevant toxicity information, to estimate ambient screening values for such pollutant that will protect humans from health effects other than cancer, and aquatic life from acute and chronic effects.
      2. (ii) Using the procedures under subdivision (1), the commissioner shall develop PELs for the discharge of the pollutant from the point source to protect human health, acute aquatic life, and chronic aquatic life based upon the estimated ambient screening values.
      3. (iii) The commissioner shall compare the PEQs developed according to the procedures under subdivision (1) to the PELs developed under item (ii). If the monthly or daily PEQ exceeds the respective monthly or daily PEL, the commissioner shall generate or require the permittee to generate the data necessary to derive Tier II values for noncancer human health, acute aquatic life, and chronic aquatic life.
      4. (iv) The data generated under item (iii) shall be used in calculating a Tier II value as required under subdivision (1). The calculated Tier II value shall be used in calculating the PELs under subdivision (1). These PELs shall be used for purposes of determining whether a WQBEL must be included in the permit under subdivision (1).

   2. (B) With the exception of BCCs, the commissioner is not required to apply the procedures under clause (A) or include WQBELs to protect aquatic life for any pollutant discharged by an existing point source into the Great Lakes system if the following occur:

      1. (i) There is insufficient data to calculate a Tier I criterion or Tier II value for aquatic life for the pollutant.
      2. (ii) The permittee has demonstrated that the whole effluent does not exhibit acute or chronic toxicity.
      3. (iii) The permittee has demonstrated, through a biological assessment, that there are no acute or chronic effects on aquatic life in the receiving water.

   3. (C) Nothing in clause (A) or (B) shall preclude or deny the right of the commissioner to:

      1. (i) determine, in the absence of the data necessary to derive a Tier II value, that the discharge of the pollutant will cause, have the reasonable potential to cause, or contribute to an excursion above a narrative criterion for water quality; and
      2. (ii) incorporate a WQBEL for the pollutant into an NPDES permit.
   4. (D) If the commissioner develops a WQBEL consistent with clause (C) that is at least as stringent as a WQBEL that would have been developed based upon the Tier II value or values for that pollutant, the commissioner may require the permittee to generate the data necessary to derive a Tier II value or values for that pollutant.

4. (4) The determinations under this subdivision shall be made on a pollutant-by-pollutant, outfall-by-outfall basis. This subdivision applies only in the absence of an EPA-approved TMDL applicable to the discharge or in the absence of an assessment and remediation plan submitted and approved in accordance with section 11.4(a)(2) of this rule. The following procedures shall be used in the consideration of intake pollutants in determining reasonable potential:

   1. (A) As used in this subdivision and section 11.6(i) of this rule, "intake pollutant" means a pollutant that is present in waters of the state at the time it is withdrawn from such waters by the discharger or other facility, such as a public water system supplying the discharger with intake water.

   2. (B) As used in this subdivision, subsection (g), and section 11.6(i) of this rule, an intake pollutant is considered to be from the same body of water as the discharge if the following conditions exist:

      1. (i) The commissioner finds that the intake pollutant would have reached the vicinity of the outfall point in the receiving water within a reasonable period had it not been removed by the permittee. This finding may be deemed established if:

         1. (AA) the representative background concentration of the pollutant in the receiving water, as determined under section 11.4(a)(8) of this rule, (excluding any amount of the pollutant in the facility's discharge) is similar to or greater than that in the intake water;
         2. (BB) there is a direct hydrological connection between the intake and discharge points (the water at the point of intake naturally flows toward the water at the point of discharge); and
         3. (CC) any difference in a water quality characteristic (such as temperature, pH, and hardness) between the intake and receiving waters does not result in an adverse impact on the receiving water.
      2. (ii) The commissioner may also consider other site-specific factors relevant to the transport and fate of the pollutant to make the finding in a particular case that a pollutant would or would not have reached the vicinity of the outfall point in the receiving water within a reasonable period had it not been removed by the permittee.
      3. (iii) An intake pollutant from ground water may be considered to be from the same body of water if the commissioner determines that the pollutant would have reached the vicinity of the outfall point in the receiving water within a reasonable period had it not been removed by the permittee, except that such a pollutant is not from the same body of water to the extent that the ground water contains the pollutant partially or entirely due to human activity, such as industrial, commercial, or municipal operations, disposal actions, or treatment processes.

