1. For additional reading of the Hurricane Camille event: Photo: Tom Gathright

6. THE ROLE OF DEBRIS FLOWS IN LONG TERM DENUDATION AND LANDSCAPE EVOLUTION OF THE CENTRAL APPALACHIANS L. Scott Eaton, Ph.D. Department of Geology and Environmental Science James Madison University

7. Death Valley, CA La Conchita, CA Landslide: the downslope movement of rock, soil, or artificial fill under the influence of gravity.

8. Venezuela, 1999 Photos: Matt Larsen, USGS

9. Blue Ridge Mountains, central Virginia

12. ~ 150 fatalities Photo: Tom Gathright, 1969

14. C Madison County, Virginia Rapidan Storm, June, 1995

15. 775 mm, ppt

23. Research Question: In the Appalachians, are debris flows a significant process in the transportation of sediment from mountainous terrain to the lowland floodplains?

24. What is the frequency of debris flows in the Appalachians? What is the frequency of debris flows in the Appalachians? How much sediment is transported during an event? How much sediment is transported during an event? What are the long term erosion (denudation) rates in the central Appalachians? What are the long term erosion (denudation) rates in the central Appalachians? What are the dominant geomorphic processes What are the dominant geomorphic processes operating within the basin?

25. Frequency of debris flows

27. DEBRIS FLOW FREQUENCY IN THE UPPER RAPIDAN BASIN from Eaton and others, 2003

28. Nelson County

29. Sediment Transport and Denudation (from Springer, Shroyer, and Eaton, 1997)

30. 0.398 km 2

32. BeforeAfter ?? ?

33. 13, 364 m 3 0.398 km 2

34. Volume = 13, 364 m 3 Area 0.398 km 2 or 398,000 m 2 = 0.034 m = 3.4 cm

35. Summary of Basin Denudation of Blue Ridge Systems Event Basin Basin Area (km 2 ) Volume of Sediment Eroded (m 3 ) Mean Basin Denuda- tion (cm) Hurricane Camille Nelson Co. Willis Cove 4.08173,4884.3 Hurricane Camille, Nelson Co. Ginseng Hollow 1.7588,7275.1 Hurricane Camille, Nelson Co. Polly Wright Cove 2.4787,7073.6 Rapidan Flood, Madison Co. Jenkins Hollow 0.39813,3643.4 Rapidan Flood Teal Hollow0.1232,4922.0

37. Hurricane Camille Rapidan Storm

38. Dominant geomorphic processes….

40. ~ 2 m From Ballantyne and Harris,1994 Solifluction Deposits and Landforms

41. From Ballantyne and Harris,1994

46. One model of Appalachian landscape evolution and sediment transport…..

47. BEFORE…..

49. AFTER…..

50. High Magnitude Low Frequency Low Magnitude High Frequency

51. Other considerations…… regional frequency (~15 yrs) multi-basin impacts