Water Use
What is the hydrologic cycle?
The
water cycle
 Precipitation
 Evaporation
 transpiration
What is ground water?
Groundwater
is water that is below the
water table (level where the ground is
saturated).
 Aquifer=
from
zone where groundwater can be obtained
What is surface water?
 Surface
water is water found above the water
table/at the surface of the earth.
Why do we have groundwater use
problems?
½
the people in the US use ground water as a primary
source of drinking water, sometimes at a rate of
overdraft.

Amount of water withdrawn is greater than inflow into the
well.
What is the difference between instream and off stream use?

Off stream use = water removed
from its source for use

Some water is returned to the
source (i.e. industrial cooling
water)

Consumptive use = water taken in
(not returned to source) by
humans, plants or animals

In stream use = the use of water
NOT removed from its source/ in
rivers, dams, fish and wildlife
habitats…etc.
How can we conserve water through
agricultural use?
 Agriculture
accounts for 65% of total freshwater withdrawls of water between 1950-2005.
 (in
reading)
How can we reduce our public supply and
domestic use (at home)?

Think ecological footprint (in reading)
Water Use 2
What is water pollution?

The degradation of water quality, so that it harms living
organisms or is not fit for human use.
What is Biochemical oxygen
demand?
The
amount of oxygen required for
biochemical decomposition
processes.

When BOD increases, dissolved oxygen decreases
What is water borne disease and how
is it most commonly detected?
 Illness
caused by bacteria or viruses in the
water, whose symptom vary from a stomach
ache to death.
How do we monitor disease carrying
organisms?
Fecal
coliform
What nutrients most commonly cause
water pollution?
Nitrogen
and phosphorus
What is Eutrophication?
 The
process by which a body of water develops a high
concentration of nutrients, such as nitrogen and
phosphorus (in the forms of nitrates and phosphates).
What are the effects of Eutrophication?

1. Increased aquatic plant and algae growth

2. Blockage of sunlight by algae

3. plants and good bacteria die, and start to decompose

4. Decomposition increases BOD as the number of decomposers increase

5. Dissolved oxygen decreases

6. Fish die/ecosystem starts falling apart
What is cultural
Eutrophication
Eutrophication?
accelerated by humans
Urban = sewage
Rural = agricultural run off
What are some causes of water pollution?
 Oil
 Sediment
 Acid
mine drainage
 Agricultural
Run off