      4. (iv) Notwithstanding any other provision in this clause, an intake pollutant shall be considered to be from the same body of water if the permittee's intake point is located on Lake Michigan and the outfall point is located on a tributary of Lake Michigan and the following conditions are met:

         1. (AA) The representative background concentration of the pollutant in the receiving water, as determined under section 11.4(a)(8) of this rule (excluding any amount of the pollutant in the facility's discharge) is similar to or greater than that in the intake water.
         2. (BB) Any difference in a water quality characteristic (such as temperature, pH, and hardness) between the intake and receiving waters does not result in an adverse impact on the receiving water.

   3. (C) The commissioner may use the procedure to determine reasonable potential described in this subdivision in lieu of the procedures contained under subdivisions (1) through (3) provided the following conditions are met:

      1. (i) The commissioner may determine that there is no reasonable potential for the discharge of an intake pollutant or pollutant parameter to cause or contribute to an excursion above a narrative criterion or numeric water quality criterion or value under 327 IAC 2-1.5 when a discharger demonstrates to the satisfaction of the commissioner (based upon information provided in the permit application or other information deemed necessary by the commissioner) that:

         1. (AA) the facility does not contribute any additional mass of the intake pollutant to its wastewater;
         2. (BB) the facility withdraws one hundred percent (100%) of the intake water containing the pollutant from the same body of water into which the discharge is made;
         3. (CC) the facility does not alter the intake pollutant chemically or physically in a manner that would cause adverse water quality impacts to occur that would not occur if the pollutants were left in-stream;
         4. (DD) the facility does not cause an increase in the intake pollutant concentration at the edge of the mixing zone, or at the point of discharge if a mixing zone is not allowed, as compared to the pollutant concentration in the intake waterbody unless the increased concentration does not cause or contribute to an excursion above an applicable narrative criterion or numeric water quality criterion or value; and
         5. (EE) the timing and location of the discharge would not cause adverse water quality impacts to occur that would not occur if the intake pollutant were left in the waterbody.

      2. (ii) If a discharge of an intake pollutant or pollutant parameter is not able to qualify under item (i), the commissioner may decide not to impose WQBELs on the discharge, if the following conditions are met:

         1. (AA) The discharge consists of one (1) or more internal wastestreams that do qualify (qualifying wastestreams) under item (i) and one (1) or more internal wastestreams that do not qualify (nonqualifying wastestreams) under item (i).
         2. (BB) For nonqualifying wastestreams composed entirely of storm water, the permittee accepts permit conditions for the storm water wastestream that the commissioner determines to be necessary to protect the water quality of the receiving waterbody. The requirements imposed shall be as if the storm water wastestream discharged directly into the receiving waterbody and shall be consistent with requirements imposed on other similar storm water discharges to the waterbody.
         3. (CC) For nonqualifying wastestreams not composed entirely of storm water, the permittee accepts WQBELs on each of the nonqualifying wastestreams that have a reasonable potential for the discharge of the intake pollutant or pollutant parameter to cause or contribute to an excursion above a narrative criterion or numeric water quality criterion or value as determined using the procedures under subdivisions (1) through (3). For purposes of determining reasonable potential and developing WQBELs for these nonqualifying wastestreams, the preliminary WLAs and WLAs in the absence of a TMDL shall be determined as if these nonqualifying wastestreams discharged directly into the receiving waterbody without combining with the qualifying wastestreams.

