Water Section #2: Water Use & Management

“We all live downstream” Everyone living downstream can be affected by pollution & overuse of water supplies As populations increase, the demands on our freshwater resources is becoming a problem More than 1 billion people lack access to a clean, reliable source of fresh water

Major Uses of Water Residential Agricultural Industrial

Global Water Use

Patterns of water use are not the same everywhere, but most fresh water is used to irrigate crops People use water based on: –availability of fresh water –population sizes –economic conditions

Residential Water Use average person in the U.S. uses about 300 L every day average person in India uses about 41 L every day typical activities = drinking, cooking, washing, toilet flushing, watering lawns, washing cars

Residential Water Use

Water Treatment potable = safe to drink removes elements such as mercury, arsenic, & lead which are poisonous to humans even in small amounts removes pathogens (bacteria, viruses, protozoa, & parasitic worms) that cause illness or disease

Water Treatment

One Treatment Method first filtration – remove large organisms & trash coagulation – bacteria & other impurities settle in globs on the bottom of the tank second filtration – water is filtered through layers of sand, gravel, & hard coal chlorination – chlorine added to prevent bacteria growth aeration – air is forced through to help release unwanted gases & odors additional treatment – add fluorine to prevent tooth decay or lime to soften hard water

Industrial Water Use accounts for 19% of world water use used to manufacture goods, dispose of waste, & generate power typical car production requires 500,000 L of water per car

Cooling Power Plants cooling systems usually pump water from a nearby surface water source (river or lake) this water is usually returned back to the source, it is clean & can be reused, but it is usually warmer

Nuclear Power Plant

Agricultural Water Use accounts for 67% of the water used in the world plants require a lot of water – takes 300 L to produce just one ear of corn unfortunately, most of the water (~80%) used in agriculture will evaporate and never reach the plant’s roots

Irrigation by Overhead Sprinklers

Irrigation a method of providing plants with water from sources other than direct precipitation in regions where the soil is fertile but the rainfall is inadequate, extra water from irrigation can make it viable

Water Management historically, humans have been altering streams and rivers, building aqueducts (Rome, Spain, France), etc. to make access to water easier often humans would flood a field from a nearby river for growing crops

Ancient Spanish Aqueducts

Project Goals bring water in to make a dry area habitable create a reservoir for recreation & drinking water generation of electric power people can live & grow crops in desert regions dams or water diversion canals

Dams & Reservoirs a dam is a structure built across a river to control the river’s flow the artificial lake, called a reservoir, forms behind the dam some dams are built for flood control, generate electricity through turbines, provide water for irrigation, drinking, recreation, & industrial use

Dams & Reservoirs

Dams Concerns although building a dam can bring multiple benefits, interrupting a river’s flow can have some far-reaching consequences land can flood behind the dam, displacing people, other creatures, and destroying entire ecosystems can cause a loss of fertile soil down river dam failure can be deadly & costly

Water Conservation water is becoming more expensive as water sources are depleted, wells must be dug deeper, water must be piped greater distances, polluted water must be cleaned up

Conservation in Agriculture water is lost to evaporation, seepage or leaks, & runoff drip irrigation systems can limit water loss by delivering small amounts of water directly to the plant roots by using perforated tubing water is released to plants as needed & at a controlled rate – sometimes using computer programs

Drip Irrigation System

Conservation in Industry industries today are recycling water used for cooling & wastewater instead of discharging used water back into a river, they use the same water over & over again some cities offer incentives to small businesses to introduce water conservation measures so more water is available for agricultural & residential use

Conservation at Home although residential use is not too much to start with, every little bit can help in the long run people can change a few everyday habits & only use the water they need to make a big difference water-saving technology includes low-flow toilets & shower-heads which are found in most newer buildings & some areas will pay for you to change over older systems

Conservation at Home most water is used for landscaping purposes (i.e. watering the lawn) if you water the lawn at night, less water is lost to evaporation you can also design your landscaping to require minimal water use – called xeriscaping

Xeriscaping

Conservation in the Future when conservation alone is not enough to prevent water shortages, people must find alternatives to fresh water sources

Desalinization the process of removing salt from salt water so it can be used as a fresh water source mostly done by coastal communities heat the salt water, collect the fresh water that evaporates off too expensive overall because of the amount of energy the process consumes

Transporting Water the process of moving fresh water from one place to another a ship towing plastic bags full of fresh water from one port to another where it is then pumped onto the island or mainland for use Ex. = Alaska to California towing icebergs to communities not a practical solution at this time