gregory indivero 31 october 2011. what discharge (cfs) is required to entrain the d 84 (84 th...
TRANSCRIPT
Channel Morphology ofRed Canyon Wash
Gregory Indivero31 October 2011
What discharge (cfs) is required to entrain the D84 (84th percentile of sediment size distribution) in Red Canyon Wash?
What discharge was required to deposit observed flood debris from August 16, 2010 flood?
Research Questions
Location of Red CanyonRed & Columbus Canyons
Un-gauged,
Ephemeral Wash
5th Largest
Drainage of CNM
Satellite Photograph
Red
Canyon
Col
umbu
s Can
yon
Red Canyon Wash Study Reach
No
Thoroughfare
Canyon
Specific Study Reach Site
Fairly Straight Alluvial Channel
300 Feet Long≅ 20 Feet Wide
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,
τc
Model Channel With HEC-RAS◦ -Fluctuate Discharge In Channel Until τc Is Achieved
◦ -Fluctuate Discharge Until Flood Debris Elevation is Achieved
Methods
Surveying Long Profile & Cross Sections
Run Tape Measure down the ThalwegEstablish Bench Mark
Photo Credits: Gigi Richard
0 50 100 150 200 250 300 3504922
4924
4926
4928
4930
4932
4934
4936
4938
f(x) = − 0.0261428145273286 x + 4935.33757365684R² = 0.98459205971073
Red Canyon Wash Long Profile
Red Canyon Wash Thalweg
Energy Gradient (Slope)
Distance Downstream in Feet
Ele
vati
on in F
eet
Surveying Long Profile & Cross Sections Cont’d
Surveying the Thalweg
o Slope = 0.0261
Photo Credit: Gigi Richard
Surveying Long Profile & Cross Sections Cont’d
Surveying Cross Section 1
Surveying Cross Section 3
Photo Credits: Gigi Richard
0 10 20 30 40 50 604929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
Cross Section 1
Distance From Left Bank in Feet
Ele
vati
on in F
eet
0 5 10 15 20 25 30 35 40 45 504928
4929
4930
4931
4932
4933
4934
Cross Section 3
Distance From Left Bank in Feet
Ele
vati
on in F
eet
o Cross Sections 1 & 3 124 Feet Apart
100 Grains Counted At Each Cross Section Average D84 = 24 mm
Pebble Count & Grain Size Distribution
1 10 100 10000
10
20
30
40
50
60
70
80
90
100
Red Canyon Wash
Cross Section 1Cross Section 2Cross Section 3
Particle Diameter (mm)
Perc
ent
Fin
er
Shields Equation◦ τc= τ*
c(ρs – ρw)gD84
Where: τ*
c = Dimensionless Shear Stress
ρs, ρw = Density of Sediment (Quartz) & Water Respectively g = Gravitational Constant D84 = 84th Percentile of Grain Size Distribution
Critical Shear Stress, τc
τc= 0.045(9.81 m/s2)(2650-1000 kg/m3)(0.024 m)
τc= 17.48 N/m2
Channel Forming Discharge = 4 cubic Feet per Second
Frequency = ??
HEC-RAS Results
Distance From Left Bank (ft)
HEC-RAS Model At Cross Section 1
Q = 4 ft3/s
What was the discharge of this flow?
What about this August 16, 2010 Flood?
Photo Credits: Teri Lindaur
Surveyed High Water Mark Using Flood Debris Indicators
What about the flood?
0 50 100 150 200 250 300 3504922
4924
4926
4928
4930
4932
4934
4936
4938
f(x) = − 0.0261428145273286 x + 4935.33757365684R² = 0.98459205971073
Red Canyon Wash Long Profile With High Water Mark
Red Canyon Wash Thalweg
Energy Gradient (Slope)
REW
LEW
Distance Downstream in Feet
Ele
vati
on in F
eet
Photo Credits: Gigi Richard
Discharge of Flood on August 16, 2010 ≈ 200 cubic feet per second
HEC-RAS Results for High Water Mark Estimate
Distance From Left Bank (ft)
HEC-RAS Model At Cross Section 1
Q = 200 ft3/s
Flood Debris
Red Canyon Wash’s Dry Channel
Photo Credits: Greg Indivero
August 16, 2010 Videos
Video Credits: Teri Lindaur
How often do these types of flows occur?◦ Speculation◦ Historical Events (September 7, 1978 ≈ 2,890 cfs)
Conclusions
Photo Credits: Jim Johnson
A Big Thank You Goes Out to the following:
◦ Dr. Gigi Richard
◦ Mrs. Teri Lindaur
◦ Mr. Con Trumbull
◦ Ms. HeidlHausner
◦ Mr. Frank Jacobs
Acknowledgements
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.
References