Estuarine geomorphodynamic assessment of environmental change and stressor impacts: a geographic information systems and remote sensing (geoinformatic) modelling approach for sustainable management of southeast Australian coastal ecosystems

Increased habitation and global warming is posing growing threats to the coastal zone and estuarine settings through direct and indirect environmental and anthropogenic modification of sensitive coastal systems and their relevant catchments. It is essential to understand the impact of the different stressors on the coastal environment under current conditions and within the historical record in order to predict future responses of estuaries and coastal wetlands. Short-term remote sensing and GIS modelling and field assessment have made a significant contribution to our knowledge on estuarine and coastal wetland dynamism within the last few decades. This thesis assesses the potential impacts of anthropogenic modifications, climatic factors and sea level rise on estuarine eco-geomorphic intertidal sedimentary landforms and their associated coastal wetlands in southeastern Australia based on three estuarine systems on the south coast of NSW: the estuarine Comerong Island, Wandandian deltaic estuary, and Towamba estuary. The thesis’ short-term evaluation approach shows that the degradation levels on estuarine platforms are dependent on catchment development, sediment characteristics, ecosystem stability and sea level rise inundation. During anticipated climate change and rising sea level conditions, estuaries depend on their sediment source areas, especially on modifications to their river catchment. Catchments with high anthropogenic modification levels, like the dam infrastructure in the Shoalhaven River catchment, influence sediment availability and transportation with clear impacts on eco-geomorphic coastal platform losses. In contrast, mostly unmodified but high-sloped catchments, such as the Towamba example, may have other negative effects on the estuary since the sediments are poorly sorted and coarser noncohesive quartz-dominated particles cause the geomorphic landforms and associated ecosystems to be more vulnerable to erosion and lead to less stable vegetation. Regions with small moderately modified catchments, such as the Wandandian site, allow ideal geomorphic processes to occur. Here, sediment is weathered slowly and moved downstream naturally to a secure inner estuarine deltaic setting where fine sandy/silty particles accumulate and provide more geomorphic stability. Associated vegetation assemblages ensure the progradation and steady growth of the deltaic eco-geomorphic system. The thesis assessment shows the eco-geomorphic-dynamism of the Towamba estuary, which has a mostly unmodified catchment surface (only 14% anthropogenic modifications), has grown a total of 0.17 km2 since 1949. This growth rate indicates that the Towamba estuary future scenarios will mostly be filled at the completion of the 21st Century. In comparison, the partially modified (22.1%) catchment has prograded the Wandandian deltaic shorelines resulting in the total growth of 0.24 km2 during the study period (1949-2016). However, results on Comerong Island show significant changes in the spatial extent, elevation, and shorelines with total net losses of 0.3 km2 over the investigated timespan (1949-2014). Changes included northern accretion (0.4 km2), and western, middle and southern erosion (0.7 km2) of the island. The thesis emphasises the dynamic character of the estuarine eco-geomorphic system, particularly using Normalised Difference Vegetation Index (NDVI) as a vegetation canopy assessment approach. This approach illustrates the significant correlations between vegetation and climatic and geomorphic influences at the study sites, indicating that these factors are the main drivers of vegetation canopy disturbance on intertidal sedimentary landforms during the 21st Century. Locally, map-algebra expression shows the spatial distribution of the NDVI identifies areas that need to be managed in relation to the causes and drivers. This modelling confirms the LiDAR-DEMs-driven character of the existing situations to their influencing factors, which also control the estimated future-scenarios and illustrate clear inundatable landform zones at the study sites by 2100. Results indicate that the rise of sea level will have tremendous effects on the coastal eco-geomorphic systems, particularly wetlands, throughout southeastern Australia and equivalent systems overseas by the end of this century. This thesis develops possible mitigation and adaptation strategies and sustainable solutions that might be utilized to minimize the indirect devastating consequences of climate change and anthropogenic modifications, particularly damming rivers, which cause direct sedimentation problems as implied by the Tallowa Dam case study. The thesis shows that intertidal sedimentary landforms will have a future negative or positive vegetarian response according to their evolving morphological character. Within a short-term timescale, the whole eco-geomorphic system will interact with many environmental and anthropogenic variables (particularly sedimentation rates) to evolve its own character over a longer timescale. Therefore, the long term assessment approach can be directed by having a better understanding of the existing situation and accurately identifying the past drivers. Future projections indicate that indirect anthropogenic-induced global warming will have a great effect on estuaries and coastal wetlands in the 21st Century. This research helps to provide an important framework for quantifying the current situation, future stressors and vulnerability responses during any intensification of natural and artificial coastal hazards, which may be of concern to the general public and environmental scientists who are currently focusing their attention on the best way to preserve estuaries and their wetland ecosystems at the current stage of global warming and human settlement

Sustainable solutions for exposed concrete surfaces to climatic influences - Within various regions: An industrial-geographic letter to civil-constructors

