Rivers forms and processes

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  • Satellite photo of the Songhua River, northeast China - includes Oxbow lakes .
  • The catchment and reach under study: the Upper Wharfe, Yorkshire Dales National Park, North Yorkshire. Sedimentsensors were installed in the Oughtershaw and Greenfield subcatchments, and at Beckermonds, Deepdale, Hubberholme, Buckden and Starbotton.
  • Predictions of areas inundated in the 1 in 0·5 with 2002 geometry and flows and with 2002 geometry and 2050s flows
  • Predictions of are as inundated in the 1 in 0·5 with 2002 geometry and flows and with 2004 geometry and 2002 flows.For the 1-in-0·5-year event, the increase in inundated area was almost one-half of the increase in inundated area estimated as resulting from simulated climate change to the 2050s.The indirect impacts of the climate change signal upon sediment delivery will act so as to reinforce the importance of short-term aggradation upon the magnitude and frequency of floodplain inundation, and that short-term variability in aggradation rates may be superimposed on top of a longer-term, aggradational trend. This emphasizes that the changing flood risk identified here will be strongly impacted upon by climate change, not only because of the direct impacts of climate upon the magnitude and frequency of high flow events, but also because of the indirect effects of changing climate upon coarse sediment delivery which in turn will impact upon coarse sediment delivery and hence aggradation rates.
  • Hawkcombe Stream, Porlock – 1960 flood
  • 2 million properties in floodplains along rivers, estuaries and coasts in the UK are potentially at risk of river or coastal flooding. In England and Wales alone, over 4 million people and properties valued at over £200 billion are at risk. Flooding, and managing it, cost the UK around £2.2 billion each year: we currently spend around £800 million per annum on flood and coastal defences; and, even with the present flood defences, we experience an average of £1,400 million of damageForesight Future Flooding(Office of Science and Technology – April 2004)
  • River Mississippi
  • Issues with the stability of the channel
  • Issues with the stability of the channel
  • Issues with the stability of the channel
  • Issues with the stability of the channel
  • Issues with the stability of the channel
  • Issues with the stability of the channel
  • Issues with the stability of the channel
  • Issues with the stability of the channel
  • Issues with the stability of the channel
  • Rivers forms and processes

    1. 1. Rivers: Forms and Processes<br />Dr. Chris Parker<br />Fluvial Geomorphologist / Senior Lecturer in Physical Geography<br />Department of Geography and Environmental Management<br />University of the West of England<br />
    2. 2.
    3. 3. Rivers move!!!<br />
    4. 4. Why do we care if rivers move?<br />
    5. 5. Why it is important to understand how and why rivers move: Flood Risk<br />
    6. 6. Why it is important to understand how and why rivers move: Flood Risk<br />
    7. 7. Why it is important to understand how and why rivers move: Flood Risk<br />Lane et al, 2007<br />
    8. 8. Why it is important to understand how and why rivers move: Flood Risk<br />+12.2%<br />1 in 0.5 year flood: 2002 climate<br />1 in 0.5 year flood: 2050 climate<br />Lane et al, 2007<br />
    9. 9. Why it is important to understand how and why rivers move: Flood Risk<br />Lane et al, 2007<br />
    10. 10. Why it is important to understand how and why rivers move: Flood Risk<br />+5.7%<br />1 in 0.5 year flood: 2002 channel<br />1 in 0.5 year flood: 2004 channel<br />Lane et al, 2007<br />
    11. 11. Why it is important to understand how and why rivers move: Flood Risk<br />
    12. 12. Why it is important to understand how and why rivers move: Flood Risk<br />
    13. 13. Why it is important to understand how and why rivers move: Navigation<br />
    14. 14. Why it is important to understand how and why rivers move: Damage to infrastructure<br />
    15. 15. Why it is important to understand how and why rivers move: Damage to ecology<br />
    16. 16. Why it is important to understand how and why rivers move: Damage to ecology<br />
    17. 17. Why do rivers move?<br />
    18. 18. What do rivers transport apart from water?<br />
    19. 19. Why do rivers move?<br />
    20. 20. How do rivers move?<br />
    21. 21. How do rivers move?<br />Sediment available to be transported > Capacity to transport sediment...<br /><ul><li>Channel size shrinks
    22. 22. Channel becomes straighter (and therefore steeper)</li></li></ul><li>How do rivers move?<br />
    23. 23. How do rivers move?<br />
    24. 24. How do rivers move?<br />Capacity to transport sediment > <br />Sediment available to be transported...<br /><ul><li>Channel size expands
    25. 25. Channel becomes more sinuous (and therefore less steep)</li></li></ul><li>How do rivers move?<br />
    26. 26. How will rivers move in the future?<br />
    27. 27. How will rivers move in the future?<br />
    28. 28. How will rivers move in the future?<br />Cellular Catchment Model<br />
    29. 29. How will rivers move in the future?<br />Cellular Catchment Model (CAESAR)<br />Coulthard et al<br />
    30. 30. How will rivers move in the future?<br />Average modelled sediment percent increase from baseline for the River Eden catchment, Cumbria<br />Average rainfall percent increase from baseline for the River Eden catchment, Cumbria<br />Coulthard et al<br />
    31. 31. How will rivers move in the future?<br />Modelled morphological change in the River Eden, Carlisle resulting from 90% increase in sediment yield<br />Predicted increase in flood inundation resulting from predicted morphological change<br />Coulthard et al<br />

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