Developing Empirical Hydraulic Geometry Relationships for Tidal Channels in NSW Wetlands
WRL Project staff, Dr William Glamore, Duncan Rayner and Jamie Ruprecht, recently teamed up to undertake a range of exciting new research projects in wetland hydraulics and reflooding. The first of three projects currently underway aims to develop hydraulic relationships for predicting depth, top width and cross-sectional area of tidal channels as functions of tidal prism and marsh area, rather than discharge. By knowing the tidal prism of the wetland, it will be possible to design and predict the evolution trajectory of a given channel for wetland restoration projects throughout NSW.
These empirical hydraulic geometry relationships will provide a practical geomorphic based design tool to plan tidal wetland restoration projects (Williams et. al., 2002) and assess tidal channel stability, which is of key interest to a wide range of stakeholders. The relationships will be based on data obtained from field investigations for up to eight sites (of varying size) in the lower Hunter region of NSW. At least one control site within the Tomago wetland will be considered, and the remaining sites will be investigated for size and comparison purposes. Numerical modelling of these sites will be undertaken using a calibrated hydrodynamic model of the Tomago wetland.
Additional wetland research is currently underway examining: (i) Large scale overbank reflooding dynamics of tidal wetlands; (ii) transport dynamics of organic bed material; and (iii) predicting salt marsh distribution extents under changing climate pressures.