The science that studies water on the Earth is known as hydrology, and the people who study hydrology are hydrologists. Although there is plenty of water.

The science that studies water on the Earth is known as hydrology, and the people who study hydrology are hydrologists.

Although there is plenty of water on Earth, it is not always in the right place, at the right time and of the right quality.

Hydrology has evolved as a science in response to the need to understand the complex water systems of the Earth and help solve water problems.

Hydrologists play a vital role in finding solutions to water problems, and interesting, challenging careers are available to those who choose to study hydrology.

Most cities meet their needs for water by withdrawing it from the nearest river, lake or reservoir.

Hydrologists help cities by collecting and analyzing the data needed to predict how much water is available from local supplies and whether it will be sufficient to meet the city's projected future needs. They also study water pollution data, snowpack depths, flow rates etc…

When the Cuyahoga River, near Cleveland Ohio caught fire in 1969, it became a symbol of polluted America.

This fire, along with many other “water-pollution” issues eventually led the CWA (Clean Water Act) of 1972. By 2002, a dramatic 94% of the community water

systems in the nation met the standards for clean water, up from only 79% in 1992.

Americans do have some of the cleanest drinking water (from tap sources) on the planet. From the time of the passage of the CWA of 1972, yearly increases in cleanliness of source waters have been found, allowing for more and more fishing and swimming.

One continual problem that contributes to pollution of source water is runoff from land that carries excess nutrients and pollutants into streams.Agricultural runoff carries nutrients and pesticides to streams, rivers, and other surface waters.This can result in large dead zones, and fish kills along coastal areas…which may result in increased shark attacks!

Global dead zones are becoming more and more prevalent, as ocean temperatures rise due to global warming.

Eutrophication can occur naturally, and artificially. Since the artificial means is controllable, it is this that we will focus on.

• The process of decomposition uses up large amounts of dissolved oxygen in the water supply.• This affects the fish and other aquatic organisms reliant on that oxygen, and can cause fish-kills.

• Plants, and plant-like protists (green algae) thrive, and “choke out”, or kill other organisms

• When this process occurs due to the human addition of nutrients like phosphorous and nitrogen, to agricultural soils in the mid-west, they can cause excessive growth of algae.

Algal bloom

When the warm, nutrient rich waters of the Mississippi meet the Gulf of Mexico (a relatively cold saltwater body), an algal bloom occurs. • Phytoplankton proliferate• Zooplankton proliferate• They both die and sink to the bottom

Bacteria metabolize the available dissolved oxygen as they decompose this detritus, causing dissolved oxygen levels to drop drastically. This causes a HYPOXOC zone, in which nothing that depends upon oxygen can live. (dead zone)As you can see, there is a relatively huge “dead zone”, where the dissolved oxygen levels are so low that aerobic organisms cannot survive.

Pollution that comes from a single, easily identifiable source is known as point pollution.This pipe is discharging noxious contents into a stream, and is a source of POINT pollution.The Exxon Valdez spilled 232,000 barrels of oil (11.2 million gallons) spilled in the Prince William Sound off Alaska

Pollution that comes from many sources rather than from a single specific site is known as nonpoint pollution.

This type of pollution can be devastating, because the accumulation of small amounts of pollution adds up to a huge problem

The EPA determined that 96% of the polluted water bodies in the US are from nonpoint sources

Right now, the largest global contributor to water pollution is agricultural activities. Coming in a close second, is industrial discharge of wastewater and mining activities.Standing bodies of water are far more affected by water pollution than flowing bodies. The lack of flow prevents the dilution and eventual removal of the pollutant.

These pollutants are allowed to accumulate in the water and undergo biomagnification in the food chain.

Groundwater sources are even more apt to become polluted, as they typically move very little, and the porous rock surrounding these sources tend to absorb the pollutants.

Pollutants that contaminate groundwater, are the same as the pollutants that contaminate surface water.When compounds move through the soil and wind up in the groundwater supply it is known as leaching.Surface

contaminants such as road salt, motor oil, and pesticidesUnderground contaminants such as untreated waste from septic tanks, landfills, and buried toxic waste.

There are over 20,000 known abandoned and uncontrolled hazardous waste sites in the US, and the number grows every year.• Containment barrels lying around full of hazardous materials can leak contaminants that make their way down to the groundwater supply

• Landfills are places where our garbage is taken and buried. If the protective barrier beneath the landfill becomes cracked, the leachate can be very hazardous

Drinking contaminated groundwater can have serious health effects.• Hepatitis and Dysentery can be caused by contamination from septic tank waste• Poisoning from leaking underground gas tanks can make water unfit for consumptionDon’t forget that wildlife, too, can be harmed by contaminated groundwater…not just humans!

