N.J. Admin. Code § 7:14A-24.8

Current through Register Vol. 56, No. 21, November 4, 2024

Section 7:14A-24.8 - Sample collection procedures for individual stormwater DSW permit applications

(a) When "quantitative data" for a pollutant are required under 7:14A-24.7(a)1 viii (or under 7:14A-25.10(a) and 40 C.F.R. 122.26(d)(2)(iii) ) in an individual NJPDES permit application for a stormwater DSW, the applicant shall collect samples in accordance with 7:14A-4.4(b) (also see 7:14A-24.7(a)1 x) and the following paragraphs (procedures or requirements in (a)1 through 4 below are subject to change under (a)5 below):

1. All samples shall be collected from the discharge resulting from a storm event that is greater than 0.1 inch and at least 72 hours from the previously measurable (greater than 0.1 inch) storm event. Where feasible, the variance in the duration of the event and the total rainfall of the event should not exceed 50 percent from the average or median rainfall event in that area.

2. For all pollutants requiring analysis under N.J.A.C. 7:14A-24.7, quantitative data must be reported for a grab sample taken during the first 30 minutes (or as soon thereafter as practicable) of the stormwater discharge.

3. For all pollutants requiring analysis under 7:14A-24.7 (or under N.J.A.C. 7:14A-25.10, where applicable), quantitative data must be reported for a flow-weighted composite sample (except as provided in (a)3i and ii below). This sample must be taken for either the entire stormwater discharge or for the first three hours of the stormwater discharge. (Notwithstanding 7:14A-4.4(b)2 ii, a 24-hour composite sample of the stormwater discharge is not required.) Only one analysis of the composite of aliquots is required.

i. A minimum of one grab sample may instead be taken for stormwater discharges from holding ponds or other impoundments with a retention period greater than 24 hours.

ii. Flow-weighted composite samples shall not be taken for pH, temperature, cyanide, total phenols, chlorine produced oxidants, oil and grease, petroleum hydrocarbons, all volatile organics, and fecal coliform, fecal streptococcus, and other bacterial indicators.

iii. The flow-weighted composite sample shall be:

(1) Taken with a continuous sampler;

(2) A combination of a minimum of three sample aliquots taken in each hour of discharge for the entire discharge; with each aliquot being separated by a minimum period of fifteen minutes; or

(3) A combination of a minimum of three sample aliquots taken in each of the first three hours of the discharge, with each aliquot being separated by a minimum period of 15 minutes.

4. Notwithstanding 7:14A-4.4(b)5 ii, stormwater permit applicants are not required to report the daily maximum or daily average for any pollutant. Notwithstanding 7:14A-4.4(b)3 vi, stormwater permit applicants are not required to report as total mass:

i. Any sampling data from grab samples; or

ii. Any sampling data for flow, or for any pollutants that cannot be appropriately expressed in terms of mass (including, but not limited to, pH, acute and chronic whole effluent toxicity, temperature, and fecal coliform, fecal streptococcus, and other bacterial indicators).

5. The Department may allow or establish (in the Pollutant Analysis Summary in NJPDES Form RF or elsewhere) appropriate site-specific sampling procedures or requirements, including:

i. Sampling locations, the season in which the sampling takes place, the minimum duration between the previous storm event and the storm event sampled, the minimum or maximum level of precipitation required for an appropriate storm event, and the form of precipitation sampled (snowmelt or rainfall); and

ii. The type of sampling (for example, grab sample or flow-weighted composite sample), whether and how to measure (or estimate) and report flow, protocols for collecting samples that may differ from protocols for collecting samples under 40 C.F.R. 136 or N.J.A.C. 7:18, time duration between the collection of sample aliquots in flow-weighted or other composite samples, mode of reporting sampling results (for example, concentration or loading) or other sampling or storm event information, and additional time for submitting data on a case-by-case basis.

N.J. Admin. Code § 7:14A-24.8