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Indiana Department of Environmental Management

IDEM > Permitting > Water Permits > Wastewater Permits > 327 IAC 5-10-4 Lake Dischargers and Sinkhole Dischargers 327 IAC 5-10-4 Lake Dischargers and Sinkhole Dischargers

Authority: IC 13-13-5; 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. 4. (a) The following effluent limitations apply to all POTWs or other sanitary discharges directly to lakes or reservoirs (either natural or manmade impoundments) or within two (2) miles upstream from such a waterbody, and to discharges of sanitary wastewater directly to sinkholes, underground streams, or to surface streams within two (2) miles upstream of such features (where a discharge of industrial process wastewater contains a sanitary component, these standards apply only to the sanitary component of such discharges):

  1. Concentrations table as follows:
Pollutant Monthly Average
Concentrations (mg/l)
Weekly Average
Concentrations (mg/l)
CBOD5 10 15
Total Suspended Solids (TSS) 12 18
T. Ammonia, as N    
Summer (May through November) 1.1 1.6
Winter (December through April) 1.6 2.4
  1. Ammonia nitrogen limitations are derived using conservation of mass principles, assuming no stream flow dilution (Q7,10) and using the criteria contained in 327 IAC 2-1-6(b)(5)(A), using year-round stream pH of seven and eight-tenths (7.8) s.u., instream temperature of twenty-five degrees Celsius (25C) summer, ten degrees Celsius (10C) winter, with the results rounded to the nearest one-tenth (0.1) milligram per liter. If the receiving stream is regulated by criteria contained in 327 IAC 2-1-6(b)(5)(B) through 327 IAC 2-1-6(b)(5)(D) or 327 IAC 2-1.5-8, these criteria will be used to determine water quality-based effluent limitations for ammonia in lieu of the criteria in subdivision (1) to derive appropriate ammonia nitrogen limitations
  2. Dissolved oxygen in the effluent from any facility deemed to be a lake discharger or sinkhole discharger shall not fall below six (6.0) milligrams per liter minimum daily average.
  3. Notwithstanding the provisions of section 2(a) of this rule, effluent phosphorus for any lake discharger shall not exceed one (1.0) milligram per liter.
  4. In addition, water quality-based limitations for any other toxic substance may be included in the permit if the toxic substance is or may be discharged at a level which will cause, have the reasonable potential to cause, or contribute to an excursion above any applicable narrative or numeric water quality criteria or value promulgated under 327 IAC 2-1 or 327 IAC 2-1.5.
    1. If deemed necessary to comply with water quality standards, such as discharges to streams which are classified for cold water aquatic life, more stringent limitations may be applied on a case-by-case basis.
    2. Additional requirements for sinkhole dischargers include the following:
      1. Disinfection is required on a year-round basis. Where chlorine or bromine compounds are used as the disinfectant, dechlorination is required in accordance with section 6(c)(3) of this rule.
      2. Effluent limitations, monitoring, and reporting requirements for E. coli will be included in the NPDES permit.
      3. As part of any initial application and as part of any subsequent application for renewal, the following information shall be included:
        1. A statement as to why a direct discharge to surface waters is impractical. This statement should address the proximity of surface waters and the cost associated with locating or relocating the discharge to such waters.
        2. The results of two (2) dye-tracing studies, one (1) conducted during low flow conditions and one (1) conducted during high flow conditions. This study shall be signed by a qualified hydrologist and shall include a review and identification of all ground water users (private wells) within a five (5) mile radius and demonstrate to the extent possible the direction of movement and ultimate fate of ground water in the area. Sampling shall also be conducting of any readily accessible cave streams and at any rises. A diligent effort to notify all potentially affected ground water users in the area of the intent to discharge and the dye-tracing study shall be made, which may include a public notice.
      4. If a dye-tracing study conducted as required by subdivision (3) indicates the presence of effluent in private wells (or the probability of such for new discharges):
        1. the permittee (or applicant) shall conduct routine (a minimum of twice annually, once during high flow and once during low flow conditions) monitoring of each such well for nitrates and E. coli and shall report the results to the private users and the Department of Environmental Management, Office of Water Quality; and
        2. permit limitations may be imposed based on drinking water standards from 327 IAC 8-2.
      5. If the well sampling required by subdivision (4) demonstrates that bacterial or nitrate contamination (above the values prescribed by 327 IAC 8-2) of private wells is occurring:
        1. the commissioner may require that the discharger supply potable water to any and all such affected parties; and
        2. the permit may be reopened to include revised effluent limitations.
      6. Before a NPDES permit is issued for any planned new discharge, all possible alternative methods of disposal shall be considered and evaluated. This NPDES permit will not be issued unless no alternative disposal method is feasible. Alternatives may include, but not be limited to, land application, connection with an existing POTW not discharging to a sinkhole, piping to surface waters, or off-site transport and disposal.

(Water Pollution Control Board; 327 IAC 5-10-4; filed Feb 26, 1993, 5:00 p.m.: 16 IR 1772; filed Jan 14, 1997, 12:00 p.m.: 20 IR 1473; errata filed Aug 11, 1997, 4:15 p.m.: 20 IR 3380)