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APPENDIX A
Tables of Ratings and Ranges
for Geographic Targeting System Parameters
TABLE A-1. ASSIGNED WEIGHTS FOR DRASTIC PARAMETERS
| Feature
| "Generic"
DRASTIC Weights
| "Pesticide"
DRASTIC Weights
| | Depth to Water
| 5
| 5
| | Net Recharge
| 4
| 4
| | Aquifer Media
| 3
| 3
| | Soil Media
| 2
| 5
| | Topography
| 1
| 3
| | Impact of the Vadose Zone Media
| 5
| 4
| | Hydraulic Conductivity
| 3
| 2
| |
TABLE A-2. RANGES AND RATINGS FOR DEPTH TO WATER
| DEPTH TO WATER (FEET)
| | Range
| Rating
| | 0 - 5
| 10
| | 5 - 15
| 9
| | 15 - 30
| 7
| | 30 - 50
| 5
| | 50 - 75
| 3
| | 75 - 100
| 2
| | >= 100
| 1
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TABLE A-3. RANGES AND RATINGS FOR NET RECHARGE
| NET RECHARGE (INCHES/YEAR)
| | Range
| Rating
| | 0 - 2
| 1
| | 2 - 4
| 3
| | 4 - 7
| 6
| | 7 - 10
| 8
| | >= 10
| 9
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TABLE A-4. RANGES AND RATINGS FOR AQUIFER MEDIA
| AQUIFER MEDIA
| | Range
| Rating
| Typical Rating | | Massive Shale
| 1 - 3
| 2
| | Glacial Till
| 4 - 6
| 5
| | Bedded Sandstone and Shale Sequences
| 5 - 9
| 6
| | Massive Sandstone
| 4 - 9
| 6
| | Sand and Gravel
| 4 - 9
| 8
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TABLE A-5. RANGES AND RATINGS FOR SOIL MEDIA
| SOIL MEDIA
| | Range
| Rating
| | Thin or Absent
| 10
| | Gravel
| 10
| | Sand
| 9
| | Peat
| 8
| | Shrinking and/or Aggregated Clay
| 7
| | Sandy Loam
| 6
| | Loam
| 5
| | Silty Loam
| 4
| | Clay Loam
| 3
| | Muck
| 2
| | Non-shrinking and Non-aggregated Clay
| 1
|
TABLE A-6. RANGES AND RATINGS FOR TOPOGRAPHY
| TOPOGRAPHY (PERCENT SLOPE)
| | Range
| Rating
| | 0 - 2
| 10
| | 2 - 6
| 9
| | 6 - 12
| 5
| | 12 - 18
| 3
| | >= 18
| 1
|
TABLE A-7. RANGES AND RATINGS FOR IMPACT OF THE VADOSE ZONE MEDIA
| VADOSE ZONE MEDIA
| | Range
| Rating
| Typical Rating | | Confining Layer
| 1
| 1
| | Silt/Clay
| 2 - 6
| 3
| | Shale
| 2 - 5
| 3
| | Bedded Sandstone and Shale
| 4 - 8
| 6
| | Sand and Gravel with significant Silt and Clay
| 4 - 8
| 6
| | Sand and Gravel
| 6 - 9
| 8
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TABLE A-8. RANGES AND RATINGS FOR HYDRAULIC CONDUCTIVITY
| HYDRAULIC CONDUCTIVITY (GPD/FT2)
| | Range
| Rating
| | 1 - 100
| 1
| | 100 - 300
| 2
| | 300 - 700
| 4
| | 700 - 1000
| 6
| | 1000 - 2000
| 8
| | >= 2000
| 10
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TABLE A-9. RANGES AND RATINGS FOR VULNERABILITY FACTOR
| PESTICIDE DRASTIC SCORE
| | Range
| Rating
| | 0 - <130
| 1 (Low)
| | 130 - <160
| 2 (Moderate)
| | >= 160
| 3 (High)
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TABLE A-10. RANGES AND RATINGS FOR SENSITIVITY FACTOR
| MARKET VALUE OF PRODUCTION PER ACRE (BY COUNTY)
| | Range
| Rating
| | $ 0 - <40
| 1 (Low)
| | 40 - <60
| 2 (Moderate)
| | >= 60
| 3 (High)
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TABLE A-11. RANGES AND RATINGS FOR RISK FACTOR
| PERMITTED WATER VOLUME (AC_FT/YEAR)
| | Range
| Rating
| | 0 - <200
| 1 (Low)
| | 200 - <1200
| 2 (Moderate)
| | >= 1200
| 3 (High)
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TABLE A-12. RANGES AND RATINGS FOR MONITORING PRIORITY
| TOTAL MONITORING SCORE
| | Range
| Rating
| | 3 - 4
| Low
| | 5 - 7
| Moderate
| | 8 - 9
| High
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Ground Water Home
DISCLAIMER
Last Updated:
01/06/2006
Scott Radig - ND Dept. of Health
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