Abstract
In transport-limited alluvial streams, the suspended sediment concentration C exhibits power functional relationships with the flow discharge Q at a given station. Once the power-law C-Q relationships at multiple stations along a stream are compiled, these relationships either systematically lag in the downstream direction (i.e., decreasing C downstream for a constant Q) or overlap each other (i.e., similar C for a constant Q anywhere along the stream). It has been claimed that the mode of downstream C-Q (lag or overlap) is associated with the downstream channel geometry. This poses a fundamental question as to whether different modes of downstream C-Q relationships are the mechanistic consequences of channel hydraulics functions induced by different channel geometries or distinct channel geometries are the signatures of adaptation to the varying C-Q relationships. This question is investigated in this study with theoretical streams by applying a numerical model which solves sediment flux and shallow water equations simultaneously. Simulation results are consistent with observations from natural rivers in many respects, such as power-law at-a-station and downstream hydraulic geometry relationships. Lagged C-Q relationships are reproduced whereas the degree of a lag depends on the imposed channel geometry. This agrees with field observations and can be explained through the downstream increase rate in the bed shear stress. These findings imply that the downstream lag in C-Q relationships is the resultant feature of a given channel geometry.
| Original language | English |
|---|---|
| Article number | 04018006 |
| Journal | Journal of Hydraulic Engineering |
| Volume | 144 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2018 Apr 1 |
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Keywords
- Channel geometry
- Hydraulic geometry
- River training
- Sediment rating curve
ASJC Scopus subject areas
- Civil and Structural Engineering
- Water Science and Technology
- Mechanical Engineering
Cite this
Channel geometry controls downstream lags in sediment rating curves. / Kim, Dae Hong; Paik, Kyungrock.
In: Journal of Hydraulic Engineering, Vol. 144, No. 4, 04018006, 01.04.2018.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Channel geometry controls downstream lags in sediment rating curves
AU - Kim, Dae Hong
AU - Paik, Kyungrock
PY - 2018/4/1
Y1 - 2018/4/1
N2 - In transport-limited alluvial streams, the suspended sediment concentration C exhibits power functional relationships with the flow discharge Q at a given station. Once the power-law C-Q relationships at multiple stations along a stream are compiled, these relationships either systematically lag in the downstream direction (i.e., decreasing C downstream for a constant Q) or overlap each other (i.e., similar C for a constant Q anywhere along the stream). It has been claimed that the mode of downstream C-Q (lag or overlap) is associated with the downstream channel geometry. This poses a fundamental question as to whether different modes of downstream C-Q relationships are the mechanistic consequences of channel hydraulics functions induced by different channel geometries or distinct channel geometries are the signatures of adaptation to the varying C-Q relationships. This question is investigated in this study with theoretical streams by applying a numerical model which solves sediment flux and shallow water equations simultaneously. Simulation results are consistent with observations from natural rivers in many respects, such as power-law at-a-station and downstream hydraulic geometry relationships. Lagged C-Q relationships are reproduced whereas the degree of a lag depends on the imposed channel geometry. This agrees with field observations and can be explained through the downstream increase rate in the bed shear stress. These findings imply that the downstream lag in C-Q relationships is the resultant feature of a given channel geometry.
AB - In transport-limited alluvial streams, the suspended sediment concentration C exhibits power functional relationships with the flow discharge Q at a given station. Once the power-law C-Q relationships at multiple stations along a stream are compiled, these relationships either systematically lag in the downstream direction (i.e., decreasing C downstream for a constant Q) or overlap each other (i.e., similar C for a constant Q anywhere along the stream). It has been claimed that the mode of downstream C-Q (lag or overlap) is associated with the downstream channel geometry. This poses a fundamental question as to whether different modes of downstream C-Q relationships are the mechanistic consequences of channel hydraulics functions induced by different channel geometries or distinct channel geometries are the signatures of adaptation to the varying C-Q relationships. This question is investigated in this study with theoretical streams by applying a numerical model which solves sediment flux and shallow water equations simultaneously. Simulation results are consistent with observations from natural rivers in many respects, such as power-law at-a-station and downstream hydraulic geometry relationships. Lagged C-Q relationships are reproduced whereas the degree of a lag depends on the imposed channel geometry. This agrees with field observations and can be explained through the downstream increase rate in the bed shear stress. These findings imply that the downstream lag in C-Q relationships is the resultant feature of a given channel geometry.
KW - Channel geometry
KW - Hydraulic geometry
KW - River training
KW - Sediment rating curve
UR - http://www.scopus.com/inward/record.url?scp=85041367560&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85041367560&partnerID=8YFLogxK
U2 - 10.1061/(ASCE)HY.1943-7900.0001418
DO - 10.1061/(ASCE)HY.1943-7900.0001418
M3 - Article
AN - SCOPUS:85041367560
VL - 144
JO - Journal of Hydraulic Engineering
JF - Journal of Hydraulic Engineering
SN - 0733-9429
IS - 4
M1 - 04018006
ER -