Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no...
Transcript of Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no...
![Page 1: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/1.jpg)
Roughness of Floodplain PlantsUsing Plants to Improve Flood Management
![Page 2: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/2.jpg)
What is Roughness?
TextureFrictionBlockage
Resistance toflow
![Page 3: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/3.jpg)
Plants have roughness
![Page 4: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/4.jpg)
So do theThings we Put in channels
![Page 5: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/5.jpg)
We measure roughness using Mannings n –a number used in a whole bunch of hydraulic
analyses
(1/ )R2/3S 1/2n=(1/v)R2/3Sf1/2
R= hydraulic radiusSf= friction slopeV = water velocity
![Page 6: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/6.jpg)
Manning n has no units.
Manning's n Coefficients for Open Channel Flow
Material Manning n Material Manning nNatural Streams Excavated Earth ChannelsClean and Straight 0.030 Clean 0.022
The fluid mechanics calculations website
Major Rivers 0.035 Gravelly 0.025Sluggish with Deep Pools 0.040 Weedy 0.030
Stony, Cobbles 0.035Metals FloodplainsBrass 0.011 Pasture, Farmland 0.035Cast Iron 0.013 Light Brush 0.050Smooth Steel 0.012 Heavy Brush 0.075Corrugated Metal 0.022 Trees 0.15Non-MetalsGlass 0.010 Finished Concrete 0.012Clay Tile 0.014 Unfinished Concrete 0.014Brickwork 0.015 Gravel 0.029Asphalt 0.016 Earth 0.025Masonry 0.025 Planed Wood 0.012
Unplaned Wood 0.013
![Page 7: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/7.jpg)
Type of Channel and Description Minimum Normal Maximum
Natural streams - minor streams (top width at floodstage < 100 ft)
1. Main Channels
a. clean, straight, full stage, no rifts or deep pools 0.025 0.030 0.033
b. same as above, but more stones and weeds 0.030 0.035 0.040
c. clean, winding, some pools and shoals 0.033 0.040 0.045
d. same as above, but some weeds and stones 0.035 0.045 0.050
e. same as above, lower stages, more ineffective slopes and sections
0.040 0.048 0.055
f. same as "d" with more stones 0.045 0.050 0.060
g. sluggish reaches, weedy, deep pools 0.050 0.070 0.080
h. very weedy reaches, deep pools, or floodways with heavy stand of timber and underbrush
0.075 0.100 0.150
2. Mountain streams, no vegetation in channel, banks usually steep, trees and brush along banks submerged at high stages
a. bottom: gravels, cobbles, and few boulders 0.030 0.040 0.050
b bottom: cobbles with large boulders 0.040 0.050 0.070
![Page 8: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/8.jpg)
Mannings n – average of all textures, but used as a model fitting parameter.
Inaccuracy in other model parameters:Shape, channel form, grade, slope, sinuosity velocity water densitysinuosity, velocity, water density, …
get assigned to roughness
![Page 9: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/9.jpg)
O’Connor Lakes, Star Bend
Lots of variation:
Pre‐project velocities
Lots of variation:∆ velocity = ∆ roughness
![Page 10: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/10.jpg)
The need for improving safety and ecosystem management prompted us
to look at the role some common plants play in creating roughness.
Plants selected because they are adapted to flooding, are common in our floodways, and
provide good habitat value
![Page 11: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/11.jpg)
Mulefat Wild Rose
Sandbar willow
California Blackberry
![Page 12: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/12.jpg)
![Page 13: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/13.jpg)
H
Depth Control Weir
x= 47'
x =60'
V
2’
Flume tail tank
x =0'
x=33'
Pumps
6’
AC
x=19'
B
Point gage locations and
velocity measurement sections
Pumps
![Page 14: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/14.jpg)
Velocity measurement locations in a cross-section
Flume width 5 ft
6 ft
Flume width 5 ft
6 ft
4 ft bin Width
8 ft
2 ft
4 ft bin Width
8 ft
2 ft
Water depth higher than 2 ft
Water depth lower than 2 ft
![Page 15: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/15.jpg)
Velocity and Water Surface Profiles
V Scale X 19.5 33.5 472 Z 2.65 2.54 2.56
2.17 4.39 4.69 4.861.67 4.18 4.56 4.641.17 4.11 4.42 4.440.67 4.00 4.20 4.030.25 3.62 3.47 3.36
V (ft/s)
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
0 10 20 30 40 50 60 70
X [ft]
Elev
atio
n [f
t]
Water Surface Flume Top Elevation Bottom Elevation
Velocity at P#2 Velocity at P#3 Velocity at P#4
V= 2 ft/s
Flow Regime S15
![Page 16: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/16.jpg)
STREAMBED BARE SOIL SAMPLE PREPARATION
