Chapter 11 - Water

Water Is a major limiting factor on populations because organisms must have to survive. Is considered a renewable resource because water is replaced by the water cycle. Condensation Precipitation Evaporation

Water Resources 97 % of Earth’s water (hydrosphere) is Salt Water water with 3.5% salt concentration or greater is considered salt water

Water Resources (cont.) 3 % of the Hydrosphere is Fresh Water 77% of fresh water (most of it) is trapped in polar ice caps

Water Resources (cont.) 22% of Fresh Water is Ground Water – water that percolates through the soil and is trapped. Aquifers – underground areas of porous rock that hold water.

Water Resources (cont.) 1% of fresh water is Surface Water: Most large cities depend on surface water for residential and industrial needs. For Example: Lakes Streams Ponds

Renewal of Surface/Ground Water A watershed is the area drained by a river. Some surface water seeps into aquifers and becomes groundwater. Major Watersheds

Renewal of Surface/Ground Water (cont.) Groundwater (in aquifers) is replenished by precipitation in the recharge zone. development can lead to obstruction of recharge zone.

Subsidence

Water Usage 67 % for Agriculture 19 % for Industry Worldwide water usage breaks down to : 67 % for Agriculture 19 % for Industry 14 % for Residential Usage these are average usage worldwide, but it can vary between areas

There are many types of irrigation. Water Usage (cont.) 1. Agriculture There are many types of irrigation. Furrow Overhead Flood

Water Usage (cont.) 2. Industrial used to generate power, dispose of waste, and manufacture of goods.

Water Usage (cont.) 3. Residential For Personal hygiene For cooking For Drinking

Water Usage (cont.) 3. Residential (cont.) water usage varies from one area to another USA = greatest usage = 300L (80 gallons) per day India = 41L per day water must be treated to be considered potable 1st Filtration 4. Chlorination Coagulation 5. Aeration Second Filtration 6. Additional Treatment (Fluorine)

Water Management Projects 1. Aqueducts - built to move water around Ancient aqueducts still standing Modern structures are also in use

Water Management Projects (cont.) 2. Water Diversion Projects – diversion of river or lake water for use elsewhere. Can cause huge problems for areas like Mono Lake where a decrease of replenishing water leads to increased salinity level of lake. Bad for organisms!

Water Management Projects (cont.) 3. Dams Creates reservoirs for recreation, and is good for flood control, and the production of hydroelectricity Can be bad for the ecosystem and cause disputes with neighboring states or countries.

Water Conservation Is an inexpensive way to maintain fresh water resources. Agriculture Drip Irrigation is a method of delivering water to crops that can save huge amounts of water. Israel water usage cut by 75% by drip irrigation.

Water Conservation Industry Recycling of wastewater and cooling water from manufacture of goods.

Water Conservation Residential Use xeriscaping (planting of native plants) in lawns to decrease a need to water. Installing low flow shower heads and toilets as well as just turning off the water when you brush!

Desalination Processes The process by which salts are removed from ocean water making it potable. 1. Distillation - boil and condense water leaving behind impurities. 2 1. Heat salt water until turns to steam 2. Steam travels down tube where it cools and condenses. 1 3. Water (now free of salts and impurities) is collected and can be used. 3

Desalination Processes (cont.) 2. Reverse Osmosis achieved by forcing water through a membrane (filter) that removes salts and impurities.

Desalination Processes (cont.) 3. Freezing only the fresh water will freeze. Salts are trapped in brine slush that can be taken away.

Transporting Water Towing icebergs has been suggested, but has many risks and complications involved. Floating giant bags of water from one area to another has also been suggested, but this technique has many problems associated with it as well.

Pollution of Water The introduction of chemical, physical, or biological agents into a water source. Two Major Classifications : 1. Point-Source Pollution – pollution from a single (usually easily identifiable) source Leak from underground gas tank From Industry, Mines, and Buried Gas or Septic Tanks

Pollution of Water 96 % of H2O pollution is non-point source pollution 2. Non-Point Source Pollution - pollution from many different (often hard to identify) sources. 96 % of H2O pollution is non-point source pollution

Types of Pollutants and Sources Pathogens – cause disease – parasitic worms, virus, bacteria. Organic Matter – feces, animal remains Chemicals – both organic and inorganic Heavy Metals – mercury, arsenic Physical agents – heat, solid material (trash)

Consequences of Pollution Oxygen Depletion in Water Causing death of organisms Artificial Eutrophication – caused by nutrients (phosphorous and nitrogen) from runoff materials. 2. Thermal Pollution - disrupts ecosystems and kills organisms.

Biomagnification The accumulation of pollutants in higher level organisms.

Ground H2O Pollution Comes from many sources Underground storage tanks, and unlined landfills. Modern landfills are lined. Clean-up very difficult

Ocean Pollution Most comes from activities on land. Some from polluted rivers dumping into the sea Occurs mostly near coasts having a devastating effect on wetlands and estuaries that actually help filter out pollutants. Oil spills only account for 5% (road oil is far greater percentage)

Water Quality Laws 1972 – Clean Water Act – first major legislation 1972 – Marine Protection, Research, and Sanctuaries Act 1975 – Safe Drinking Water Act 1980 – Superfund Act – held polluters accountable for cleanup 1987 – Water Quality Act 1990 – Oil Pollution Act

The End