Chapter 11 water 11.1 Water Resources 11.2 Water Use and Management 11.3 Water Pollution
Key Terms • Surface Water • River System • Watershed • Groundwater • Aquifer • Porosity • Permeability • Recharge Zone • Percolation • Infiltration • Precipitation • Transpiration • Evaporation • Condensation
11.1 Water Resources Objectives • Describe the distribution of Earth’s water resources • Explain why freshwater is one of Earth’s limited resources • Describe the distribution of Earth’s surface water • Describe the relationship between groundwater and surface water in a watershed
THE WATER CYCLE • Water is a renewable resource because it is circulated in the water cycle • The water cycle is the continuous movement of water between Earth and its atmosphere
THE WATER CYCLE • Precipitation results when condensation is occurring rapidly within a cloud • Rain is formed when cloud droplets in large numbers form into drops too large to remain suspended in air. • Sleet consists of pellets of ice, grown directly from the freezing of rain • Snow consists of masses of crystals of ice grown directly from water vapor of the air
WATER CYCLE CONTINUED • Infiltration is when the precipitation enters the soil • Percolation is the downward flow of water by gravity through soil into ground water zone • Runoff is water flowing over land to oceans • Transpiration is discharge of water vapor from plants • Evaporation is change of water into water vapor by solar energy
GLOBAL WATER DISTRIBUTION • 97% of Earth’s water is salt water • Of the 3% freshwater 77% is frozen • Evaporation from ocean surfaces totals 109,000 cu. mi/yr. Evap. From soils, plants, & water totals 15,000 cu. mi/yr • Precipitation is 98,000 cu. mi/yr on oceans and 26,000 cu. mi/yr over continents • The excess 11,000 is what we may use
SURFACE WATER • Surface water is the freshwater on Earth’s land surface. It is found in lakes, rivers, streams, and wetlands. • As streams and rivers move across the land, they form a flowing network of water called a river system. • WATER SHED-The area of land that is drained by a river is known as a water shed.
GROUND WATER • Most of the freshwater that is available for human use exists underground. It’s stored in sediment and rock formations and is called groundwater. A formation underground that contains groundwater is an aquifer. • The water table is the level or upper boundary of the zone of saturation of water in an aquifer. Most aquifers consist of rock, sand, & gravel that have lots of spaces to store water.
GROUND WATER CONTINUED • Rocks appear solid, however many kinds of rocks contain small holes or pore spaces. Porosity is the amount of space in rocks. • Permeability is the ability of a substance to allow water to flow through it. • Materials such as gravel that allow the flow of water are permeable. • Materials such as clay or granite that stop the flow of water are impermeable.
GROUND WATER CONTINUED • The recharge zone is the area of the Earth’s surface where water percolates into the aquifer. A hole that is dug or drilled to reach the groundwater is called a well. • Groundwater may be a more reliable source of water than surface water because it is filtered and purified as it travels underground.
11.2 KEY TERMS • Potable • Pathogen • Irrigation • Dam • Reservoir • Desalination
11.2 Water Use and Management Objectives • 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, industry, and agriculture • Describe how dams and water diversion projects are used to manage freshwater resources
GLOBAL WATER USE The three major uses for water are residential use, agricultural use and industrial use. Most of the fresh water used worldwide is used in agriculture to irrigate crops.
RESIDENTIAL WATER USE • The average person in the United States uses about 300L or 80 gal. of water every day. • In India, the average person uses only of water every day.
WATER TREATMENT • Potable means water that is safe to drink. • Water treatment removes elements such as mercury, arsenic, and lead which are poisonous to humans. Water treatment also removes pathogens, which are organisms that cause illness or disease. • Bacteria, viruses, protozoa, and parasitic worms are common pathogens.
WATER TREATMENT PROCESS 1st-The first filtration removes the large organisms and trash. 2nd-Coagulation is where alum is rapidly mixed into the water and forms sticky globs called flocs. Bacteria attaches to the flocs. 3rd- During the second filtration layers of sand, gravel, and hard coal filter remaining impurity. 4th-During chlorination, chlorine is added to prevent bacteria from growing in the water.
WATER TREATMENT PROCESS 5th- Aeration is the process where air is forced through the water to release unwanted gases, which reduces odor and improves the taste. 6th- In some communities fluoride may be added to prevent tooth decay. Sodium compounds may be added to soften the hard water.
INDUSTRIAL WATER USE • Industry accounts for 19% of water used in the world. • Water is used to manufacture goods, to dispose of wastes, and to generate power. For example around 500,000 L of water are needed to manufacture a car.
