Tapping groundwater – problems

• Saltwater Intrusion–Normal interface between

freshwater and saltwater moves inland

–Figure 15-17

• Subsidence:–Land sinks

• Sinkholes–Roof of cavern

collapses

Reducing Water Waste

Why do we really waste so much?

• Underpricing! We don’t really pay for it!!!!

Conventional Irrigation

• “About 60% of the irrigation water applied throughout the world does not reach targeted crops.”–Most lost to evaporation and

run-off

Examples:

• Flood irrigation:

• Conventional spray irrigation:

More efficient irrigation technologies include:

Center Pivot

LEPA: Low Energy Precision Application

Drip Irrigation, Microirrigation

Other ways to reduce water waste:

Xeriscaping

• Replace green lawns with vegetation adapted to the climate! (natural)

Gray Water System

Using storm run-off

This storm water system will reduce the building’s water bill by 90% and save water

resources

• In the U.S.: Flushing toilets with water clean enough to drink is the single largest use of domestic water.

Solution: Desalinization??

– Reverse osmosis or Distillation

–Disadvantages: •Expensive

•Energy Intensive

•Produces Briny Water

Water Pollution

Major Categories: Table 22-1

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Point Source: discharge pollutants at specific locations

• Non-Point Source: scattered and diffuse; can not be traced to any single point.

–The leading Non-Point Source of water pollution:

Eutrophication: Natural nutrient enrichment

• Cultural Eutrophication: excessive inputs of nutrients due to human activities.

• What are NUTRIENTS????

–Produce “blooms” of algae, cyanobacteria, or aquatic plants

–Initially, produce Oxygen; however, massive die-offs and decomposition via bacteria sucks OUT all Oxygen

–Ecosystem suffocates!!

• Animal wastes• Fertilizer run-off (agricultural

and domestic)• Sewage

–80-90% of raw sewage in developing countries dumped directly into lakes/streams

–Approx. 85% of raw sewage from people around Mediterranean Sea dumped along the coast

1.3 billion tons of animal waste produced in the U.S.

Pollution strength up to 160 times greater than raw municipal waste.Animal wastes contribute to large

oceanic “dead zones,” which extended to nearly 7,903 sq. miles

in the Gulf of Mexico during Summer of 2007.

Dead Zones

• Oxygen Depleted Zones

• Also known as Hypoxic or Anoxic conditions

• HAB’s: harmful aglal blooms–Red, green, or brown TOXIC

tides

A few of the world’s dead zones…

Water Quality Parameters

Fecal Coliform Colonies

Measuring Turbidity using aSecchi Disc