Abstract Understanding how wave climate variability and its trends change over time are crucial analyses required to mitigate potential wave-induced impacts and adapt coastal areas to such effects. The long-term trends and breakpoints of the wave energy flux (WEF) and its relationship with teleconnection patterns in southern Brazil were studied using ERA-5 wave reanalysis with validation using a waverider. We determined that the interannual mean WEF (WEFm) and extreme WEF (WEF98) that reaches the southern Brazil have increased over the past four decades, with a increment of 0.063 and 0.17 kW/m/year, respectively 0.63 and 0.29% per year. By the Muggeo method we determined that subperiods with increasing WEFm trends are related to the SSE and SSW quadrants and that these are also the most energetic ones and with the highest annual increment rates of WEFm and WEF98. Our results also suggest that the positive trends observed in interannual WEF values are likely related to the long term transition of cold to warm Atlantic Multidecadal Oscillation (AMO) phase in the western South Atlantic Ocean. From a coastal risk perspective, it is important to understand the relationship between climatic indices and the wave climate to support long-term coastal management policies.

Abstract This paper describes wave prediction results for Patos Lagoon's northern sector through numerical modeling using Delft3D software. ERA-Interim satellite reanalysis data of wind intensity and direction were used as inputs to force the hydrodynamic model. For SWAN calibration and validation in the study region, wave parameters were used. These parameters were acquired in situ by a directional waverider buoy. Statistical data showed the good performance of the model, albeit with a tendency to overestimate significant wave height and underestimate peak period and propagation direction. Once validated, wave parameters for five points at different depths were obtained during the four seasons of the year between 2017 and 2018. In general, it was observed that the largest ripples come from the S and SSW directions and occurred during spring at the deepest point under wind conditions exceeding 10 m s-1. Ripples up to 0.30 m account for 77.9 % at the shallowest point and 65.7 % at the deepest point. Thus, the study area was classified as low energy and characterized by small, high-frequency, short-period ripples strongly influenced and determined by the local depth because larger ripples are always observed in the deepest locations, giving the lagoon a characteristic of depth-limited ripples. The results obtained here have the potential to contribute to territorial management of the region, with emphasis on the Integral Protection Conservation Unit located in the study area (Itapuã State Park) and on the development and safety of the important, heavily used navigation route that connects Rio Grande Port to the state capital, Porto Alegre.

Resumo Geoindicadores são medidas de processos e fenômenos geológicos que ocorrem perto ou sobre a superfície da Terra e que variam significantemente durante um período de até 100 anos. Nas últimas três décadas, o uso de geoindicadores foi direcionado para avaliações de impactos e riscos geológicos. Seu uso, porém, ainda é pouco difundido e explorado em relação aos demais indicadores ambientais. Este estudo tem por objetivo contribuir à difusão de informação e aplicabilidade dos geoindicadores. Definimos como geoindicador um parâmetro ou aspecto comumente estudado ou monitorado nos ambientes costeiros. Os geoindicadores aqui propostos foram testados com vistas à avaliação da vulnerabilidade física costeira das praias do Rio Grande do Sul, Brasil. Quatro geoindicadores foram definidos e aplicados: altura e estado morfo-ecológico de dunas frontais, posição de linha de costa e concentração de sangradouros. Além destes indicadores de caráter físico, outro de caráter socioambiental foi incluído, qualidade sanitária. Os indicadores foram agregados para gerar um Índice de Vulnerabilidade Física para sete localidades ao longo do litoral costeiro do Rio Grande do Sul. Um mapa cartográfico de linguagem acessível ao público comum e aos tomadores de decisão foi gerado a partir dos indicadores e do Índice.

Abstract Geoindicators are means adopted for the measurement of geological processes and phenomena that occur at or near the Earth's surface and vary significantly over periods of 100 years or less. These tools have focused on assessing geological impacts and risks over the last three decades. However, the use of geoindicators is not widely known and has not been as greatly exploited as have most environmental indicators. The objective of this study is to contribute to the diffusion of information about and the application of geoindicators. We have defined, in terms of geoindicators, parameters and aspects of coastal environments that are commonly studied or monitored. The geoindicators proposed were designed for assessing coastal physical vulnerability in the case of the coastal beaches of Rio Grande do Sul, Brazil. Four geoindicators were defined and tested: the height and morpho-ecological state of the foredunes, shoreline position, and washout concentrations. An additional sócio-environmental indicator was included, sanitary quality. These indicators were brought together to constitute a Physical Vulnerability Index that represented seven locations along the coastline assessed. In addition, the indicators and Index values were used to generate a cartographic map that could be understood by the public and used by decision makers.

