TY - JOUR
TI - Morphological Process of a Restored Estuary Downstream of a Tidal Barrier
AU - Kuang, C
AU - Liang, H
AU - Gu, J
AU - Su, T
AU - Zhao, X
AU - Song, H
AU - Ma, Y
AU - Dong, Z
T2 - Ocean & Coastal Management
AB - Hydrodynamic and morphological processes become more complex with large spatial variations after tidal barrier building and estuary restoration. Using a process-based model, responses in the estuary to a two-phase restoration measure in the Shuanglong Estuary are investigated. Numerical modeling indicates that tide-asymmetry in the barraged estuary is the primary factor that determines responses of morphology. After partial absence of tidal flats (first-phase restoration), flood tide-asymmetry is switched to ebb tide-asymmetry in the lower unrestored reach. This induces lower estuary erosion via increased tidal prism, though it is enhanced in the upper widened-deepened restored reach leading to severe siltation. After full restoration (second-phase restoration), current velocities are significantly increased with reduced flood tide-asymmetry. A quantitative comparison of the impact of the cross-sectional profile to net sediment transport shows that a switch from flood-dominated estuary to ebb-dominated estuary can be caused by reshaping the tidal flat which may reduce flood tide-asymmetry. The sediment flushing efficiency after the estuary restoration is further investigated in different sluice discharges with regards to two floodgate operations. Low sluice discharge during ebb tides increases the sediment flushing efficiency, but continuous high sluice discharge contributes to significant improvement of sediment flushing capacity and reduction of flushing duration. We conclude to prevent the flushed sediment from re-deposition into the estuary, a larger flushing capacity discharge released in a short period is required after the second-phase restoration in the Shuanglong Estuary.
DA - 2017/03//
PY - 2017
VL - 138
SP - 111
EP - 123
UR - https://www.sciencedirect.com/science/article/pii/S0964569117300315
DO - 10.1016/j.ocecoaman.2017.01.012
LA - English
KW - Tidal
KW - Marine Energy
KW - Changes in Flow
KW - Sediment Transport
KW - Physical Environment
ER -