Stream erosion is a natural process. Stream and river geomorphology is constantl
ID: 112837 • Letter: S
Question
Stream erosion is a natural process. Stream and river geomorphology is constantly changing As human land use activities modify the land and water surface, these activities cause non- equilibrium conditions in the sediment erosion and transport process. (a) Mathematically describe how sediment transport can be described quantitatively. (b) What methods and information would you collect in order to help describe and predict sediment transport throughout a stream, river, or other aquatic water column?
Explanation / Answer
Stream erosion is a natural process.
A) mathematically the stream erosion transport can be defined or calculated quantitatively as the following.
The transportation can be done only by overcoming some forces like settling velocity,shear stress,shear velocity,sheilds stress etc.
Quantitatively the transport can be found as the following
qb = 0.053*[(s-1)*g]0.5* d 1.550 *[(T)2.1 /(D)0.3]
qb = bedload transport rate
S= specific density of sediment
g= gravitational constant
d 50 = median particle diameter
T = transport stage parameter
D = dimensionless grain size
For suspended load transportation is
q s = u *h * c a * { [(a/h)z1 _ (a/h)1.2]/ [(1- a/h)z1 * (1.2-z1)]}
Qs = suspended load transport rate
u = average flow velocity
h= average flow depth
Ca = reference concentration
a = height above the bed relative to particle size
Z1 = suspension number
b) the information to collect is1) erosion hillslope
2) interaction between weathering and physical erosion
3) transport mechanisms in a river
4) chemical weathering
d