A conceptual model of the species composition of the original riparian rainforest of the Clarence River Floodplain, New South Wales.

Coastal floodplains provide essential nursery habitat for a large number of fish and prawn species, many of which are commercially and recreationally important. Human activities in coastal floodplains, such as those associated with agriculture and (or) development, can have detrimental impacts on this nursery function. We examined the potential role of flood mitigation structures, in particular tidal floodgates, in depleting estuarine and inshore fisheries stocks in eastern Australia. We compared species assemblages (abundance and biomass) in reference and gated drainage systems in the Clarence River floodplain (New South Wales, Australia) over a 1-year period. We subsequently determined which environmental variables were associated with the observed patterns in species assemblages. Our results show that abundance, biomass, and assemblages of juvenile fishes and invertebrates differed significantly and consistently between drainage systems with and without floodgates. The major environmental variables of concern in systems with floodgates were (i) presence of a floodgate, (ii) elevated concentrations of nutrients, and (iii) abundance of aquatic weeds. We discuss our findings in light of potential strategies to improve coastal floodplain management for fisheries production purposes.

River stabilisation due to changing climate and vegetation during the late Quaternary in western Tasmania, Australia

The general and urgent need for conservation of O. richmondia devolves largely on the losses of rainforests in the region, a process that has had severe impacts on many native animals and plants, and for which the Richmond birdwing has become a notable flagship species to publicise the less heralded plight of many other invertebrates, and also some of the basic principles of landscape ecology and the critical specialised needs of interdependences between species in communities. Whilst loss of lowland rainforests of subtropical eastern Australia, and the food plant vine P. praevenosa are regarded as principal threats to the Richmond birdwing, the implications of those losses are very broad, despite notional formal protection of the communities. As emphasised earlier, suitable forest areas are now highly fragmented. In Queensland, this type of lowland rainforest survives only as fragments near the coast along Kin Kin Creek, east of Pomona, near Caloundra, and at Burleigh Heads National Park. Lower sub-coastal birdwing habitats are further inland on ridges and low valleys of the Blackall, Conondale and D’Aguilar Ranges, at Mount Tamborine, and NSW Border Ranges. In NSW there are coastal birdwing habitats in national parks, patchily distributed from the Tweed River, Byron Bay and Broken Head National Parks on the coast, and on Mount Warning and further inland near Mallanganee, near the Richmond Range. Although the vine was previously known in the area, it is not known if there are any rainforests where P. praevenosa is currently present in the Clarence River Catchment, where almost all riparian rainforest was cleared for grazing cattle in the late 1800s and early 1900s. The conservation status of P. praevenosa has been evaluated by the State Government, to be ‘lower risk’ in Queensland while the vine is not considered to have conservation significance in New South Wales.

The interactions of physical processes between estuaries and upstream river floodplains are of great importance to the fish habitats and ecosystems in coastal regions. Traditionally, a hydraulic analysis of floodplains has used one- or two-dimensional models. While this approach may be sufficient for planning the engineering design for flood protection, it is inadequate when floodwaters inundate the floodplain in a complex manner. Similarly, typical estuarine and coastal modeling studies do not consider the effect of upstream river floodplains because of the technical challenge of modeling wetting and drying processes in floodplains and higher bottom elevations in the upstream river domain. While various multi-scale model frameworks have been proposed for modeling the coastal oceans, estuaries, and rivers with a combination of different models, this paper presents a modeling approach for simulating the hydrodynamics in the estuary and river floodplains, which provides a smooth transition between the two regimes using an unstructured-grid, coastal ocean model. This approach was applied to the Skagit River estuary and its upstream river floodplain of Puget Sound along the northwest coast of North America. The model was calibrated with observed data for water levels and velocities under low-flow and high-flood conditions. This study successfully demonstrated that a three-dimensional estuarine and coastal ocean model with an unstructured-grid framework and wetting-drying capability can be extended much further upstream to simulate the inundation processes and the dynamic interactions between the estuarine and river floodplain regimes.

