New Mexico Administrative Code › Title 20 - ENVIRONMENTAL PROTECTION › Chapter 6 - WATER QUALITY › Part 2 - GROUND AND SURFACE WATER PROTECTION › Section 20.6.2.5202 - AREA OF REVIEW

Current through Register Vol. 35, No. 13, July 16, 2024
A. The area of
				review is the area surrounding a Class I non-hazardous waste injection well or
				Class III well or the area within and surrounding a well field that is to be
				examined to identify possible fluid conduits, including the location of all
				known wells and fractures which may penetrate the injection zone.
B. The area of review for each Class I
				non-hazardous waste injection well, or each Class III well or well field shall
				be an area which extends:
(1) two and one
				half (2 1/2) miles from the well, or well field; or
(2) one-quarter (1/4) mile from a well or
				well field where the area of review is calculated to be zero pursuant to
				Paragraph (3) of Subsection B below, or where the well field production at all
				times exceeds injection to produce a net withdrawal; or
(3) a suitable distance, not less than
				one-quarter (1/4) mile, proposed by the discharger and approved by the
				secretary, based upon a mathematical calculation to determine the area of
				review; computations to determine the area of review may be based upon the
				parameters listed below and should be calculated for an injection time period
				equal to the expected life of the Class I non-hazardous waste injection well,
				or Class III well or well field; the following modified This equation
				illustrates one form which the mathematical model may take to compute the area
				of review; the discharger must demonstrate that any equation or simulation used
				to compute the area of review applies to the hydrogeologic conditions in the
				area of review.
Click to
				  View Image
Where:
4BKH (Hw -
				  Hbo)x
				  SpGb
r = Radius of the area of review for a Class I non-hazardous
				  waste injection well or Class III well (length)
K = Hydraulic conductivity of the injection zone
				  (length/time)
H = Thickness of the injection zone (length)
t = Time of injection (time)
S = Storage coefficient (dimensionless)
Q = Injection rate (volume/time)
Hbo = Observed original hydrostatic
				  head of injection zone (length) measured from the base of the lowest aquifer
				  containing ground water of 10,000 mg/l or less TDS
Hw = Hydrostatic head of underground
				  source of drinking water (length) measured from the base of the lowest aquifer
				  containing ground water of 10,000 mg/l or less TDS
SpGb = Specific
				  gravity of fluid in the injection zone (dimensionless)
B = 3.142 (dimensionless)
(4) The above equation is based on the
				following assumptions:
(a) the injection zone
				is homogenous and isotropic;
(b)
				the injection zone has infinite areal extent;
(c) the Class I non-hazardous waste injection
				well or Class III well penetrates the entire thickness of the injection
				zone;
(d) the well diameter is
				infinitesimal compared to "r" when injection time is longer than a few minutes;
				and
(e) the emplacement of fluid
				into the injection zone creates an instantaneous increase in
				pressure.