All estuaries and coastal waterways fundamentally comprise assemblages of sedimentary environments, which have distinctive characteristics such as sediment types, nutrient cycling, plant and animal communities, and hydrological properties (McLean et al., 1993, Roy et al., 2001). These sedimentary environments, or habitats, are distinct geographical entities that can be considered structural components from which all estuaries and coastal waterways are formed. Sedimentary environments are the key components used in the development of conceptual geomorphic facies models (Reinson, 1992). The geomorphic framework presented in this study attempts to identify the inherent links between sedimentary environments, and estuarine ecology.
The conceptual models depict the relative associations of thirteen recognisable and well-documented sedimentary environments. These include tidal sand banks, central basins, fluvial (bayhead) deltas, barriers, flood and ebb tidal deltas, intertidal flats, mangroves, saltmarshes, saltflats, rocky reefs, channels, and the inner continental shelf.
Habitat associations are based on previous geomorphic and sedimentary models (e.g. Boyd et al., 1992; Dalrymple et al., 1992) and the distribution of habitats found in for Australia's coastal waterways (Heap et al., 2001). The distribution and abundance of the key sedimentary environments (particularly saltmarshes, saltflats, and mangroves) varies with latitude, and between coastal waterway types (Adam, 1998, Duke et al., 1998, Saenger et al., 1977).