Environmental factors significantly influence concrete surfaces. Infrastructures are affected by variety climatic conditions including: extreme temperatures, droughts, moist and humid conditions or even inundation, and they are more likely to experience negative influences on their concrete surfaces. Thus, this research aims to identify sustainable solutions to decrease the vulnerability of concrete exposed to climatic and environmental influences by assessing the response of concrete surfaces to high solar radiation, high temperatures, and wet weather conditions. Our results within warm and tropical regions show that temperature fluctuations lead to expansion and shrinkage of concrete, particularly in buildings with poor thermal insulation. Including iron components are prone to these shrink-swell processes, causing crack development and expansion over time. Then, this study is suggested some responding solutions including; plant covering over concrete surfaces of the structures as well as use of some light-coloured silicates to reduce solar radiation absorption. Another focus of this study is to analyse the roles of some environmental factors including salinity, humidity, rain, and snow that may influence the concrete surfaces, particularly within wet and coastal regions. Previous studies show that the permeability of concrete surfaces increase the Infiltration of water which can lead to corrosion of iron components, and salt accumulation within cavities, particularly affecting coastal-zone infrastructures. Thus, a suggestion of high-density, low-porous concrete to be used to prevent the diffusion of water into concrete surfaces. The concrete surface problems that are occurring due to various environmental factors can cause severe damage. The corrosions including peeling process is an example of such damage that often is not-repairable. Notably, if peeling occurs within the primary reinforcing structure, the metal bodies are likely exposed to corrosion, which then requires a greater response to be fixed. Thus, the information provided in this study yield base suggestions which can support informed decision-making during planning and construction stages to sustain longer-lasting concrete surfaces under different environmental conditions. Additionally, the concrete material industry can benefit from this research, as the findings provide guidance to the use of more suitable materials for improved structural integrity under various climatic conditions

Geoinformatic analysis of vegetation and climate change on intertidal sedimentary landforms in southeastern Australian estuaries from 1975-2015

Vegetation canopies represent the main ecosystems on intertidal landforms and they clearly respond to changes in coastal environments. Climate change, including temperature, precipitation and sea level rise, are affecting the health and distribution of coastal vegetation, as well as the runoff and sedimentation rates that can impact coastal areas. This study has used the normalized difference vegetation index (NDVI) to investigate vegetation canopy dynamics on three different coastal sites in southeastern Australia over the past 47 years (1975 2015). NDVIs temporal-datasets have been built from satellite images derived from Landsat 1 8. These were then regressed to the climatic and geomorphic variables. Results show clear increases in NDVI at Towamba and Wandandian Estuaries, but a decline at Comerong Island (southeastern Australia). The sedimentation rate has the most significant positive impact on NDVI since it has the potential to provide additional space for vegetation. Temperature and sea level rise have positive effects, except on Comerong Island, but rainfall has no significant effect on the NDVI at any site. Different NDVI trends have been recorded at these three coastal sites reflecting different correlations between the vegetation, climatic and geomorphic (as independent) variables. The geomorphological characteristics of the highly-dynamic intertidal estuarine landforms, which are subject to active erosion and deposition processes, have the largest impact on vegetation cover and, hence, on NDVI. Assessing the vegetation canopy using NDVI as an evaluation tool has provided temporal-dynamic datasets that can be correlated to the main individual environmental controls. Such knowledge will allow resource managers to make more informed decisions for sustainable conservation plans following the evaluation the potential consequences of any environmental changes

Causes and consequences of environmental degradation along the Shatt Al–Arab River: a coupled human and natural systems (CHANS) perspective

© 2020, Springer Nature B.V. The Shatt Al-Arab River region (SARR) in Iraq was an economically important area for food production. By the 1970s the environment of this region had begun to deteriorate, and since then the SARR has suffered from severe human- and natural-induced problems. In this study we use a coupled human and natural systems (CHANS) perspective to identify these problems, their interconnections, and the degree to which human or natural systems have contributed to environmental degradation. We used several measures of ecological, economic and social systems to quantify the problems and document changes over the past five decades. The SARR has experienced significant climatological changes from 1975 to 2017, including lower precipitation and humidity, and increases in temperature and sea level, which affected the salinity of groundwater and river water. Human systems in the SARR also experienced tremendous stresses, including war and economic sanctions. We calculated and analyzed changes in vegetation via NDVI classification of Landsat imagery for five dates between 1975 and 2017 to understand how the environment has been affected. Changes in climatological variables were associated with lower NDVI throughout the region. However, vegetation decreased on the Iraqi side of the river, while it increased slightly on the Iranian side. This drop appears related to higher salinity in both surface and groundwater in Iraq, while irrigation from less saline water has maintained more consistent vegetation in Iran, suggesting that hydrologic diversion may be driving distinct trajectories for land use and vegetation on either side of the Shatt Al-Arab River

Short-term Geoinformatics Evaluation in the Shatt Al-Arab Delta (Northwestern Arabian/Persian Gulf)

