Hypsometry of estuaries, creeks and breached sea wall sites

The way in which the plan area of a drainage basin varies
with elevation, is known as the hypsometry and is a useful
way of capturing key elements of the geomorphological
form. Variations in this form can alter the way the tide
propagates and change the ebb and flood properties of the
tide. The hypsometry can be particularly relevant where a
sea wall is to be breached to create new mudflat and
saltmarsh within a managed re-alignment site. A number of
parametric relationships are examined and used to fit data
obtained from bathymetry and topography for a range of
estuaries, creeks and breached sea wall sites. These results
are used as the basis for a method to characterise the
hypsometry of inlets and breached sea wall sites. This is
particularly useful for the design of breaches in managed
re-alignment sites because the hypsometry has a major
influence on the rate of infilling and hence the size of breach required to avoid scour problems. It also provides an
indication of the likely habitat composition of the site
ranging from mudflat to saltmarsh to supra-tidal.