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. 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

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!!!