The hydrological cycle and a few other memorable definitions

1. The hydrological cycle and a few other memorable definitions • = Cyclical movement of water from ocean to atmosphere, land and back to the ocean • Ground water = mass of water beneath the surface • Infiltration= Soaking into ground • Runoff = Rainwater that collects into streams and rivers • Reservoir = Place where large quantities of water are stored • Aquifer = Beds that store and transmit groundwater • Water table = upper limit of the zone of sediment saturated with water. See Fig. 13.2

2. GROUNDWATER 1) Why bother? • Why bother • The water table • Groundwater storage and movement • Springs, hot springs, geysers • Wells • Problems, contamination • Geologic alterations

3. GROUNDWATER 1) Why bother? • Groundwater is • drinking water for more 50% of all people • 40% of irrigation water • important for livestock & industry • an overused resource resulting in: • - water shortages • - land subsidence • - contamination

4. GROUNDWATER 1) Why bother? • Groundwater is • typically misunderstood Underground “lakes” and “rivers” are rare Most underground water exists in spaces between grains (in “pore spaces”) • geological important erosional agent

5. 94% of all non-glacier fresh water GROUNDWATER 1) Why bother? See Fig. 13.1

6. humid region arid region GROUNDWATER 2) The water table • The water table is the upper limit of the zone of • sediment saturation with water. • Its shape depends on water influx and drainage • Groundwater moves very slowly: Effluent streams discharge ground water Influent streams recharge ground water See Fig. 13.8

7. GROUND- WATER 3) Groundwater storage & movement Important factors: porosity - percent of the volume of material that is taken up by pore spaces permeability - the ability of a material to transmit a fluid Aquifer - rock/sediment which easily transmits water Aquiclude, aquitards - barrier to water flow (low permeability) See Table 13.2, Fig. 13.17

8. GROUND- WATER 3) Groundwater storage & movement Important factors: Table 13.2

9. 4) Springs, hot springs, geysers GROUNDWATER Spring: Outflow of ground water from water table intersecting Earth’s surface See Fig. 13.11 Marble Canyon AZ

10. 4) Springs, hot springs, geysers GROUNDWATER Springs

11. 4) Springs, hot springs, geysers GROUNDWATER Desert Oases See Fig. 13.10 on artesian wells

12. 4) Springs, hot springs, geysers GROUNDWATER Spring w/ water 6-9oC (10-15o F) warmer than mean annual air temperature Hot springs:

13. 4) Springs, hot springs, geysers GROUNDWATER Geysers: Intermittent hot fountains/columns of water

14. See Fig. 13.22

15. GROUNDWATER A “cone of depression” develops around the pumping hole 5) Wells Well: A drilled hole into a saturated zone See Fig. 13.14

16. GROUNDWATER 6) Problems, contamination • Saltwater contamination (coastal areas) Freshwater-seawater boundary is maintained by the balance between recharge and discharge. See 13.14

17. GROUNDWATER 6) Problems, contamination • Subsidence (from pumping out water faster than replenishing)

18. GROUNDWATER 6) Problems, contamination • Subsidence (from pumping out water faster than replenishing)

19. GROUNDWATER 6) Problems, contamination • Groundwater contamination (due to human involvement) Contaminants enter aquifers and water supplies trough wells. See Fig. 13.20.

20. GROUNDWATER 6) Problems, contamination • Groundwater contamination (due to human involvement)

21. 7) Geologic alterations GROUNDWATER • caverns • karst topography • sink holes Limestone, usually formed just below water table Bedrock shaped (dissolved) by groundwater Either gradual or abrupt depression in surface due to dissolved limestone bedrock.

22. GROUNDWATER Some MC • After oceans, which of the following reservoirs contains the most water? • A. atmosphere • B. glaciers and polar ice • C. lakes and rivers • D. underground water

23. GROUNDWATER Some MC • Karst topography forms in regions underlain by __________. • A. basalt • B. limestone • C. sandstone • D. shale

24. GROUNDWATER Some MC • What is the average annual precipitation in Phoenix, Arizona? • A. less than 20 cm • B. 20-40 cm • C. 40-60 cm • D. more than 60 cm

25. GROUNDWATER Some MC • Layers that transmit groundwater are called ______. • A. aquicludes • B. aquifers • C. influent streams • D. unsaturated zones

26. GROUNDWATER Some MC • Which of the following unfractured rocks has the highest porosity? • A. granite • B. sandstone • C. schist • D. shale

27. GROUNDWATER Some MC • What is the difference between the saturated and unsaturated zones of groundwater? • A. The saturated zone has a higher porosity than the unsaturated zone. • B. The saturated zone has a lower porosity than the unsaturated zone. • C. The pore spaces in the saturated zone are full of water; the pore spaces in the unsaturated zone are not full of water. • D. The pore spaces in the saturated zone are not full of water; the pore spaces in the unsaturated zone are full of water.

28. GROUNDWATER Some MC • Which of the following statements about groundwater in coastal regions is true? • A. Fresh water is denser than seawater, therefore fresh groundwater floats on top of salty groundwater. • B. Fresh water is denser than seawater, therefore salty groundwater floats on top of fresh groundwater. • C. Seawater is denser than fresh water, therefore fresh groundwater floats on top of salty groundwater. • D. Seawater is denser than fresh water, therefore salty groundwater floats on top of fresh groundwater.