Revista Recursos Hdricos

DOI:10.5894/rh36n1-1
O texto deste artigo foi submetido para reviso e possvel publicao em novembro de 2014, tendo sido aceite pela Comisso de Editores Cientficos Associados em janeiro de 2015. Este artigo parte integrante da Revista Recursos Hdricos, Vol. 36, N 1, 5-14, maio de 2015.

Efeito de um incndio florestal nas propriedades fsico-qumicas da gua da ribeira de So Domingos
(regio oeste de Portugal)

Effect of a forest fire on physicochemical
properties of the water of So Domingos stream
(western region of Portugal)

Bruno Miguel Meneses¹, Nuno Cortez²

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1 - Mestre em Gesto do Territrio, Geografia Fsica e Engenharia do Ambiente. Doutorando do IGOT (ULisboa) e Investigador do Centro de Estudos Geogrficos (RISKam) /// bmeneses@campus.ul.pt /// Instituto de Geografia e Ordenamento do Territrio da Universidade de Lisboa
2 - Professor Auxiliar /// Departamento de Recursos Naturais, Ambiente e Territrio, Instituto Superior de Agronomia, Universidade de Lisboa /// nunocortez@isa.ulisboa.pt /// Associado n 664

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RESUMO
Esta comunicao apresenta a avaliao do efeito de um incndio florestal nas propriedades fsicoqumicas da gua da Ribeira de So Domingos (Regio Oeste de Portugal), resultante do arrastamento de elementos e compostos qumicos pela gua de escorrncia superficial da rea ardida. Para esta avaliao selecionaram-se dois locais de amostragem na ribeira (um a montante e outro a jusante da rea ardida), onde se fizeram quatro colheitas de gua em diferentes momentos, aps o incndio. Nas amostras de gua recolhidas foram feitas determinaes de pH, da condutividade eltrica e dos teores de N, P, Ca, Mg, K e Na. Os resultados obtidos revelaram ter havido input de nutrientes na ribeira, arrastados pela gua da precipitao que escorreu superficialmente na rea ardida. Este arrastamento foi mais elevado na sequncia das primeiras chuvadas aps o incndio, reduzindo-se depois ao longo do tempo.

Palavras-chave: propriedades fsico-qumicas da gua, incndios florestais, escorrncia superficial, perda de nutrientes.

ABSTRACT
This communication presents the assessment of the effect of a forest fire on physicochemical properties of the water of So Domingos Stream (Western Region of Portugal), resulting from nutrient leaching by surface runoff from the burned area. For this evaluation have been selected two sampling locations along this river (one upstream and other downstream of the burned area), where water samples were collected at four different times after the forest fire. Water samples were analyzed for measuring pH, electric conductivity and N, P, Ca, Mg, K and Na concentrations. The measured data confirmed the input of nutrients in the river from burned area through surface runoff. This nutrient leaching reduced over time, resulting from diminished availability of elements in burnt areas.

Keywords: physicochemical properties of the water, forest fires, surface runoff, nutrients loss.

 

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