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The Iberian Peninsula is affected by different levels of water scarcity due to extensive droughts that frequently occur, creating conflicts between Portugal and Spain, and even between Spanish autonomic regions. As such, the available water resources need to be more efficiently used to fulfil the multiple demand from different uses (urban consumption, agriculture, industries, tourism), meaning that better management tools are required for that purpose.This study aims to quantify water resources availability in the Iberian Peninsula using the physically-based, fully-distributed MOHID-Land model. This model considers four compartments or mediums (atmosphere, porous media, soil surface and river network), computing water dynamics through the different mediums using mass and momentum conservation equations.The model was implemented in the simulation domains with a resolution of 5 km. Data inputs included the digital terrain model from Shuttle Radar Topography Mission of NASA with a resolution of 90 m; the soil map from the European Soil Data Centre (1:1,000,000); the Corine land cover map from 2012 with a resolution of 100 m; the soil hydraulic properties from the HYPRES class pedotransfer functions; the hourly weather data (precipitation, wind velocity, relative air humidity, solar radiation and surface air temperature) from the SAFRAN model with a resolution of 8 km; the reservoir discharge data from governmental and regional agencies.Simulations were run from October 1979 to June 2014, with model warm-up being set from 1979 to 1985, model calibration from 1985 to 2004, and model validation from 2004 to 2014. The calibration and validation process focused on the comparison of simulated flows with those measured in hydrometric stations (81 stations) with no reservoir influence, and those estimated using satellite products.Four statistical parameters (R2, RMSE, PBIAS and NSE) were used to evaluate model performance. Results differed substantially along the domain, with better results being obtained in the northern region of the Iberian Peninsula when compared with the southern region. This highlight the need for better include information related to water transfers between different catchments in the model. Additionally, information related to reservoir management needs to be included to improve the reliability of model predictions in the downstream areas. Nonetheless, considering the coarse scale of simulation domain, model performance was considered to be generally good considering the scale of the application. [ABSTRACT FROM AUTHOR]

In recent decades forest fires have taken on a new form, becoming increasingly destructive. The latest catastrophic fires occurred on Portuguese territory in 2017 have forced governmental institutions to take rapid decisions to minimize the impact of those events on the environment. The use of models to support those decisions is a way to improve management solutions and to reduce the damage caused by fires.This study focuses on the effects of 2017 forest fires, on the water quality of Rio Zêzere watershed and the downstream reservoir of Castelo de Bode. The Zêzere watershed has a draining area of approximately 3489.86 km2, with an elevation ranging from 105 to 1970 m. The Castelo de Bode reservoir, with a total capacity of 1095 hm3, supplies Lisbon and the surrounding areas (approximately 2,000,000 inhabitants). During 2017, more than one hundred thousand hectares of land (50% of its area) in the watershed burned, making it one of the most affected areas in Portugal.The Soil Water Assessment Tool (SWAT) was first calibrated/validated for simulating streamflow and sediment and nutrient transport in the watershed during 1986-2000. Afterwards, SWAT model outputs were used as boundary conditions for the application of CE-QUAL-W2 model, capable of simulating the movements of the water quality components (nutrients, chlorophyll, and dissolved oxygen, within the reservoir. The calibration and validation of the models confirmed the validity of their complementary use, and the possibility to simulate the effects of fires in the watershed and its impacts on the water quality of the reservoir. Changes in the land use (curve number, crop vegetation management factor) and soil properties (soil erodibility) were considered by taking into account the different scale of the fire events (low, medium, and high severity).Simulations showed a significant increase in runoff and sediment concentration at the sub-basin level in the year following the 2017 fire events, with high concentrations of nutrients characterizing the reservoir inlet, leading to the increase of both nutrients and chlorophyll concentrations. Nonetheless, these concentrations never overcome the thresholds limits foreseen in legislation for drinking water, likely due to the large volume of the reservoir which diluted the inflow concentrations. [ABSTRACT FROM AUTHOR]