Arsenic (As) contamination in groundwater represents a major global health threat, potentially impacting billions of individuals. Elevated As concentrations are found in river floodplains across south and southeast Asia, as well as in the inland basins of China, despite varying sedimentological and hydrogeochemical conditions. The specific mechanisms responsible for these high As levels remain poorly understood, complicating efforts to predict and manage the contamination. Applying hydro-chemical, geological, and soil parameters as explanatory variables, this study employs multiple linear regression (MLIR) and random forest regression (RFR) models to estimate groundwater As concentrations in these regions. Additionally, random forest classification (RFC) and multivariate logistic regression (MLOR) models are applied to predict the probability of As levels exceeding 10 μg/L in the Hetao Basin (China) and Bangladesh. Model validation reveals that RFR explains 80% and 70% of spatial variability of As concentration in the Hetao Basin and Bangladesh, respectively, outperforming MLIR, which accounts for only 35% and 32%. Similarly, RFC outperforms MLOR in predicting high As probability, achieving correct classification rates of 98.70% (Hetao Basin) and 98.25% (Bangladesh) on training datasets, and 82.76% (Hetao Basin) and 91.20% (Bangladesh) on validation datasets. The performance of the MLOR model on the validation set yields accuracy rates of 81.60% and 72.18%, respectively. In the Hetao Basin, Ca2+, redox potential (Eh), Fe, pH, SO42−, and Cl− are key predictors of As contamination, while in Bangladesh, soil organic carbon (SOC), pH, and SO42− are significant predictors. This study underscores the potential of random forest (RF) models as robust tools for predicting groundwater As contamination.

The objective of the authors’ work in the area of flood forecasting and distributed modelling is to determine how different model formulations and different rainfall inputs contribute to forecast accuracy and uncertainty. To address these issues within the EU project FLOODRELIEF, a comprehensive distributed catchment model has been formulated and tested for the upper and middle Odra River. Within the FLOODRELIEF project multiple distributed modelling approaches, including the model presented here, are being developed for the Odra basin. The objectives of developing these different modelling approaches are; to evaluate the performance of these different models in representing the catchment processes and river flows, to examine the effect of model structure on the character of flow simulation and prediction uncertainty and to examine the sensitivity of these models to different rainfall input The Odra basin was selected for these analyses as a flood-prone catchment representing highly developed European catchments where comprehensive modelling of the river system, flood plains, polder subsystems, and structures as well as rainfall-runoff and snowmelt processes in the tributary catchments are required. Flood forecasting in the Odra requires both fast and reliable simulations for this complicated river basin and therefore a careful balance between accurate representation of the catchment flood processes, the flood wave movement and inundation extent and the need for rapid forecasts This paper describes the formulation, calibration, validation and real-time implementation of an operational distributed model for flood forecasting for the upper and middle Odra. This application shows that the MIKE 11 distributed model is able to reproduce the large-scale rainfall-runoff processes and the propagation of the flood wave through the main river channel system including the catastrophic flood of July 1997. This model is therefore suitable as a reference for the evaluations of different models and model structures in our investigations of simulation and forecast uncertainty. A model post-audit was carried out which identified cases where simplified representations in the rainfall-runoff models that performed well in the calibration, requires revision for the validation period. This type of post-audit analysis is extremely valuable in evaluating model performance and ensuring continuing improvement in flood forecasting accuracy

Polders (enclosed coastal embankments) are often constructed to protect river and coastal floodplains in deltas. In Bangladesh, a total of 139 polders have been constructed between the 1960s and 1980s to safeguard agricultural lands from potential damage due to tidal floods, storm surge floods, and salinity intrusion. Whilst such flood control measures reduce the probability of flooding, they have had complex impacts on geomorphological and hydrological processes with consequence for human wellbeing. This legacy of interventions in the coastal system and subsequent human adaptations, now makes decision making even more challenging at a time of increasing environmental pressures. This thesis analyses historical floods in the coastal zone in Bangladesh, diagnosing whether the floods were attributable to monsoonal precipitation (pluvial flooding), high upstream river discharge into the tidal delta (fluvio-tidal flooding), or cyclone-induced storm surges. It quantifies polders’ effectiveness by modelling different forms of inundation to estimate what flooding might have been had the polders not been constructed. Considering the societal impacts of flooding, the effects of changing land-use and flood risk on poverty are quantified. The results answer the questions of (i) how the pattern of land use/land cover (LULC) change influences flood risk at present and continue to do so in the future; (ii) how LULC change and flood risk impact poverty spatially. The last section of the thesis focuses on estimating the impacts of potential Tidal River Management (TRM) on elevating the floodplains and reducing the annual probability of flooding. It identifies suitable TRM sites to model sediment deposition in those areas. The potential impact of TRM on flooding is investigated by comparing flood susceptibility ‘before and after’ the implementation of TRM. By analyzing complex coastal flood processes and adaptation options spatially and quantitatively, this thesis provides new evidence to the effectiveness of the past (polders), and potential future (TRM) adaptation options. It also presents a new approach to flood risk estimation, considering the societal impacts of flooding. The results of this thesis could be of importance both in research and practice for making scientifically informed decisions on coastal flood risk management, particularly in Bangladesh.

