A landslide susceptibility map is an essential tool for land-use spatial planning and management in mountain areas. However, a classification system used for readability determines the final appearance of the map and may therefore influence the decision-making tasks adopted. The present paper addresses the spatial comparison and the accuracy assessment of some well-known classification methods applied to a susceptibility map that was based on a discriminant statistical model in an area in the Eastern Pyrenees. A number of statistical approaches (Spearman’s correlation, kappa index, factorial and cluster analyses and landslide density index) for map comparison were performed to quantify the information provided by the usual image analysis. The results showed the reliability and consistency of the kappa index against Spearman’s correlation as accuracy measures to assess the spatial agreement between maps. Inferential tests between unweighted and linear weighted kappa results showed that all the maps were more reliable in classifying areas of highest susceptibility and less reliable in classifying areas of low to moderate susceptibility. The spatial variability detected and quantified by factorial and cluster analyses showed that the maps classified by quantile and natural break methods were the closest whereas those classified by landslide percentage and equal interval methods displayed the greatest differences. The difference image analysis showed that the five classified maps only matched 9 % of the area. This area corresponded to the steeper slopes and the steeper watershed angle with forestless and sunny slopes at low altitudes. This means that the five maps coincide in identifying and classifying the most dangerous areas. The equal interval map overestimated the susceptibility of the study area, and the landslide percentage map was considered to be a very optimistic model. The spatial pattern of the quantile and natural break maps was very similar, but the latter was more consistent and predicted potential landslides more efficiently and reliably in the study area.
The final publication is available at Springer via http://dx.doi.org/10.1007/s12665-016-6124-1
Criollo, R.; Velasco Mansilla, D.V.; Vazquez-Suñe, E.; Serrano, A.; Alcaraz, M.; García, A. Environmental earth sciences Vol. 75, num. 5, p. 391-1-391-11 DOI: 10.1007/s12665-016-5292-3 Data de publicació: 2016-03 Article en revista
The quantification of the hydraulic parameters is important to support decision making in environmental impact assessment, water resources evaluation or groundwater contamination remediation, among others. These kind of parameters derived from aquifer tests usually encompasses a vast amount of data (spatial and non-spatial) for management and analysis. To achieve this in a clear and understandable manner, the GIS environment is a useful instrument. Development of innovative software to analyze pumping tests in a GIS platform environment to support the hydraulic parameterization of groundwater flow and transport models is presented in this paper. This new platform provides three interconnected modules to improve (a) pumping test interpretation code through a user-friendly interface, (b) pumping test data visualization supported by a set of tools that perform spatiotemporal queries in a GIS environment and (c) the storage and management of hydrogeological information. Additionally, within the GIS platform, it is possible to process the hydraulic parameters obtained from the pumping test and to create spatial distribution maps, perform geostatistical analysis and export the information to an external software platform. Finally, a real-world application in the area of Barcelona (Spain) has shown the usefulness of the tools developed in support of hydrogeological analysis.
A screening survey of 81 pharmaceuticals was carried out at a wastewater facility and in a detrital aquifer (Barcelona, Spain), where treated wastewater (TWW) was injected through wells to build up a hydraulic barrier against seawater intrusion. The monitored data correspond to the 2007–2010 period. The TWW was tertiary treated with additional treatment consisting of ultrafiltration, reverse osmosis and UV disinfection. During the monitoring period groundwater monitoring was carried out in wells located within a 1-km radius distance from the injection wells. During monitoring period 20 new pharmaceuticals were detected in the aquifer media and 11 compounds were found with concentration above 0.1 µg l-1 (selected threshold) in both TWW and wells. After 1 year of TWW injection change of redox conditions, a decrease of Cl- concentration and presence of 11 pharmaceuticals (4-AAA, 4-FAA, carbamazepine, ciprofloxacin, diazepam, diclofenac, hydrochlorothiazide, mepivacaine, sulfamethoxazole, sulfamethazine and sulfapyridine) was observed in the monitoring wells. After the studied period the sodium-chloride aquifer water type evolved to a bicarbonate-sulphate facies. Decrease of the pharmaceuticals concentration in groundwater appears to be driven by the dilution process and hydraulic characteristics of the aquifer media, with the attenuation or degradation process much less important.
The final publication is available at Springer via http://dx.doi.org/10.1007/s12665-015-4956-8
For many years there has been a general consensus on the need to consider surface and groundwater together to achieve the more general paradigm of integrated water resource management. Nevertheless, in many countries this goal is far from being achieved in practice as in Spain, presented here. Much of continental and insular Spain conditions are semi-arid, making it the most arid country in the European Union (EU). The use of groundwater for urban water supply and irrigation is therefore relevant, especially along the Mediterranean coast, the south and the center, and in the islands. There is however divergence between the reality of groundwater use and the attitude of many policy makers who do not consider it and favor other water resources, traditionally surface water and recently seawater desalination, in many parts of Spain. This mindset of the governmental water planners influenced the 1985 water code and also affected the implementation in Spain of the EU Water Framework Directive 2000. Although some improvements have been made, overall groundwater management is still chaotic in some aspects. A significant handicap is that although in theory groundwater is in the public domain, most of it remains in private hands. Water planning also relies on concessions and this creates stressful situations and problems which are difficult to solve. In this paper some significant aspects of groundwater policy are outlined, such as its role in mitigating the effects of climate variability and change, the water mining of aquifers, the associations of groundwater users, and the groundwater ecosystems.
In the old mining area of Rodalquilar, mine
wastes, soil and sediments were characterized and the results revealed high concentration of Au, Ag, As, Bi,Cu, Fe, Mn, Pb, Se, Sb and Zn in tailings and sediments.
The contaminant of greatest environmental concern is As. The mean concentration in the tailings was 679.9, and 345 mg/kg in the sediments of Playazo creek. The groundwater samples from the alluvial aquifer showed
high concentration of Al, As, Cd, Fe, Hg, Mn, Ni, Pb, Se, Sb and Zn and very high concentration of chloride and sulfate, which were above the concentration defined
in the European standards for drinking water. The presence of As in groundwater may be caused by the oxidation of arsenian pyrite, the possible As desorption from goethite and ferrihydrite and the jarosite dissolution.
Groundwater concentrations of Cd, Fe, Mn, and
possibly Cu, were associated with low values of Eh, indicating the possible dissolution of oxy-hydroxides of Fe and Mn. The mobility of metals in the column experiments show the release of Al, Fe, Mn, Cr, Cu, Ni, V and Zn in significant concentrations but below the
detected values in groundwater. However, As, Cd, Sb, Se Pb and Au, are generally mobilized in concentrations above the detected values in groundwater. The possible
mass transfer processes that could explain the presence of the contaminants in the aquifer and the leachates was simulated with the PHREEQC numerical code and revealed the possible dissolution of the following mineralphases: jarosite, natrojarosite, arsenian pyrite, alunite, chlorite, kaolinite and calcite.