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GEOG3839.20, Paleofloods

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GEOG3839.20, Paleofloods

  1. 1. Photograph: Paul Kelly
  2. 2. MAJOR LOSSES IN 2010 ACCORDING TO LOSS CATEGORY Storms $20,126 Earthquakes $12,943 Floods $6,393 Cold, frost $397 Droughts $10 (in USD m)Source: Swiss Re, Natural catastrophes and man-made disasters in 2010
  3. 3. during the 1990s, freshwater flooding affected more than1.4 BILLION PEOPLE
  4. 4. Photograph: puuikibeach
  5. 5. Photograph: eyebar
  6. 6. PAST BEHAVIOR FUTURE RISKS
  7. 7. Photograph: skooksie
  8. 8. “100-year flood”
  9. 9. Paleoflood hydrology uses physical evidence le behindon the landscape to make inferences about past floodsthat were not directly observed or recorded by humans.
  10. 10. Photograph: David Snyder Slackwater deposits Fine-grained sediments laid down by floodwaters
  11. 11. “ The forts now stand like a castle of romance in the midst of an ocean of deep contending currents, the water extending for at least a mile behind them, and they are thereby only approachable by boats and canoes.” Francis Heron Hudson Bay Company, 1826St.. George and Rannie, Canadian Water Resources Journal, 2003
  12. 12. scarring microclimatologyinjury “flood rings”
  13. 13. FLOOD SCARS
  14. 14. Photograph: Mark’s Postcards from Beloit
  15. 15. Photograph: NDSU Ag Comm
  16. 16. FLOOD SCARSThe timing of the flood can be determined by counting the numberof rings between the scar and the outside ring, and the height ofthe scar represents the minimum elevation of high water.
  17. 17. INJURY
  18. 18. Floods can damage trees by tilting or partial uprootingor can uproot them completely, causing their death.
  19. 19. MICROCLIMATEPhotograph: Alex Drainville
  20. 20. Photograph: Alex Drainville
  21. 21. Photograph: ouelle e001.com
  22. 22. FLOOD RINGS
  23. 23. Winnipeg Manitoba
  24. 24. WinnipegThe name Winnipeg is a transcription ofthe western Cree word wi-nipe-k meaning"muddy waters"
  25. 25. Photograph: Greg Brooks
  26. 26. AP Photo/U.S. Coast Guard, Lt. Brendan Evans
  27. 27. Greg Brooks, Geological Survey of Canada
  28. 28. Grand Forks, North Dakota 1997 flood and fire
  29. 29. Photograph: Ma hew Bietz
  30. 30. Lake Agassiz
  31. 31. How large can Red River floods get and how o endo the large ones occur?Are there geological processes that may bechanging the Red River flood hazard?What are the geological controls that govern thecharacter of Red River flooding?
  32. 32. Instrumental and historical estimates of major Red River floods
  33. 33. Erik Nielsen Manitoba Geological Survey
  34. 34. Photograph: Greg Brooks
  35. 35. 2008
  36. 36. 1875
  37. 37. Photo: Erik Nielsen
  38. 38. 51Photo: Erik Nielsen
  39. 39. “ The forts now stand like a castle of romance in the midst of an ocean of deep contending currents, the water extending for at least a mile behind them, and they are thereby only approachable by boats and canoes.” Francis Heron Hudson Bay Company, 1826St.. George and Rannie, Canadian Water Resources Journal, 2003
  40. 40. Source: St. George and Nielsen, Geographie Physique et Quaternaire, 2002
  41. 41. In hydrology, flood observations reported as having occurredabove some threshold are known as censored data sets.
  42. 42. Photograph: USGS 1979 Red River flood Drayton, North Dakota
  43. 43. Source: St. George and Nielsen, Geographie Physique et Quaternaire, 2002
  44. 44. Source: St. George and Nielsen, Geographie Physique et Quaternaire, 2002
  45. 45. St. George et al. (2002), Tree-Ring Research
  46. 46. How large can Red River floods get and how o endo the large ones occur?Are there geological processes that may bechanging the Red River flood hazard?What are the geological controls that govern thecharacter of Red River flooding?
  47. 47. 350 years of Red River floodsSource: St. George and Nielsen, The Holocene, 2003
  48. 48. TREES AS PALEOFLOOD INDICATORSStrengths and limitations
  49. 49. Photograph: David Snyder
  50. 50. Redrawn from Stahle (1990)
  51. 51. Photograph: Steffano A ardi
  52. 52. scarring microclimatologyinjury “flood rings”
  53. 53. ReadingSt. George (2010), Tree rings as paleoflood andpaleostage indicators. In Stoffel et al., (eds.),Tree Rings and Natural Hazards.
  54. 54. ReadingSt. George and Nielsen (2002), Flood ringevidence and its application to paleofloodhydrology of the Red River and AssiniboineRiver in Manitoba. Geographie physique etQuaternaire.
  55. 55. PALEOFLOODSPhotograph: Morningstar Photo

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