![Page 17: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/17.jpg)
Sandbar Willow1st replicate
![Page 18: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/18.jpg)
Sandbar Willow3rd replicate
![Page 19: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/19.jpg)
3
4
5V|x=16ftV|x=34ftV|x=47ft
3
4
5V|x=16ftV|x=34ftV|x=47ft
V=1.5 ft/s H=1.5 ft V=3.0 ft/s H=1.5 ft
Velocity Profile Sandbar Willow
0
1
2
0 2 4 6Velocity (ft/s)
Z(ft)
0
1
2
0 2 4 6Velocity (ft/s)
Z(ft)
![Page 20: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/20.jpg)
3
4
5V|x=16ftV|x=34ftV|x=47ft
3
4
5V|x=16ftV|x=34ftV|x=47ft
V=1.5 ft/s H=5 ft V=3.0 ft/s H=5 ftVelocity Profile Sandbar Willow
0
1
2
0 2 4 6Velocity (ft/s)
Z(ft)
0
1
2
0 2 4 6Velocity (ft/s)
Z(ft)
![Page 21: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/21.jpg)
3
4
5V|x=16ftV|x=34ftV|x=47ft
3
4
5V|x=16ftV|x=34ftV|x=47ft
V=4.5 ft/s H=3 ft V=6.0 ft/s H=3 ft
Velocity Profile Sandbar Willow
0
1
2
0 2 4 6Velocity (ft/s)
Z(ft)
0
1
2
0 2 4 6Velocity (ft/s)
Z(ft)
![Page 22: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/22.jpg)
0.050.060.070.080.09
ng's
n
Bare Soil
Willow1
Willow2
Willow3
Roughness Coefficient vs Reynolds Number
Sandbar Willow
0.000.010.020.030.04
0 200,000 400,000 600,000Re
Man
ni Linear (Bare Soil)
Linear (Willow1)
Linear (Willow2)
Linear (Willow3)
![Page 23: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/23.jpg)
3
4
5
h (ft
)
V|x=16ftV|x=34ftV|x=47ft
Velocity Profile Mulefat
3
4
5
h (ft
)
V|x=16ftV|x=34ftV|x=47ft
V=4.5 ft/s H=3ft V=6 ft/s H=3 ft
0
1
2
0 2 4 6
Velocity (ft/s)
Dep
th
0
1
2
0 5 10
Velocity (ft/s)
Dep
th
![Page 24: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/24.jpg)
0.06
0.08
0.10
0.12
ning
's n
Bare SoilWillow (March)Willow (April)Willow (May)Mule Fat (Nov-Dec)Mule Fat (Oct-Nov) Linear (Bare Soil)Linear (Willow (March))Linear (Willow (April))Linear (Willow (May))Linear (Mule Fat (Nov-Dec))Linear (Mule Fat (Oct-Nov) )
Comparative Roughness: Mulefat & Sandbar Willow
0.00
0.02
0.04
0 100,000 200,000 300,000 400,000 500,000 600,000 700,000
Re
Man
![Page 25: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/25.jpg)
3
4
5
6
ht (f
t)
V|x=16ftV|x=34ftV|x=47ft
V=6 ft/s Ht=3.4ft
4
5
6
t (ft
)
V|x=16ftV|x=34ftV|x=47ft
V=3 ft/s Ht=5ft
Velocity Profile California Blackberry
0
1
2
3
0.0 2.0 4.0 6.0
Velocity (ft/s)
Hei
gh
0
1
2
3
0.0 2.0 4.0 6.0
Velocity (ft/s)
Hei
ght
![Page 26: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/26.jpg)
0 08
0.10
0.12
0.14
0.16
ng's
n
Blackberry(Mar)Blackberry(Apr)Blackberry(May)Willow (March)Willow (April)Willow (May)Mule Fat (Oct-Nov) Mule Fat (Nov-Dec)Mule Fat (January)Mule Fat (February)Bare SoilLinear (Blackberry(Mar))Linear (Blackberry(Apr))Linear (Blackberry(May))
Roughness coefficients vs Reynolds NumberCalifornia Blackberry
0.00
0.02
0.04
0.06
0.08
0 100,000 200,000 300,000 400,000 500,000 600,000 700,000Re
Man
nin Linear (Blackberry(May))
![Page 27: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/27.jpg)
Velocity profile Wildrose
3
4
5
6
dept
h (f
t)
V|x=16ftV|x=34ftV|x=47ft
3
4
5
6
r de
pth
(ft)
V|x=16ftV|x=34ftV|x=47ft
V=4.5ft/s H=3ft V=6ft/s H=3.4ft
0
1
2
0 2 4 6 8
Velocity (ft/s)
Wat
er
0
1
2
0 2 4 6 8
Velocity (ft/s)
Wat
er
![Page 28: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/28.jpg)
0.10
0.12
0.14
0.16s
nBlackberry(Mar)Blackberry(Apr)Blackberry(May)Willow (March)Willow (April)Willow (May)Mule Fat (Oct-Nov) Mule Fat (Nov-Dec)Mule Fat (January)Mule Fat (February)Bare SoilWildrose#1(Jun)Wildrose#2(Jun)Wildrose#3(Jul)Linear (Blackberry(Mar))Linear (Blackberry(Apr))Linear (Blackberry(May))Linear (Wildrose#1(Jun))Li (Wild #2(J ))
Mannings Coefficient vs Reynolds NumberRose and Blackberry
0.00
0.02
0.04
0.06
0.08
0 100,000 200,000 300,000 400,000 500,000 600,000 700,000Re
Man
ning
's Linear (Wildrose#2(Jun))Linear (Wildrose#3(Jul))
![Page 29: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/29.jpg)
Erosion Summary
2
3Erosion (in)
mulefat
Bare soil
3 51
1
Velocity (ft/sec)
willow
rose
![Page 30: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/30.jpg)
![Page 31: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/31.jpg)
Swim Response to Sandbar Willow
○ = TBF Swim Chamber● = MO2■ = TBF Flume
(1 5 ft/s)
(3.0 ft/s)
(0.5 ft/s)
(1.5 ft/s)
![Page 32: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/32.jpg)
As built – velocity A Mosaic of Plants
![Page 33: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/33.jpg)
![Page 34: Roughness of Floodplain Plants Using Plants to Improve ... · V = water velocity. Manning n has no units. Manning's n Coefficients for Open Channel Flow Material Manning n Material](https://reader034.fdocuments.net/reader034/viewer/2022042223/5ec982fb7012ec4d2f70fcd9/html5/thumbnails/34.jpg)