Acid sulfate soils (ASS) are distributed worldwide on coastal floodplains, presenting a great challenge to coastal development and urbanisation. Upon oxidation, these soils become stratified with visibly distinguishable soil strata that are progressively less oxidised with depth. In this study, the geotechnical properties, quantified by hydraulic conductivity and consolidation coefficient, of an ASS profile from the Tweed River floodplain, north-eastern New South Wales, Australia, were investigated at a laboratory scale and compared with results obtained from the field. Measurements were conducted with a Rowe cell (or hydraulic consolidometer) by controlled compressive and pore water pressures. The results indicated that hydraulic conductivity and consolidation coefficient values gradually decreased with increasing consolidation pressure or decreasing void ratio, but were significantly higher for the more oxidised ASS horizons. These results suggest that controlled soil consolidation along ASS drainage banks may prove to be effective at reducing acid discharge. Passing low pH (pH 3) or high cation concentration (50 mm CaCl2) solutions through intact consolidated potential ASS samples did not induce changes in the hydraulic conductivity or consolidation coefficient of this material indicating that ASS soil ripening involves more than acidification reactions, and the practice of flushing drains with high ionic strength estuarine tidal waters is unlikely to induce soil subsidence as a result of ASS structural change and clay flocculation.

Mobile forms of nitrogen leach from upland environments into aquatic systems, often discharging to coastal zones. Addition of nitrogen to once N-limited systems results in a host of changes ranging from eutrophication to loss of biodiversity. Floodplains can ameliorate these changes by removing and sequestering nitrogen. In many coastal floodplains, sedimentation causes lakes to transition to baldcypress swamps, and ultimately to bottomland hardwood (BLHW) forests. These habitats differ in their contact with floodwater, which directly and indirectly affects their ability to process nutrients, but the effects of habitat change on denitrification at the floodplain scale cannot be predicted because of lack of suitable data. This study compared denitrification characteristics among the aforementioned habitats within the Atchafalaya River Basin (ARB). Microcosms were established in the laboratory, and the acetylene block technique was used to estimate four denitrification characteristics: background denitrification rates, maximum rates, time to reach maximum rates, and the linear response of denitrification to nitrate concentration. There were significant differences in denitrification characteristics among the three habitat types; specifically, all habitats differed in the time required for denitrification to respond to nitrate in the overlying water, and denitrification in lake habitats differed from both BLHWs and baldcypress swamps. Landscape-scale models should account for different linear relationships between denitrification and nitrate concentrations, and different response times to nitrate concentrations for different habitats. Because denitrification characteristics differ across habitats within the ARB, continued habitat change within the floodplain will alter nutrient discharge to coastal waters.

This research presents a geomorphological map of the Entella River floodplain (scale 1:10,000), one of the largest and urbanized Ligurian Tyrrhenian flat area. The coastal floodplain suffered substantial modifications due to human activities since the latter half of the nineteenth century, which transformed the natural landscape into an anthropogenic environment. Fluvial, marine and anthropogenic geomorphological features have been investigated through a multi-temporal analysis and the reviewing, re-elaboration and summarization of previous geographical and geomorphological materials. An historical analysis has been performed to reconstruct morphological modifications and their correlation with anthropogenic interventions. The main geomorphological map includes a multi-temporal analysis of shoreline and major anthropogenic landforms. Small sketch maps on the geographical, geological and land use settings are also provided. The detailed geomorphological map can be used for urban and land planning, including the mitigation of the meteo- and geo-hydrological risk, which historically has dramatically influenced the Entella coastal floodplain.

