Strategic environmental assessment in Tróia (Portugal)

Proceedings of the First International Conference on Coastal Conservation and Management in the Atlantic and Mediterranean, p. 91-98Over the last two decades, the Tróia peninsula (SW coast of Portugal) has been designated by the Portuguese authorities both as a protected area and as an area of tourism development. The private investor that took over the tourism developments in Tróia asked the Institute of Marine Research (IMAR) to undertake an SEA, to help frame the design and management of the future resort. SEA results were changed by local/central government decisions, granting “more” than stakeholder/owner’s proposal, in terms of loads and densities. This process, as well as the main characteristics and results of the SEA, are presented and discussed

Assessment of a Sand Spit Morphodynamics Under Extreme Flood Events

&lt;p&gt;Spits are landforms that present a complex morphology, which depends on currents, waves, sediment transport, tidal range and anthropic-induced changes. Their position and shape is subject to extreme events like flood river discharges and storms. They can also respond to processes that take place at larger time scales, as plate tectonics, sea level rise or even climatological patterns with teleconnections all over the world, as the well know North Atlantic Oscillation (NAO) or El Ni&amp;#241;o-Southern Oscillation (ENSO). This is the case of the Douro river mouth sand spit located on the northern coast of Portugal. This naturally dynamic sand spit, which has moved landwards over the past decades, has caused frequent nuisance to navigation, affecting width and depth of the navigation channel. Therefore, a breakwater was constructed in an attempt to stabilise the sand spit and the estuary inlet.&lt;/p&gt;&lt;p&gt;Validated hydrodynamic numerical models (openTELEMAC-MASCARET and Delft3D) of the Douro river estuary have demonstrated ability to accurately describe the estuarine hydrodynamic patterns and water elevation under extreme flood conditions. Model results showed that for higher river flow discharges the sand spit is partially inundated.&lt;/p&gt;&lt;p&gt;In this work a morphodynamic model (Delft3D) of the estuary was implemented to assess both the morphodynamics of the sand spit under extreme events, including the effect of sea level rise due to climate change, and the variation of extreme water levels along the estuary due to spit erosional processes that can occur during flood events.&lt;/p&gt;&lt;p&gt;Preliminary results show that the sand spit will be locally eroded for the higher river flood discharges, forming a two-secondary-channels system, with one channel located near the breakwater&amp;#8217;s southern extremity and the other, narrower, near the south bank. Associated with these two channels, two depositional bars will be formed in front of the channels at the coastal platform. However, the inner immersed sand spit will be suffering a sedimentation process for all of the simulated scenarios. This way, neither the river mouth discharge conditions nor the water levels inside the estuary will suffer significant changes according to the simulated scenarios.&lt;/p&gt;&lt;p&gt;These results will be complemented with further analyses considering the sediment size influence, tidal level, storm surge, sea level rise and river flood discharges.&lt;/p&gt;&lt;p&gt;Acknowledgements: To the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 (FCT and ERDF) and to the project EsCo-Ensembles (PTDC/ECI-EGC/30877/2017, NORTE 2020, Portugal 2020, ERDF and FCT). The authors also want to acknowledge the data provided by EDP and IH.&lt;/p&gt;</jats:p

Efeito da frequência de preparo periódico nos indicadores da compactação do solo.

O uso contínuo de máquinas nas operações de preparo do solo para o plantio resulta em significativas alterações nos seus atributos físicos, dentre as quais, destacam-se a compactação, um dos principais problemas enfrentados pelos agricultores em diversas regiões do Brasil. O objetivo deste trabalho foi avaliar o efeito de operações sucessivas de aração e gradagem sobre os indicadores de compactação do solo. Para tanto, aplicou-se, em um Latossolo Amarelo Distrocoeso argissólico, sob pastagem natural, cinco níveis de distúrbios, resultantes de eventos mensais de aração e gradagem, sendo: T0 (Controle); T1 (2 eventos); T2 (4 eventos); T3 (6 eventos); T4 (8 eventos). Verificou-se que a frequência das operações de aração e gradagem reduziu o diâmetro médio de agregados, a macroporosidade e a condutividade hidráulica do solo saturado, aumentando a densidade do solo e a resistência à penetração

