Predictive models for the environmental degradation of coastal lagoon beaches in New South Wales

To date a large proportion of coastal researchers have focused their texts and reviews on estuaries to the detriment of coastal lagoons, which have virtually been ignored (Bird 1994). Lagoons are characteristic of much of the temperate southeast coastline of Australia. New South Wales alone has over 70 coastal lagoons and lakes. The NSW coastline is densely populated and developed and is under increasing environmental pressure. Continued population growth in the coastal region demands enhanced coastal management. The current high level of coastal development means that coastal lagoons are frequently subject to a range of direct and indirect impacts due to land use in the catchment, changes to hydrology and tidal processes, and the direct use of the lagoon waterways. This thesis has focussed on the physical and geomorphic variable interactions of lagoons to facilitate the construction of four predictive models. This study encompassed the sampling of sixty-one lagoon beaches within New South Wales. From the data collected, a total of fifty-two relationships were statistically tested between four general lagoon health indicators and thirteen observed physical and geomorphic variables. The relationships were statistically tested using the chi square analysis in an attempt to link them with the observed variations in lagoon beach health. Eighteen relationships were found to be statistically significant. The four predictive models were then developed based upon these results. These models enable us to predict what will happen to the health of lagoon beaches and therefore may be utilised in management practices for more appropriate land uses.