Time-dependent methods to evaluate the effects of urban sprawl on groundwater quality: a synthesis

Freshwater resources are threatened worldwide with unknown and unpredictable fate, due to non-stationarity and change of water cycle dynamics, and increasing demand resulting from population growth and economic expansion. Thus, practical actions, strategies and solutions are necessary to ensure the short-term and long-term provision of adequate, affordable, accessible and safe freshwater supply to meet the needs of the growing human population and ecosystems. Since the mid-1950s, Europe is experiencing the phenomenon of urban sprawl, characterized by an unplanned incremental urban development, no more tied with population growth (EEA 2006). Impacts of urban sprawl threaten both the natural and rural environments and the quality of life for people living in cities, with worsening of air quality, and surface- and groundwater quality and quantity. For the protection of groundwater, the European Union issued a series of Directives (Water Framework Directive, 2000/60/EC; Groundwater Directive, 2006/118/EC) that require member states to achieve a good chemical status of their groundwater bodies and the identification of areas where groundwater suffers increasing trends in contaminant concentrations. In order to cope with EU Directives, a time-dependent approach for groundwater vulnerability assessment is developed to account for both the recent status of groundwater contamination and its evolution in the Po Plain area of Lombardy Region (northern Italy). Such approach takes the advantages of a Bayesian spatial statistical method to assess groundwater vulnerability and satellite scatterometer data to delineate urban areas and monitor their evolution. The proposed approach can determine potential impacts of contamination events on groundwater quality, if policies are maintained at the status quo or if new measures are implemented for safeguarding groundwater resources

Groundwater vulnerability assessment: from overlay methods to statistical methods in the Lombardy Plain area

Groundwater is among the most important freshwater resources. Worldwide, aquifers are experiencing an increasing threat of pollution from urbanization, industrial development, agricultural activities and mining enterprise. Thus, practical actions, strategies and solutions to protect groundwater from these anthropogenic sources are widely required. The most efficient tool, which helps supporting land use planning, while protecting groundwater from contamination, is represented by groundwater vulnerability assessment. Over the years, several methods assessing groundwater vulnerability have been developed: overlay and index methods, statistical and process-based methods. All methods are means to synthesize complex hydrogeological information into a unique document, which is a groundwater vulnerability map, useable by planners, decision and policy makers, geoscientists and the public. Although it is not possible to identify an approach which could be the best one for all situations, the final product should always be scientific defensible, meaningful and reliable. Nevertheless, various methods may produce very different results at any given site. Thus, reasons for similarities and differences need to be deeply investigated. This study demonstrates the reliability and flexibility of a spatial statistical method to assess groundwater vulnerability to contamination at a regional scale. The Lombardy Plain case study is particularly interesting for its long history of groundwater monitoring (quality and quantity), availability of hydrogeological data, and combined presence of various anthropogenic sources of contamination. Recent updates of the regional water protection plan have raised the necessity of realizing more flexible, reliable and accurate groundwater vulnerability maps. A comparison of groundwater vulnerability maps obtained through different approaches and developed in a time span of several years has demonstrated the relevance of the continuous scientific progress, recognizing strengths and weaknesses of each research

TIME-DEPENDENT METHODS TO EVALUATE THE EFFECTS OF URBAN SPRAWL ON GROUNDWATER QUALITY

As groundwater resources are becoming more vulnerable due to the increasing number of contamination sources in developed and developing countries (such as urbanization and agricultural activities), practical actions, strategies and solutions to protect the resource are widely required. The most efficient tool, which helps supporting land use development, while protecting groundwater from contamination, is represented by groundwater vulnerability assessment. European Directives require member states, for the protection of groundwater quality, to assess the current groundwater quality status, detect changes or trends in groundwater quality, assess the threat of deterioration and predict future changes in groundwater quality. In order to cope with the EU requirements, this study focuses on the development of a time-dependent approach, which could take into account both the current groundwater quality status and its changes, assessing groundwater vulnerability to nitrate contamination in the Po Plain area of Lombardy Region, through a Bayesian spatial statistical method (Weights of Evidence). In addition, an innovative dataset to delineate urban areas with satellite scatterometer data (QuikSCAT-DSM) is explored. To evaluate its reliability in groundwater vulnerability assessments, QuikSCAT-DSM dataset is compared with population density and land use derived from aerial images. Results showed that: a) urbanization prevails on agricultural activities in causing the degradation of groundwater quality; b) QuikSCAT-DSM data is a reliable variable to represent urban nitrate sources, with the advantages of a worldwide coverage, a continuous data collection and an adequate resolution; c) the time-dependent approach allows to identify areas both affected by nitrate contamination and characterized by an upward concentration trend of contamination; d) the time-dependent approach allows to determine what could happen to groundwater resources if land use policies are maintained or new ones will be proposed and/or if natural factors are changing under climatic or anthropogenic stresses

