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Projecting Future Impacts of Global Change Including Fires on Soil Erosion to Anticipate Better Land Management in the Forests of NW Portugal
Publication . Pastor, Amandine V; Nunes, João Pedro; Ciampalini, Rossano; Koopmans, Myke; Baartman, Jantiene; Huard, Frédéric; Menezes, Tomás; Le Bissonnais, Yves; Keizer, Jacob; Raclot, Damien
Combined impacts of climate and socio-economic scenarios on irrigation water availability for a dry Mediterranean reservoir
Publication . Nunes, João Pedro; Jacinto, Rita; Keizer, Jacob
The impacts of climate and associated socio-economic changes on water availability, including supply and demand, quality, and storage volume, were evaluated for the Vale do Gaio reservoir in southern Portugal, located in a dry Mediterranean climate and already under drought stress. The SWAT model was applied with 6 scenarios for 2071-2100, involving two storylines (A1B and B1) with individual changes in climate (-9% rainfall, increasing in winter by +28 to +30%), socio-economic conditions (an increase in irrigation demand by 11%, and a replacement of cereals and pastures by sunflower), and a combination of both. Most future scenarios resulted in lower water availability, due to lower supply (-19 to -27%) combined with higher irrigation demand (+3 to +21%). This resulted in more years with limited irrigation supplies (presently: 28%; scenarios: 37 to 43%), although limitations were mitigated by lower losses to excess discharge. Land-use changes also decreased quality by increasing P concentrations (+29 to +93%). Impacts were more severe in scenario A1B than in B1, and in combined changes than in climate or socio-economic changes only. Water availability was resilient to climate change, as impacts led only to a moderate aggravation of present-day conditions. Lower future water availability could be addressed by supply and demand management strategies and, in the most extreme scenario, by water transfers from regional water reserves; water quality issues could be addressed through land-use policies. Results also highlighted the importance of taking the characteristics of water supply systems into account when designing adaptation measures for future changes.
Hydrological and Erosion Processes in Terraced Fields: Observations from a Humid Mediterranean Region in Northern Portugal
Publication . Nunes, João Pedro; Bernard-Jannin, Léonard; Rodríguez-Blanco, María-Luz; Santos, Juliana Marisa; Coelho, Celeste; Keizer, Jacob
A simple water balance model adapted for soil water repellency: application on Portuguese burned and unburned eucalypt stands
Publication . Nunes, João Pedro; Malvar, Maruxa Cortizo; Benali, Akli; Rial Rivas, María Ermitas; Keizer, Jacob
Soil water repellency can impact soil hydrology, overland flow generation and associated soil losses. However, current hydrological models do not take it into account, which creates a challenge in repellency-prone regions. This work focused on the adaptation for soil water repellency of a daily water balance model. Repellency is estimated from soil moisture content using site-specific empirical relations, and used to limit maximum soil moisture. This model was developed and tested using c. 2 years of data from one long-unburned and two recently burned eucalypt plantations in northern Portugal, all of which showed strong seasonal soil water repellency cycles. Results indicated important improvements for the burned plantations, with the Nash-Sutcliffe efficiency increasing from -0.55 and -0.49 to 0.55 and 0.65. For the unburned site, model performance was already good without the modification and efficiency only improved slightly from 0.71 to 0.74, mostly due to the better simulation of delayed soil wetting after dry periods. Results suggested that even a simple approach to simulate soil water repellency can markedly improve the performance of hydrological models in eucalypt forests, especially after fire.
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Fundação para a Ciência e a Tecnologia
Programa de financiamento
5876-PPCDTI
Número da atribuição
PTDC/AAC-AMB/100520/2008