Examinando por Autor "Vigiak, Olga"

Mostrando 1 - 5 de 5

ESPRES: A web application for interactive analysis of multiple pressures in aquatic ecosystems
(Elsevier, 2020-11-20) Udias, Angel; Pistocchi, Alberto; Vigiak, Olga; Grizzetti, Bruna; Bouraoui, Faycal; Alfaro, Cesar
ESPRES (Efficient Strategies for anthropogenic Pressure Reduction in European waterSheds) is a web-based Decision Support System (DSS) designed to explore management options for achieving environmental targets in European freshwaters. The tool integrates multi-objective optimization (MOO) algorithms for selecting the best management options in a river basin and models assessing the consequent changes in the water quantity (water flow) and quality (nutrient concentration). The MOO engine identifies Pareto front strategies that are trade-offs between environmental objectives for water bodies and the effort required for reducing the pressures. The web interface provides tools to set the effort perceived by different river basin stakeholders considering technical feasibility, political difficulty, and social acceptability of the alternative options. The environmental impact of management options (scenarios) is assessed with models developed at the European scale. ESPRES enables comparison of management solutions and allows quantifying environmental and socio-economic trade-offs inherent to the decision making process.
ESPRES: A web application for interactive analysis of multiple pressures in aquatic ecosystems
(Elsevier, 2020-07-11) Udias, Angel; Pistocchi, Alberto; Vigiak, Olga; Grizzetti, Bruna; Bouraoui, Faycal; Alfaro, Cesar
ESPRES (Efficient Strategies for anthropogenic Pressure Reduction in European waterSheds) is a web-based Decision Support System (DSS) designed to explore management options for achieving environmental targets in European freshwaters. The tool integrates multi-objective optimization (MOO) algorithms for selecting the best management options in a river basin and models assessing the consequent changes in the water quantity (water flow) and quality (nutrient concentration). The MOO engine identifies Pareto front strategies that are trade-offs between environmental objectives for water bodies and the effort required for reducing the pressures. The web interface provides tools to set the effort perceived by different river basin stakeholders considering technical feasibility, political difficulty, and social acceptability of the alternative options. The environmental impact of management options (scenarios) is assessed with models developed at the European scale. ESPRES enables comparison of management solutions and allows quantifying environmental and socio-economic trade-offs inherent to the decision making process.
GREENeR: An R Package to Estimate and Visualize Nutrients Pressures on Surface Waters
(The R Foundation, 2023-09) Udías , Angel; Grizzetti, Bruna; Vigiak, Olga; Aloe, Alberto; Alfaro, Cesar; Gomez, Javier
Nutrient pollution affects fresh and coastal waters around the globe. Planning mitigating actions requires tools to assess fluxes of nutrient emissions to waters and expected restoration impacts. Conceptual river basin models take advantage of data on nutrient emissions and concentrations at monitoring stations, providing a physical interpretation of monitored conditions, and enabling scenario analysis. The GREENeR package streamlines water quality model in a region of interest, considering nutrient pathways and the hydrological structure of the river network. The package merges data sources, analyzes local conditions, calibrate the model, and assesses yearly nutrient levels along the river network, determining contributions of load in freshwaters from diffuse and point sources. The package is enriched with functions to perform thorough parameter sensitivity analysis and for mapping nutrient sources and fluxes. The functionalities of the package are demonstrated using datasets from the Vistula river basin.
Predicting biochemical oxygen demand in European freshwater bodies
(Elsevier, 2019-05-20) Vigiak, Olga; Grizzetti, Bruna; Udias, Angel; Zanni, Michela; Dorati, Chiara; Bouraoui, Fayçal
Biochemical Oxygen Demand (BOD) is an indicator of organic pollution in freshwater bodies correlated to microbiological contamination. High BOD concentrations reduce oxygen availability, degrade aquatic habitats and biodiversity, and impair water use. High BOD loadings to freshwater systems are mainly coming from anthropogenic sources, comprising domestic and livestock waste, industrial emissions, and combined sewer overflows. We developed a conceptual model (GREEN+BOD) to assess mean annual current organic pollution (BOD fluxes) across Europe. The model was informed with the latest available European datasets of domestic and industrial emissions, population and livestock densities. Model parameters were calibrated using 2008–2012 mean annual BOD concentrations measured in 2157 European monitoring stations, and validated with other 1134 stations. The most sensitive model parameters were abatement of BOD by secondary treatment and the BOD decay exponent of travel time. The mean BOD concentrations measured in monitored stations was 2.10 mg O2/L and predicted concentrations were 2.54 mg O2/L; the 90th percentile of monitored BOD concentration was 3.51 mg O2/L while the predicted one was 4.76 mg O2/L. The model could correctly classify reaches for BOD concentrations classes, from high to poor quality, in 69% of cases. High overestimations (incorrect classification by 2 or more classes) were 2% and large underestimations were 5% of cases. Across Europe about 12% of freshwater network was estimated to be failing good quality due to excessive BOD concentrations (>5 mg O2/L). Dominant sources of BOD to freshwaters and seas were point sources and emissions from intensive livestock systems. Comparison with previous assessments confirms a decline of BOD pollution since the introduction of EU legislation regulating water pollution.
Probability maps of anthropogenic impacts affecting ecological status in European rivers
(Elsevier, 2021-07) Vigiak, Olga; Udias, Angel; Pistocchi, Alberto; Zanni, Michela; Aloe, Alberto; Grizzetti, Bruna
Abstract: Understanding how anthropogenic pressures affect river ecological status is pivotal to designing effective management strategies. Knowledge on river aquatic habitats status in Europe has increased tremendously since the introduction of the European Union Water Framework Directive, yet heterogeneities in mandatory monitoring and reporting still limit identification of patterns at continental scale. Concurrently, several model and data-based indicators of anthropogenic pressures to freshwater that cover the continent consistently have been developed. The objective of this work was to create European maps of the probability of occurrence of river conditions, namely failure to achieve good ecological status, or to be affected by specific pervasive impacts. To this end, we applied logistic regression methods to model the river conditions as functions of continental-scale water pressure indicators. The prediction capacity of the models varied with river condition: the probability to fail achieving good ecological status, and occurrence of nutrient and organic pollution were rather well predicted; conversely, chemical (other than nutrient and organic) pollution and alteration of habitats due to hydrological or morphological changes were poorly predicted. The most important indicators explaining river conditions were the shares of agricultural and artificial land, mean annual net abstractions, share of pollution loads from point sources, and the share of upstream river length uninterrupted by barriers. The probability of failing to achieve good ecological status was estimated to be high (>60%) for 36% of the considered river network of about 1.6 M km. Occurrence of impact of nutrient pollution was estimated high (>60%) in 26% of river length and that of organic pollution 20%. The maps are built upon information reported at country level pursuant EU legal obligations, as well as indicators generated from European scale models and data: both sources are affected by epistemic uncertainty. In particular, reported information depend on data collection scoping and schemes, as well as national knowledge and interpretation of river system pressures. In turn, water pressure indicators are affected by heterogeneous biases due to incomplete or incorrect inputs and uncertainty of models adopted. Lack of effective reach- and site-scale indicators may hamper detection of locally relevant impacts, for example in explaining alteration of habitats due to morphological changes. The probability maps provide a continental snapshot of current river conditions, and offer an alternative source of information on river aquatic habitats, which may help filling in knowledge gaps. Foremost, the analysis demonstrates the need for developing more effective continental-scale indicators for hydromorphological alterations and chemical pollution.