© Coastal Education and Research Foundation, Inc. 2020. Al-Aesawi, Q.; Al-Nasrawi, A.K.M., and Jones, B.G., 2020. Short-term geoinformatics evaluation in the Shatt Al-Arab delta (northwestern Arabian/Persian Gulf). Journal of Coastal Research, 36(3), 498-505. Coconut Creek (Florida), ISSN 0749-0208. Riverine deltas are records of past hydrosedimentary conditions, in conjunction with nearshore tidal and wave dynamics. Within recent human developments, these variables have been affected by increased global warming as well as anthropogenic modifications on the feeder catchment, the delta itself, and the active/discharge channel. This paper investigates the recent (1971-2016) changes at the mouth of the Shatt Al-Arab delta, which includes migration of the navigation channel to inside the Iraqi border. Farther upstream, the channel is migrating toward the Iranian side. A mapping study was conducted with new data obtained from bathymetric surveys as used in the digital shoreline analysis system in GIS applications. The results highlight significant changes regarding the shoreline positions and rates of erosion and sediment accumulation. Additionally, mapping the coastal dynamics has revealed significant shoreline migration with differences between the left and right sides of the river mouth and an increased salinity intrusion up the channel. The effect of these findings could potentially affect the classification of the river mouth, changing it from delta to estuary and affect the international demarcation border

Geoinformatics vulnerability predictions of coastal ecosystems to sea-level rise in southeastern Australia

Coastlines are dynamic environments, with their Eco-geomorphology controlled by a complex range of natural and anthropic processes. Estuarine environments and associated wetland ecosystems are a critical shoreline types with regards to biodiversity, and are particularly susceptible to the influence of sea-level rise. This project applied future sea-level rise of Intergovernmental Panel on Climate Change (IPCC) hydro-scenarios to assess its impact on the eco-geomorphic aspects of coastal ecosystems in terms of risk assessment and sustainability. Comerong Island is used as a case study and is compared with other surrounding ocean-influenced and lagoonal deltas to assess the regional effects of sea-level rise. Applying the IPCC scenarios to the chosen geomorphic coastal data-sets resulted in a hydro-geomorphic model that shows the study site was already under pressure in 2015, with significant land area projected to be lost by 2050 and 2100. These findings are also expected to occur across the remaining estuaries in southeastern Australia. Applying this broad-scale, multi-strand application of geoinformatics simulation (GIS & RS), together with the various IPCC sea-level rise scenarios, will be necessary to assess future ecosystem sustainability management plans for coastal zones worldwide

Geoinformatics vulnerability predictions of coastal ecosystems to sea-level rise in southeastern Australia

Coastlines are dynamic environments, with their Eco-geomorphology controlled by a complex range of natural and anthropic processes. Estuarine environments and associated wetland ecosystems are a critical shoreline types with regards to biodiversity, and are particularly susceptible to the influence of sea-level rise. This project applied future sea-level rise of Intergovernmental Panel on Climate Change (IPCC) hydro-scenarios to assess its impact on the eco-geomorphic aspects of coastal ecosystems in terms of risk assessment and sustainability. Comerong Island is used as a case study and is compared with other surrounding ocean-influenced and lagoonal deltas to assess the regional effects of sea-level rise. Applying the IPCC scenarios to the chosen geomorphic coastal data-sets resulted in a hydro-geomorphic model that shows the study site was already under pressure in 2015, with significant land area projected to be lost by 2050 and 2100. These findings are also expected to occur across the remaining estuaries in southeastern Australia. Applying this broad-scale, multi-strand application of geoinformatics simulation (GIS & RS), together with the various IPCC sea-level rise scenarios, will be necessary to assess future ecosystem sustainability management plans for coastal zones worldwide

Surface Elevation Dynamics Assessment Using Digital Elevation Models, Light Detection and Ranging, GPS and Geospatial Information Science Analysis: Ecosystem Modelling Approach

Surface elevation dynamics have always responded to disturbance regimes. Creating Digital Elevation Models (DEMs) to detect surface dynamics has led to the development of several methods, devices and data clouds. DEMs can provide accurate and quick results with cost efficiency, in comparison to the inherited geomatics survey techniques. Nowadays, remote sensing datasets have become a primary source to create DEMs, including LiDAR point clouds with GIS analytic tools. However, these data need to be tested for error detection and correction. This paper evaluates various DEMs from different data sources over time for Apple Orchard Island, a coastal site in southeastern Australia, in order to detect surface dynamics. Subsequently, 30 chosen locations were examined in the field to test the error of the DEMs surface detection using high resolution global positioning systems (GPSs). Results show significant surface elevation changes on Apple Orchard Island. Accretion occurred on most of the island while surface elevation loss due to erosion is limited to the northern and southern parts. Concurrently, the projected differential correction and validation method aimed to identify errors in the dataset. The resultant DEMs demonstrated a small error ratio (≤ 3%) from the gathered datasets when compared with the fieldwork survey using RTK-GPS. As modern modelling approaches need to become more effective and accurate, applying several tools to create different DEMs on a multi-temporal scale would allow easy predictions in time-cost-frames with more comprehensive coverage and greater accuracy. With a DEM technique for the eco-geomorphic context, such insights about the ecosystem dynamic detection, at such a coastal intertidal system, would be valuable to assess the accuracy of the predicted eco-geomorphic risk for the conservation management sustainability. Demonstrating this framework to evaluate the historical and current anthropogenic and environmental stressors on coastal surface elevation dynamism could be profitably applied worldwide