Coastal areas are highly susceptible to the effects of climate change, particularly to sea-level rise and extreme rainfall events, resulting in increased social and environmental vulnerabilities. In this context, the need for predictive planning instruments, especially in densely populated coastal areas, is a critical management priority. A number of indexes has been developed to assess coastal vulnerability. However, coastal vulnerability indexes are yet to simultaneously consider inland (e.g., landslides and flooding) and ocean (sea-level rise and coastal erosion) hazards in conjunction. To help fill this gap, we developed the Socio-Environmental Vulnerability Index for Coastal Areas. The proposed index is a diagnostic tool to assess the socio-environmental vulnerability of coastal regions in the context of climate change. Applied to the city of Santos, a coastal municipality in São Paulo state, Brazil, the index revealed that most of the city are in areas highly vulnerable to sea-level rise and floods related to extreme rainfall events. Findings show that, in fact, approximately 70% of the area of Santos (27.5 km²) consists of high vulnerability areas mostly located close to urban drainage channels, residential, and other built-in areas. Another 0.12% (0.05 km²) were classified as very high vulnerability areas compromising port and industrial infrastructure. These results highlights the susceptibility of the urban insular area of Santos to climatic change hazards. This study might prove relevant to support local decision-makers in preparing adaptation plans and responding to climate-related risks in vulnerable coastal cities.

Most of the water supplied in Brazil comes from water streams that may have higher values for apparent color than turbidity. Treatability trials were performed for color and turbidity removal to evaluate the advantages of coagulation during the charge neutralization mechanism when compared to sweep flocculation for water with those characteristics. There were three types of trials: conventional Jar Test with raw water, with and without filtration, and in a pilot Water Treatment Plant, direct downward filtration, with synthetic water. Auxiliary equipment such as Continuous Flocculation Monitoring Equipment (CFME) and image analysis were used to evaluate the growth of flocs. In the Jar Tests experiments, similar levels of color (61.49%) and turbidity (61.30%) removal were observed, with a lower dosage of coagulant (46 mg/L) in the charge neutralization mechanism compared to the ones with sweep flocculation (58.22% for color and 54.73% for turbidity removal with 52 mg/L of aluminium sulfate). Similar results were found on pilot plant. At filtration rates of 180 and 300 m³ m⁻² day⁻¹, sweep flocculation mechanism had shorter filtration cycle (<5 m³) compared to other mechanisms. Therefore, a change in the operation of Water Treatment plants that use a coagulant dosage associated with sweep flocculation can bring advantages such as the reduction of coagulant consumption and sludge productions, as well as the increase of chlorine disinfection and filtration cycles.

This paper examines barriers and opportunities for climate change adaptation in an urban coastal setting where adaptation is in its infancy. It draws on a diagnostic framework as a foundation for identifying and organising barriers and opportunities in terms of three broad phases of the adaptation process, i.e. (1) understanding the problem, (2) planning adaptation options and (3) managing implementation of such options. Data come from the analysis of documents (e.g. policy, plans and reports) and a survey of 49 representatives from 42 organisations (e.g. government, environmental non-governmental organisations, businesses and local industry and professional associations). Nineteen barriers and/or opportunities pertaining to the different phases of the adaptation process were identified. Three of those barriers (i.e. competing priorities, existing management context and existing ecological context) are our additions to the initial list of common barriers proposed in the diagnostic framework. Barriers pertaining to the understanding phase were the most frequently noted by respondents. The understanding phase was also one which most of the barriers were nevertheless considered as opportunities. Emerging critical barriers and/or opportunities for climate change adaptation included perception of signal, availability and accessibility of information, existing management context and leadership. We propose that addressing these barriers and opportunities would involve improving perception about climate change and availability and accessibility of information, fostering anticipatory planned adaptation through the existing management context and developing leadership for adaptation. Findings from this study may prove useful to other jurisdictions, particularly those where climate adaptation is at its early stages of development.