      3. (iii) Upon a finding under item (i) or (ii) that a pollutant in the discharge does not cause, have the reasonable potential to cause, or contribute to an excursion above an applicable narrative criterion or numeric water quality criterion or value, the commissioner is not required to include a WQBEL in the facility's permit for the intake pollutant provided:

         1. (AA) the NPDES permit fact sheet or statement of basis includes a specific determination that there is no reasonable potential for the discharge of an intake pollutant to cause or contribute to an excursion above an applicable narrative criterion or numeric water quality criterion or value and references appropriate supporting documentation included in the administrative record;
         2. (BB) the permit requires all influent, effluent, and ambient monitoring necessary to demonstrate that the conditions in item (i) or (ii) are maintained during the permit term; and
         3. (CC) the permit contains a reopener clause authorizing modification or revocation and reissuance of the permit if new information indicates changes in the conditions under item (i) or (ii).
      4. (iv) Absent a finding under item (i) or (ii) that the discharge of an intake pollutant or pollutant parameter does not cause, have the reasonable potential to cause, or contribute to an excursion above an applicable narrative criterion or numeric water quality criterion or value, the commissioner shall use the procedures contained under subdivisions (1) through (3) to determine whether the discharge of that pollutant causes, has the reasonable potential to cause, or contribute to an excursion above an applicable narrative criterion or numeric water quality criterion or value.

5. (5) Notwithstanding this subsection, if the commissioner determines that the geometric mean of a pollutant in fish tissue samples collected from a waterbody exceeds the tissue basis of a water quality criterion or value, after consideration of the variability of the pollutant's bioconcentration and bioaccumulation in fish, the following provisions apply:

   1. (A) If such pollutant is a BCC, each facility that discharges detectable levels of the BCC to that water has the reasonable potential to cause or contribute to an excursion above a water quality criterion or value for that BCC and the commissioner shall establish a WQBEL for such pollutant in the NPDES permit for each such facility.
   2. (B) If such pollutant is not a BCC, the commissioner may determine that any or all of the facilities that discharge detectable levels of the pollutant to that water have the reasonable potential to cause or contribute to an excursion above a water quality criterion or value for that pollutant and the commissioner shall establish a WQBEL for such pollutant in the NPDES permit for each such facility.

(c) Except as provided in subdivision (3), where the commissioner determines that the WET of an effluent is or may be discharged at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above any numeric interpretation of a narrative WET criterion contained in 327 IAC 2-1.5-8, the commissioner shall incorporate WQBELs for WET in the NPDES permit and in all cases, the commissioner shall use any valid, relevant, or representative information pertaining to the discharge of WET as follows:

1. (1) When facility-specific WET data are available, the commissioner may take into account the source and nature of the discharge, existing controls on point and nonpoint sources of pollution, the variability of the WET in the effluent, and, where appropriate, the dilution of the effluent in the receiving water in making the determination to develop effluent limitations for WET. The WET of an effluent is or may be discharged at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above any applicable WET criterion contained under 327 IAC 2-1.5, when effluent-specific information demonstrates the following:

   1. (A) The acute WET of an effluent is or may be discharged at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above an applicable acute WET criterion applied to the undiluted discharge, when effluent-specific information demonstrates the following: (TU_a)(F) > 0.2

      Where:	TUa	=	The geometric mean of the measured acute toxicity values expressed in acute toxic units (TUa or TUc). Individual toxicity values may be estimated for the missing endpoint using a default ACR of ten (10), when data exist for chronic WET, but not for acute WET.
      	F	=	Fraction of the measured toxicity values greater than the preliminary WLA for acute WET determined under section 11.4(c) of this rule (fraction failed).

   2. (B) The acute WET of an effluent is or may be discharged at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above an applicable acute WET criterion applied outside an alternate mixing zone, when effluent-specific information demonstrates the following: F > 0.2

      Where:

      F

      =

      Fraction of the measured toxicity values greater than the preliminary WLA for acute WET determined under section 11.4(c) of this rule (fraction failed). Individual toxicity values may be estimated for the missing endpoint using a default ACR of ten (10), when data exist for chronic WET, but not for acute WET.

