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WATER RESOURCES
The Walker School
Environmental Science
Importance of Water
Keeps Us Alive
Moderates Climate
Sculpts the Land
Dilutes Solid Wastes
Removes Pollutants
Distribution of Earth’s Water
1.36 billion km3 of water on Earth
Pacific Institute Monitors World’s Water
http://www.worldwater.org/data.html
Samples Hydrograph
Fig. 15-19, p. 475
Properties of Water
Strong Forces of Attraction
Exists as Liquid Over Wide Temperature Range
Changes Temperature Slowly
Evaporation Takes Large Amounts of Energy
Can Dissolve a Variety of Compounds
Filters UV Radiation
Expands When Frozen
Hydrologic Cycle
Fig. 15-3, p. 460
Water Characteristics•Flow•Viscosity•Infiltration Capacity•Gradiant
WHAT IS SURFACE WATER?
Surface Water is RunOff
Streams
Lakes
Wetlands
Reservoirs
World Drainage Basin
An area which a stream or river and its tributaries carry all surface runoff.
Ocean Drainage Basins
The Atlantic Ocean drains approximately 47% of all land
in the world.
The Pacific Ocean drains just over 13% of the land in the
world.
The Arctic Ocean basin drains most of Western and
Northern Canada east of the Continental Divide.
The Indian Ocean drains around 13% of the Earth's land.
The Southern Ocean drains Antarctica.
Watershed
A watershed or drainage basin is a region from which water drains into a stream, lake, reservoir, wetland or other body of water
River Basins
The three largest river basins (by area), in order of largest to smallest, include the Amazon basin, the Congo basin, and the Mississippi basin.
The three rivers that drain the most water, from most to least, are the Amazon, Congo , and Ganges Rivers.
Mississippian Drainage Basin
Fig. 15-22b, p. 480
Primary River
Secondary Tributary
Confluence Point
Endorheic Drainage Basins
Inland basins that do not drain into an ocean;
18% of all land drains to endorheic lakes or seas.
The largest of these consists of much of the interior of Asia, and drains into the Caspian Sea and the Aral Sea.
Evaporation is the primary means of water loss
Water is typically more saline than the oceans.
Aral Sea Drainage Basin
Types of Drainage Systems
Fig. 15-23, p. 481
1. DendriticDrainage2. Rectangular Drainage3. Trellis Drainage4. Radial Drainage5. Deranged Drainage
Drainage Patterns and Geology
Dentritic Drainage
Rectangular Drainage
Trellis Drainage
Radial Drainage
Deranged Drainage
Erosion Deposits
Regional Joint Systems
Folded Sedimentary Rock
Volcanoes
Swamps and Lakes
Tennessee Drainage Basin
Watershed is part of Alabama, Georgia, Mississippi, North Carolina, and Tennessee
The Tennessee River is formed at the confluence of the Holston and French Broad Rivers Georgia
The river has been dammed numerous times, primarily by Tennessee Valley Authority (TVA) projects. Tennessee
Check Google Earth and Identify the Type of Drainage Basin
Stream Piracy
Occurs when headward erosion breaches a divide
and diverts some or all of the drainage of another
stream system.
The Hadhramawt Plateau of South Yemen exhibits a complex dendritic drainage pattern and excellent examples of "stream piracy”.
A
BA. - Wadi Hadhramawt opens into the sand-filled RamlatSabatayn in the southwest corner of the Rub-al-Khali (The Empty Quarter), B - yet drainage is toward the sea.
• Deliver nutrients to the sea
sustain coastal fisheries
• Deposit silt that maintains deltas
• Purify water
• Renew and nourish wetlands
• Provide habitats for aquatic life
• Conserve species diversity
WHAT IS GROUND
WATER?
Importance of Ground Water
Aesthetic Value: beautiful caves, caverns and
deposits
Economic Value: source of fresh water for
agriculture, industry and domestics use.
Bequeath Value: need to conserve water for future
generations.
Ecological Services: supports ecosystems, filters
chemical pollutants, filters microscopic organisms
Groundwater
Water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations.
Includes soil moisture, permafrost (frozen soil), immobile water in very low permeability bedrock, and deep geothermal or oil formation water.