Pesquisas referentes à dinâmica sedimentar em lagos são escassas e a maioria trata da distribuição e textura dos sedimentos, sendo raras aquelas que fazem menção ao padrão de ondas e suas relações com a ressuspensão destes sedimentos e suas consequências. Este trabalho analisa as características das ondas incidentes no Lago Guaíba (Brasil) por meio da utilização do SWAN (Simulating Waves Nearshore) e suas relações com a ressuspensão de sedimentos junto ao fundo. Os resultados mostraram que as maiores ondas incidentes atingiram 0.55 m, particularmente quando de ventos do quadrante S e SE e com velocidades maiores que 7 m/s. Em termos gerais, as características das ondas seguem os padrões de intensidade e direção dos ventos, atingindo seus máximos valores aproximadamente 1 ou 2 horas após a velocidade de pico dos ventos. Em conclusão, os ambientes de sedimentação do lago foram mapeados e classificados da seguinte forma: 1) Ambientes Depositionais (51% da área do lago); 2) Ambientes Transicionais (41%); e 3) Ambientes Erosionais ou de não deposição (8%).Como forma de contribuir à gestão ambiental da região, foram gerados subsídios referentes ao potencial de concentração de material particulado em suspensão.

Little research has been undertaken into sediment dynamics in lakes, and most of it only analyses particular aspects such as the texture of the sediments. In this study, the characteristics of the wave field in Guaíba Lake are investigated. The parameters significant wave height (Hs), period (T) and direction of wave propagation are examined together with their relation to the resuspension of sediments at the bottom. For this purpose, the mathematical model SWAN (Simulating Waves Nearshore) has been validated and employed. The results pointed out that the highest waves modeled reached 0.55 m at a few points in the lake, particularly when winds were blowing from the S and SE quadrants with an intensity over 7 m.s-1. Generally speaking, waves follow wind intensity and direction patterns, and reach maximum height in about 1 to 2 hours after wind speed peaks. Whenever winds were stronger, waves took some 2 hours to reach 0.10 m. However, with weak to moderate winds, the waves took around 3 hours to achieve this value in significant wave height. In addition to speed and direction, wind regularity proved relevant in generating and propagating waves on Lake Guaíba. In conclusion the lake's sediment environments were mapped and classified as follows: 1) Depositional Environments (51% of the lake); 2) Transitional Environments (41%); and 3) Erosional or Non-Depositional Environments (8%). As a contribution to the region's environmental management, elements have been created relating to the concentration of suspended particulate matter.

A gestão costeira e marinha do Brasil dá-se a partir de espaços definidos pela legislação específica do tema, tais como ‘Mar Territorial’, ‘Zona Costeira’, entre outros. A partir de 2004 o Decreto 5.300, que regulamentou a Lei do Gerenciamento Costeiro no país, definiu um novo espaço geográfico de gestão do território: a Orla Marítima. No Brasil, uma das principais frentes de ação do Ministério do Meio Ambiente é o Projeto ORLA, que tem como objetivo otimizar o ordenamento dos espaços litorâneos sob domínio da União, aproximando as políticas ambiental, urbana e patrimonial. O presente artigo descreve os dez anos de existência do Projeto ORLA sob a ótica da situação legal dos espaços de orla marítima e praia, identificando as principais contribuições e entraves do referido projeto à gestão da zona costeira brasileira. Como principal conclusão, aponta-se para a necessidade de retomada do Projeto junto aos municípios atendidos, com foco na revisão dos Planos de Gestão da Orla e na definição das formas de apoio à implementação das ações propostas nos Planos de Gestão. Embora apresente problemas específicos, principalmente na implementação das ações supracitadas, o Projeto Orla pode ser considerado uma ação governamental exitosa, dada a consistente mobilização por parte da sociedade em torno de seus objetivos e por tratar-se de um projeto consolidado, com metodologia validada e amplamente aplicada ao longo de seus dez anos de existência.

The coastal and marine management in Brazil was defined from specific legislation, such as ‘Territorial Waters’, ‘Coastal Zone’, among others. From 2004, Decree 5300, which regulated the Coastal Management Act in the country, set a new geographical area of land management: the seashore. In Brazil, one of the main line of action of the Ministry of Environment is the ORLA Project, which aimed to optimize planning of coastal areas under national jurisdiction, by harmonizing environmental, urban, and national heritage policies. This paper is a proposed study on Orla Project’s ten years of existence from a legal perspective; a review of the situation of coastlines and beaches, plus a description of the main contributions - as well as obstacles - of the Orla Project to management of the Brazilian coastal zone. As a main conclusion, pointing to the need to resume the project in the municipalities served, focusing on reviewing the seashore Management Plans and defining ways to support the implementation of actions proposed in the management plans. Although it has specific problems, especially in implementing the above actions, the Orla Project can be considered a successful government action; given the consistent mobilization by the society around their goals and that this is a consolidated project, with validated methodology and widely applied throughout its ten years of existence.