The hydrological cycle and a few other memorable definitions See Fig = 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.

1) Why bother? GROUNDWATER 1.Why bother 2.The water table 3.Groundwater storage and movement 4.Springs, hot springs, geysers 5.Wells 6.Problems, contamination 7.Geologic alterations

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

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

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

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

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

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

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

4) Springs, hot springs, geysers GROUNDWATER Springs

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

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

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

See Fig

5) WellsGROUNDWATERWell: A drilled hole into a saturated zone A “cone of depression” develops around the pumping hole See Fig

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

6) Problems, contamination GROUNDWATER l Subsidence (from pumping out water faster than replenishing)

6) Problems, contamination GROUNDWATER l Subsidence (from pumping out water faster than replenishing)

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

6) Problems, contamination GROUNDWATER l Groundwater contamination (due to human involvement)

7) Geologic alterations GROUNDWATER u caverns u karst topography u 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.

Some MC GROUNDWATER 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

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

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

Some MC GROUNDWATER 15.Layers that transmit groundwater are called ______. A. aquicludes B. aquifers C. influent streams D. unsaturated zones

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

Some MC GROUNDWATER 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.

Some MC GROUNDWATER 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.