1. Water Use and Management Environmental Science Spring 2011

2.  Identify patterns of global water use  Explain how water is treated so that it can be used for drinking  Identify how water is used in homes, in industry, and in agriculture  Describe how dams and water diversion projects are used to manage freshwater resources  Identify 5 ways that water can be conserved

3.  A shortage of clean, fresh water is one of the world’s most pressing environmental problems  According to World Health Organization, more than 1 billion people lack access to a clean, reliable source of fresh water

4.  Three major uses for water: residential, agriculture, industrial  Agriculture > industrial > residential  Amounts used

5.  Average person in US uses about 300L of water every day  Average person in India uses about 41L of water every day Daily Water Use in the United States (per person) UseWater (L) Lawn Watering and Pools95 Toilet Flushing90 Bathing70 Brushing Teeth10 Cleaning (inside and outside) 20 Cooking and Drinking10 Other5

6.  Water treatment  Potable: safe to drink  Most water must be treated to make it potable  Removes elements such as mercury, arsenic, lead (found in polluted water and occur naturally)

7.  Water treatment  Pathogens: organisms that cause illness or disease  Water treatment removes these  Ex. Bacteria, viruses, protozoa, parasitic worms  Often found in water contaminated by sewage or animal feces  Water treatment methods usually include physical and chemical treatments

8.  Accounts for 19% of water used in world  Used to manufacture goods, dispose of waste, and to generate power  Most of water used is to cool power plants  Pump from river or lake, carry to cooling tower, return to source  Returned water is usually warmer but clean and can be reused

9.  Accounts for 67% of water used in the world  Plants require a lot of water to grow, and as much as 80% of water used in agriculture evaporates before reaching plant roots

10.  Irrigation: method of providing plants with water from sources other than direct precipitation  In areas where rainfall is inadequate, extra water is supplied by irrigation  Cotton is irrigated by shallow water filled ditches  High pressure overhead sprinklers are common form of irrigation in US  Inefficient because nearly half of water evaporates

11.  Humans have altered streams and rivers to make them more useful  Aqueducts: Romans built these huge canals that brought water from mountains to dry areas of France and Spain

12.  Dams and water diversion canals, are designed to meet needs of those that live in areas of inadequate surface water distribution  Water management projects have various goals: bringing in water to make dry area habitable, creating a reservoir for recreation or drinking water, or generating electric power

13.  Water Diversion Projects  To supply dry regions with water, all or part of a river can be diverted into canals that carry water across great distances  Owen River in California  Colorado River meets needs of western states

14.  Dams and Reservoirs  Dam: structure built across a river to control rivers flow  Reservoir: when a river is dammed, artificial lake or reservoir, is formed behind the dam

15.  Dams and Reservoirs  Water from reservoir can be used for flood control, drinking water, irrigation, recreation, and industry  Dams are also built to generate electric energy  Hydroelectric dams use power of flowing water to turn turbine that generates electricity

16.  Dams and Reservoirs  Interrupting river’s flow can have far-reaching consequences  People are often displaced and entire ecosystems can be destroyed  Also effect land below dam, sediments will build up behind dam instead of below and farther down river  Farmland may become less productive  Dam failure!

17.  In Agriculture  Technologies that reduce problems of water loss (evaporation, seepage, runoff) help to conserve water  Drip irrigation systems: deliver small amounts of water directly to plant roots by using perforated tubing  Water is released as needed and at a controlled rate

18.  In Industry  Recycling of cooling water and waste water  Instead of discharging water into river, businesses often recycle water

19.  At Home  People can conserve water by changing a few habits and using water only when needed  Low flow toilets and showerheads  Water lawns at night  Xeriscaping: designing a landscape that requires minimal water use

20. What You Can Do To Save Water Take shorter showers, and avoid taking baths unless you keep the water level low Install a low-flow shower head in shower Install inexpensive, low-flow aerators in your water faucets at home Purchase a modern, low-flowing toilet, install a water-saving device in toilet, or simply place a water filled bottle inside your toilet tank to reduce the water used for each flush Do not let the water run when you brush your teeth Fill up the sink basin, rather than letting water run when you are shaving, washing your hands or face, or washing dishes Wash only full loads in your dishwasher and washing machine Water your lawn sparingly

21.  In some places conservation alone will not be enough to prevent water shortages  As populations grow other sources of fresh water need to be developed  Two possible solutions are desalination and transporting fresh water

22.  Desalination: process of removing salt from salt water  Costal communities  Middle east, built desalination plants to provide fresh water  Heat salt water and collect fresh water that evaporates  Process consumes a lot of energy, often too expensive

23.  Transporting Water  Islands of Greece have fresh water brought in by boat  May be used in US where half of fresh water is in Alaska  Icebergs are another potential source