Using healthy estuaries to provide a morphological characterisation of the Dee Estuary and the estuaries in and adjacent to Morecambe Bay.
Abstract
This study used existing data to characterize the functioning of the Dee Estuary and the estuaries within and immediately outside Morecambe Bay under four headline parameters to support condition assessment judgments. This work was based on the assumption that the 'health' or condition of these estuaries is founded on the relationship between their physical forms (geometry) and the forces driving their forms (function/process) in line with the Regime Theory concepts and approaches developed by the Healthy Estuaries 2020 project. Regime Theory has been used in the Dee Estuary and the estuaries within and adjacent to Morecambe Bay to predict their equilibrium widths, which have been compared with their observed widths to determine, at a high level, how far they are from equilibrium forms. How close each estuary is to morphological equilibrium defines the condition of this attribute. The method has been combined with known natural and human constraints on morphology, where adjustment of the estuary form may not be possible due to hard geology or essential infrastructure. The method also supports identification of potential locations to restore intertidal habitat in such a way that a more sustainable estuary form is produced.