FRESHWATER SYSTEMS & RESOURCES

UNIT 5 AP- 1.3, 1.8, 4.6, 5.13, 8.1, 8.2, 8.5

Watershed (drainage basin)

Area of land drained by a river ystem (river and its tributaries)

Floodplains

warmer water, least amount of DO.

Riparian

situated on the banks of rivers

Lakes and Ponds

bodies of open, standing water.

Oligotrophic

low supply of plant nutrients, high oxygen conditions.

Glaciers and mountain streams

Low NPP, crystal clear water

Eutrophic

Sediment, organic material, and decomposing material form bottom sediments

Shallow murky or green water

High nutrient, low oxygen, high NPP

Freshwater

water that is relatively pure, with few dissolved salts—only 2.5% of total water

tied up in glaciers, ice caps, and aquifers

Surface water

water located atop earth’s surfaces

becomes groundwater through infiltration

Groundwater

water beneath the surface held in pores in soil of rock

becomes surface water through springs or human drilled wells

Aquifers

porous, sponge-like formations of rock, sand, or gravel that hold water

Zone of aeration

pore spaces partly filed with water

zone of saturation

spaces filled with water

water table

boundary between 2 zones

recharge zone

any area where water infiltrates Earth’s surface and reaches aquifers

saltwater intrusion

salt water intrudes in costal areas making water undrinkable

Flooding

normal, natural process where water spills over a river’s banks

spreading nutrient-rich sediments over large areas

Levees/dikes

Long, raised mounds of earth along the banks of rivers that hold water in chnnels

Advantages of using dams and reservoirs

• Cheap, constant electricity

• Reduces downstream flooding

• storing water year-round for irrigation and cities

• can provide recreational activities

disadvantages of dams and reservoirs

• displaces people

• disrupts aquatic ecosystems

• flooding can destroy surrounding forests and croplands

• large loss of water through evaporation

• reservoirs behind dams collected increased levels of silt and slow water flow

Desalination

removing dissolved salts

Distillation

evaporate water, leaving salts behind

Problems of desalination

• High cost and energy footprint

• Keeps down algal growth and kills many marine organisms

• Large quantity of brine waste

Improvements

• Desalination on offshore ships

  • Solar/wind energy

  • use ocean waves for power

• Build desalination plants near electric power plants

Reducing water use agriculture

• Line irrigation canals to prevent leaks

• Level fields to reduce runoff

• Low-pressure spray irrigation sprays water downward

• Drip irrigation systems target individual plants

• Match crops to land and climate

• Eliminate water subsidies

• Selective breeding and genetic modification to produce crops require less water

Reducing water use residental

• Install low-flow faucets, toilets

• Rainwater haversting= capturing rain from roofs

• Gray water= water water from showers and sinks hat can be used to water lawns

• Xeriscaping= using plants adapted to arid conditions

Water pollution

any chemical, biological, or physical change in water quality that had a harmful effect on living organisms and mae’s water unsuitable for desired uses

Point sources

Discharge pollutants at specific locations through drain pipes, ditches, or sewer lines

• Dumps into bodies of water OR surface water

• Easy to identify and monitor

  • Factories

  • Sewage treatment plants

  • Underground mines

  • Oil tankers

Nonpoint sources

• Broad, diffuse areas from which pollutants enter bodies of surface water OR air

• Poorly defined and scattered

  • Runoff of chemicals and sediments from cropland

  • livestock feedlots

  • logged forests

  • urban streets

  • parking lots

  • golf courses

Agricultural activities of water pollution

• LEADING CAUSE OF WATER POLLUTION

• Sediment eroded from agricultural lands is the largest source

  • Fertilizers

  • Pesticides

  • Livestock waste bacteria

  • food processing water bacteria

  • excess salt from soils or irrigated cropland

Industrial facilities and mining operations

• emit harmful inorganic and organic chemicals

• parking lots and roads (URBANIZATION)

• grease, toxic metals, and sediments

• disreupt water cycle by preventing rain from soaking into round

• use salt to lower freezing temp of water

• worsens local flooding and erosion

Pathogens and waterborne diseases

Viruses, protists, and bacteria

• Enter water supplies through nontreated human and animal waste from feedlots

Fecal coliform bacteria indicate fecal contamination

• Not pathogenic organisms

• may hold diseases causing typhoid, hepatitis

Types of water pollution

• Organic waste

• chemicals

• nutrients

• sediments

Organic wastes

Large quantities of organic compounds, act as substrates for microorganisms released into water sources

BOD- biochemical oxygen demand

• High BOD: high levels of anoxia, low DO

Inorganic chemicals

• Heavy metals

• acids from mine

• drainage

• acid rain

• road salts

Organic chemicals

• Petroleum

• pesticides

• industrial chemicals

• cleaning solvents and detergents

Sediments solutions

• better management of farms and forests

• avoid large-scale disturbance of vegetation.

Phosphorus

most common limiting factor

Nitrogen

Limiting factors in marine ecosystems

• fertilizers, causes excessive algae growth

• limiting factors for aquatic plants, high quantities in runoff

  • pet and wildlife wastes

  • sewage and farm animal wastes

  • fertilizers (farm, lawns, golf courses)

Cultural eutrophication steps

1. Fertilizers add phosphorus/nitrogen to water, which boost algal and aquatic plant growth.

2. Spreading algae cover the surface, decreasing sunlight

3. Bacteria eat dead algae, reducing dissolved oxygen, accumulation of detritus.

4. Suffocation, fish and shellfish die

What is cultural eutrophication

• areas of low oxygen become “dead zones”

• Wastewate solutions:

  • reducing fertilizer application

  • using phosphate-free detergents

  • planting vegetation to increase nutrient uptake

Ways to clean up lakes

• removal of weeds and excess plant growth

• pumping air into lakes and reservoirs to prevent oxygen depletion

Thermal pollution

• Water that is too warm causes problems

  • Warmer water holds less oxygen.

  • DO decreases as temp increases.

  • Industial cooling heats water.

  • Removing streamside cover raises water temp.

Cold thermal pollution

• Water at the bottom of reservoirs behind dams is colder

• When water is released, downstream water temps drop suddenly, favoring cold-loving invasive fish

Groundwater pollution

• flows slowly

• smaller populations of decomposing bacteria

• colder water

• less DO

  • fertilizers, pesticides, gasoline, organic solvents

Groundwater difficulties

• Hidden from view

• Difficult to monitor

• Doesn’t flow so it retains contaminants for decades and longer

• NO SUNLIGHT= NO DO

clean water act

1972 & 1977

• establishes the basic structure for regulating discharges of pollutants into their waters of the U.S.

• Set standards for allowed levels of certain pollutants in industrial wastewater

• Funded sewage treatment plans

• DOES NOT address groundwater pollution or drinking water

SAFE WATER DRINKING ACT

• 1974

• ENSURE SAFE DRINKING WATER FOR THE PUBLIC

• PUBLIC WELLS AND SYSTEMS ARE REGULATED

• SETS STANDARDS FOR DRINKING WATER QUALITY

• DOES NOT ADDRESS BOTTLED WATER
  FALLS UNDER FDA