ch12

Classroom presentations to accompany Understanding Earth, 3rd edition: 

Classroom presentations to accompany Understanding Earth, 3rd edition prepared by Peter Copeland and William Dupré University of Houston Chapter 12 The Hydrologic Cycle and Groundwater

Hydrologic Cycle and Groundwater: 

Hydrologic Cycle and Groundwater M. L. Sinibaldi/Stock Market

Groundwater: 

Groundwater The study of groundwater and its effects is called Hydrology. Uses of Water: Living Engineering Recreation Drinking Cooling Swimming Photosynthesizing Heating Fishing Respiring Cleaning Sailing Metabolizing Flushing Skating Irrigating Skiing

Distribution of H2O on Earth: 

Fig. 12.1 Distribution of H2O on Earth

Uses of Groundwater: 

Uses of Groundwater Why is groundwater such a valuable resource? 1.Abundant - 70 times more in the subsurface than in surface reservoirs. 2.Because groundwater moves so slowly it is stored in the earth and remains available even in dry periods. 3.In some regions groundwater flows from humid environments to dry ones, making water available.

Groundwater: 

Groundwater Water contained in spaces within soil, bedrock, and regolith Less than 1% of all H2O on Earth 40 times more abundant than water found in lakes and streams

Hydrologic Cycle: 

Hydrologic Cycle Fig. 12.2

Rain Shadow Deserts: 

Rain Shadow Deserts Fig. 12.3

Average Annual Precipitation in the U.S.: 

Fig. 12.4a Average Annual Precipitation in the U.S.

Average Annual Runoff in the U.S.: 

Average Annual Runoff in the U.S. Fig. 12.4b

Swamps as Reservoirs: 

Fig. 12.5 Swamps as Reservoirs

Groundwater terms: 

Groundwater terms zone of aeration: portion of soil and rock near the surface in which open spaces are filled primarily with air (a.k.a vadose zone) saturated zone: zone in which pore spaces are filled with water water table: boundary between zone of aeration and saturated zone

Geologic activity of groundwater: 

Geologic activity of groundwater Dissolution (most important in carbonates and evaporites) Cementation Replacement

Springs: 

Springs Locations where a perched water table intersects the ground

Soils and rocks are not completely solid.: 

Soils and rocks are not completely solid. porosity: portion of volume of a material that consists of open spaces permeability: measure of the speed at which fluid can travel through a porous medium Imagine two vertical pipes, one filled with gravel, one with sand. Out of which one will the water flow faster?

Porous Sandstone: 

Fig. 12.7a Porous Sandstone

Cemented Sandstone: 

Fig. 12.7b Cemented Sandstone

Well-sorted Sandstone: 

Fig. 12.7c Well-sorted Sandstone

Poorly-sorted Sandstone: 

Poorly-sorted Sandstone Fig. 12.7d

Unfractured Shale: 

Unfractured Shale Fig. 12.7e

Fractured Shale: 

Fractured Shale Fig. 12.7f

More groundwater terms: 

More groundwater terms aquifer: body of rock that is sufficiently water permeable to yield economically significant quantities to wells and springs aquitard: body of rock that retards but does not prevent flow of water to or from an adjacent aquifer aquiclude: body of relatively impermeable rock that is capable of absorbing water slowly but does not transmit it rapidly enough to supply a well or spring

Groundwater Table: 

Fig. 12.8 Groundwater Table

Groundwater Movement in Temperate Regions: 

Groundwater Movement in Temperate Regions Fig. 12.9

Slide27: 

Wet Period Fig. 12.10

Slide28: 

Dry Period Fig. 12.10

Confined Aquifer: 

Fig. 12.11 Confined Aquifer

Perched Water Table: 

Fig. 12.12 Perched Water Table

Drawdown Due to Pumping: 

Fig. 12.13 Drawdown Due to Pumping

Fissures and Depressions Caused by Overpumping: 

Fissures and Depressions Caused by Overpumping Fig. 12.13 James W. Borchers/USGS

Saltwater Intrusion: 

Saltwater Intrusion Fig. 12.15

Rates of groundwater movement: 

Rates of groundwater movement Slow to very slow (depending on permeability) Generally within the range of 10 to 100 cm per day

Darcy’s Law: 

Darcy’s Law Q = discharge (m3/sec) A = cross-sectional area (m2) K = coefficient of permeability (m/sec) h1 = beginning height (m) h2 = ending height (m) l = length of flow (m) Q = AK(h1– h2) l

Darcy’s Law : 

Fig. 12.16 Darcy’s Law

U.S. Groundwater Withdrawals1950–1995: 

Fig. 12.17 U.S. Groundwater Withdrawals 1950–1995

Ogallala Aquifer:“Mining” Groundwater: 

Ogallala Aquifer: “Mining” Groundwater

Slide39: 

Fig. 12.18 David Muench

Sinkhole in Florida: 

Fig. 12.19 Sinkhole in Florida Leif Skoogfors/Woodfin Camp.

Major Features of Karst Topography: 

Major Features of Karst Topography Fig. 12.20

Water Quality and Groundwater Movement: 

Water Quality and Groundwater Movement Fig. 12.21

Groundwater Contamination: 

Fig. 12.22 Groundwater Contamination

Groundwater Distribution in a Typical Section of Continental Crust: 

Fig. 12.23 Groundwater Distribution in a Typical Section of Continental Crust

Geyser: 

Fig. 12.24 Geyser Peter Kresan