The Impacts of Climate Change on Irrigated Agriculture in Southern Portugal

Climate change projections point to increasing air temperature and reduced precipitation in southern Portugal, which would affect farming systems. This study aims to assess the impacts of climate change on irrigated agriculture in southern Portugal. These impacts were assessed by combining climate model data with a soil water balance model and a numerical model for the design of irrigation systems. Meteorological data from two weather stations were used along with three climate models (HadRM3P, HIRHAMh and HIRHAMhh; 2071–2100). The crop rotations studied included sugar beet–maize–tomato–wheat and sunflower–wheat–barley. Two adaptation measures were considered: (i) maintaining the current crop varieties; (ii) using new crop varieties. The results from the considered climate change scenarios indicated that the impacts of climate change on irrigation requirements depend on the adopted adaptation measures. On average, the seasonal irrigation requirements increased by 13–70% when new crop varieties were used and by −13 to 7% when the current crop varieties were maintained. The impacts of climate change on irrigation system design were considerable, with the design flow rate increasing by 5–24%.

Regras de operação do reservatório de Magos para controlo de cheias

Face à Directiva 2007/60/CE relativa à avaliação e gestão do risco de inundações, ao Decreto-Lei nº 344/2007 que aprova o Regulamento de Segurança de Barragens, ao aumento de áreas urbanizadas e às projecções dos modelos de clima para o fim do século, que apontam para o aumento da frequência e da intensidade da ocorrência de inundações causadas por eventos de precipitação intensa de curta duração, é crucial a definição de regras de operação nos reservatórios com controlo de cheias. O Reservatório de Magos pertence à bacia hidrográfica do rio Tejo, está situado no Concelho de Salvaterra de Magos e tem como usos principais a rega e o controlo de cheias. Este trabalho tem como objecto de estudo a definição das regras de operação (restrição no caudal descarregado) do Reservatório de Magos para controlo de cheias no troço a jusante. São aplicados o modelo hidrológico HEC-HMS 3.1.0, o modelo hidráulico HEC-RAS 3.1.3 e o modelo de simulação de reservatórios HEC-ResSim 3.O para o cálculo do hidrograma de cheia, da zona inundável e para simulação do balanço de água no reservatório, respectivamente. Como resultado são apresentadas as regras de operação (caudal máximo e mínimo a descarregar) do Reservatório de Magos para controlo da zona inundável a jusante, no caso de um evento de cheia. /ABSTRACT: Based on the Directive 2007/60/CE related to the Assessment and Management of Flood Risks, on the Decree-Law n. o 344/2007 which approves the Regulation for Dam Safety, the increased urban areas and to the projections of climate models by the end of the century which is pointing to an increased frequency and intensity of occurrence of floods caused by intense rainfall events of short duration, establishing rules of operation for flood control in reservoirs becomes crucial. The Magos Reservoir belongs to the river Tagus basin, located in the county of Salvaterra de Magos and has as its main uses the irrigation and flood control. This study aims to establish the rules of operation (flow discharged restriction) of the Reservoir of Magos for flood control in the downstream reach. The methodology used in the present work includes the application of the Hydrological model HEC-HMS 3.1.0, the Hydraulic model HEC-RAS 3.1.3 and a reservoir simulation model HEC-ResSim 3.0 to calculate the hydrograph of peak discharge, floodplain zone and simulate reservoir operations, respectively. As a result, the rules of operation (maximum flow and minimum discharge) of Magos Reservoir for flood control in a downstream reach in case of flood event are presented.

New measures for assessing model equilibrium and prediction mismatch in species distribution models

Models based on species distributions are widely used and serve important purposes in ecology, biogeography and conservation. Their continuous predictions of environmental suitability are commonly converted into a binary classification of predicted (or potential) presences and absences, whose accuracy is then evaluated through a number of measures that have been the subject of recent reviews. We propose four additional measures that analyse observation-prediction mismatch from a different angle – namely, from the perspective of the predicted rather than the observed area – and add to the existing toolset of model evaluation methods. We explain how these measures can complete the view provided by the existing measures, allowing further insights into distribution model predictions. We also describe how they can be particularly useful when using models to forecast the spread of diseases or of invasive species and to predict modifications in species’ distributions under climate and land-use change