A pesquisa analisou a estabilidade lateral em ambientes fluviais do Semiárido paraibano na bacia Riacho do Tigre. O foco principal foi estudar a capacidade de ajuste lateral e sua relação com a energia do fluxo, através da identificação da composição do material das margens por meio de teste de textura e consistência, sendo também realizadas análise da cobertura vegetal e da distribuição da energia. Dos oitos trechos avaliados, dois foram classificados como estáveis; quatro, instáveis; e dois com estabilidade intermediária. A partir dos resultados gerados foi possível concluir que a vegetação desempenha um papel fundamental na estabilidade das margens, pois mesmo nas margens compostas de materiais pouco coesos não foram identificados indicios de processos erosivos devido à resistência exercida pela cobertura vegetal.
<p>The interaction between riparian vegetation growth and river evolution is characterised by complex nonlinear feedback. When dealing with non-perennial rivers, this interaction presents growth patterns directly affected by the temporality of the flow, which controls water availability. Dry periods reduce the diversity and coverage of herbaceous species along the channel and riparian area. When prolonged, it modifies/prevents ecological succession in geomorphic units, such as bars and islands and riverbanks, delaying the growth process. The long periods of gentle precipitation allow moisture to permeate the channel, allowing the maintenance of herbaceous strata. On the other hand, extreme flood events act by removing the riparian vegetation and structurally modifying the bio-geomorphological patterns. To contribute to these analyses, the present work evaluated how ecohydrological and bio-geomorphological seasonality affects the morphology of non-perennial sandy channels in Northeast Brazil. For this purpose, DEMs and orthomosaics, generated from five UAV surveys in three stretches of the basin that present a different hydrological behaviour between October 2021 and September 2022, were analysed, allowing the analysis of morphological changes in the coverage of the watershed. Vegetation. Simultaneously, we installed field quadrants to monitor the coverage and growth of some riparian vegetation species of some geomorphic units of the stretches. This information was related to data from six pluviometric pluviometric stations. The rainfall volume of the hydrological year was between 400mm and 500mm, with an average of 46 days of rain and two daily events of extreme rainfall (above 50mm/day) during the year. The wettest period was between March 20th and April 9th, when rainfall accumulated from 56mm to 118mm around the watershed and had two daily extreme rainfall events. The surveys between January 7th and March 19th identified insignificant bio-geomorphological changes in the stretches; at the beginning of the first precipitation events, erosion processes were identified in the sandy bars, which soon after were stabilised by the growth of herbaceous species. The rain events between March 20th and April 9th generated an accumulation of precipitation between 90mm and 117mm and a low flow in the channel in the monitored sections. In one of the stretches, an increase in erosive processes on the banks was identified, and in all stretches, there was the growth of herbaceous vegetation in the alluvial bed. In general, there was a significant increase in vegetation cover, mainly herbaceous, in all quadrants; some stood out for showing a 70% increase in area coverage and a 100% increase in the number of bushy species (<em>Jatropha mollissima </em>). It is essential to highlight that this quadrant is located in a sandy bar formed from the accumulation of sediment from an invasive tree individual (<em>Prosopis juliflora</em>) that was removed and relocated in an anterior extreme event and regrowth in the bed. These results highlight that the growth and maintenance of riparian vegetation and its spatial location strongly depend on the hydrological regime. The presence of vegetation associated with the deposition of sediments, stabilisation of banks and changes in morphology are vital features to river dynamic understanding.</p>
O aprimoramento metodológico e técnico do Estudo de Impacto Ambiental deve ser uma realidade a ser estudada e aprofundada para o aperfeiçoamento do licenciamento ambiental. O trabalho foi baseado numa pesquisa aplicada e descritiva sob o método documental. A pesquisa elaborou uma matriz de critérios adotada para a análise da abordagem geomorfológica do EIA de cada empreendimento, buscando orientar o trabalho e reduzir a subjetividade da análise. No recorte temporal de dez anos (2005-2014) foram analisados dezoito EIAs de diversos ramos de atividades. Verificaram-se acertos, mas também a existência de estudos deficientes em informações, dados equivocados, falta de clareza e objetividade, comprometendo a efetividade da abordagem geomorfológica nos Estudos de Impacto Ambiental.
A viabilidade ambiental de empreendimentos com significativo poder de degradação ambiental é submetida as diretrizes do licenciamento ambiental por meio do Estudo e do respectivo Relatório de Impacto Ambiental (EIA/RIMA). Este artigo busca discutir a composição das equipes profissionais elaboradoras dos EIAs/RIMAs protocolados no órgão ambiental do estado da Paraíba, entre os anos de 2000 e 2015, baseado numa pesquisa aplicada e descritiva sob o método documental. Várias deficiências na composição das equipes e no exercício profissional foram constatadas. Portanto, almeja-se um maior aprimoramento do licenciamento ambiental por parte do poder público, na busca por estudos ambientais bem elaborados, que contribuam para o aprimoramento do licenciamento ambiental e sejam efetivamente aplicados na gestão ambiental dos empreendimentos. Palavras-chave: Licenciamento ambiental, Estudo de Impacto Ambiental, Equipe multidisciplinar. A B S T R A C TThe environmental feasibility of projects with significant environmental degradation power is subject to environmental licensing guidelines through the Study and Environmental Impact Report (EIA / RIMA). This article aims to discuss the composition of the professional teams elaborating the EIAs / RIMAs filed in the environmental agency of the state of Paraíba, between 2000 and 2015, based on an applied and descriptive research under the documentary method. Several deficiencies in the composition of the teams and in the professional exercise were verified. Therefore, a greater improvement of the environmental licensing by the public power is sought, in the search for well-designed environmental studies, that contribute to the improvement of the environmental licensing and are effectively applied in the environmental management of the enterprises.Keywords: Environmental licensing, Environmental Impact Study, Multidisciplinary team.
Resumo: O Estudo de Impacto Ambiental (EIA) está previsto na legislação brasileira com o objetivo de subsidiar o licenciamento ambiental de empreendimentos e atividades consideradas efetiva ou potencialmente causadoras de significativa degradação do meio. O EIA contempla a abordagem dos conhecimentos do meio físico, destacando-se a importância da geomorfologia, que se justifica por subsidiar o planejamento para ocupação de novas áreas. O trabalho tem o objetivo de analisar a abordagem da geomorfologia nos EIAs aprovados pelo órgão ambiental da Paraíba entre os anos de 2005 e 2014. Os dados apresentados e discutidos neste trabalho demonstram que o conhecimento geomorfológico tem sido subutilizado no âmbito dos estudos de impactos ambientais e que, se for aplicado à solução/prevenção de problemas ambientais ao invés de somente descrever o ambiente, dará substância à tomada de decisão no processo de licenciamento de empreendimentos que causam grande impacto ao equilíbrio ambiental.Palavras-chave: Estudo de Impacto Ambiental; Geomorfologia; Planejamento.
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