CETN IV-15
Rev. September 1999
∑Q
∑Q
∑ ∆V
+ ∑ P - ∑ R = Residual = 0
-
-
source
sink
[Q ebb _ A 2] - [Q net _ A 2 + Q j _ A 2 + Q sl _ A 2] - [ ∆V A 2] + [ PA 2] = 0
[Q ebb _ A 2] - [141 + 16 + 7.3] - [ -48 ] + [ 25 ] = 0
Q ebb _ A 2 = 91
in units of thousands of cubic meters.
The control volume for the ebb-tidal shoal now has one unknown, the rate of sediment transport
from the channel to the ebb-tidal shoal, Qebb_ch. Applying Equation 1 gives,
∑Q
∑Q
∑ ∆V
+ ∑ P - ∑ R = Residual = 0
-
-
source
sink
[Q ebb _ A1 + Q ebb _ ch ] - [Q ebb _ A 2] - [ ∆ Vebb ] = 0
[0 + Q ebb _ ch ] - [91] - [77 ] = 0
Q ebb _ ch = 168
The final unknown is the rate of sediment transport from the channel to the flood-tidal shoal,
Qfl_ch. Equation 1 applied to the inlet channel control volume gives,
∑Q
- ∑ Qsink - ∑ ∆V + ∑ P - ∑ R = Residual = 0
source
[Qj _ A1 + Qj _ A2] - [Qebb _ ch + Qfl _ ch] - [∆Vch] - [ Rch] = 0
[189+16] - [168 + Qfl _ ch] - [19] - [2.4] = 0
Qfl _ ch = 15.6 ~ 15
The calculated value of Qfl_ch = 15.6 approximately agrees with the assumed change in volume
for the flood-tidal shoal, ∆Vfl = 15, indicating that there are no other significant sediment sources
contributing to the growth of the flood-tidal shoal.
Discussion of Examples. These example problems illustrate one approach that can be taken for
formulating a sediment budget. The following assumptions entered:
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