1. Gregory Indivero 31 October 2011

2.  What discharge (cfs) is required to entrain the D 84 (84 th percentile of sediment size distribution) in Red Canyon Wash?  What discharge was required to deposit observed flood debris from August 16, 2010 flood?

3.  Red & Columbus Canyons  Un-gauged, Ephemeral Wash  5 th Largest Drainage of CNM

4. Red Canyon Columbus Canyon Red Canyon Wash Study Reach No Thoroughfare Canyon

5.  Fairly Straight Alluvial Channel  300 Feet Long ≅ 20 Feet Wide

6.  Establish Reach & Cross Sections  Survey Thalweg, Flood Debris & Cross Sections  Conduct a Pebble Count at Cross Sections ◦ Create Grain Size Distribution Plots  Solve Shields Equation for Critical Shear Stress, τ c  Model Channel With HEC-RAS ◦ -Fluctuate Discharge In Channel Until τ c Is Achieved ◦ -Fluctuate Discharge Until Flood Debris Elevation is Achieved

7.  Run Tape Measure down the Thalweg  Establish Bench Mark Photo Credits: Gigi Richard

8.  Surveying the Thalweg o Slope = 0.0261 Photo Credit: Gigi Richard

9.  Surveying Cross Section 1  Surveying Cross Section 3 Photo Credits: Gigi Richard

10. o Cross Sections 1 & 3 124 Feet Apart

11.  100 Grains Counted At Each Cross Section  Average D 84 = 24 mm

12.  Shields Equation ◦ τ c = τ * c (ρ s – ρ w )gD 84 Where:  τ * c = Dimensionless Shear Stress  ρ s, ρ w = Density of Sediment (Quartz) & Water Respectively  g = Gravitational Constant  D 84 = 84 th Percentile of Grain Size Distribution

13.  Channel Forming Discharge = 4 cubic Feet per Second  Frequency = ?? Distance From Left Bank (ft) HEC-RAS Model At Cross Section 1 Q = 4 ft 3 /s

14.  What was the discharge of this flow? Photo Credits: Teri Lindaur

15.  Surveyed High Water Mark Using Flood Debris Indicators Photo Credits: Gigi Richard

16.  Discharge of Flood on August 16, 2010 ≈ 200 cubic feet per second Distance From Left Bank (ft) HEC-RAS Model At Cross Section 1 Q = 200 ft 3 /s Flood Debris

17. Photo Credits: Greg Indivero

18. Video Credits: Teri Lindaur

19.  How often do these types of flows occur? ◦ Speculation ◦ Historical Events (September 7, 1978 ≈ 2,890 cfs) Photo Credits: Jim Johnson

20.  A Big Thank You Goes Out to the following: ◦ Dr. Gigi Richard ◦ Mrs. Teri Lindaur ◦ Mr. Con Trumbull ◦ Ms. HeidlHausner ◦ Mr. Frank Jacobs

21.  Arcement, G. J., 1989, Guide for selecting Manning's roughness co-efficients for natural channels and flood plain, USGS water-supply paper: 2339, v. 38.  Cooke, R., Warren, A., Goudie, A., 1993, Desert Geomorphology: University College London, UCL Press Limited, p. 143-167.  Becker, A., DiPema, L, Ladig, K, Wellik, J, and Richard, G., 2007, Channel morphology and channel-forming discharge of No Thoroughfare Canyon, Colorado, Geological Society of America, Abstracts with Programs, Vol. 39, No. 6, p. 306  Elliott, J.G. and Hammack, L.A., 2000, Entrainment of Riparian Gravel and Cobbles in an Alluvial Reach of a Regulated Canyon River: Regulated Rivers: Research and Management, v. 16, p. 37-50.  Knighton, D., 1998, Fluvial Forms and Processes: A New Perspective. London: Arnold, p. 383  Richard, G.A., 2004, Flash Flooding at the Colorado National Monument 1921-2003: Colorado National Monument, National Park Service, p. 21  U.S. Army Corps of Engineers (USACOE), Hydrologic Engineering Center, 2010, HEC-RAS River Analysis System Hydraulic Reference Manual, Version 4.1, U.S. Army Corps of Engineers, Davis, CA, 417 pp.  Van Steeter, M. M., and J. Pitlick. 1998, Geomorphology and endangered fish habitats of the upper Colorado River: historic changes in streamflow, sediment load, and channel morphology. Water Resources Research 34:303-316.  Wilcock, P. R., 2001, Toward a practical method for estimating sediment transport rates in gravel-bed rivers, Earth Surf. Processes Landforms 26, 1395 –1408.  Wilcock, P. R., Pitlick, J., Cui, Y., 2009, Sediment Transport Primer: Estimating Bed-Material Transport in Gravel-bed Rivers, U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Research Station, 78 pp.