Louisiana Department of Environmental Quality Risk Evaluation/Corrective Action Program (RECAP)

1
Louisiana Department of Environmental
QualityRisk Evaluation/Corrective Action
Program(RECAP)
2

Aquifer Tests
3
Appendix F

• Current Use
• 1-mile radius water well survey
• 500-feet radius walking receptor survey
• Potential Use
• Maximum sustainable well yield
• Direct Measurement
• Estimated Measurement
• Total Dissolved Solids (TDS) of groundwater
• EPA Standard Method 160.1

4
Figure 3
NOTE CLASS 1A - Currently supplies a public
water supply. CLASS 2A - Currently supplies a
domestic, agricultural, or other supply.
5
Determine Site Constraints

• Soil Type
• Thickness of Encountered Formations
• Identification of Aquifers and Water Levels
• Aquitards Encountered
• Hydraulic Barriers

6
Determine Aquifer Properties

• Hydraulic Conductivity (K)
• Saturated Thickness (b)
• Transmissivity (T)
• Specific Yield (Sy)
• Specific Storage (Ss)
• Storativity (S)
• Porosity (n)

7
Unconfined Aquifer
Unsaturated Zone
Saturated Zone
8
Confined Aquifer
Unsaturated Zone
Confining Layer
Saturated Zone
Confining Layer
9
Direct Measurement of Aquifer Properties

• PUMPING TESTS
• Constant Rate
• Step-drawdown
• SLUG TESTS
• Slug In
• Slug Out

10
SLUG TESTS
Slug In
Unsaturated Zone
Saturated Zone
Water Flow
Water Flow
11
SLUG TESTS
Slug Out
Unsaturated Zone
Saturated Zone
Water Flow
Water Flow
12
Conceptual Pumping Test Models
13
Conceptual Slug Test Models
14
Estimation of Aquifer Properties

• HYDRAULIC CONDUCTIVITY
• Published References
• Laboratory Procedures
• Field Procedures
• AQUIFER THICKNESS
• USGS, LGS, DNR, DOTD
• SPECIFIC YIELD/SPECIFIC STORAGE
• Published References

15
Estimated Well Yield forConfined Aquifer
16
Estimated Well Yield forUnconfined Aquifer