Evaluation of the deposition, infiltration and drainage of the atmospheric pollutants in the vadose zone

In the last decades, a large effort has been carried out to reduce atmospheric pollutant emissions in Europe. However, despite the progresses of the last 30 years (Rogora et al., 2016), water and soil acidification, nutrition unbalance in forest trees, and eutrophication in surface waters are still of great concern. In particular, nutrients that fall on the ground from the atmosphere represent a minor component of the total nitrogen input to soils, especially when compared to agricultural, civil and industrial inputs (EEA, 2005). Although often underestimated, this source apportionment becomes a part of leaching from the soil to groundwater. Therefore, the overarching goal of this study is to identify anthropogenic background values of pollutants in groundwater, not related to direct sources of contamination (e.g., industrial wastes, leakages from sewage systems, fertilizers)

Una escuela en movimiento(s)

En este artículo se analizan los movimientos que una escuela pública realiza desde su proceso de experimentación pedagógica con la forma escolar. Se nombra movimientos, en plural, porque son varios los que en este conjunto de docentes tiene que efectuar en relación a la organización de la escuela, a la forma de concebir el trabajo docente, al vínculo con la comunidad, al trabajo con otros actores como la Universidad. Estos movimientos permiten recentrar la escuela a partir de la premisa que "todos pueden aprender" y permite analizar sus efectos en la organización de la propuesta escolar y en la forma de organizar y concebir el trabajo pedagógico y como estos movimientos están marcados por el trabajo colectivo. A partir de una experiencia concreta se analizan las posibilidades de transformación general que esta escuela propone reposicionando a los docentes como sujetos políticos capaces de liderar transformaciones pedagógicas

Using statistical analyses for improving rating methods for groundwater vulnerability in contamination maps

With the aim of developing procedures coping with the disadvantages and emphasising the advantages of existing rating methods and the use of statistical methods for assessing groundwater vulnerability, we propose to combine the two approaches to perform a groundwater vulnerability assessment in a study area in Italy. In the case study, located in an area of northern Italy with both urban and agricultural sectors, keeping the structure of the DRASTIC rating method, we used a spatial statistical approach to calibrate weights and ratings of a series of variables, potentially affecting groundwater vulnerability. In order to verify the effectiveness of these procedures, the results were compared to a non-modified approach and to the map resulting from the ‘‘Time–Input’’ method, highlighting the advantages that can be obtained, and defining the general limit of these applications. The revised method shows a more realistic distribution of vulnerability classes in accordance with the distribution of wells impacted by high nitrate concentration, demonstrating the importance of taking into account the specific hydrogeological conditions of the area

Un punto de partida en la igualdad de las inteligencias

El presente artículo se desprende directamente de la tesis de doctorado realizada por el autor[1], se plantea aquí de que forma la igualdad de las inteligencias opera como un punto de partida que permite a la escuela reposicionar lo pedagógico como elemento central de la respuesta que como institución le compete desarrollar. Para la investigación este tema constituye un pilar sobre el cuál se sustenta el proceso de experimentación pedagógica en desarrollo por esta escuela pública en Uruguay. La Escuela 321 parte por plantear que “todos pueden aprender” y que es la escuela la que debe generar las condiciones pedagógicas adecuadas para que los aprendizajes se desarrollen. Esa capacidad intrínseca de los sujetos es emparentada aquí con la proclama planteada por Rancière (2007) sobre la “igualdad de las inteligencias”, entendiendo que los efectos políticos que produce son similares, colocando el desafío en construir una respuesta pedagógica en la que no hay lugar para poner en duda la capacidad del otro. A partir de allí se abren otras posibilidades para pensar y experimentar.[1] “Alteraciones a la forma escolar y producción de política educativa desde el cotidiano. Experimentación pedagógica en la escuela 321 de Unidad Casavalle, Montevideo – Uruguay” tesis para aspirar al grado de doctor  (en revisión por el jurado), Universidad Nacional de Entre Ríos, Doctorado en Educación, Tercera cohorte. Directora Dra. Flavia Terigi

Specific yield of aquifer evaluation by means of a new experimental algorithm and its applications

A simplified method to determine specific yield (i.e., effective porosity) from hydraulic conductivity data obtained through pumping tests is proposed. This new method derives from a reprocessing of literature data and a subsequent calibration with results from pumping tests performed in different hydrogeological contexts. The use of the algorithm allows obtaining values of specific yield (Sy), which could be useful for the resolution of problems concerning the water balance and the transport of contaminants in groundwater. The proposed algorithm is applied to a large-scale area (Milan and its suburbs, northwestern Italy) to determine a map of the specific yield of a sandy-gravel aquifer and the effects on the estimation of water volumes stored in the subsoil from a hydrogeological point of view, considering about seventy years of measures. It is demonstrated that the great variation in water volumes reflects the socio-economic history of the territory