AGRICULTURAL WATER USE • It takes nearly 300 L or 80 gal. of water to produce one ear of corn. The same amount of water that a typical U.S. citizen uses per day. • Agriculture accounts for 67% of the water used in the world. • Where rainfall is inadequate extra water can be supplied. • Irrigation is a method of providing extra water.
WATER MANAGEMENT PROJECTS Water management projects, such as dams and water diversion canals, are designed to distribute water to areas where surface water is inadequate. In some dry areas all or part of a river can be diverted into canals. For example the Colorado River is diverted to provide water for 7 SW states. It begins as a glacial stream in the Rocky Mt.’s and flows into the Gulf of California, but in some years it is dry before reaching the gulf.
DAMS AND RESERVOIRS • A dam is a structure built across a river to control a river’s flow. After a river is dammed, an artificial lake or reservoir, is formed. • These reservoirs can be used for flood control, drinking water, irrigation, recreation, electrical power, and industry. • When a river is dammed the land is flooded, people are displaced, ecosystems are destroyed and animals loose their habitats.
WATER CONSERVATION Most water loss in agriculture comes from evaporation, seepage, and runoff. Drip Irrigation Systems offer a solution to conserving water. This system delivers small amounts of water directly to plant roots by using perforated tubing.
WATER CONSERVATION CONT. Many industries use recycling of cooling water and wastewater to conserve water lower costs. In homes water-saving technologies like low-flowtoilets and shower heads help reduce water use Some communities only allow watering at night. Xeriscaping is a technique where only native plants are used in landscaping.
WATER CONSERVATION CONT. Desalination is used by some coastal communities which remove salt from saltwater to provide freshwater. Some areas such as Greece transport water by ships into their countries.
11.3 KEY TERMS • Water Pollution • Point-source pollution • Non-point source pollution • Wastewater • Artificial eutrophication • Thermal pollution • Biomagnification
11.3 OBJECTIVES • Compare point-source pollution and non-point source pollution • Classify water pollutants by 5 types • Explain why groundwater is difficult to clean • Describe the major sources of ocean pollution, and explain the effects of pollution on the ecosystems • Describe 6 major laws designed to improve water quality in the United States
WATER POLLUTION • Water pollution is the introduction of chemical, physical, or biological agents into water that degrade water quality and adversely effect the organisms that depend on the water. • The two main causes are industrialization and rapid human population growth.
POINT AND NON-POINT SOURCE POLLUTION *Point-source pollution is pollution dischage from a single source. *Non-point source pollution comes from many different sources that are often difficult to identify.
WASTEWATER • Wastewater is water that contains wastes from home or industry. • Most of the wastewater from homes contains biodegradable material that can be broken down by living organisms. • Sewage sludge is the solid material that remains after treatment. Sludge is often incinerated the ashes buried in a secure landfill. Some sludge is hazardous waste and some if not toxic is used as a fertilizer.
ARTIFICIAL EUTRPHICATION • When lakes and slow-moving streams contain an abundance of nutrients, they are eutrophic (yoo TRUH fik). Eutrophication is a natural process, when organic matter builds up in a body of water, it will begin to decay. • Decomposition uses up oxygen. Eventually plants take root in the nutrient-rich sediment at the bottom. Then it becomes a swamp or marsh • Artificial eutrophication is caused by humans adding fertilizers to farms, lawns, and gardens.
ARTIFICIAL EUTROPHICATION • Algal blooms are large floating mats of algae. As the algae die and decompose, most of the dissolved oxygen is used up and fish and other organisms suffocate and die.
THERMAL & GROUNDWATER POLLUTION • When the temperature of a body of water, such as a lake or stream, increases, thermal pollution can result. Increase in temp./decrease in O2. • Pollution on Earth’s surface like pesticides, herbicides, chemical fertilizers, & petroleum products may be picked up by precipitation and then percolate into the groundwater. • Leaking underground storage tanks also are a source of groundwater pollution.
OCEAN POLLUTION • Pollutants are often dumped directly into the oceans. Ships can legally dump wastewater and garbage overboard. • 85% of ocean pollution comes from the land. • About 37 million gal. of oil from tanker spills enter the ocean each year. • Each year, as many as 200 to 300 million gal. of oil enter the ocean from non-point sources on land.
WATER POLLUTION AND ECOSYSTEMS • Biomagnification occurs as accumulation of pollutants at successive levels of the food chain builds up in the organisms.