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Advisor(s)
Abstract(s)
As centrais Mini-Hídricas são aproveitamentos hidroelétricos com potências instaladas
inferiores a 10 MVA. Regra geral, estas centrais são a fio de fio-de-água, ou seja, havendo
armazenamento de água este será em pequena quantidade, minimizando os impactos ambientais
em relação a uma central de albufeira. No entanto, os açudes característicos das mini-hídricas
podem impedir a passagem de peixes, isolando as populações existentes a montante do açude.
O presente trabalho incidiu no estudo das comunidades piscícolas presentes a montante e a
jusante da Mini-hídrica da Ribeira de Santa Natália, pertencente à Região Hidrográfica 3 (RH3),
afluente da margem direita do Rio Tâmega. O principal objetivo foi o de apurar a existência ou
não de continuidade fluvial na zona da Mini-Hídrica e verificar a necessidade da implementação
de um dispositivo de transposição para peixes no referido local.
A amostragem da ictiofauna, foi realizada em três locais, tendo em consideração a localização de
elementos (como açudes) que poderiam constituir barreira à passagem da mesma. Foram
inventariadas quatro espécies piscícolas, nomeadamente, truta-de-rio (Salmo trutta), bordalo
(Squalius alburnoides), boga do Norte (Pseudochondrostoma duriense) e enguia-europeia
(Anguilla anguilla).A truta-de-rio e o bordalo, principais espécies capturadas, foram encontradas
nos três locais de amostragem, verificando-se que a Ribeira de Santa Natália apresenta uma
comunidade piscícola saudável e relativamente bem estruturada. As espécies boga e enguia
apresentaram-se como residuais.
Deste estudo, foi possível concluir que os açudes intermédios (açudes semi-desagregados de
pequena dimensão), construídos no trecho da Ribeira de Santa Natália, não constituem por si só
um obstáculo à passagem de peixes, pois é potencialmente possível, principalmente durante o
período de Inverno, a sua transposição por esta comunidade para os troços mais a montante.
Small Hydropower plants are hydroelectric power installed with less than 10 MVA. This diversion dams do not generally impound water in a reservoir, minimizing environmental impacts in relation to a central reservoir. However, the reservoirs characteristic of Small hydro can prevent fish passage, isolating existing populations upstream of the weir. The present work focused on the study of fish communities present upstream and downstream of the Small hydro installed in the Santa Natalia stream, belonging to River Basin District 3 (RH3), a right bank tributary of the River Tâmega. The main objective was to determine if exist fluvial continuity in the area of Small-Hydro and verify the need for the implementation of a device for fish passage. The sampling of fish fauna was conducted at three locations, taking into account the location of elements (such as weirs) that could constitute a barrier to its passage. Four fish species were surveyed including brown trout (Salmo trutta), calandino (Squalius alburnoides), northern straightmouth nase (Pseudochondrostoma duriense) and European eel (Anguilla anguilla). Brown trout and calandino, the main captured species, were found in the three sampling sites, confirming that the Santa Natalia stream has a healthy fish community and relatively well structured. The species northern straight-mouth nase and eel showed up as residual. We conclude that the intermediate reservoirs (semi-disaggregated small weirs), built on the studied stretch of the Santa Natalia stream, not constitute by itself a barrier to fish passage. Potentially it is possible, especially during the winter period, the transposition of fish fauna to the upstream sections.
Small Hydropower plants are hydroelectric power installed with less than 10 MVA. This diversion dams do not generally impound water in a reservoir, minimizing environmental impacts in relation to a central reservoir. However, the reservoirs characteristic of Small hydro can prevent fish passage, isolating existing populations upstream of the weir. The present work focused on the study of fish communities present upstream and downstream of the Small hydro installed in the Santa Natalia stream, belonging to River Basin District 3 (RH3), a right bank tributary of the River Tâmega. The main objective was to determine if exist fluvial continuity in the area of Small-Hydro and verify the need for the implementation of a device for fish passage. The sampling of fish fauna was conducted at three locations, taking into account the location of elements (such as weirs) that could constitute a barrier to its passage. Four fish species were surveyed including brown trout (Salmo trutta), calandino (Squalius alburnoides), northern straightmouth nase (Pseudochondrostoma duriense) and European eel (Anguilla anguilla). Brown trout and calandino, the main captured species, were found in the three sampling sites, confirming that the Santa Natalia stream has a healthy fish community and relatively well structured. The species northern straight-mouth nase and eel showed up as residual. We conclude that the intermediate reservoirs (semi-disaggregated small weirs), built on the studied stretch of the Santa Natalia stream, not constitute by itself a barrier to fish passage. Potentially it is possible, especially during the winter period, the transposition of fish fauna to the upstream sections.
Description
Keywords
Mini-hídrica Ictiofauna Continuidade fluvial
Citation
Santos, Cátia; Varandas, Simone; Lopes, Marisa; Pereira, Vitor; Santos, Pedro; Teixeira, Amílcar (2013). Continuidade fluvial em mini-hídricas- o caso da Ribeira de santa Natália. In 7º Congresso Florestal Nacional. Bragança: Sociedade Portuguesa de Ciências Florestais. p. 430-440. ISBN 978-972-99656-2-3
Publisher
Sociedade Portuguesa de Ciências Florestais