Assessing community vulnerability to floods and hurricanes along the Gulf Coast of the United States

Hurricanes and flooding have affected millions of people and generated massive economic losses over the past several decades. Geographic information system (GIS) methods are employed in this paper to analyse coastal communities' vulnerability to these two hazards along the Gulf Coast of the United States. Specifically, two types of quantitative indicators are developed: (i) exposure to hurricanes and flooding, based on information from multiple sources; and a social vulnerability index, constructed using census data. These indices are combined to depict the spatial patterns of overall community vulnerability to hurricanes and flooding along the US Gulf Coast. The results of this study can potentially inform disaster management agencies, county governments, and municipalities in areas at heightened risk. Furthermore, the demonstration of the geographic distribution of community vulnerability can assist decision-makers in prioritising to-do items and designing policies and plans for the more effective allocation of resources. The paper ends by discussing the study's limitations and its practical implications.     

An Ecological and Economic Assessment Methodology for Coastal Ecosystem Management

An adaptation of the Drivers-Pressure-State-Impact-Response methodology is presented in this work. The differential DPSIR (ΔDPSIR) was developed to evaluate impacts on the coastal environment and as a tool for integrated ecosystem management. The aim of the ΔDPSIR is to provide scientifically-based information required by managers and decision-makers to evaluate previously adopted policies, as well as future response scenarios. The innovation of the present approach is to provide an explicit link between ecological and economic information related to the use and management of a coastal ecosystem within a specific timeframe. The application of ΔDPSIR is illustrated through an analysis of developments in a Southwest European coastal lagoon between 1985 and 1995. The value of economic activities dependent on the lagoon suffered a significant reduction (ca. −60%) over that period, mainly due to a decrease in bivalve production. During that decade the pressures from the catchment area were managed (ca. 176 million Euros), mainly through the building of waste water treatment plants. Notwithstanding this, the ecosystem state worsened with respect to abnormal clam mortalities due to a parasite infection and to benthic eutrophication symptoms in specific problematic areas. The negative economic impacts during the decade were estimated between −565 and −315 million Euros, of which 9–49% represent the cost of environmental externalities. Evaluation of these past events indicates that future management actions should focus on reducing the limitation on local clam seeds, which should result in positive impacts to both the local socio-economy and biodiversity.     

Bankfull Regional Curves for North and Northwest Florida Streams1

Abstract: Regional curves, which relate bankfull channel dimensions and discharge to watershed drainage area, are developed to aid in identifying the bankfull stage in ungaged watersheds, and estimating the bankfull discharge and dimensions for river studies and natural channel design applications. This study assessed 26 stable stream reaches in two hydro‐physiographic regions of the Florida Coastal Plain: the Northwest Florida Coastal Plain (NWFCP) and the North Florida Coastal Plain (NFCP). Data from stream reaches in Georgia and Alabama were also used to develop the Florida regional curves, since they are located in the same hydro‐physiographic region. Reaches were selected based on the presence of U.S. Geological Survey gage stations and indicators of limited watershed development (e.g., <10% impervious surface). Analyses were conducted to determine bankfull channel dimensions, bankfull discharge, average channel slope, and Rosgen stream classification. Based on these data, significant relationships were found between bankfull cross‐sectional area, width, mean depth, and discharge as a function of drainage area for both regions. Data from this study suggested that bankfull discharges and channel dimensions were larger from NWFCP streams than from Coastal Plain streams in North Carolina and Maryland. Bankfull discharges were similar between NFCP and Georgia coastal plain streams; therefore, the data were combined into one regional curve. In addition, the data were stratified by Rosgen stream type. This stratification strengthened the relationships of bankfull width and mean depth as a function of drainage area.     

Comparative study of different advective schemes: Application to the MECCA model

A 3-D version of the MECCA model (Model of Estuarine and Coastal Circulation Assessment) is used to simulate the dynamics of the Eastern part of the English Channel. This area is characterized by a strong tidal turbulent regime and a frontal zone identified near the French coast by a low-salinity band. The model uses the upwind scheme to approximate the advective terms. Results show that the model overestimates the band width of the frontal zone and that this anomaly is definitely caused by the numerical diffusion introduced by the so-called upwind scheme (first-order approximation). In this paper, we study the flux-limiter schemes as an alternative to the upwind method in order to reduce this non-physical diffusion. To illustrate the improvements provided by this type of schemes, a comparison in 2-D schematic cases is made between the upwind and centered scheme with more recent higher-order schemes combined with limiter namely Minmod, Superbee, Van Leer and Monotonized Centered (MC) (called also MUSCL scheme). Respecting the CFL condition, our numerical simulations show that the flux-limiter schemes reduce the numerical diffusion and eliminate the oscillations caused by the non-limited higher-order schemes. For the schematic and realistic cases, the Superbee limiter is a good compromise between shape preservation and computational cost.     