Future estuarine circulation patterns characterization based on a hydrodynamic models ensemble

&lt;p&gt;Estuarine regions are strategically important from an environmental, economic, and social point of view. To reduce vulnerability and increase resilience, it is crucial to know their dynamics that usually are poorly understood. Numerical models have proven to be an appropriate tool to improve this knowledge and simulate scenarios for future conditions. However, as the modelling results may be inaccurate, the application of the ensembles technique can be very useful in reducing possible uncertainties. In the EsCo-Ensembles project, this technique is proposed to improve hydrodynamic predictions for two Portuguese estuaries: Douro and Minho.&lt;/p&gt;&lt;p&gt;Two already validated numerical models (openTELEMAC-MASCARET and Delft3D), which have demonstrated their ability to accurately describe estuarine hydrodynamic patterns and water elevation for river flow in normal and extreme conditions, were applied. Several scenarios for climate change effects were defined including river flood peak flows for the 100 and 1000 year return periods and sea level extreme values for RCPs 4.5 and 8.5 in 2100.&lt;/p&gt;&lt;p&gt;The results demonstrated a clear difference between the hydrodynamic behaviour of the two estuaries. Model outcomes for the Minho estuary, which is dominated by the tide and therefore by oceanographic conditions, show a pronounced effect of rising sea levels on estuarine hydrodynamics. Whereas, for the Douro estuary, which is heavily dominated by the river flow, the effect of the sea level rise is hardly noticeable during flood events.&lt;/p&gt;&lt;p&gt;These and further results of this ongoing project are expected to (i) provide a complete hydrodynamic characterization of the two estuaries; (ii) evaluate future trends; (iii) estimate the flood risks associated with extreme events and (iv) demonstrate that the combined use of different models reduces their uncertainty and increases the confidence and consistency of the forecasts.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgements: &lt;/strong&gt;To the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 (FCT and ERDF) and to the project EsCo-Ensembles (PTDC/ECI-EGC/30877/2017, NORTE 2020, Portugal 2020, ERDF and FCT). The authors also want to acknowledge the data provided by EDP, IH and Confederaci&amp;#243;n Hidrogr&amp;#225;fica Mi&amp;#241;o-Sil.&lt;/p&gt;</jats:p

The HARPS search for southern extra-solar planets XXXV. The interesting case of HD41248: stellar activity, no planets?

The search for planets orbiting metal-poor stars is of uttermost importance for our understanding of the planet formation models. However, no dedicated searches have been conducted so far for very low mass planets orbiting such objects. Only a few cases of low mass planets orbiting metal-poor stars are thus known. Amongst these, HD41248 is a metal-poor, solar-type star on which a resonant pair of super-Earth like planets has In the present paper we present a new planet search program that is using the HARPS spectrograph to search for Neptunes and Super-Earths orbiting a sample of metal-poor FGK dwarfs. We then present a detailed analysis of an additional 162 radial velocity measurements of HD41248, obtained within this program, with the goal of confirming the existence of the proposed planetary system. We analyzed the precise radial velocities, obtained with the HARPS spectrograph, together with several stellar activity diagnostics and line profile indicators. A careful analysis shows no evidence for the planetary system previously announced. One of the signals, with a period of about 25 days, is shown to be related to the rotational period of the star, and is clearly seen in some of the activity proxies. The remaining signal (P~18 days) could not be convincingly retrieved in the new data set. We discuss possible causes for the complex (evolving) signals observed in the data of HD41248, proposing that they may be explained by the appearance and disappearance of active regions on the surface of a star with strong differential rotation, or by a combination of the sparse data sampling and active region evolution.Comment: Accepted for publication in A&