Water

1. Water EB Lecture 11 2008 Spring

2. Agenda • Understand freshwater systems • Use of water • Depletion of water • Water Pollution • Marine water • Ocean Impact • Marine Conservation

3. Case Study 1 Aral Sea

4. Aral Sea • Location: Asia • Type: Freshwater • Issue: Overuse • What was the fourth biggest inland sea is now mostly desert

6. Too much use • Soviet Union diverted two rivers which fed the Aral Sea • to grow cotton in the desert • However, they created an ecological and human disaster • Disease and cancer are rife in the population. • 60,000 fishing jobs are gone • Cotton fields are down • The fresh water is contaminated with salt

7. Case Study 2 Colorado River

8. Colorado River

9. Nevade • Southern Nevada gets nearly 90 percent of its water supply from the Colorado River. • The river begins as snowmelt in the Rocky Mountains. • The snowmelt travels through a series of tributaries into the river, which winds its way south for 1,400 miles and empties into the Gulf of California

10. Seven States • The Colorado River is one of the most controlled and litigated rivers in the world. • Seven western states and Mexico share the water, which serves about 25 million people • The river is divided among Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming according to a 1922 Colorado River Compact.

11. Where is my water? • Most times not a single drop empties into the Gulf of Mexico. • Every drop is used now. • What of the future? • Disputes have already started. • What alternatives exist?

12. Freshwater Systems

13. Two types of water • Fresh water - low in minerals • Sea water - high in salt and other minerals • How much of each type is there on Earth?

15. Hydrologic Cycle • Water circulates between the different sources • Constantly moving physical and organic elements • Key to life

16. Rivers and Streams • These begin life from • Rainfall • Snowmelt • Springs • Tributaries flow into each other and then rivers, then to either lakes or oceans • Key in spreading silt - vital for organic life • Floodplains also receive silt.

17. Lakes and Ponds • Bodies of standing water • Demarcation to; • Littoral zone - where plant life grows to emerge from water • Benthic zone - bottom surface • Limnetic zone - where light penetrates • Profundal zone - no light - it is dark!

18. Marshes, Swamps, Bogs • Mix of dryland and freshwater = wetlands • Marsh • Shallow water covering • Swamp • As marsh but with forests • Bog • Water covered with thick vegetative mats

20. Wetlands • Extremely important • Buffers • Pollution controls • Over 50% of US wetlands are gone! • Most made into farmland, or • developments

21. Groundwater • Water not sequestered elsewhere will percolate into the ground to form groundwater • Aquifers - porous rocks containing water • Water table - boundary between water saturated rock and layer above.

22. Groundwater • Fresh water • Slow to form • Most aged at 1,400 years • Large deposits • Ogallala Aquifer - largest in the world • Reduced by 10%

23. Water distribution is uneven • Different regions have differing rainfall • Differing groundwater • Differing surface water • Some regions have more water than other per head • Most in Hawaii • Least in Chile

24. Water Usage

25. We depend on water • 70% for agriculture • 20% for industry • 10% for residential and municipal use • Consumptive use - not returned • Non-consumptive use - returned

26. I’ll be DAMMED • Humans have erected dams on nearly every water way in the world. • Why? • Drinking water • Irrigation • Hydroelectric energy • Colorado River extensively dammed.

27. Water ‘mining’ • Extraction of water faster than replacement is leading to problems • Subsidence • Falling water tables • Salt water intrusion • Drying wetlands

28. Water Wars • As water becomes limiting there will likely be conflict • Middle East - started • Even current treaties such as India and Pakistan will be faces with strains as the demand for clean fresh water increases

29. Water woes • One can • Ship it in - from other places • Make it - from sea water - desalination • Expensive and energy intensive • Reverse osmosis • Filtration • Distillation

30. Solutions • Reduce demand • Better irrigation - drip irrigation • Match plants to region • Genetically improve plants • Reduce amount of meat eaten! • Increase supply • From where?

31. Water Pollution

32. Water Quality • Amount is one aspect • The other is quality • Polluted water has a cost • Disease • Poisonous

33. Point source pollution • Point source pollution comes from a single defined source - factors • Non-point source pollution comes from multiple sources • Farm runoff • Fertilizer use • Winter salting • Oil leaks • Animal waste

34. Eutrophication • Fresh water can suffer from this too • Phosphorus causes issues of overgrowth • Hypoxia results from bacterial activity • Biological pollution is the major issue • Contaminated water - from sewage • Spinach anyone???????

35. Toxic outcomes • Heavy metals in water • Acid rain • Water erosion • Sediment release • Temperature pollution • Water treatment facilities

36. Marine Systems • Complex interactions exist.

37. Human Impact

38. On the Oceans • Nets • Plastics • Oil • Nutrients • Red tides

39. Overfishing • On the brink • Over fishing • Smaller fish • Younger fish • Non-target kills • Market driven fisheries management

40. Help is coming • From the UN • From each country • From the community • MPAs • Marine Reserves • Data suggests that they may work!!!