The study of the distribution and movement of groundwater is hydrogeology.
Aquifers
A unit of rock or an unconsolidated deposit is
called an aquifer when it can yield a usable
quantity of water.
Ogallala Aquifer is one of the largest in the world.
Confined vs. Unconfined
The upper level of this saturated layer of an unconfined aquifer is called the water table or phreatic surface.
Water Table
The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table.
Zones of the Water Table
Groundwater Movement
Gravity
HOW MUCH OF THE WORLD’S
RELIABLE WATER SUPPLY ARE WE
WITHDRAWING?
Global Water Withdrawal
78% of Global Water
Supply Withdrawn Each Year
18% is for Irrigation;
40% is for World Food
Production
20% for Industry
National Water Footprints
United States China
Industry 11% Public 10%
Power
cooling
38%
Agriculture
41% Agriculture 87%
Public 6% Industry 7%
U.S. Water Withdrawal & Use
Global Water Withdrawal
Global withdrawal has increased 9x in the
last 100 years
Humans now withdraw about 34% the
worlds reliable runoff
Rates are predicted to double in the next
20 years and exceed demand in a number
of regions
Projected World Water Availability
5,500
5,000
4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
1900 1920 1940 1960 1980 2000
Wate
r u
se (
cu
bic
kilo
mete
rs p
er
year)
Total use
Agricultural use
Industrial use
Domestic use
Year
Water Usage by Production
Average annual precipitation (centimeters)
Less than 41
41-81
81-22
More than 122
Acute shortage
Shortage
Adequate supply
Metropolitan regions with population
greater than 1 million
Serious Water Problems 1. Flooding2. Urban Shortages3. Pollution
Groundwater Withdrawl
Agriculture
Industry
Wells and Cones of Depression
A cone of depression forms when water is withdrawn from a well. The cone will grow in depth and circumference, lowering the water table and making nearby shallow wells go dry.
Saltwater Intrusion
Subsidence of Cities
Contamination of Groundwater
WHAT CAUSES FRESHWATER
SHORTAGES?
Causes of Fresh Water Shortages
Dry Climate
Drought
Desiccation
Water Stress
High None
NorthAmerica
SouthAmerica
Stress
Africa
Europe
Asia
Australia
Stress on World’s Major River
Basins
World Water Hotspotshttp://news.bbc.co.uk/1/shared/spl/hi/world/03/world_forum/water/html/default.st
m
World Water Facts
http://news.bbc.co.uk/2/low/science/nature/4787758.stm
One billion people without access to clean drinking water
2.6 billion without adequate sanitation
Rapid urbanization increasing pressure on water resources
30-40% of water 'lost' through illegal tapping and leaks
Populations w/o Access to Safe
Drinking Water
Populations w/o Access to Sanitation Services
Movie: Running Dry
What We Can Do
Build Dams and Reservoirs to Store Runoff
Bring in Surface Water from Other Areas
Withdraw Ground Water
Convert Salt Water to Fresh Water
Waste Less Water
Import Food to Reduce Water Use
Problems With Privatized Water
They have more incentive to
sell as much water as they
can rather than to conserve it.
The poor will continue to be
left out because of a lack of
money to pay water bills.
WHAT ARE THE ADVANTAGES AND
DISADVANTAGES OF LARGE DAMS AND
RESERVOIRS?
Trade-Offs of Dams
Dams Around the World
800,000 dams, total estimate
45,000 large dams
22,000 large dams on the world’s 227 largest
rivers
DamAqueductor canalUpper Basin
Lower Basin
IDAHOWYOMING
UTAH
Salt Lake City
Las Vegas
CALIFORNIABoulder City
Los Angeles
Palm Springs
San DiegoMexicali
Yuma
Phoenix
Tucson
LOWER
BASIN
ARIZONA
GrandCanyon
UPPER
BASIN
Grand Junction
Denver
COLORADO
NEW MEXICO
Albuquerque
MEXICO
Lake
PowellGlenCanyonDam
All-AmericanCanal
Gulf ofCalifornia
0
0
100 mi.