   3. (C) The chronic WET of an effluent is or may be discharged at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above an applicable chronic WET criterion, when effluent-specific information demonstrates the following:

      Where:	TUc	=	The geometric mean of the measured chronic toxicity values expressed in chronic toxic units. Individual toxicity values may be estimated for the missing endpoint using a default ACR of ten (10), when data exist for acute WET, but not for chronic WET.
      	Qe	=	The effluent flow rate as determined under section 11.4(a)(9) of this rule.
      	Qw	=	The portion of the receiving waterbody allocated for mixing as determined under section 11.4(b) of this rule.
      	F	=	Fraction of the measured toxicity values greater than the preliminary WLA for acute or chronic WET determined under section 11.4(c) of this rule (fraction failed).

2. (2) When WET data are not available, the commissioner shall exercise best professional judgment, taking into account the source and nature of the discharge, existing controls on point and nonpoint sources of pollution, and, where appropriate, the dilution of the effluent in the receiving water to determine whether it is necessary to impose WET requirements in accordance with the following:

   1. (A) For a new Great Lakes discharger, the commissioner shall determine whether it is necessary to impose WET limitations.

   2. (B) For an existing Great Lakes discharger, whether it is necessary to require the applicant to collect the data required to make a determination under this subsection. The commissioner may include in the NPDES permit the following conditions to generate additional data and control toxicity if found:

      1. (i) WET testing requirements to generate the data needed to adequately characterize the toxicity of the effluent to aquatic life.
      2. (ii) A toxicity reduction evaluation and a schedule to comply with WET limits if any toxicity testing data indicate that the WET of an effluent is or may be discharged at levels that will cause, have the reasonable potential to cause, or contribute to an excursion above any applicable WET criterion.
      3. (iii) WET limits that become effective upon completion of the compliance schedule.
3. (3) Limitations on WET are not necessary where the commissioner demonstrates in the fact sheet or briefing memo of the NPDES permit that chemical-specific limits for the effluent are sufficient to attain and maintain the applicable narrative water quality criteria for WET.

(d) Once the commissioner has determined in accordance with this section that a WQBEL must be included in an NPDES permit, the commissioner shall do the following:

1. (1) Rely upon the WLA established for the point source either as part of any EPA-approved TMDL prepared under section 11.4 of this rule, or as part of an assessment and remediation plan developed and approved in accordance with section 11.4(a)(2) of this rule, or, in the absence of such TMDL or plan, calculate WLAs for the protection of acute and chronic aquatic life, wildlife, and human health in accordance with the provisions for developing WLAs under section 11.4 of this rule.
2. (2) Develop WQBELs using these WLAs in accordance with section 11.6 of this rule.

(e) The commissioner may require monitoring for a pollutant or pollutant parameter even if it is determined that a WQBEL in the NPDES permit for that pollutant or pollutant parameter is not required.

(f) In addition to this section, effluent limitations shall be established to comply with all other applicable state and federal laws and regulations, including technology-based requirements and antidegradation policies.

(g) Notwithstanding subsection (b) or (c) and only in situations where the intake and outfall points are located on the same body of water as defined in subsection (b)(4)(B), the commissioner shall not impose WQBELs for a discharge consisting solely of once-through noncontact cooling water, except in accordance with the following:

1. (1) The commissioner may require a WQBEL based on an acute aquatic life criterion or value for a substance or acute WET when information is available indicating that such a limit is necessary to protect aquatic life unless the discharger is able to demonstrate that the presence of the substance or WET is due solely to its presence in the intake water.
2. (2) The commissioner shall establish limitations or other requirements in the permit for the noncontact cooling water wastestream to prevent impairment of the receiving waterbody if a valid biological assessment of the receiving waterbody indicates that the noncontact cooling water discharge impairs an existing or designated use of the waterbody, exclusive of thermal impacts from a discharge for which alternative thermal effluent limitations have been established in accordance with Section 316(a) of the CWA and 327 IAC 5-7.
3. (3) If a substance is present at elevated levels in the noncontact cooling water wastestream due to improper operation or maintenance of the cooling system, and this substance is or may be discharged at a level that will cause, have the reasonable potential to cause, or contribute to an excursion above a numeric criterion or value for a toxic substance as determined under subsection (b), WQBELs shall be established using the procedures in sections 11.4 and 11.6 of this rule.
4. (4) If the permittee uses or proposes to use additives in the noncontact cooling water wastestream, the additives shall be evaluated using the reasonable potential procedures contained under this section to determine whether WQBELs are necessary for the wastestream.
5. (5) If the source of the noncontact cooling water wastestream is contaminated ground water, this subsection does not apply to the discharge of the substances contaminating the ground water.

