Indiana Administrative Code › Title 327 - WATER POLLUTION CONTROL DIVISION › Article 15 - NPDES GENERAL PERMITS AND SPECIFIC CATEGORY INDIVIDUAL PERMIT REQUIREMENTS › Rule 6 - Storm Water Discharges Exposed to Industrial Activity › Section 6-7.3 - Monitoring requirements

Current through July 10, 2024
Authority: IC 13-14-8; IC 13-15-1-2; IC 13-15-2; IC 13-18-3;
				  IC 13-18-4
Affected: IC 13-12-3-1; IC 13-18-1
Sec. 7.3.
(a)
				Monitoring requirements shall be as follows:
(1) Each discharge outfall identified in
				section 5(4) of this rule, or representative discharge outfall identified in
				section 5(5) of this rule, composed entirely of storm water and allowable
				nonstorm water run-off, shall be monitored as follows:
Parameter
Units
Sample Type
Frequency
Oil and grease
mg/l
grab
Annual
CBOD5 (Carbonaceous biochemical
							 oxygen demand)
mg/l
grab
Annual
COD (Chemical oxygen demand)
mg/l
grab
Annual
TSS (Total suspended solids)
mg/l
grab
Annual
TKN (Total Kjeldahl nitrogen)
mg/l
grab
Annual
Total phosphorous
mg/l
grab
Annual
pH
s.u.
grab
Annual
Nitrate plus nitrite nitrogen
mg/l
grab
Annual
(2)
				Each discharge outfall subject to subdivision (1) shall be monitored for any
				pollutant attributable to a facility's industrial activity that is reasonably
				expected to be present in the discharge, as well as for any other pollutant
				that has the potential to be present in a storm water discharge as requested by
				the commissioner.
(3) Within one
				(1) year of the original or renewal NOI letter submittal and prior to
				implementation of the SWP3, a permittee regulated under this rule shall sample
				and analyze the discharge from the outfall identified in the approved NOI
				letter. The monitoring data taken from this first year event shall be used by
				the permittee as an aid in developing and implementing the SWP3. Subsequent
				annual sampling data shall be used to verify the effectiveness of the SWP3 and
				will aid the permittee with revising the SWP3 and implementation of additional
				BMPs, as necessary.
(4) The
				commissioner may require a permittee to sample additional storm events beyond
				the required five (5) annual events upon finding reasonable cause. The
				commissioner shall notify the facility in writing that additional sampling is
				required.
(5) A grab sample must be
				collected during the first thirty (30) minutes of discharge at the storm water
				outfalls identified in the NOI letter or as soon thereafter as
				practicable.
(6) The pH measurement
				must be taken at the time the grab sample is collected and by using a pH meter
				that has been properly calibrated according to manufacturer's specifications
				and provides results displayed in numeric units. A color comparison analysis
				for pH is not acceptable.
(7) There
				shall be a minimum of three (3) months between reported sampling
				events.
(8) Samples must be taken
				at a point representative of the discharge but prior to entry into surface
				waters of the state or a municipal separate storm sewer conveyance unless an
				alternative location has been granted by the commissioner. For discharges that
				flow through on-site detention basins, samples shall be taken at a point
				representative of the discharge from the basin.
(9) All samples must be collected from a
				discharge resulting from a measurable storm event at least seventy-two (72)
				hours from the previous measurable storm event. Documentation of weather
				conditions that prevent sampling as described in this subsection must be
				provided to the commissioner.
(10)
				The analytical and sampling methods used must meet the requirements of
				327 IAC 5-2-13(d)(1)
				 and
				327 IAC 5-2-13(d)(2)
				 for quality assurance and quality
				control.
(11) Run-off events
				resulting from snow or ice melt should not be sampled and shall not be used to
				meet the minimum annual monitoring requirements.