Bi 105a environmental biology
This presentation is the property of its rightful owner.
Sponsored Links
1 / 22

BI 105A Environmental Biology PowerPoint PPT Presentation


  • 82 Views
  • Uploaded on
  • Presentation posted in: General

BI 105A Environmental Biology. Professor Jill Nissen Montgomery College Fall 2006. Water: A Limited Resource. Chapter 14. Why study water?. We depend on water for our survival and convenience Drinking Cooking Washing Travel over water Agriculture

Download Presentation

BI 105A Environmental Biology

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Bi 105a environmental biology

BI 105AEnvironmental Biology

Professor Jill Nissen

Montgomery College

Fall 2006


Water a limited resource

Water: A Limited Resource

Chapter 14


Why study water

Why study water?

  • We depend on water for our survival and convenience

    • Drinking

    • Cooking

    • Washing

    • Travel over water

    • Agriculture

      • Irrigation accounts for the greatest percentage of the world’s water usage (71%)

    • Manufacturing

    • Mining

    • Energy production

    • Waste disposal


Water supply on earth

Water Supply on Earth

  • Water covers ¾ of the Earth’s surface, but

    • 97.5% of water is saltwater

    • Most of the fresh water is frozen (ice caps and glaciers)

    • Less than 1% of water is available for humans

    • The available fresh water is distributed unevenly, leading to regional water supply problems


Water terms

Water Terms

  • Surface Water

    • Fresh water in streams, rivers, lakes, ponds, reservoirs, and wetlands:

      • Areas of land that are covered with water all or part of the year

    • Replenished by runoff:

      • The movement of fresh water from precipitation and snow melt to rivers, lakes, wetlands, and ultimately, the ocean


Water terms con t

Water Terms (con’t)

  • Watershed (also called a drainage basin)

    • The area of land drained by a single river or river system

  • Groundwater

    • The supply of fresh water under Earth’s surface stored in aquifers:

      • Underground caverns and porous layers of sand, gravel, or rock in which ground water is stored

  • Water Table

    • The upper surface of the saturated zone of groundwater


Water resource problems

Water Resource Problems

  • Too much water

  • Too little water

  • Poor water quality (Chapter 22)


Too much water

Too much water

  • Flood plains are areas bordering a river that are subject to flooding

  • Humans have caused increased flooding and damage by flooding by removing plant cover and developing along flood plains


Too little water

Too Little Water

  • Approximately 40% of the worlds population lives in arid or semiarid lands, primarily Asia and Africa

  • Population growth intensifies the problem:

  • More food = more irrigation, more grazing


Overdrawing surface waters

Overdrawing Surface Waters

  • When surface water is overdrawn (greater than 30%), the organisms in fresh water ecosystems suffer, wetlands dry up, and estuaries become saltier


Aquifer depletion

Aquifer Depletion

  • Aquifer depletion is the removal of more groundwater than can be replenished by precipitation or snow melt

    • Lowers the water table

    • Drains the aquifer dry, loss of water source

    • Leads to

      • Subsidence

      • Sink holes

      • Saltwater intrusion


Saltwater intrusion

Saltwater Intrusion

  • Saltwater intrusion is the movement of seawater into a freshwater aquifer located near the coast; caused by aquifer depletion

  • The result is water that is unfit to drink


Salinization

Salinization

  • Salinization is the gradual accumulation of salt in the soil; usually caused by improper irrigation

  • The result is decreased soil productivity


Water problems in the u s

Water Problems in the U.S.

  • Mono Lake

    • Surface water diverted to Los Angeles had lowered water level and increased salinity

    • In 1994, the state of CA required the L.A. Department of Water and Power to reduce water export by 20%

  • The Colorado River Basin

    • Population growth in Colorado, Utah, and Wyoming threatens the regions water supply

    • The water available for Mexico is insufficient

  • The Ogallala Aquifer

    • This is the largest groundwater deposit in the world, but farmers are drawing water from it 40 times faster than nature can replenish it


Water management

Water Management

  • Providing a Sustainable Water Supply

  • Sustainable water use seeks to provide water to future generations without damaging ecosystems.


Dams and reservoirs

Dams and Reservoirs

  • Dams and Reservoirs

    • most dams are designed to form reservoirs from which the flow can be regulated

    • Benefits

      • Ensure a year round supply of fresh water for human use

      • Control floods in downstream areas

      • Generate electricity (renewable energy source)

    • Drawbacks

      • Alter the quantity and quality of water upstream and downstream of dam, leading to habitat degradation or destruction

      • Interfere with fish migration


Water recycling

Water Recycling

  • Water recycling, also known as water reclamation or water reuse, is reusing treated wastewater for beneficial purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, and replenishing a ground water basin.

  • Source: http://www.epa.gov/region9/water/recycling/


Environmental benefits of water recycling

Environmental Benefits ofWater Recycling

  • Decreases diversion of freshwater from sensitive ecosystems (e.g., Mono Lake)

  • Decreases discharge to sensitive water bodies

  • Can be used to create or enhance wetlands and riparian (stream) habitats

  • When used for agriculture, naturally stimulates production which reduces fertilizer use

  • Source: http://www.epa.gov/region9/water/recycling/


Reducing water waste

Reducing Water Waste

  • Techniques for reducing agricultural water waste

    • Microirrigation (=trickle irrigation)

    • Planting level fields

    • Scheduling irrigation according to rainfall and soil moisture

    • Using reclaimed water for irrigation

  • Techniques for reducing industrial water waste

    • Recycling water

    • Implementing stricter pollution control laws


Reducing water waste1

Reducing Water Waste

  • Techniques for reducing water waste in homes and buildings

    • Educating consumers in water conservation methods

    • Using water-saving fixtures

      • http://www.h2ouniversity.org/html/library_conserve_bathroom.html

    • Developing economic incentives to save water

    • Charging for water according to usage

    • Charging what the water actually costs


Water facts

Water Facts

  • The average household uses 350 gallons of water per day, or 127,400 gallons per year

    • If all U.S. households installed water-saving fixtures, water use would decrease by 30 percent, saving an estimated 5.4 billion gallons per day.

    • This would result in dollar-volume savings of $11.3 million per day or more than $4 billion per year!

  • More than 50% of household water is used outdoors to maintain the lawn!

    • Xeriscaping is a method of landscaping with rocks and plants that need very little water.

    • Traditional landscaping requires large amounts of water, fertilizer, and pesticides - Time and Money!

  • Source: http://www.co.kane.il.us/kcstorm/waterfacts.htm


Review objectives

Review Objectives

The Importance of Water• Describe surface water and groundwater, using the following terms in your descriptions: wetland, runoff, drainage basin, aquifer, and water table.

Water Use and Resource Problems• Describe the role of irrigation in world water consumption.• Define flood plain and explain how humans exacerbate flood damage.• Relate some of the problems caused by overdrawing surface water, aquifer depletion (including saltwater intrusion), and salinization of irrigated soil.

Water Problems in the United States• Relate the background for each of the following U.S. water problems: Mono Lake, the Colorado River Basin, and the Ogallala Aquifer.• Define reclaimed water.

Water Management• Define sustainable water use.• Contrast the benefits and drawbacks of dams and reservoirs.

Water Conservation• Give examples of water conservation by agriculture (including microirrigation), industry, and individual homes and buildings.


  • Login