1. Ground Water Basics continued

2. Aridic arid climate, usually dry, irrigation required for crop production.
Ustic—semiarid climate, rainfall during a growing season.
Xeric—semiarid climate, Mediterranean climate, cool, moist winters, dry summers,
dryland crop possible from stored soil water.
Udic—humid climate, usually moist, generally irrigation not required for crop
production.
Perudic—precipitation exceeds evapotranspiration in all months, but soil is not
saturated for long periods.
Aquic—soil saturated long enough to cause anaerobic conditions

3. Soil Moisture Regimes

4. Types of Porous Media
Isotropic
Anisotropic
Homogeneous
Heterogeneous

5. Layered media (horizontal conductivity)Q4 Q3 Q2 Q1
Q = Q1 + Q2 + Q3 + Q4 K2 b2
Flow K1 b1

6. Layered media (vertical conductivity)Q4 R4
Flow Q3 R3 K2 b2 R2 K1 b1 Q2
Controls flow Q1 R1
Q ≈ Q1 ≈ Q2 ≈ Q3 ≈ Q4
The overall resistance is controlled by the largest resistance:
The hydraulic resistance is b/K
R = R1 + R2 + R3 + R4

7. Aquifers
Lithologic unit or collection of units capable of yielding water to wells
Confined aquifer bounded by confining beds
Unconfined or water table aquifer bounded by water table
Perched aquifers

8. Transmissivity
T = Kb
gpd/ft, ft2/d, m2/d

9. Schematic
T2 (or K2)
b2 (or h2)
i = 2 k2 d2 T1 b1
i = 1 k1 d1

10. Pumped Aquifer Heads k1 T1 k2 T2 (or K2) b2 (or h2) i = 2 d2 b1 i = 1

11. Heads h2 - h1 k1 T1 k2 T2 (or K2) b2 (or h2) h2 i = 2 d2 h1 b1 i = 1

12. Leakance Leakage coefficient, resistance (inverse)
From below:
From above:

13. Flows qv h2 h2 - h1 k1 T1 k2 T2 (or K2) b2 (or h2) h1 i = 2 d2 b1

14. Poisson Equation