<abstract xmlns="http://www.w3.org/1999/xhtml"><p>In the Baixo Vouga region of north-central Portugal, forests occupy half of the territory, of which two thirds are Eucalypts plantations. The hydrological implications of this large-scale introduction of eucalypt are unknown and the aim of this exploratory study, realized in the Caramulo Mountains, was to describe overland flow (OLF), subsurface flow (SSF) and stream flow (Q) in a catchment dominated by Eucalyptus plantations. The main conclusions are that annual OLF rate is low, spatially heterogeneous between 0.1% and 6% and concentrated during the wet season as saturation excess, particularly as return flow. Infiltration-excess OLF due to the strong soil water repellence (SWR) is dominant during dry season, but produces residual runoff amount. SSF is the principal mechanism of runoff formation. It originates from matrix flow and pipe flow at the soil-bedrock interface, principally during the wet season. Matrix flow is correlated with soil moisture (SM) content, with a threshold of 25 %. Pipe flow starts with saturation of soil bottom but without saturation of the entire soil profile, due to a large network of macropores. Stream flow response is highly correlated with matrix flow behaviour in timing and intensity. SWR induces a very patchy moistening of the soil, concentrates the fluxes and accelerates them almost 100 times greater than normal percolation of the water in the matrix.</p></abstract>

In the Baixo Vouga region of north-central Portugal, forests occupy half of the territory, of which two thirds are Eucalypts plantations. The hydrological implications of this large-scale introduction of eucalypt are unknown and the aim of this exploratory study, realized in the Caramulo Mountains, was to describe overland flow (OLF), subsurface flow (SSF) and stream flow (Q) in a catchment dominated by Eucalyptus plantations. The main conclusions are that annual OLF rate is low, spatially heterogeneous between 0.1% and 6% and concentrated during the wet season as saturation excess, particularly as return flow. Infiltration-excess OLF due to the strong soil water repellence (SWR) is dominant during dry season, but produces residual runoff amount. SSF is the principal mechanism of runoff formation. It originates from matrix flow and pipe flow at the soil-bedrock interface, principally during the wet season. Matrix flow is correlated with soil moisture (SM) content, with a threshold of 25 %. Pipe flow starts with saturation of soil bottom but without saturation of the entire soil profile, due to a large network of macropores. Stream flow response is highly correlated with matrix flow behaviour in timing and intensity. SWR induces a very patchy moistening of the soil, concentrates the fluxes and accelerates them almost 100 times greater than normal percolation of the water in the matrix.

Surface and subsurface flow in eucalyptus plantations in north-central Portugal

Centro de Estudos do Ambiente e do Mar (CESAM), Departamento de Ambiente e Ordenamento, Universidade de Aveiro, 3810-193 Aveiro, Portugal

Departamento de Ciências Exatas e Ambientais, Escola Superior Agrária de Coimbra, Bencanta, 3040-316 Coimbra, Portugal

Journal of Hydrology and Hydromechanics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"Surface and subsurface flow in eucalyptus plantations in north-central Portugal"}

In the Baixo Vouga region of north-central Portugal, forests occupy half of the territory, of which two thirds are Eucalypts plantations. The hydrological...

Surface and subsurface flow in eucalyptus plantations in north-central Portugal

Published Online: Jun 25, 2015

Page range: 193 - 200

Received: Nov 24, 2014

Accepted: Jan 13, 2015

DOI: https://doi.org/10.1515/johh-2015-0015

© 2015

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.