Chapter 11 Water

The Water Cycle Plants absorb water through roots. Plants lose water through transpiration. Moisture also evaporates from bodies of water and forms clouds during condensation. Water returns to earth through precipitation. Runoff water flows into lakes, etc. Water enters the soil and is filtered and becomes part of the groundwater. Some is absorbed by plants.

The Water Cycle Condensation Precipitation Evaporation Transpiration Runoff Seepage Root Uptake

Global Water Distribution

Surface Water: fresh water on Earth’s land surface Includes lakes, rivers, streams, wetlands Used for drinking water, growing crops, food such as fish, power, and transportation

River Systems Flowing network of rivers and streams Mississippi, Amazon (largest), and Nile are large river systems because they collect water from vast areas of land

Watersheds (Area of land drained by a river.) *Mississippi – largest in U.S.

Groundwater Water beneath Earth’s surface in sediment and rock “water table” : level where rocks and soil are saturated with water

Aquifers body of rock or sediment that stores groundwater—very important for cities and agriculture Most consist of rock, sand, and gravel, etc. that have a lot of spaces where water can accumulate. Groundwater can also dissolve rock formations creating caves with water and underground lakes

Major Aquifers of Georgia 1,2,3 – Floridan aquifer 4. Claiborne, Clayton, Providence aquifers 5. Cretaceous Aquifer

Porosity % of the total volume of a rock or sediment that consists of open spaces Water in an aquifer is stored in the pore spaces and flows form one pore space to another. The more porous a rock is, the more water it can hold.

Permeability ability of a rock or sediment to let fluids pass through its open spaces or pores. 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. The most productive aquifers usually form in permeable materials, such as sandstone, limestone, or layers of sand and gravel.

The Recharge Zone

The Recharge Zone An area in which water travels downward to become part of an aquifer. environmentally sensitive to pollution size of zone is affected by the permeability of the surface above the aquifer—buildings & parking lots may reduce the amt of water entering aquifer Aquifers can take thousands of years to recharge

Wells We dig wells because water is filtered and purified as it travels underground. The height of the water table changes seasonally, so wells are drilled to extend below the water table.

Wells con’t. If the water tables falls below the bottom of the well during a drought, the well will dry up. In addition, if groundwater is removed faster than it is recharged, the water table may fall below the bottom of a well. To continue supplying water, the well must be drilled deeper.

Section 2 Water Use and Management

Global Water Use Patterns of water use are not the same everywhere. The availability of fresh water, population, sizes, and economic conditions affect how people used water. Most of the fresh water used worldwide is for agriculture. 8% is used by households for drinking and washing.

There are 3 major uses for water: residential, industrial, and agricultural.

Residential Use Differences in residential water use in the world: US average person uses 300 L (80 gal) a day, India it is only 41 L. In the U.S., only about half of residential water use is for activities inside the home, such as drinking and cooking. The remainder of the water used residentially is used for activities outside the home such as watering lawns.

Residential Water Use

Drinking Water Treatment

Not harmful to others or environment Water IN OUT Potable Taste good No pathogens Wastes carried away No stinking Not harmful to others or environment

Drinking water treatment Coagulation Alum is added Flocs formed Bacteria and stuff cling to flocs and sink

Drinking water treatment Sedimentation Flocs settle to the bottom Water skimmed from top

Filtration Layers of sand, gravel, and hard coal filter out impurities

Disinfection Chlorine is added to kill bacteria

Aeration Air forced in Removes gases Reduces odor Improves taste

Additional treatment Add fluoride Sodium cpds or lime to soften hard water Acids or bases to neutralize Then to storage

Industrial Water Use 19% of water use in the world Used for: a. manufacturing goods b. disposing of waste c. generating power. Most of the industrial water use is used to cool power plants.

Agricultural Water Use 67% of water use in world 80% of the water used in agriculture evaporates before it reaches the plant Irrigation supplies water in areas with inadequate rainfall Irrigation may involve: a. shallow, water-filled ditches b. high-pressure overhead sprinklers

Water Management Projects Projects designed to bring water to areas with inadequate water supplies: a. aqueducts (early form) b. dams c. water diversion canals

Goals for water management projects: a. bringing water to make a dry area habitable b. creating a reservoir for recreation or drinking water c. generating electric power

Diversion Projects: Rivers may be diverted to into canals to carry needed water to an area Ex. Colorado River supplies water for irrigation and drinking in AZ, UT, and CA

Dams Built to control a river’s flow. Artificial lakes or reservoirs are formed behind the dam. Reservoir water is used for: a. drinking water b. irrigation c. recreation d. flood control e. industry f. hydroelectric dams for producing electric energy (produces 20% of our energy)

Water Conservation Agriculture: a. drip irrigation systems- deliver small amounts of water directly to roots through perforated tubing. Industry: a. recycling of cooling water and waste- water. b. In some areas, small businesses are paid to conserve water.

Water Conservation con’t. Homes: a. Water-saving technologies such as low- flow toilets and shower heads b. New buildings may be required to install these new technologies. People in older buildings may be paid to install them. c. Water lawn at night to reduce water loss from evaporation. d. xeriscaping- designing landscape that requires minimal water use.

Future Solutions Desalination- removing salt from salt water. Mostly used in Middle East at the present. Transporting Water- a. Ships towing bags of freshwater to needed areas. Ex. Greek Islands b. Some have considered towing icebergs to areas that need freshwater, but an efficient means to do so has not been discovered.

Section 3 Water Pollution

Point and Non-Point Pollution Sources- pgs 304-305

Principal Water Pollutants-pg. 306

Wastewater Treatment Water travels from homes, businesses, etc through sewage pipes to a wastewater treatment plant where it is treated and filtered and then returned to a river, creek, lake, etc. Diagram on pg. 307

Wastewater Treatment Process

Where does it go?

Waste water treat-ment

Sewage Sluge Solid material left after treatment Toxic & disposed of as hazardous waste Often burned and ashes buried in landfill If toxicity reduced, then may be used as fertilizer or to make brick for buildings

Eutrophication Caused by an abundance of nutrients. Natural process that may be accelerated by an increase in phosphorus and nitrogen from sewage and fertilizer runoff.

Thermal Pollution Occurs when the temperature of pond or lake increases. May be caused by power plants and other industries dumping warm water into lakes and ponds. Warmer water holds less oxygen and as the amount decreases aquatic organisms may suffocate and die.

Groundwater Pollution Occurs when polluted surface water percolates down through the Earth’s surface. Sources: 1)pesticides, herbicides, fertilizers and petroleum products 2) leaking underground storage tanks 3) septic tanks, unlined landfills, industrial wastewater lagoons

Groundwater Pollution

Ocean Pollution 85% comes from land activities. Examples of pollutants: oil, toxic wastes, medical wastes Sensitive coastal ecosystems, such as coral reefs and estuaries, are the most affected. Oil spills from tankers only accounts for 5% of ocean pollution. The majority of oil pollution in oceans comes from cities and towns.

Oil Spills

Biomagnification Causes Accumulation of toxins in the food chain. Pollutants can move up the food chain. predators eat contaminated prey pollution accumulates at each stage of the food chain Top consumers, including humans, are most affected.

Biomagnification