Lecture Outlines PowerPoint Chapter 5 Earth Science, 12e Tarbuck/Lutgens © 2009 Pearson Prentice Hall This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching their courses and assessing student learning. Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work and is not permitted. The work and materials from it should never be made available to students except by instructors using the accompanying text in their classes. All recipients of this work are expected to abide by these restrictions and to honor the intended pedagogical purposes and the needs of other instructors who rely on these materials.

Running Water and Groundwater Chapter 5 Earth Science, 12e Running Water and Groundwater Chapter 5

Earth as a system: the hydrologic cycle Illustrates the circulation of Earth’s water supply Processes involved in the cycle Precipitation Evaporation Infiltration Runoff Transpiration

The hydrologic cycle Figure 5.3

Sources of Earth’s water Figure 5.2

Water beneath the surface (groundwater) Largest freshwater reservoir for humans Geological roles As an erosional agent, dissolving by groundwater produces Sinkholes Caverns An equalizer of streamflow

Water beneath the surface (groundwater) Distribution and movement of groundwater Distribution of groundwater Belt of soil moisture Zone of aeration Unsaturated zone Pore spaces in the material are filled mainly with air

Water beneath the surface (groundwater) Distribution and movement of groundwater Distribution of groundwater Zone of saturation All pore spaces in the material are filled with water Water within the pores is groundwater Water table – the upper limit of the zone of saturation

Features associated with subsurface water Figure 5.26

Water beneath the surface (groundwater) Distribution and movement of groundwater Distribution of groundwater Porosity Percentage of pore spaces Determines storage of groundwater Permeability Ability to transmit water through connected pore spaces Aquitard – an impermeable layer of material Aquifer – a permeable layer of material

Water beneath the surface (groundwater) Features associated with groundwater Springs Hot springs Water is 6–9°C warmer than the mean air temperature of the locality Heated by cooling of igneous rock Geysers Intermittent hot springs Water turns to steam and erupts

Old Faithful geyser in Yellowstone National Park Figure 5.29

Water beneath the surface (groundwater) Features associated with groundwater Wells Pumping can cause a drawdown (lowering) of the water table Pumping can form a cone of depression in the water table Artesian wells Water in the well rises higher than the initial groundwater level

Formation of a cone of depression in the water table Figure 5.31

Artesian systems Figure 5.32

Water beneath the surface (groundwater) Environmental problems associated with groundwater Treating it as a nonrenewable resource Land subsidence caused by its withdrawal Contamination

Water beneath the surface (groundwater) Geologic work of groundwater Groundwater is often mildly acidic Contains weak carbonic acid Dissolves calcite in limestone Caverns Formed by dissolving rock beneath Earth’s surface Formed in the zone of saturation

Water beneath the surface (groundwater) Geologic work of groundwater Caverns Features found within caverns Form in the zone of aeration Composed of dripstone Calcite deposited as dripping water evaporates Common features include stalactites (hanging from the ceiling) and stalagmites (growing upward from the floor)

Cave Features in Lehman Caves, Great Basin National Park, and Carlsbad Caverns National Park Figure 5.38

Water beneath the surface (groundwater) Geologic work of groundwater Karst topography Formed by dissolving rock at, or near, Earth’s surface Common features Sinkholes – surface depressions Sinkholes form by dissolving bedrock and cavern collapse Caves and caverns Area lacks good surface drainage

Features of karst topography Figure 5.39 C

End of Chapter 5