1. Environmental Sciences: Towards a Sustainable Future Chapter 7 Water: Hydrologic Cycle and Human Use

2. The Water Cycle Exists to Purify Water There are three principal loops in the water cycle. Human have managed to pollute or compromise the function of each loop. We are running out of water in terms of quantity and quality. Water conservation and stewardship are imperative actions.

3. Earth’s Water

4. Water Cycle Processes Evaporation: water molecules move from liquid to gaseous state; e.g. steam Condensation: water molecules move from gaseous to liquid or frozen state; e.g. water droplets on cold beverage container Purification: occurs as a result of evaporation and condensation; impurities are left behind

5. Condensation

6. Precipitation Adiabatic cooling: warm air rises, expands and cools 100% relative humidity + cooling = clouds Increasing condensation = water droplets

7. Global Precipitation Global precipitation distribution depends on patterns of rising and falling air currents Two main factors: global convection currents rain shadow effect

8. Rain Shadow Effect

9. The Water Cycle

10. A B C D E Water Cycle Filters Ground Water Loop Surface Runoff Loop Evapotranspiration Loop F G

11. A B C D E Water Cycle F G H

12. Human Impacts on the Water Cycle Changing the earth’s surface Pollution Withdrawal for use

13. Changing Earth’s Surface Through Urbanization Decreased infiltration Increased runoff

14. Water Pollution

15. Water Use

16. Consequences of Overdrawing Water Supplies Surface waters: shortages ecological effects

17. Water Use

18. Vanishing Wetlands

19. Chemical and Biological Values of Wetlands: Hydrological Cycle Purify waters Control floods Protect shorelines Recharge groundwater

20. Chemical and Biological Values of Wetlands: Chemical Cycles Nitrogen cycle Sulfur cycle Carbon cycle

21. Chemical and Biological Values of Wetlands: Increase Biodiversity Terrestrial ecosystems Aquatic ecosystems

22. Wetland Values - Economic Pelt and skin harvesting (alligator) Waterfowl hunting Sport and commercial fishing Timber harvesting (hardwood and cypress swamps) Energy source Food source

23. Wetland Values - Intrinsic Bird watching and wildlife photography Recreation (hiking, boating) Biological laboratory for students of all ages

24. Consequences of Overdrawing Groundwater: Falling water tables Diminishing surface waters (wetlands) Land subsidence Saltwater intrusion

25. Aquifer Exploitation

26. Sinkholes: YIKES!

27. Saltwater Anyone?

28. Using Less Water Irrigation Surge flow Drip irrigation $$$$ Municipal uses Incentives and regulations limiting water use Gray water

29. Desalting Seawater Reverse osmosis Distillation

30. Storm Water Mismanagement

31. Other Consequences of Storm Water Mismanagement Stream bank erosion Increased pollution Fertilizers Pesticides Pet fecal matter Road salts and chemicals Oil

32. Channelization: Solution or Problem? Stream bed was straightened and lined with rock or concrete Passed the problem of flooding downstream to your neighbors

33. Water Stewardship Working Together Louisiana Wetlands Conservation and Restoration Trust Fund $1.5 billion to restore LA wetlands