Author(s): James Simpson, William Glamore, Stefan Felder
Linked Author(s): Stefan Felder
Keywords: Buoyancy-automated tidal gate, head discharge relationship, hydraulic design, physical modelling, self-regulating tidal gate
Abstract:
Around the world, many low-lying estuaries has been converted into agricultural and commercial land via the installation of floodgates. These floodgates prevent natural tidal flushing upstream, causing the estuaries to degrade and acidify. The purpose of the study is to design and develop an improved buoyancy-automated tidal gate, allowing tidal flushing to resume upstream, improving water quality and aiding fish migration. The conceptual design was based upon hydrostatic pressure and buoyancy considerations while identifying optimal dimensions of buoyancy floats, pivot arm and counter weight. For a range of upstream and downstream flow depths, the hydraulic performances of the tidal gate is tested in a laboratory flume. The experiments confirmed that the gate met the design and operation objectives. This finding is in close agreement between observed closing profiles in the laboratory tests and the design calculations based upon hydrostatic considerations. The flow patterns of the gate exposed different flow regimes with variations in upstream and downstream flow depths including unsubmerged weir flows, submerged weir flows and submerged orifice flows. Head discharge curves and best fit equations were determined for each flow regime allowing the numerical modelling of tidal flows through the structure. The present study introduced a new tidal gate design, and the successful test of its hydraulic performance confirming its suitability for estuary remediation projects.
(2632, 80, 369)
Year: 2017