6. (6) If one (1) or more wastestreams consisting solely of noncontact cooling water are combined with one (1) or more wastestreams not consisting solely of noncontact cooling water, this subsection may still be applied to the wastestreams consisting solely of noncontact cooling water if, for the wastestreams that do not consist solely of noncontact cooling water, the following requirements are imposed:

   1. (A) For each of the wastestreams composed entirely of storm water, permit conditions that the commissioner determines to be necessary to protect the water quality of the receiving waterbody shall be imposed. The requirements imposed shall be as if the storm water wastestream discharged directly into the receiving waterbody and shall be consistent with requirements imposed on other similar storm water discharges to the waterbody.
   2. (B) For each of the wastestreams not composed entirely of storm water, each wastestream shall be evaluated to determine if there is a reasonable potential for the discharge of a pollutant or pollutant parameter to cause or contribute to an excursion above a narrative criterion or numeric water quality criterion or value as determined using the procedures in this section. For purposes of determining reasonable potential and developing WQBELs for these wastestreams, the preliminary WLAs and WLAs in the absence of a TMDL shall be determined as if these wastestreams discharged directly into the receiving waterbody without combining with the wastestreams consisting solely of noncontact cooling water.
7. (7) As used in this subsection, "once-through noncontact cooling water" means water used for cooling that does not come into direct contact with any raw material, intermediate product, final product, or waste product and makes one (1) or two (2) passes for the purpose of removing waste heat.

(h) The multiplying factors to be used in subsection (b) are established in Tables 11.5-1 and 11.5-2 and shall be obtained as follows:

1. (1) Round the coefficient of variation (CV) identified in subsection (b) to the nearest CV in Table 11.5-1 or Table 11.5-2. If the CV identified in subsection (b) is greater than two (2.0), set the CV equal to two (2.0).

2. (2) Obtain the appropriate multiplying factor from Table 11.5-1 or Table 11.5-2 using the number of samples identified in subsection (b) and the CV determined under subdivision (1). If the number of samples identified under subsection (b) is greater than one hundred (100), obtain the multiplying factor using one hundred (100) samples.

