Large numbers of people live along and depend upon the world's coastal resources. Human modifications of the coastal zone, in combination with climate induced environmental changes, have had a major effect on the natural ecological systems. GIS analysis of remote sensed data, combined with fieldwork and laboratory tests, can be used to determine the resultant eco-geomorphic changes that need to be managed sustainably on a worldwide scale. Modelling the eco-geomorphic dynamics between 1949 and 2016 on the Wandandian Creek delta (southeastern NSW, Australia) provides a case study of management options for such coastal resources. Results from the Wandandian Creek delta show that sand/silt sediment derived from the partially (22%) modified terrestrial catchment has prograded into the wave-dominated St. Georges Basin where it is impacted by nearshore processes. Clear spatio-temporal growth of the areal extent and elevation of the deltaic levees and sandspits, with their associated mangroves and saltmarshes, has occurred over the past 65 years. Although the growth rate has fluctuated during the study period, due to flood events in 1974, 1990s and 2010, the overall subaerial and subaqueous delta area has had an average growth of 4168 m 2 annually with the shoreline extending 1.451 m/year on average. This geomorphic growth has stabilised the estuarine deltaic habitats with high proportions of nutrients and organic matter, particularly within saltmarsh, mangrove, Casuarina/Juncus and other mixed native plant areas. This research shows the importance of analysing morphological changes observed on the delta that can be related to both anthropogenic modifications and natural processes to the catchment and thus should be used in the development of catchment and coastal management plans.

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Monitoring estuarine ecological-geomorphological dynamics has become a crucial aspect of studying the impacts of climate change and worldwide infrastructure development in coastal zones. Together, these factors have changed the natural eco-geomorphic processes that affect estuarine regimes and comprehensive modelling of coastal resources can assist managers to make appropriate decisions about their sustainable use. This study has utilised Towamba estuary (southeastern NSW, Australia), to demonstrate the value and priority of modelling estuarine dynamism as a measure of the rates and consequences of eco-geomorphic changes. This research employs several geoinformatic modelling approaches over time to investigate and assess how climate change and human activities have altered this estuarine eco-geomorphic setting. Multitemporal trend/change analysis of sediment delivery, shoreline positions and land cover, determined from fieldwork and GIS analysis of remote sensing datasets, shows significant spatio-temporal changes to the elevation and areal extent of sedimentary facies in the Towamba estuary over the past 65 years. Geomorphic growth (~ 2600 m annually) has stabilised the estuarine habitats, particularly within native vegetation, salt marsh and mangrove areas. Geomorphic changes have occurred because of a combination of sediment runoff from the mostly unmodified terrestrial catchment, nearshore processes (ocean dynamics) and human activities. The construction of GIS models, verified with water and sediment samples, can characterise physical processes and quantify changes within the estuarine ecosystem. Such robust models will allow resource managers to evaluate the potential effects of changes to the current coastal ecosystems.

Early civilizations have inhabited stable-water-resourced areas that supported living needs and activities, including agriculture. The Mesopotamian marshes, recognised as the most ancient human-inhabited area (~6000 years ago) and refuge of rich biodiversity, have experienced dramatic changes during the past five decades, starting to fail in providing adequate environmental functioning and support of social communities as they used to for thousands of years. The aim of this study is to observe, analyse and report the extent of changes in these marshes from 1972 to 2020. Data from various remote sensing sources were acquired through Google Earth Engine (GEE) including climate variables, land cover, surface reflectance, and surface water occurrence collections. Results show a clear wetlands dynamism over time and a significant loss in marshlands extent, even though no significant long-term change was observed in lumped rainfall from 1982, and even during periods where no meteorological drought had been recorded. Human interventions have disturbed the ecosystems, which is evident when studying water occurrence changes. These show that the diversion of rivers and the building of a new drainage system caused the migration and spatiotemporal changes of marshlands. Nonetheless, restoration plans (after 2003) and strong wet conditions (period 2018 - 2020) have helped to recover the ecosystems, these have not led the marshlands to regain their former extent. Further studies should pay more attention to the drainage network within the study area as well as the neighboring regions and their impact on the streamflow that feeds the study area.

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