Effects of reduced water quality on coral reefs in and out of no‐take marine reserves

Near‐shore marine environments are increasingly subjected to reduced water quality, and their ability to withstand it is critical to their persistence. The potential role marine reserves may play in mitigating the effects of reduced water quality has received little attention. We investigated the spatial and temporal variability in live coral and macro‐algal cover and water quality during moderate and major flooding events of the Fitzroy River within the Keppel Bay region of the Great Barrier Reef Marine Park from 2007 to 2013. We used 7 years of remote sensing data on water quality and data from long‐term monitoring of coral reefs to quantify exposure of coral reefs to flood plumes. We used a distance linear model to partition the contribution of abiotic and biotic factors, including zoning, as drivers of the observed changes in coral and macro‐algae cover. Moderate flood plumes from 2007 to 2009 did not affect coral cover on reefs in the Keppel Islands, suggesting the reef has intrinsic resistance against short‐term exposure to reduced water quality. However, from 2009 to 2013, live coral cover declined by ～50% following several weeks of exposure to turbid, low salinity water from major flood plume events in 2011 and subsequent moderate events in 2012 and 2013. Although the flooding events in 2012 and 2013 were smaller than the flooding events between 2007 to 2009, the ability of the reefs to withstand these moderate floods was lost, as evidenced by a ～20% decline in coral cover between 2011 to 2013. Although zoning (no‐take reserve or fished) was identified a significant driver of coral cover, we recorded consistently lower coral cover on reserve reefs than on fished reefs throughout the study period and significantly lower cover in 2011. Our findings suggest that even reefs with an inherent resistance to reduced water quality are not able to withstand repeated disturbance events. The limitations of reserves in mitigating the effects of reduced water quality on near‐shore coral reefs underscores the importance of integrated management approaches that combine effective land‐based management with networks of no‐take reserves.     

The direct influence of ship traffic on atmospheric PM2.5, PM10 and PAH in Venice

The direct influence of ship traffic on atmospheric levels of coarse and fine particulate matter (PM_2.5, PM₁₀) and fifteen polycyclic aromatic hydrocarbons (PAHs) has been estimated in the urban area of Venice. Data analysis has been performed on results collected at three sites over the summer, when ship traffic is at a maximum. Results indicate that monitoring of the PM daily concentrations is not sufficiently detailed for the evaluation of this contribution, even though it could be useful for specific markers such as PAHs. Therefore a new methodology, based on high temporal resolution measurements coupled with wind direction information and the database of ship passages of the Harbour Authority of Venice has been developed. The sampling sites were monitored with optical detectors (DustTrack^® and Mie pDR-1200) operating at a high temporal resolution (20s and 1s respectively) for PM_2.5 and PM₁₀. PAH in the particulate and gas phases were recovered from quartz fibre filters and polyurethane foam plugs using pressurised solvent extraction, the extracts were then analysed by gas chromatography- high-resolution mass spectrometry. Our results shows that the direct contribution of ships traffic to PAHs in the gas phase is 10% while the contribution to PM_2.5 and to PM₁₀ is from 1% up to 8%.     

Reconstructing historical trends of Berre lagoon contamination from surface sediment datasets: influences of industrial regulations and anthropogenic silt inputs

These last decades, the Berre lagoon (in southeastern France) has been deeply affected since the 1930s by strong inputs of contaminants associated with industrial development and since 1966 by huge inputs of freshwater and silts due to the installation of a hydroelectric power plant. Surveys of the surface sediment contamination have been sparsely performed since 1964 for management and research purposes. These surveys were performed by various laboratories that investigated different chemicals and sampling areas using different analysis protocols. Therefore, the available data are disconnected in time and space and differ in quality. In order to reconstruct coherent time series of sediment contamination from this heterogeneous datasets and to discuss the influences of industrial and hydroelectric discharges we used a statistical approach. This approach is based on Principal Component Analysis (PCA) and Fuzzy clustering analysis on data from one extensive survey realized on surface sediments in 1976. The PCA allowed identifying two geochemical indexes describing the main surface sediment geochemical characteristics. The fuzzy clustering analysis on these indexes allowed identifying sub-areas under the specific influence of industrial or hydroelectric discharges. This allowed us to reconstruct, for each sub-area, a coherent and interpretable long-term time series of sediment contamination from the available database. Reconstructed temporal trends allowed us to estimate: (i) the overall decrease of sediment contamination since the mid-1970 attributed to industrial discharge regulations enacted at this period and (ii) the dilution of the concentrations of sediment bound contaminants induced by the hydroelectric power plant and its associated particulate matter inputs.     

辽宁省海洋经济对地区经济发展的影响分析

基于辽宁省海洋经济的发展现状,从研究辽宁省海洋产业结构的角度出发,利用多元相关分析方法,重点分析了辽宁省海洋各产业对地区经济发展的影响程度.结果表明,在辽宁省海洋产业中,海洋渔业、造船业、交通运输业和旅游业推动了地区经济的增长,而海洋油气业和海盐业对地区经济的拉动作用不明显.     

厦门环同安湾海岸带景观空间格局动态变化分析

利用遥感和地理信息技术,运用平均斑块面积与分离度指数、多样性指数、破碎度指数、优势度指数和分维数等景观格局指数,以厦门环同安湾区1989年、1997年和2007年3个时期遥感影像解译数据作为基本信息源,对过去18年间环同安湾海岸带的景观格局的时空变化过程和演变趋势进行了研究。结果表明：1989—2007年,农田面积大量...