150 km
Drainage Basin of Colorado River
Problems w/ River Water Usage from The Colorado
River
Supplies water to some of the driest land in the S.
West.
Legal pacts have legislated more water usage to
U.S. and Mexico than the river can supply
Low water threatens spawning fish
80% is used to irrigate crops and raise cattle
Three Gorges Dam
Location of the Dam
RUSSIA
MONGOLIA
CHINA
NEPAL BHUTAN
INDIABANGLADESH
BURMA LAOS
VIETNAM PACIFIC
OCEAN
Beijing
CHINA
Jailing
River
Chongquing
YichangWunan
Yangtze
River
Shanghai
YELLOW
SEA
EAST
CHINA
SEA
ThreeGorges
Dam
Reservoir
WHAT ARE THE CAUSES AND
EFFECTS OF FLOODING?
Humans Increase Flood Damage
Removing Water Absorbing Vegetation
Draining Wetlands that Absorb Floodwaters and
Reduce
Living in Flood Plains
Oxygenreleased byvegetation
Diverseecological
habitat
Evapotranspiration
Trees reduce soilerosion from heavyrain and wind
Agriculturalland
Steadyriver flow
Leaf litterimprovessoil fertility
Tree rootsstabilize soil andaid water flow Vegetation releases
water slowly andreduces flooding
Forested Hillside
Protect Forests
After Deforestation
Tree plantation
Evapotranspiration decreases
Ranchingacceleratessoil erosion bywater and wind
Winds removefragile topsoil
Gullies andlandslides
Heavy rain leachesnutrients from soiland erodes topsoil Rapid runoff
causes flooding
Roadsdestabilizehillsides
Agriculture landis flooded andsilted up
Silt from erosion blocksrivers and reservoirs andcauses flooding downstream
FloodplainLevee Flood
wall
Dam
Reservoir
Humans Modify Flood Plains
Flood Plain Services
Provide Natural Flood and Erosion control
Maintain High Water Quality
Recharge Groundwater
Advantages to Living in a Floodplain
Provide Fertile Soil for Farming
Provide Ample Water for Irrigation
Provide Flat Land for Crops, Buildings, Highways
and Railroads
Availability of Nearby Rivers for Transportation
and Recreation
World’s Largest Floodshttp://pubs.usgs.gov/circ/2004/circ1254/
Flood Frequency Curve
Fig. 15-20b, p. 475
Note: Meteorologists typically watch for 2, 5, 10, 20 and 100 years floods.
Flood Control Methods
Dams and Reservoirs
Levees
Floodways
Floodwalls
Fig. 15-21a, p. 478
HOW USEFUL IS
DESALINATION?
Desalination, An Old Technology
Desalination Plant
Desalination Process
Uses of Desalination
Removing dissolved salts from ocean water or
from brackish ground water is called desalination
Methods include distillation
Process is expensive because it takes large
amounts of energy
Produces large quantities of wastewater
CAN CLOUD SEEDING AND TOWING
ICEBERGS IMPROVE WATER SUPPLIES?
Cloud Seeding Process
Cloud Seeding
Not useful in very dry areas were it is mostly needed
Would introduce large amounts of cloud-seeding chemical into the water system, possibly harming people, wildlife and agricultural productivity
Many legal disputes over clouds ownership between states
HOW CAN WE WASTE
LESS WATER?
Reducing Water Waste
65-70% of water use by people is lost through
evaporation
Decrease the burden of wastewater plants
Reduce the need for expensive dams and water transfer
project that destroy wildlife habitats and displace people
Slow depletion of groundwater aquifers
Save energy and money
Reducing Water Usage in Agriculture
• Redesign manufacturing processes
• Landscape yards with plants that require little water
• Use drip irrigation
• Fix water leaks
• Use water meters and charge for all municipal
water use
• Raise water prices
• Require water conservation in water-short cities
• Use water-saving toilets, showerheads, and front-
loading clothes washers
• Collect and reuse household water to irrigate lawns
and nonedible plants
• Purify and reuse water for houses, apartments, and
office buildings
Xerascaping
HOW CAN WE USE WATER
MORE SUSTAINABLY?
