Title: Water Resources
1Chapter 13
2Supply of Water Resources
3Core Case Study Water Conflicts in the Middle
East - A Preview of the Future
- Many countries in the Middle East, which has one
of the worlds highest population growth rates,
face water shortages.
Figure 14-1
4Water Conflicts in the Middle East A Preview of
the Future
- Countries are in disagreement as to who has water
rights. - Currently, there are no cooperative agreements
for use of 158 of the worlds 263 water basins
that are shared by two or more countries.
5Soil Properties
Clay, granite
Sand, gravel
6 Zone of aeration Zone of saturation
Groundwater
Unconfined Aquifer Recharge Area
Evaporation and transpiration
Evaporation
Precipitation
Confined Recharge Area
Runoff
Flowing artesian well
Recharge Unconfined Aquifer
Stream Well requiring a pump
Water table
Infiltration
Lake
Infiltration
Unconfined aquifer
Less permeable material such as clay
Confined aquifer
Confining impermeable rock layer
Fig. 13-3,
7Tapping Groundwater
8Other Effects of Groundwater Overpumping- Sea
water intrusion
- Groundwater overpumping can cause land to sink,
and contaminate freshwater aquifers near coastal
areas with saltwater.
9Other Effects of Groundwater Overpumping-subsidenc
e
- Sinkholes
- Chemical contamination.
10Use of Water Resources
11Case Study The California Experience
- A massive transfer of water from water-rich
northern California to water-poor southern
California is controversial. - Water rights
- Prior appropriation
- riparian
Figure 13-17
12Converting Salt Water to Fresh Water and Making
it Rain
- Distillation desalination
- Reverse osmosis desalination
- Desalination is very expensive
13 Provides water for year-round irrigation of
cropland
Flooded land destroys forests or cropland and
displaces people
Large losses of water through evaporation
Provides water for drinking
Downstream cropland and estuaries are deprived of
nutrient-rich silt
Reservoir is useful for recreation and fishing
Risk of failure and devastating downstream
flooding
Can produce cheap electricity (hydropower)
Downstream flooding is reduced
Migration and spawning of some fish are disrupted
Fig. 13-12
14Case Study Chinas Three Gorges Dam
- There is a debate
- The electric output
- It will facilitate ship travel reducing
transportation costs. - Dam will displace 1.2 million people.
- Dam is built over seismatic fault and already has
small cracks.
15Dam Removal
- Some dams are being removed for ecological
reasons and because they have outlived their
usefulness. - The Federal Energy Regulatory Commission has
approved the removal of nearly 500 dams. - Removing dams can reestablish ecosystems, but can
also re-release toxicants into the environment.
16Using Water More Efficiently
- Reduce losses due to leakage
- Improve irrigation efficiency
- Improving manufacturing processes
- Water efficient landscaping
- Water efficient appliances
17INCREASING WATER SUPPLIES BY WASTING LESS WATER
- Sixty percent of the worlds irrigation water
- Center-pivot, low pressure sprinklers sprays
water directly onto crop. - It allows 80 of water to reach crop.
18 Drip irrigation
(efficiency 9095)
Gravity flow
(efficiency 60 and 80 with surge valves)
Center pivot
(efficiency 8095)
Water usually pumped from underground and sprayed
from mobile boom with sprinklers.
Above- or below-ground pipes or tubes deliver
water to individual plant roots.
Water usually comes from an aqueduct system or a
nearby river.
Fig. 13-20
19Solutions Getting More Water for Irrigation in
Developing Countries The Low-Tech Approach
- low-tech methods to pump groundwater
- Arsenic in India
20Raising the Price of Water A Key to Water
Conservation
- We can reduce water use and waste by raising the
price of water while providing low lifeline rates
for the poor. - When Boulder, Colorado introduced water meters,
water use per person dropped by 40.
21 What Can You Do?
Water Use and Waste
Use water-saving toilets, showerheads, and
faucet aerators.
Shower instead of taking baths, and take short
showers.
Stop water leaks.
Turn off sink faucets while brushing teeth,
shaving, or washing.
Flush toilets only when necessary.
Wash only full loads of clothes or use the
lowest water-level for smaller loads.
Use recycled (gray) water for lawn, gardens,
house plants, car washing.
Wash a car from a bucket of soapy water, and
use the hose for rinsing only.
If you use a commercial car wash, try to find
one that recycles its water.
Replace your lawn with native plants that need
little if any watering and decorative gravel or
rocks.
Water lawns and gardens in the early morning or
evening.
Sweep or blow off driveways instead of hosing
off with water.
Use drip irrigation and mulch for gardens and
flowerbeds.
22Too Much Water Floods
- Aggravated by human activities
Flood zone
23TOO MUCH WATER
- Comparison of St. Louis, Missouri under normal
conditions (1988) and after severe flooding
(1993).
24Water Conservation
- The average American uses 90 gallons of water
each day. European-53 and Sub-Saharan Africa-5 - Fix leaks, replace old toilets (trade ins),
efficient washers (50 less water and energy). - A switch to water efficient appliances family of
4- save 23,000 gallons a year. - End chapter 13
-