Exam 3: Water Quality

Water quality

freedom from waterborne diseases and hazards

water supply (quantity)

adequate amount/availability of water

chlorination

one of the greatest public health achievements of the 20th century

Xeriscaping

the practice of designing landscapes to reduce or eliminate the need for irrigation.

• Means xeriscaped landscaped need little or no water beyond what the natural climate provides

• embraced in dry regions of the western US

Hydrology

the study of water including its movement and distribution

Source water

untreated water used to produce drinking water

finished water

water delivered through a distribution system for human use after treatment, if provided

Clean Water Act (1970)

regulates pollutant discharges into the waters

Safe Drinking Water Act (1974)

authorizes EPA to establish minimum standards to protect tap water

surface water

water found on Earth’s surface, such as rivers, lakes, and reservoirs

groundwater

water stored naturally underground

aquifer

a layer or section of Earth that contains water and supplies springs and wells

watershed

an area of land where streams and rivers drain into one larger body of water

stormwater runoff

rainwater or snowmelt that flows over land or paved surfaces instead of soaking into the ground

• generated when precipitation from rain and snowmelt events flows over land or impervious surfaces (paved streets, parking lots, and building rooftops) and does not percolate into the ground

• potential for pollutants from these sources to runoff into water supplies

renewable water

freshwater replenished by the hydrological cycle within a reasonable time

nonrenewable water

water that is not replenished, or is replenished so slowly that significant use can deplete the supply

Water stress

when the demand for fresh water exceeds the available renewable supply during a specific period, or when poor water quality restricts its safe use

• annual supply of renewable freshwater is between 1,000 and 1,700 cm3 per person

Water scarcity

occurs when a country’s annual supply of renewable freshwater is less than 1,000 cubic meters per person

Water use in the US

• average person uses about 100 gallons (about 400 liters) of water per day

• most household water (50-70%) is used for outdoor purposes such as watering lawns and washing cars

• water required in immense quantities for agriculture and industry

stormwater runoff pollution prevention

proper disposal of household hazardous waste, yard waste (including pet waste), and cooking grease; making simple lawn care choices; maintaining cars and driveways properly; and do not litter, volunteer for clean-ups and other events

Wastewater management

efforts that promote responsible water use, treatment, and disposal and encourage the protection of watersheds