   Table 11.5-1
   Reasonable Potential Multiplying Factors
   Number of Samples	Coefficient of Variation
   0.05	0.1	0.2	0.3	0.4	0.5	0.6	0.7	0.8	0.9	1.0	1.1	1.2	1.3	1.4	1.5	1.6	1.7	1.8	1.9	2.0
   1	1.2	1.4	1.9	2.6	3.6	4.7	6.2	8.0	10.1	12.6	15.5	18.7	22.3	26.4	30.8	35.6	40.7	46.2	52.1	58.4	64.9
   2	1.1	1.3	1.6	2.0	2.5	3.1	3.8	4.6	5.4	6.4	7.4	8.5	9.7	10.9	12.2	13.6	15.0	16.4	17.9	19.5	21.1
   3	1.1	1.2	1.5	1.8	2.1	2.5	3.0	3.5	4.0	4.6	5.2	5.8	6.5	7.2	7.9	8.6	9.3	10.0	10.8	11.5	12.3
   4	1.1	1.2	1.4	1.7	1.9	2.2	2.6	2.9	3.3	3.7	4.2	4.6	5.0	5.5	6.0	6.4	6.9	7.4	7.8	8.3	8.8
   5	1.1	1.2	1.4	1.6	1.8	2.1	2.3	2.6	2.9	3.2	3.6	3.9	4.2	4.5	4.9	5.2	5.6	5.9	6.2	6.6	6.9
   6	1.1	1.1	1.3	1.5	1.7	1.9	2.1	2.4	2.6	2.9	3.1	3.4	3.7	3.9	4.2	4.5	4.7	5.0	5.2	5.5	5.7
   7	1.1	1.1	1.3	1.4	1.6	1.8	2.0	2.2	2.4	2.6	2.8	3.1	3.3	3.5	3.7	3.9	4.1	4.3	4.5	4.7	4.9
   8	1.1	1.1	1.3	1.4	1.6	1.7	1.9	2.1	2.3	2.4	2.6	2.8	3.0	3.2	3.3	3.5	3.7	3.9	4.0	4.2	4.3
   9	1.1	1.1	1.2	1.4	1.5	1.7	1.8	2.0	2.1	2.3	2.4	2.6	2.8	2.9	3.1	3.2	3.4	3.5	3.6	3.8	3.9
   10	1.0	1.1	1.2	1.3	1.5	1.6	1.7	1.9	2.0	2.2	2.3	2.4	2.6	2.7	2.8	3.0	3.1	3.2	3.3	3.4	3.6
   11	1.0	1.1	1.2	1.3	1.4	1.6	1.7	1.8	1.9	2.1	2.2	2.3	2.4	2.5	2.7	2.8	2.9	3.0	3.1	3.2	3.3
   12	1.0	1.1	1.2	1.3	1.4	1.5	1.6	1.7	1.9	2.0	2.1	2.2	2.3	2.4	2.5	2.6	2.7	2.8	2.9	3.0	3.0
   13	1.0	1.1	1.2	1.3	1.4	1.5	1.6	1.7	1.8	1.9	2.0	2.1	2.2	2.3	2.4	2.5	2.5	2.6	2.7	2.8	2.9
   14	1.0	1.1	1.2	1.3	1.4	1.4	1.5	1.6	1.7	1.8	1.9	2.0	2.1	2.2	2.3	2.3	2.4	2.5	2.6	2.6	2.7
   15	1.0	1.1	1.2	1.2	1.3	1.4	1.5	1.6	1.7	1.8	1.8	1.9	2.0	2.1	2.2	2.2	2.3	2.4	2.4	2.5	2.5
   16	1.0	1.1	1.1	1.2	1.3	1.4	1.5	1.6	1.6	1.7	1.8	1.9	1.9	2.0	2.1	2.1	2.2	2.3	2.3	2.4	2.4
   17	1.0	1.1	1.1	1.2	1.3	1.4	1.4	1.5	1.6	1.7	1.7	1.8	1.9	1.9	2.0	2.0	2.1	2.2	2.2	2.3	2.3
   18	1.0	1.1	1.1	1.2	1.3	1.3	1.4	1.5	1.6	1.6	1.7	1.7	1.8	1.9	1.9	2.0	2.0	2.1	2.1	2.2	2.2
   19	1.0	1.1	1.1	1.2	1.3	1.3	1.4	1.5	1.5	1.6	1.6	1.7	1.8	1.8	1.9	1.9	2.0	2.0	2.0	2.1	2.1
   20	1.0	1.1	1.1	1.2	1.2	1.3	1.4	1.4	1.5	1.5	1.6	1.6	1.7	1.7	1.8	1.8	1.9	1.9	2.0	2.0	2.0
   21	1.0	1.1	1.1	1.2	1.2	1.3	1.3	1.4	1.5	1.5	1.6	1.6	1.7	1.7	1.7	1.8	1.8	1.9	1.9	1.9	2.0
   22	1.0	1.1	1.1	1.2	1.2	1.3	1.3	1.4	1.4	1.5	1.5	1.6	1.6	1.7	1.7	1.7	1.8	1.8	1.8	1.9	1.9
   23	1.0	1.0	1.1	1.2	1.2	1.3	1.3	1.4	1.4	1.4	1.5	1.5	1.6	1.6	1.6	1.7	1.7	1.8	1.8	1.8	1.8
   24	1.0	1.0	1.1	1.1	1.2	1.2	1.3	1.3	1.4	1.4	1.5	1.5	1.5	1.6	1.6	1.6	1.7	1.7	1.7	1.8	1.8
   25	1.0	1.0	1.1	1.1	1.2	1.2	1.3	1.3	1.4	1.4	1.4	1.5	1.5	1.5	1.6	1.6	1.6	1.7	1.7	1.7	1.7
   26	1.0	1.0	1.1	1.1	1.2	1.2	1.3	1.3	1.3	1.4	1.4	1.4	1.5	1.5	1.5	1.6	1.6	1.6	1.6	1.7	1.7
   27	1.0	1.0	1.1	1.1	1.2	1.2	1.2	1.3	1.3	1.4	1.4	1.4	1.4	1.5	1.5	1.5	1.6	1.6	1.6	1.6	1.6
   28	1.0	1.0	1.1	1.1	1.2	1.2	1.2	1.3	1.3	1.3	1.4	1.4	1.4	1.4	1.5	1.5	1.5	1.5	1.6	1.6	1.6
   29	1.0	1.0	1.1	1.1	1.1	1.2	1.2	1.2	1.3	1.3	1.3	1.4	1.4	1.4	1.4	1.5	1.5	1.5	1.5	1.5	1.6
   30	1.0	1.0	1.1	1.1	1.1	1.2	1.2	1.2	1.3	1.3	1.3	1.3	1.4	1.4	1.4	1.4	1.5	1.5	1.5	1.5	1.5
   31	1.0	1.0	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.3	1.3	1.3	1.3	1.4	1.4	1.4	1.4	1.4	1.5	1.5	1.5
   32	1.0	1.0	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.3	1.3	1.3	1.3	1.3	1.4	1.4	1.4	1.4	1.4	1.4	1.5
   33	1.0	1.0	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.3	1.3	1.3	1.3	1.3	1.4	1.4	1.4	1.4	1.4	1.4
   34	1.0	1.0	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.3	1.3	1.3	1.3	1.3	1.3	1.4	1.4	1.4	1.4	1.4
   35	1.0	1.0	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.3	1.3	1.3	1.3	1.3	1.3	1.3	1.4	1.4	1.4
   36	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.3	1.3	1.3	1.3	1.3	1.3	1.3	1.3	1.4
   37	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.2	1.3	1.3	1.3	1.3	1.3	1.3	1.3	1.3
   38	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.3	1.3	1.3	1.3	1.3	1.3
   39	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.3	1.3	1.3	1.3
   40	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.3	1.3

