Human Impact on the Hydrosphere

1. Human Impact on the Hydrosphere NCES for Earth Science/Environmental Created Fall 2012

2. The Population Problem • The world’s population is not distributed evenly over the land available.

3. The Population Problem • Currently, there are over 7 billion people living on Earth. • The United States currently has about 315 million people. • The most populous countries are China, India, the US, Indonesia, Brazil, Pakistan, Nigeria, Bangladesh, Russia and Japan.

4. Developed vs. Developing • A developed country is one that has…. • a highly developed economy • advanced technology • Birth rates tend to be low • people on average live longer.

5. Developed vs. Developing • A developing country is one that has… • no stable economic system • Birth rates tend to be very high, and • infant mortality is high as well • Not enough natural resources for all of the people. • serious problems with providing their citizens with access to clean water.

6. Developed vs Developing Developed Country Population Structure Developing Country Population Structure

7. Developing vs Developed

8. Clean Water – A Life Sustaining Liquid • Remember that freshwater makes up a very small fraction of all water available on Earth.

9. Clean Water – A Life Sustaining Liquid • The human body needs clean water to survive. Water is also necessary for growing/producing food, agriculture, cleaning and bathing, getting rid of waste.

10. Clean Water – A Life Sustaining Liquid • Clean water prevents diseases like cholera, diarrhea, spread by poor personal hygiene and cooking issues.

11. Clean Water – A Life Sustaining Liquid • Charitable organizations fundraise and bring the means to drill wells to needy areas. Clean Water

12. Wells • Wells are dug or drilled to tap into underground water. With a “dug” well it is hard to prevent contamination of the water.

13. Wells • Drilled wells are made into underground aquifers. These are lined, sealed, and do a much better job of keeping out microorganisms and chemicals. • Water is usually disinfected with bleach and filtered.

14. Problems with wells • Contamination by microorganisms or by chemicals. • Soil salination – as the water table drops, the salt in the soil dries out which can cause a problem for nearby vegetation.

15. Saltwater Intrusion – Coastal Issue • Saltwater is denser and has a higher water pressure than fresh water, so it can seep beneath the groundwater. • Agricultural and drainage channels can provide ways for salt water to intrude further.

16. Saltwater Intrusion – Coastal Issue • Agricultural and drainage channels can provide ways for salt water to intrude further.

17. Saltwater Intrusion – Coastal Issue • Many wells will draw down the water table and allow salt water to push further inland.

18. Dams and Dam Removal • Dams are used to provide drinking water, water for agriculture, generate hydroelectric power, and recreational opportunities. • Dams can also cause problems: • Flooding of natural habitats upstream • Fragmentation of migratory fish population • Sedimentation behind dam can cause there to be less water available for hydroelectric power

19. Dams • Negativeeffects: • reservoir is a breeding ground for disease causing insectslike mosquitoes. • Some people may lose their home to the area now covered by water. • Disrupts the natural flow of streams and rivers. This could cause flooding in different areas.

20. Dam Removal • Dam removal benefits • Avoid catastrophic dam failure • Benefit aquatic life and migratory fish • Restore downstream habitats • Restore the natural flow of streams and rivers

21. Water Conservation • Goals of water conservation • Sustainability: withdrawal of water should not exceed its natural replacement rate • Energy conservation: pumping and treating water takes a lot of energy • Habitat conservation • Reduce water consumption per capita – use water more efficiently and responsibly.

22. Municipal Programs • Restrictions on outdoor water use include: • No lawn watering • No car washing • Increasing cost with increasing use – tiered water rates

23. Agricultural Efforts at Conservation • Drip irrigationis more effective and less wasteful than other methods that have been used in the past.

24. Household Water Conservation Things we can do or use in our homes are: • Low flow toilets and shower heads • Wastewater reuse – catch water from shower as it as warming up and use it to water plants • High efficiency washing machines • Turn off water while brushing teeth • Only wash full loads of laundry and dishes • Use water barrels to collect rainwater to water plants.

25. Cisterns • Some places use cisterns to gather rain water for use in things like flushing toilets, irrigation or showers. • Parks and recreation areas are now using cisterns for landscaping and toilet flushing uses.