North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 02 - Environmental Management › Subchapter B - SURFACE WATER AND WETLAND STANDARDS › Section .0500 - SURFACE WATER MONITORING: REPORTING › Section 02B .0503 - DEFINITIONS

Current through Register Vol. 39, No. 2, July 15, 2024
Unless the context otherwise requires, the terms used in
					 this Section shall be as defined in
					 G.S.
					 143-212 and
					 143-213; the federal Clean Water
					 Act (33 U.S.C.
					 1251 et seq.); 40 CFR Parts 122, 124, and
					 125; and as follows:
(1) "Biological
				  monitoring" shall mean the sampling or testing of the biological integrity of
				  surface waters and measurements of impacts, including accumulations of
				  pollutants in tissue, toxicity monitoring, and characterization of instream
				  biological populations.
(2)
				  "Classified water pollution control facility" means a treatment works
				  classified by the Water Pollution Control System Operator Certification
				  Commission pursuant to Chapter 90A of the North Carolina General Statutes as
				  class I, class II, class III, or class IV facility, or such other
				  classifications as the Water Pollution Control System Operator Certification
				  Commission may hereafter adopt.
(3)
				  "Commercial laboratory" means any laboratory that analyzes water samples for a
				  fee.
(4) "Composite sample" means a
				  sample gathered over a 24 hour period in such a manner as to result in a total
				  sample that is representative of the wastewater discharge during the sample
				  period. This sample may be obtained by methods set forth in this Item; however,
				  the Director may designate the method to be used, the number and size of
				  aliquots necessary, and the time interval between grab samples on a
				  case-by-case basis to ensure a representative sample. Samples may be collected
				  manually or automatically.
(a) Continuous - a
				  single, continuous sample collected over a 24 hour period proportional to the
				  rate of flow;
(b) Constant
				  time/variable volume - a series of grab samples collected at equal time
				  intervals over a 24 hour period of discharge and combined proportional to the
				  rate of flow measured at the time of individual sample collection;
(c) Variable time/constant volume - a series
				  of grab samples of equal volume collected over a 24 hour period with the time
				  intervals between samples determined by a preset number of gallons passing the
				  sampling point. Flow measurement between sample intervals shall be determined
				  by use of a flow recorder and totalizer, and the preset gallon interval between
				  sample collection fixed at no greater than 1/24 of the expected total daily
				  flow at the treatment system; or
(d) Constant time/constant volume - a series
				  of grab samples of equal volume collected over a 24 hour period at a constant
				  time interval. This method may be used in situations where effluent flow rates
				  vary less than 15 percent. The grab samples shall be taken at intervals of no
				  greater than 20 minutes apart during any 24 hour period and must be of equal
				  size and of no less than 100 milliliters. Use of this method requires prior
				  approval by the Director.