   Table 11.5-2
   Reasonable Potential Multiplying Factors
   Number of Samples	Coefficient of Variation
   0.05	0.1	0.2	0.3	0.4	0.5	0.6	0.7	0.8	0.9	1.0	1.1	1.2	1.3	1.4	1.5	1.6	1.7	1.8	1.9	2.0
   41	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2
   42	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2
   43	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2	1.2
   44	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2	1.2	1.2
   45	1.0	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.2	1.2	1.2	1.2	1.2
   46	1.0	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.2	1.2
   47	1.0	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1
   48	1.0	1.0	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1
   49	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1
   50	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1
   51	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1
   52	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1	1.1
   53	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.1	1.1	1.1	1.1	1.1	1.1
   54 to 63	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0
   64	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	0.9	0.9	0.9
   65	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9
   66	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9
   67	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9
   68	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9
   69	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9
   70 to 73	1.0	1.0	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9
   74 to 77	1.0	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9
   78	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8
   79	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8
   80 to 81	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8
   82 to 83	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8
   84	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8
   85	1.0	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8
   86 to 87	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8
   88 to 89	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8
   90 to 92	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8
   93 to 96	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8
   97	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.7
   98 to 99	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.7	0.7
   100	1.0	1.0	1.0	0.9	0.9	0.9	0.9	0.9	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.7	0.7	0.7

(Water Pollution Control Division; 327 IAC 5-2-11.5; filed Jan 14, 1997, 12:00 p.m.: 20 IR 1450; errata filed Aug 11, 1997, 4:15 p.m.: 20 IR 3379; filed Feb 14, 2005, 10:05 a.m.: 28 IR 2112; filed Jul 9, 2012, 2:54 p.m.: 20120808-IR-327110320FRA; readopted filed Oct 18, 2024, 1:57 p.m.: 20241113-IR-327230810RFA)