1. Teaching the “Broken” Water Cycle: A Reality Check
Cornelia Harris & Kim Notin ;

2. Research & Education based on Ecosystem Ecology

3. The water cycle in textbooks

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

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

6. Changes in evaporation and transpiration
Transpiration is often overlooked in importance
About half of rain and snow that falls on the Pearl River Delta is evaporated or transpired before it reaches the sea
A mature tree transpires ~50 gallons of water a day in the summer

8. Agricultural Use Changes in evaporation and transpiration
Modifying vegetation can have huge effects on streamflow
Half of the 800 trillion gallons of water used each year in irrigation is “lost” to the air
Salinization of the soil
Soil runoff

9. Water quality is also affected by decreased infiltration

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

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

12. Borneo
UNEP

13. Reduced Infiltration
Baltimore Ecosystem Study

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

16. Increased runoff How many dams exist around the world?
+/-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

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

18. Dams in the Mekong Dams can cause international disputes
Source: Swaney et.al 2006

19. Normal Water Flow Has Been Obstructed by Dams

20. Several of the world’s great rivers no longer reach the sea
Ganges-Brahmaputra
Nile
Colorado
Murray-Darling
Yellow
Egypt’s withdrawals alone will exceed supply by 2017
shows the passage of the Colorado River through several southwestern states. The river begins, in this image, in Utah at the far upper right, where Lake Powell is visible as dark pixels surrounded by the salmon-colored rocks of the Colorado Plateau. The Colorado flows southwest through Glen Canyon, to the Glen Canyon Dam, on the Utah-Arizona border. From there it flows south into Arizona, and then turns sharply west where the Grand Canyon of the Colorado cuts through the mountains. The Colorado flows west to the Arizona-Nevada (upper left) border, where it is dammed again, this time by the Hoover Dam. The dark-colored pixels surrounding the bend in the river are Lake Mead. The river flows south along the border of first Nevada and Arizona and then California and Arizona. The Colorado River, which begins in Rocky Mountain National Park in Colorado, empties into the Gulf of California, seen at the bottom center of this image.

21. 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

22. 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
Largest fresh water polluter

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

25. Ogallala Aquifer
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
Depletion in next 10 years

27. 3rd UN World Water Development Report, 2009

28. Humans even alter precipitation!
Humans affect fog water inputs
El Tofo Mountain Northern Chile Crop irrigation
Air pollution may affect rainfall amounts
Particulate matter
Water quality (“acid rain”)

29. Moving water across watersheds
North South Diversion (13 billion cumecs/yr)
Hubei province to Beijing
Yangtze River
Common for irrigation and cities globally
This translocated water can move species around

30. Moving water across watersheds in bottles world wide
2009: 161 billion litres
2011: 181 billion litres

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

32. Familiar reasons “to care” about water
Yann Arthus-Bertrand
Source:
Source:

33. 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

34. Similar to amphibians, invertebrates, mussels…

35. Freshwater organisms are more imperiled than their terrestrial counterparts
60 extinctions known from eastern rivers, but only 7 bird and mammal extinctions known from NA

36. 177 described species of darters listed in Wikipedia (Aug 2009)
Source:

37. Tasmanian giant crayfish
Source: