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Mapping buried Holocene landscapes : past lowland environments, palaeoDEMs and preservation in GIS
In a geological GIS-data recombination project, a digital map was produced that contains information on the Netherlands’ former coastal and delta plain landscapes over the last 14,000 years: the Holocene and the very end of the Pleistocene. The polygon map product is accompanied by a set of palaeoDEMs (Digital Elevation Models) indicating the attention depth for buried land surfaces and aquatic deposits for four time slices. This paper provides conceptual background information on the legend and construction principles behind the polygon maps and the palaeoDEMs, i.e. the decisions taken during the making of. It also provides a basic overview of the map product: landscape structure, burial depth and preservation, visualised for the four time slices in the RCE’s Archaeology Knowledge Kit. The text links coastal plain buried landscape mapping for four time slices to the other Knowledge Kit activities described in this volume, notably that of the Archaeological Landscapes map (for the most recent time slice in the coastal plain area of the Netherlands, and for all time slices in the Pleistocene uplands).
Knowledge for informed choices : tools for more effective and efficient selection of valuable archaeology in the Netherlands
Archaeological heritage management benefits from well-informed and transparent decisionmaking. With the aim of providing ‘knowledge for informed choices’, a series of tools have been developed for archaeological heritage management in the Netherlands. They include digital maps, datasets, methods, guidelines, best practice and web-based applications to facilitate the effective, efficient and transparent selection of valuable archaeological remains. The tools relate to archaeological predictions, disturbances by agriculture and other activities, archaeological heritage maps, prospection methods, research questions, and scientific syntheses to close the archaeological heritage management cycle. They are examined in the various chapters in this publication. The tools were developed as part of the Cultural Heritage Agency’s ‘Archaeology Knowledge Kit’ programme.
Landslide susceptibility mapping of refugee camps in Bangladesh
Over the course of the Rohingya crisis, Cox’s Bazar District (CBD) in Bangladesh has become the main area that accommodates the Rohingya refugees. Many of the refugee camps are located on hilly areas, which have been deforested for accommodation of refugees. Coupling this with the fact that CBD is located in a region with high rainfall intensity and duration makes this area very susceptible to rainfall-induced landslides. Therefore, it is crucial to identify landslide prone zones in CBD and plan accommodation, protection and rescue activities, accordingly. In this study we develop landslide susceptibility maps using only publicly available data. In doing so, we gauge the usability and reliability of such data for an initial hazard assessment. Previous landslide susceptibility maps developed for the refugee camps in CBD considered a single controlling factor, namely slope. In this study, we consider 12 controlling factors: NDVI, slope, aspect, TPI, sand, silt and clay fractions, depth to the bedrock, lithology, and distance to roads, waterways and faults. The Frequency Ratio Method is used to develop the landslide susceptibility maps. Out of the 12 combinations of controlling factors examined in this study, the map that considered NDVI, slope, aspect, TPI, sand fraction, and distance to the roads resulted in the highest accuracy in finding landslide prone areas in the camps. The outcome of the study suggests that publicly available data can be used for initial evaluation of landslide susceptibility in refugee camps. The results and methodology of this study can be helpful for humanitarian organizations who face the challenge of reducing the vulnerability of refugee camps.
Proceedings of the 2nd International Conference on Natural Hazards and Infrastructure - ICONHIC2019 (23-26 June 2019, Chania, Crete Island, Greece)
Mixotrophic protists and a new paradigm for marine ecology : where does plankton research go now?
Many protist plankton are mixotrophs, combining phototrophy and phagotrophy. Their role in freshwater and marine ecology has emerged as a major developing feature of plankton research over recent decades. To better aid discussions, we suggest these organisms are termed “mixoplankton”, as “planktonic protist organisms that express, or have potential to express, phototrophy and phagotrophy”. The term “phytoplankton” then describes phototrophic organisms incapable of phagotrophy. “Protozooplankton” describes phagotrophic protists that do not engage in acquired phototrophy. The complexity of the changes to the conceptual base of the plankton trophic web caused by inclusion of mixoplanktonic activities are such that we suggest that the restructured description is termed the “mixoplankton paradigm”. Implications and opportunities for revision of survey and fieldwork, of laboratory experiments and of simulation modelling are considered. The main challenges are not only with taxonomic and functional identifications, and with measuring rates of potentially competing processes within single cells, but with decades of inertia built around the traditional paradigm that assumes a separation of trophic processes between different organisms. In keeping with the synergistic nature of cooperative photo- and phagotrophy in mixoplankton, a comprehensive multidisciplinary approach will be required to tackle the task ahead.
