Stefan Wirtz Vom Fachbereich VI (Geographie/Geowissenschaften ...

Experimentelle Rinnenerosionsforschung vs. Modellkonzepte – Quantifizierung der hydraulischen und erosiven Wirksamkeit von Rinnen
24 di
0.887
τc
= 0.0384 ( )
d50
d i
d 50 = relationship between given particle size and the subsurface d 50
Andrews (1984), Andrews and Erman (1986)
25
26
27
28
τ
cr
= ρ
(ρ g
u
2
cr
n
0.66
= (ρ
q
g R
0.66
S
0.7
S)
)
cr
cr
ρ = density of the water [kg m -3 ], u cr = shear velocity [m s -1 ], g = gravitation factor [9.81
m s -2 ], R = hydraulic radius [m], S = sin (slope), n = Manning friction factor [m 1/3 s -1 ], q
= unit discharge [m 7/6 s]
De Ploey (1990)
τ c
= 2.67 + 0.65 CLAY 0.058 VFS
for cropland > 30 % sand
τ c
= 3.5
for cropland < 30 % sand
τ = 3.23 0.056 SAND 0.244 ORGMAT + 0.9 for rangeland
c
BD dry
Clay = clay content [%], VFS = very fine sand content [%], SAND = sand content [%],
ORGMAT= organic matter content [%] (1.724 times organic carbon content), BD dry =
dry soil bulk density [g cm -3 ]
Flanagan and Livingston (1995)
Table 7 Equations for calculating transport and detachment capacity.
No.
Equation and Variables
TC
f
TC =
29
TC
( 1
ρ
S
f
)
TC = transport capacity in clear water [g L -1 ], TC f = transport capacity in sedimentwater
[g L -1 ], ρ S = density of solid material [kg m -3 ]
Govers (1990)
qb
w
TC =
30 Q
ρ
S
TC = transport capacity in clear water [g L -1 ], q b = volumetric bedload transport per
unit width [m² s -1 ], w = flow width [m], ρ S = density of solid material [kg m -3 ], Q =
runoff [m³ s -1 ]
Abrahams et al. (2001), Low (1989), Rickenmann (1990)
163