Teaching the “Broken” Water Cycle: A Reality Check

1. Teaching the “Broken” Water Cycle: A Reality Check Cornelia Harris & Kim Notin harrisc@caryinstitute.org ; notink@caryinstitute.org

2. Research & Education based on Ecosystem Ecology

3. The water cycle in textbooks

4. Does this help students analyze their water cycle?

5. How do you think the local water cycle has been altered (or “broken”)?

6. We have changed nearly all of the links in the water cycle

7. Why are forested streamflows lower in the summer?

8. Changes in evaporation and transpiration • Transpiration is often overlooked in importance • About half of rain and snow that falls on the Hudson Valley is evaporated or transpired before it reaches the sea • A mature tree transpires ~50 gallons of water a day in the summer Investigation: stomata slides & bags on trees

9. Output - transpiration Input from stem Use - water is used in the plant for photosynthesis and movement of important elements Water Budget of a Leaf

11. Changes in evaporation and transpiration • Modifying vegetation can have huge effects on streamflow

12. Changes in evaporation and transpiration • Half of the 800 trillion gallons of water used each year in irrigation is “lost” to the air

13. Deforestation & Transpiration 2000: Rondonia region of western Brazil, images from NASA

14. Deforestation & Transpiration 2008: Rondonia region of western Brazil, images from NASA

15. Borneo UNEP

16. Reduced Infiltration • Impermeable surfaces have large impact • Other changes to the land surface affect infiltration (plowing, loss of leaf litter, etc.)

17. Reduced Infiltration Baltimore Ecosystem Study

19. Water quality is also affected by decreased infiltration

20. Investigation: infiltration rates Where does the rain in your schoolyard go?

21. Or in your neighborhood?

22.  Permeable  Impermeable “Runoff Worksheet”

23. “Runoff Worksheet”

24. Increased runoff • ~1 million dams around the world • Dams double the time it takes for stream water to reach the sea • Dams hold back ¼ of the sediment from reaching the sea How many dams exist around the world?

25. Lack of sediment accumulation has severe consequences for wetlands and the mainland After Katrina www.edf.org Wetlands around New Orleans, Louisiana Before Katrina NASA

26. Dams often make grotesque patterns of water flow

27. Dams in the Hudson River Watershed Source: Swaney et.al 2006 Dams of New York http://www.dec.ny.gov/pubs/42978.html

28. Normal Water Flow Has Been Obstructed by Dams

29. Several of the world’s great rivers no longer reach the sea Lake Powell Glen Canyon Dam Grand Canyon • Nile (6X as much flow as the Hudson) • Colorado (0.9X) • Murray-Darling (0.7X) • Yellow (2.3X) • Ganges-Brahmaputra (59X) Hoover Dam Lake Mead Gulf of California http://visibleearth.nasa.gov

30. Other ecological effects of dams • Block migratory species • May release water that is low in temperature and oxygen • Alter habitat up- and downstream of the dam

31. Agricultural Water Use Irrigation is the major consumptive use of water in most parts of the world = 80% of all water consumed in North America Cost generally low since withdrawals are subsidized

32. Groundwater depletion • Happening around the world in arid and semiarid areas • Declines can be rapid and dramatic • Dries up springs and small streams

33. Ogallala Aquifer • Before 1940s, water couldn’t be accessed if it was below 70-80 feet • Technology allowed wells to extract water from more then 3,000 feet • By 1990, sixteen million acres of the high plains were irrigated with water from Ogallala • Some areas: more than 150 foot declines www.unwater.org

35. 3rd UN World Water Development Report, 2009

36. Humans even alter precipitation! • Humans affect fog water inputs • Air pollution may affect rainfall amounts • Water quality (“acid rain”)

37. Moving water across watersheds • Water doesn’t cross watershed boundaries in a textbook, but it does in the real world • New York City (390 billion gallons/yr) • Chicago (600 billion gallons/yr) • Common for irrigation and cities globally • This translocated water can move species around

38. Moving water across watersheds in bottles • 1978: 415 million gallons • 2001: 5.4 billion gallons (43 billion sixteen-ounce bottles)... An increase of 1300%

39. Water ‘Footprint’ 3rd UN World Water Development Report, 2009

40. Opportunities to teach the real water cycle • Humans materially affect the water cycle • You are connected to the water cycle (and affect it) • Where does your drinking water come from? • Where does your sewage go? • How do local activities (even on the school grounds) affect the water cycle? • Are there concerns with how the water cycle is treated locally? • If so, how could the community do better?

41. Conclusions from these lessons • The cycle is a “messy web” and humans have large effects on all parts of the water cycle. • This is just one example of how human activities (partially) control the character of the global ecosystem • We need to exercise responsibility with this control • Fresh waters contain remarkable biodiversity • That biodiversity is badly endangered

42. Resources http://water.usgs.gov/data/

43. Familiar reasons “to care” about water Yann Arthus-Bertrand Source: www.impactlab.com Source: www.4.bp.blogspot.com

44. The forgotten piece…

45. Fresh waters are hotspots of diversity (bars) and endangerment (lines)although fresh waters cover <1% of the Earth’s surface, they contain 10% of known animal species, and 1/3 of vertebrate species

46. Similar to amphibians, invertebrates, mussels… www.feow.org

47. Freshwater organisms are more imperiled than their terrestrial counterparts

48. Source: http://jrscience.wcp.muohio.edu/western/fishid/Orange-throat__amp__Rainbo.html

49. Source: www.iz.carnegiemnh.org