1. Chapter 17 Groundwater

2. Figure 17.2

3. Variations in the Water Table Water tends to mimic the land surface Variations in rainfall & permeability

4. Gaining and Losing Streams Figure 17.4

5. Groundwater Storage Porosity % of pore spaces Fluid Storage

6. Table 17.2

7. Groundwater Movement Permeability ability to transmit a fluid

8. Aquifer Yields significant quantities of water High porosity & permeability

9. Aquifers Confined/Closed Unconfined/Open

10. Long Island Aquifers Upper Glacial Magothy Lloyd

11. Aquiclude Inhibits movement of groundwater Impermeable Clay or Solid Bedrock

12. Groundwater Movement Darcy’s Law Q=K(dh/dl)A

13. Darcy’s Law Q=Discharge K=Hydraulic Conductivity dh=Change in water table elevation dl=Distance over which change occurs A=Area in question

14. Spring Resulting from a Perched Water Table Figure 17.8

15. Figure 17.13

16. Artesian Well Figure 17.15

17. Artesian Pressure System

18. Excess Groundwater Withdrawal Subsidence – land surface sinks California Venice Texas

19. Excess Groundwater Withdrawal Saltwater Contamination Excess groundwater withdrawal Saltwater is drawn into wells Coastal areas Ghyben-Herzberg Equation

20. Total thickness of freshwater lens = x + 40x

21. Saltwater Contamination Figure 17.19

22. Groundwater Contamination Sewage Extremely permeable aquifers (gravel) Travels long distances without being filtered

23. Groundwater & Erosion Caves Caverns Sinkholes

24. End of Chapter 17