Wetland influences on mercury transport and bioaccumulation in South Carolina

We have constructed a model of plasmaspheric composition and density in the region bounded by the 500‐km altitude level and by the dipole field line L = 5. We first discuss the collisionless kinetic theory model of quasi‐neutral plasma distributions along a dipole field line under the gravitation field, the ambipolar diffusion electric field and the inhomogeneous magnetic field. A simpler fluid‐equation model of the plasma distribution under the influence of the above force fields is shown to be able to incorporate effects of plasmasphere thermal structure. With O+, H+, and He+ densities at 500 km as input boundary values and with a phenomenological thermal structure of the plasmasphere abstracted from Ogo 5, Prognoz, and S3‐3 satellite data, we show that the plasma density distributions in the fluid‐equation model are consistent with the densities derived from in situ satellite measurements and from whistler observations, both in the topside ionosphere and in the outer plasmasphere.

Global degradation of coastal ecosystems is influencing the provision of ecosystem services, including fisheries maintenance services. Degradation of the Australian coastal zone and its resources following European occupation has been recognised for some time. This includes the loss of ecologically important coastal wetlands, which have strong trophic and habitat links to fisheries. In NSW, structural flood mitigation works are a principle driver of the decline of coastal wetlands; however, little action has been taken to quantify the extent of decline due to limited information of the pre-European settlement extent of coastal wetlands. We use spatial data sets in GIS to quantify prime fish habitat and calculate the loss of fish habitat for the large coastal floodplains of northern NSW, which are significant contributors to the commercial and recreational fisheries of NSW. The technique is validated by comparison with early maps of wetland distribution. We identified pre-European distribution of available fish habitat of approximately 477,000 ha, of which 87,000 ha was identified as prime fish habitat. Approximately 62,000 ha of prime fish habitat was impacted by drainage of the coastal floodplains in association with flood mitigation works which intensified in the mid-1950s and were largely completed by 1971, equating to a loss of approximately 72 % of prime fish habitat. The declining value of the ecosystem services provided by prime fish habitat following drainage is likely to be substantial. Some actions have taken place to restore the functions of this habitat although significant opportunities remain to reverse this decline through management actions that restore natural drainage and reinstate tidal exchange. These actions become even more important as pressures on coastal wetlands increase with climate change and associated sea-level rise.

The paper presents and discusses models of generic mobile services. The primary goal is to gain understanding of the challenges in designing, developing and deploying advanced mobile data services. Two types of models are introduced. First, a composition model is given, describing the components of a generic mobile service and the component relationships. Second, distribution models are presented, describing the distributions of the components in the first model across hosts, networks and domains. A brief mobility analysis is carried out, followed by a discussion of the dependency of mobility and service continuity on the service distribution. The functions necessary to provide service continuity are identified and incorporated in a service continuity layer.

Chelodina rugosa occupies seasonally ephemeral waterholes on the coastal freshwater floodplains of the wet-dry tropics of northern Australia. It is an obligate carnivore and feeds primarily on fish, fast-moving aquatic invertebrates, and carrion. Differences between wet-season and dry-season diets, notably an increase in fish consumption and a decrease in consumption of odonate nymphs, reflect changes in abundance or accessibility of prey items. Elseya dentata occupies permanent water riverine habitats and is primarily herbivorous. The bulk of its diet consists of fruit and leaves of riparian rainforest trees, and seasonal changes in fruit species consumed reflected fruiting patterns. Filamentous algae comprised 30% by mass of the dry-season diet but was absent from the river during wet-season flooding and hence was absent from the diet. Elseya dentata readily feed on meat and fish carrion when available, but animal prey such as shrimp (Macrobrachium sp.) and freshwater sponge formed only a small proportion of their diet. Because E. dentata relies on riparian trees for most of its dietary intake, it is extremely vulnerable to land management practices that have adverse impacts on riparian forests.