The costs of living with floods in the Jamuna floodplain in Bangladesh
Bangladeshi people use multiple strategies to live with flooding events and associated riverbank erosion. They relocate, evacuate their homes temporarily, change cropping patterns, and supplement their income from migrating household members. In this way, they can reduce the negative impact of floods on their livelihoods. However, these societal responses also have negative outcomes, such as impoverishment. This research collects quantitative household data and analyzes changes of livelihood conditions over recent decades in a large floodplain area in north-west Bangladesh. It is found that while residents cope with flooding events, they do not achieve successful adaptation. With every flooding, people lose income and assets, which they can only partially recover. As such, they are getting poorer, and therefore less able to make structural adjustments that would allow adaptation in the longer term.
Measuring the solids loading of urban drainage systems via run off
Sewer and urban drainage systems deal with the runoff of areas that lack infiltration capacity. During wet weather, solids that are present on the street are (re)mobilised and transported to the drainage system by the runoff. These solids and their associated pollutants can have detrimental effects on receiving water quality. This paper presents a new measurement device which has been developed to measure the inflow of solids in gully pots. This device has been applied to 100 gully pots over a period of a year, rendering a large dataset of solid inflows to the sewer. The results indicate that only 25% of solids is captured in gully pots without this device. This renders a huge potential for further optimisation of gully pot management, which is typically optimised towards prevention of blockage rather than removing a maximum amount of solids.
L'eau dans la ville - stratégies et solutions pour une gestion durable : 10e conférence internationale Novatech (Lyon, 01-04 juillet 2019) : programme et résumés
The 10th edition of Novatech was a time for multidisciplinary discussions and interactions around sustainable urban water management, with a particular focus on urban stormwater. The conference brought together perspectives from urban land management (planners, urban designers, architects, landscape architects, sociologists, etc), water management (public and private water managers, municipalities), along with researchers. Novatech aimed to facilitate a culture of collaboration and sharing on urban water management, highlight new knowledge and practice.
Quantitative assessment of the environmental risk due to climate change-driven coastline recession : A case study in Trincomalee coastal area, Sri Lanka
Climate change may exacerbate the environmental damage due to coastal hazards and increase associated risks. This would result in degradation of coastal wetlands, especially in developing countries due to the lack of sufficient resilience to coastal hazards such as inundation and coastal erosion. Environmental damages will lead to a decrease in services provided by the coastal wetland ecosystems that contribute to human wellbeing. To provide better insights on the little known issue of quantifying potential climate change-driven environmental risk, this article presents a stepwise approach to quantify coastline recession-driven risk associated with the tourism service provided by the Trincomalee beaches, dunes and pelagic system (Indian Ocean) along the East coast of Sri Lanka in 2110. To achieve this, here we first estimate the loss value of the tourism service due to sea level rise (SLR) and storm induced erosion in 2110, by using economic valuation techniques followed by a scenario-based approach. This is followed by the quantification of the environmental risk value by combining the result of the aforementioned loss value with the exceedance probability of coastal erosion derived from a prior study. Results show a medium environmental risk value ranging from 0 to 11,000 US$/Ha of beach area due to complete beach loss by 2110. This indicates that SLR and storm induced erosion in 2110 is not likely to pose a very high environmental risk associated with the tourism service of ecosystems in Trincomalee coasts. The approach presented in this study can be directly applied in other coastal areas of interest to gain a better understanding of the likely costs of climate change driven environmental risk, which is an emerging topic in coastal zone management.
The effect of tides and storms on the sediment transport across a Dutch barrier island
Under natural conditions, barrier islands might grow vertically and migrate onshore under the influence of long-term sea level rise. Sediment is transported onshore during storm-induced overwash and inundation. However, on many Dutch Wadden Islands, dune openings are closed off by artificial sand-drift dikes that prevent the influx of sediment during storms. It has been argued that creating openings in the dune row to allow regular flooding on barrier islands can have a positive effect on the sediment budget, but the dominant hydrodynamic processes and their influence on sediment transport during overwash and inundation are unknown. Here, we present an XBeach model study to investigate how sediment transport during overwash and inundation across the beach of a typical mesotidal Wadden Sea barrier island is influenced by wave, tide and storm surge conditions. Firstly, we validated the model XBeach with field data on waves and currents during island inundation. In general, the XBeach model performed well. Secondly, we studied the long-term sediment transport across the barrier island. We distinguished six representative inundation classes, ranging from frequently occurring, low-energy events to infrequent, high-energy events, and simulated the hydrodynamics and sediment transport during these events. An analysis of the model simulations shows that larger storm events cause larger cross-shore sediment transport, but the net sediment exchange during a storm levels off or even becomes smaller for the largest inundation classes because it is counteracted by larger mean water levels in the Wadden Sea that oppose or even reverse sediment transport during inundation. When taking into account the frequency of occurrence of storms we conclude that the cumulative effect of relatively mild storms on long-term cross-shore sediment transport is much larger than that of the large storm events.