Physical Geography Water Resources Chapter 9

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1. Chapter 9. Water Resources. Geosystems 5e. An Introduction to Physical Geography. Robert W. Christopherson. Charlie Thomsen. Physical Geography.
Physical Geography

Water Resources

Chapter 9 GEOGRAPHY 1710 Water Resources

Chapter 9

DAVID Geosystems R. SALLEE5e An Introduction to Physical Geography

Robert W. Christopherson Charlie Thomsen

Water Resources

Hydrologic Cycle Model

• The Hydrologic Cycle • SoilSoil-WaterWater-Budget Concept • Groundwater Resources • Our Water Supply

Figure 9.1

Surface Water

Figure 9.3

Precipitation in North America

Figure 9.6

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Potential Evapotranspiration

Types of Soil Moisture

Figure 9.8

Figure 9.9

Groundwater potential

Groundwater Resources • Groundwater Profile and Movement • Aquifers, Wells, and Springs • Overuse of Groundwater • Pollution of Groundwater

Figure 9.15

Groundwater Characteristics

Figure 9.16

Groundwater Characteristics

Figure 9.16

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What Properties of Earth’s Materials Allow Them to Absorb Water? • Porosity

What is the Water Table? • Zone of

aeration – pore spaces contain mostly air

– the percentage of a material’s volume that is pore space

• Zone of

• Permeability

saturation – pore spaces contain mostly water

– the measure of the interconnectedness of pore spaces

• Water table

• Aquifer

– the top of the zone of saturation

– permeable layer that transports water

How Does Groundwater Move?

What Are Springs? • Places where

groundwater flows or seeps out of the ground

• Gravity moves groundwater, just as it does water in channels

– moves from areas of high pressure to areas of low pressure – may move up to 250 m per day, or less than a few cm/day

What Are Water Wells? • Water percolates into a drilled or dug hole when the zone of saturation is penetrated

– when percolating water reaches the water table or impermeable layer, it flows laterally and may intersect the surface

High Plains Aquifer

– pumping can create a cone of depression – lowering of the water table is a major problem in some areas Figure 1

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Saltwater Incursion

Subsidence

• Excessive

pumping in coastal areas can result in salt water being drawn into wells – major problem in rapidly growing coastal communities – recharge wells are often used to pump water back into the system

Groundwater Contamination • Most common

• Loose grains of the aquifer are packed tighter after groundwater withdrawal – subsidence of the land has lowered Mexico City more than 3m in some places

Hydrothermal Activity-What Is It and Where Does it Occur? • Hot Springs

sources:

– water is circulated deep, where it is heated by magma or cooling igneous rocks – runs freely at the surface

– sewage, landfills, toxic waste disposal sites, and agriculture – serious problem due to indiscriminate practices by industry and citizens

• Geysers

– forcefully eject water and steam because of constrictions in the plumbing system

Global Water Scarcity

Water Withdrawal by Sector

Figure 9.21

Figure 9.22

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