North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 13 - SOLID WASTE MANAGEMENT › Subchapter C - INACTIVE HAZARDOUS SUBSTANCE OR WASTE DISPOSAL SITES › Section .0200 - PRIORITIZATION SYSTEM › Section 13C .0202 - GROUNDWATER MIGRATION

Current through Register Vol. 39, No. 2, July 15, 2024
(a) The potential
				  for groundwater contamination is based upon route characteristics, waste
				  containment, and waste characteristics. The score for groundwater migration
				  shall be determined by multiplying the score determined for route
				  characteristics in Paragraph (b) by the score determined for waste containment
				  in Paragraph (c) then multiplying that result by the score determined for waste
				  characteristics in Paragraph (d) and dividing that result by 14.82.
(b) A score for route characteristics shall
				  be determined by adding the values assigned in Subparagraphs (b)(1) through
				  (b)(4).
(1) A value shall be assigned for
				  depth to water table using either Table 1 if depth to water table is known or
				  Table 2 if depth to water table is unknown. Depth to water table is measured
				  vertically from the lowest point of the hazardous substances to the highest
				  seasonal level of the water table.
Table 1
Depth
Assigned Value
>150 feet
0
> 75 to 150 feet
2
> 20 to 75 feet
4
< 20 feet
6
Contaminant in groundwater
8
Contaminant in drinking supply
10
Table 2
Location
Assigned Value
Piedmont and Mountain
4
Coastal Plain
4
Alluvial Valley
6
(2) A value shall be assigned for net
				  precipitation using Table 3. Net precipitation shall be calculated by
				  subtracting the mean annual lake evaporation from the mean annual
				  precipitation.
Table 3
Net Precipitation
Assigned Value
< -10 inches
0
> -10 to +5 inches
1
> +5 to +15 inches
2
> +15 inches
3
(3) A value shall be assigned for hydraulic
				  conductivity using Table 4 when data for hydraulic conductivity are available,
				  and using Table 5 when hydraulic conductivity data are unavailable and soil and
				  rock types are unknown. When hydraulic conductivity data are unavailable but
				  soil and rock types are known, a value shall be assigned for hydraulic
				  conductivity using the table entitled "Permeability of Geologic Materials" that
				  is contained in 40 CFR
				  300, Appendix A, July 1, 1988, which is
				  hereby incorporated by reference and does not include subsequent amendments and
				  editions. This material is available for inspection at the Department of
				  Environment, Health, and Natural Resources, Division of Solid Waste Management,
				  Superfund Section, 401 Oberlin Road, Raleigh, North Carolina. Copies may be
				  obtained from the Superfund Section at a cost of ten cents ($ .10) per page.
Table 4
Approximate Range of Hydraulic
								Conductivity
Assigned Value
< 10-7cm/sec
0
>10-7to 10-5cm/sec
1
>10-5to 10-3cm/sec
2
>10-3cm/sec
3
Table 5
Location
Assigned Value
Triassic basin
1
Piedmont and Mountain
2
Mountain Alluvial Valley
or Coastal Plain
3
(4) A value shall be assigned for physical
				  state using Table 6. Physical state is the state of hazardous substances at the
				  time of disposal. If the site contains hazardous substances or wastes with more
				  than one physical state, the hazardous substance or waste with the highest
				  value shall be used.
Table 6
Physical State
Assigned Value
Solid, consolidated and stabilized
0
Solid, unconsolidated or
								unstabilized
1
Solid, powder or fine particles
2
Liquid, sludge or gas
3