020-17 Wyo. Code R. § 17-27

Current through April 27, 2019

Section 17-27 - Corrective Action Prioritization Ranking System

(a) Criteria. This ranking system establishes criteria for use by the department in determining priorities for conducting state corrective actions at leaking storage tank sites. The ranking is based upon the following primary factors:

(i) Degree of immediate adverse health exposure and/or safety hazards to people in nearby occupied buildings or to public utilities.

(ii) Water quality protection.

(iii) Potential for contaminant(s) migration.

(iv) Ecological protection.

(b) Scoring. The scoring system provides that the sites with the highest scores shall be of the highest priority in conducting department corrective actions. The following listing and point values compose the department's corrective action prioritization ranking system. Points will be applied to each site, as appropriate, depending upon local circumstances. The total score for each leaking storage tank site is the sum of all applicable categories as follows:

TABLE 3 Corrective Action Scoring
Free product on the surface of either surface or groundwater	Point Value
Presence of free product unknown, but possible	100
Presence of free product unknown, but probable	225
Free product in any amount, on groundwater	350
Water contaminated by dissolved chemical substances	Point Value
Greater than ten (10) times the MCL for drinking water or the Wyoming DWEL	300
Less than ten (10) times or equal to the MCL for drinking water or the Wyoming DWEL	100
The above two (2) values shall be doubled if measurements were made in wells used for drinking water.
Potential to contaminate groundwater	Point Value
Unknown, but probable Unknown, but possible	175 75
Soil Type	Point Value
High permeability (coarse gravel, silty sands, etc.)	150
Moderate permeability (loamy sands, silty clays, etc.)	75
Low permeability (clays)	25
Soil Contamination	Point Value
Heavily contaminated soils. Fails paint filter test or produces a free product layer when mixed with water and allowed to settle for ten (10) minutes	150
Moderately contaminated soils. Observed greasy feel, strong petroleum odor, black discoloration	80
Slightly contaminated soils. Any visible contamination or weak petroleum odor	40

020-17 Wyo. Code R. § 17-27