1. Groundwater

3. Infiltration Surface materials Topography Vegetation Precipitation Groundwater Distribution Zone of Aeration (unsaturated zone) Capillary Fringe Zone of saturation Water Table Availability of Groundwater Porosity Permeability Groundwater Flow Hydraulic conductivity Hydraulic gradient Discharge

4. IV. Groundwater Flow: A. Flow Rate dependent on: 1. Speeds: Depends on material, porosity and hydraulic conductivity B. Discharge: water table intersects the surface = streams, lakes, swamps, springs (confined) Groundwater

6. V. Aquifers  Permeable body or rock/sediment that transmits and stores groundwater  Best aquifer: unconsolidated sand and gravel or  Well-sorted, poorly cemented sandstones or  Highly fractured limestones and basalts A.Unconfined Aquifer Impermeable layer only below permeable material Groundwater

7. V. Aquifers A.Unconfined Aquifer Impermeable layer only below Groundwater

8. V. Aquifers B. Confined Aquifer Impermeable layers above and below the aquifer Often a deeper confined aquifer below an unconfined aquifer with an impermeable layer between the two Water may flow hundreds of miles below ground Below deserts in Nevada, eastern Utah, southern Arizona Groundwater

9. V. Aquifers C. Artesian Aquifer Water will gush out of a confined aquifer when well is drilled Occurs where the confined aquifer is tilted at an angle to the Earth’s surface Recharge location is higher than well location, pressure from behind combats gravity City water supplier use the same idea—tall water town on Craig’s Hill Groundwater

10. V. Aquifers C. Artesian Aquifer Water will gush out of a confined aquifer when well is drilled Occurs where the confined aquifer is tilted at an angle to the Earth’s surface Recharge location is higher than well location, pressure from behind combats gravity City water supplier use the same idea - tall water town on Craig’s Hill Groundwater

11. VI. Natural Springs and Geysers A. Natural Springs: water flows freely from the ground  Water table intersects the surface  Water table reaches an impermeable layer  May be hot if the groundwater is near magma or if it circulates deep enough Groundwater

12. VI. Natural Springs and Geysers

13. VI. Natural Springs & Geysers

14. VI. Natural Springs and Geysers B. Geysers: intermittent emission of hot water Water descends through fractured rock Warmed by underlying heat source Forced up by steam under great pressure that is heated above boiling point due to overlying pressure Water expands Pressure is less  flashes to steam Yellowstone: hot spot (magma) Iceland: divergent plate boundary Groundwater

15. VI. Natural Springs and Geysers B. Geysers: intermittent emission of hot water

16. VII. Threats to groundwater Groundwater can’t meet cities’ need If withdrawal > recharge  regional lowering of the water table Cone of depression Aquifer is compressed  land subsidence Las Vegas  3 feet New Orleans  7 feet Mexico City  23 feet Central California  26 feet (San Joaquin Valley) Groundwater

17. VII. Threats to groundwater Groundwater can’t meet cities’ need If withdrawal > recharge  regional lowering of the water table

18. VII. Threats to groundwater Groundwater can’t meet cities’ need If withdrawal > recharge  regional lowering of the water table

19. VII. Threats to groundwater

20. Groundwater

21. VII. Threats to groundwater Groundwater can’t meet cities’ need If withdrawal > recharge  regional lowering of the water table Aquifer is compressed  land subsidence Venice >10 feet in 1500 years  flooded (lost bottom story) Houston ~3-7 feet since 1906  problems with ocean flooding Saltwater intrusion into aquifer Brooklyn, NY in 1930’s turned into saltwater - now they have to ship the water in = very high cost of water

22. VII. Threats to groundwater Venice >10 feet in 1500 years  flooded (lost bottom story) Second century stone walkway beneath Venice, Italy. Ground subsidence and rise in sea level resulted in a 13 cm rise in relative sea level/century. Over the past century, the rise in relative sea level has reached a historical peak at 23 cm, in part due to an ill-planned industrial complex that pumped water from beneath the city from 1930 to 1970 and accelerated ground subsidence.

23. VII. Threats to groundwater Cone of depression

24. VII. Threats to groundwater Groundwater Cone of depression

25. VII. Threats to groundwater Groundwater Desalinization Plant

26. Groundwater Contamination