Madalena Moreira

Impacts of climate and land use changes on the hydrological and erosion processes of two contrasting Mediterranean catchments.

The impacts of climate and land use changes on streamflow and sediment export were evaluated for a humid (São Lourenço) and a dry (Guadalupe) Mediterranean catchment, using the SWAT model. SWAT was able to produce viable streamflow and sediment export simulations for both catchments, which provided a baseline for investigating climate and land use changes under the A1B and B1 emission scenarios for 2071-2100. Compared to the baseline scenario (1971-2000), climate change scenarios showed a decrease in annual rainfall for both catchments (humid: -12%; dry: -8%), together with strong increases in rainfall during winter. Land use changes were derived from a socio-economic storyline in which traditional agriculture is replaced by more profitable land uses (i.e. corn and commercial forestry at the humid site; sunflower at the dry site). Climate change projections showed a decrease in streamflow for both catchments, whereas sediment export decreased only for the São Lourenço catchment. Land use changes resulted in an increase in streamflow, but the erosive response differed between catchments. The combination of climate and land use change scenarios led to a reduction in streamflow for both catchments, suggesting a domain of the climatic response. As for sediments, contrasting results were observed for the humid (A1B: -29%; B1: -22%) and dry catchment (A1B: +222%; B1: +5%), which is mainly due to differences in the present-day and forecasted vegetation types. The results highlight the importance of climate-induced land-use change impacts, which could be similar to or more severe than the direct impacts of climate change alone.

Social vulnerability assessment of flood risk using GIS-based multicriteria decision analysis. A case study of Vila Nova de Gaia (Portugal)

Over the last decade, flood disasters have affected millions of people and caused massive economic losses. Social vulnerability assessment uses a combination of several factors to represent a populations differential access to resources and its ability to cope with and respond to hazards. In this paper, social vulnerability assessment to flood risk was applied to the third most populous Portuguese municipality. The study was developed at the neighbourhood level, allowing for social vulnerability analysis at inter civil parish, intra civil parish, and municipality scales. A geographic information system-based multicriteria decision analysis (GIS-MCDA) was applied to social vulnerability and allows for an increased understanding and improved monitoring of social vulnerability over space, identifying ‘hot spots’ that require adaptation policies. Mafamude, Oliveira do Douro, Vila Nova de Gaia, and Avintes civil parishes display the greatest vulnerability to flooding. According to the most pessimistic scenario 57%–68% of the area of these civil parishes is classed at a high or very high level of social vulnerability. The GIS-MCDA helps to assess what and who is at risk, and where targeted impact-reduction strategies should be implemented. The results demonstrate the importance of an urban-scale approach instead of a river basin scale to urban flood risk management plans.

Improving a DSM Obtained by Unmanned Aerial Vehicles for Flood Modelling

According to the EU flood risks directive, flood hazard map must be used to assess the flood risk. These maps can be developed with hydraulic modelling tools using a Digital Surface Runoff Model (DSRM). During the last decade, important evolutions of the spatial data processing has been developed which will certainly improve the hydraulic models results. Currently, images acquired with Red/Green/Blue (RGB) camera transported by Unmanned Aerial Vehicles (UAV) are seen as a good alternative data sources to represent the terrain surface with a high level of resolution and precision. The question is if the digital surface model obtain with this data is adequate enough for a good representation of the hydraulics flood characteristics. For this purpose, the hydraulic model HEC-RAS was run with 4 different DSRM for an 8.5 km reach of the Lis River in Portugal. The computational performance of the 4 modelling implementations is evaluated. Two hydrometric stations water level records were used as boundary conditions of the hydraulic model. The records from a third hydrometric station were used to validate the optimal DSRM. The HEC-RAS results had the best performance during the validation step were the ones where the DSRM with integration of the two altimetry data sources.

Energy and environmental performances of hybrid photovoltaic irrigation systems in Mediterranean intensive and super-intensive olive orchards

Over the last decades, traditional olive production has been converted to intensive and super-intensive cultivation systems, characterized by high plant density and irrigation. Although this conversion improves product quality and quantity, it requires a larger amount of energy input. The new contributions in this paper are, first, an analysis of the energy and environmental performance of two commercial-scale high peak-power hybrid photovoltaic irrigation systems (HPVIS) installed at intensive and super-intensive Mediterranean olive orchards; second, an analysis of PV hybrid solutions, comparing PV hybridization with the electric power grid and with diesel generators; and finally, a comparison of the environmental benefits of HPVIS with conventional power sources. Energy and environmental performances were assessed through energy and carbon payback times (EPBT and CPBT). The results show EPBT of 1.98 and 4.58 years and CPBT of 1.86 and 9.16 years for HPVIS in Morocco and Portugal, respectively. Moreover, the HPVIS were able to achieve low emission rates, corresponding to 48 and 103 g CO2e per kWh generated. The EPBT and CPBT obtained in this study were directly linked with the irrigation schedules of the olive orchards; therefore, weather conditions and irrigation management may modify the energy and environmental performances of HPVIS. The consumption of grid electricity and diesel fuel, before and after the implementation of HPVIS, was also analyzed. The results obtained show fossil energy savings of 67% for the Moroccan farm and 41% for the Portuguese installation. These savings suggest that the energy produced by HPVIS in olive orchards will avoid the emissions of a large amount of greenhouse gas and the exploitation of natural resources associated with fossil fuel production.

Climate change impact on flood hazard in a central Portugal alluvial plain

This paper presents the flood hazard projections under climate change scenarios, for a period between 2021 and 2050, in the Lis river alluvial plain located at the Centre of Portugal. Furthermore, the paper also aim at understanding the hydrological processes in the study area by coupling a hydrological (HEC – HMS) and hydrodynamic model (HEC – RAS). The Lis river basin is becoming more favourable to the production of high water flows, due to the increase of impervious areas and deforestation which have reduced the time concentration on the river basin, empowering flood events with high flood peaks and water flood levels with serious consequences for the facilities (pumping stations, centre pivots) and infrastructures (irrigation networks and roads) in the alluvial plain. The methodology was developed using the daily outputs of the ALADIN and HIRHAM from the EURO-CORDEX project with a 12.5 km horizontal resolution for the RCP4.5 scenario and coupled calibrated hydrological– hydrodynamic models. The results indicated that the annual rainfall would vary for the ALADIN model between a decrease of -24% and an increase of 22% and for the HIRHAM model between a decrease of -85% and an increase of 24%. The results also projected increases in higher runoffs and water level under future climate change scenarios. The HIRHAM model was considered unsuitable for flood impact assessment.