Dioxins occur as by-products in the incineration of chlorine-containing substances such as PVC (polyvinyl chloride), in the bleaching of paper, and from natural sources such as volcanoes and forest fires.

The effects of exposure in adults, other than chloracne are liver damage, elevated serum lipid levels, changes in thyroid function, as well as diabetes, cancer and various immunological effects

There have been many incidents of dioxin pollution resulting from industrial emissions and accidents; the earliest such incidents were in the mid 19th century during the Industrial Revolution.

The Stockholm Convention, a legally binding international agreement finalized in 2001, has participating governments agreeing to take actions to reduce or eliminate the production, use, and/or release of certain pollutants known as POPs (persistent organic pollutants) Typically, these “Dirty Dozen” have been used as pesticides of some sort, however some were not.

In surface waters, PCBs are present in substantial quantities in sediments. PCBs tend to attach to the surface of organic matter, such as clay. They can remain buried in sediments for a long time and be slowly released into the water and evaporate into air.

PCBs have been demonstrated to cause a variety of adverse health effects. PCBs have been shown to cause cancer in animals. PCBs have also been shown to cause effects on the immune, reproductive, nervous, and endocrine system.

Polychlorinated biphenyls

Beginning in the 1940s, GE used PCBs as an insulating fluid in electrical capacitors manufactured at plants along the river at Hudson Falls and Fort Edward, NY. As a result of various processes, PCBs were legally discharged into the river. The company discontinued its use of PCBs in 1977 because of lab experiments showing that PCBs could cause cancer in lab rats. General Electric was commissioned by the EPA to “clean up” its own mess, and they have done so by dredging up the bottom sediment which contains a great deal of PCBs.

Fish are the main source of food for many birds and other animals, and mercury can seriously damage the health of these species. Loons, eagles, panthers, otters, mink, kingfishers and ospreys naturally eat large quantities of fish. Because these predators rely on speed and coordination to obtain food, mercury may be particularly hazardous to these animals.

Sources of Mercury

-- Pathogens --

Pathogens are disease-causing organisms such as bacteria, and parasitic wormsThey can enter the water supply from untreated wastewater, or animal feces (including human)• cholera

• hepatitis

• typhoid

Thermal pollution primarily occurs when excessive amounts of heat are added to a body of water. This usually happens near industry and power plants, like Comanche Peak (near Glen Rose).These industries circulate surface water sources to cool their engines, and then the heated water is sent back out into the surrounding rivers, lakes or streams.

This is called “effluent”

Contaminated groundwater is very difficult and expensive to clean up.For that reason, it makes more sense to prevent contamination rather than to have to clean it up. • Manufacturers use fewer toxic raw materials• Consumers using phosphate-free detergents, and less polluting products which helps to

• The Clean-Water Act of 1972 established to protect our drinking water supply

Reduce artificial eutrophication

http://www.epa.gov/watertrain/cwa/index.htm

A few gallons in the kitchen, a few dozen in the bathroom, a few hundred on the lawn. Home water use and waste adds up quickly. • The average family of four uses 90,000 gallons of water a year.• A few modest changes to your household’s plumbing fixtures and habits can go a long way toward saving thousands of gallons a year.

In the bathroom:• Turn off the tap while brushing your teeth or shaving(4-10 gallons a day)

• Only flush when absolutely necessary(3-7 gallons per flush), or install low-flow toilets• No marathon showers(3-7 gallons per

shower)• Close tub drain before filling bath tub(3 gallons per bath)

In The Kitchen:• Fill sink basin when washing and rinsing dishes( 8-15 gallons a day)• Run dishwasher only when full, and DON’T pre-wash dishes by hand(15 gallons per load)• Run washing machine only when full load to maximum capacity

(22-25 gallons per load)• Install low-flow faucet aerators which reduce flow by 25%

Dripping, trickling, or oozing faucets and showerheads can waste 75-300 gallons of water a week, depending on the size of the drip.Hidden leaks can be responsible for gigantic amounts of water wasted.• Read your water meter• Crush a dye tablet in toilet tank• Check for leaky hoses and sprinkler valves outside

• Water only during the cool parts of the day• Add compost to your soil to improve its water holding absorptive ability• Find and plant low-water turf• Raise your lawnmower blades• Water only as neededTrees and deep rooted plants longer and less often than grasses, flowers and vegetables• Choose plants that are indigenous to your area

• Remember the one-inch rule

St. Augustine Grass

Xeriscaping

• Use drip irrigation or soaker hoses with timing devices