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Building a 3D geomodel for water resources Management: case study in the Regional Park of the lower courses of Manzanares and Jarama Rivers (Madrid, Spain)
No full textWater resources management of protected sites requires a powerful tool to analyze the process and changes that are occurring in the environment. This paper describes a 3D geomodel design of the Jarama River Detrital Aquifer located in Madrid (Spain). That hydrogeological unit is included in the “Parque Regional de los Cursos Bajos de los Ríos Manzanares y Jarama” (Regional Park of the Lower Courses of Manzanares and Jarama Rivers). The goal of this work is to define a method by which a three-dimensional (3D) model can be created with hydrogeologic geometry real of main aquifer, to accomplish an adequate management of the groundwater resources. All data used in this study were integrated in a geographic database: geological and hydrogeological information, geological map (1:25,000), eleven cross-sections, piezometric maps and a digital elevation model. The constructed 3D model of the Jarama Aquifer shows geometric features and spatial distribution and variations of geologic units. Thus, the 3D model allows the assessment of volumes of each unit, the depth and thickness variations of the main aquifer, and the spatial and temporal variations of water tables. From the 3D model, the most suitable areas (in terms of groundwater protection) for managed recharge and mining works have been identified
Conociendo el "Gas Natural". Actualidad y perspectivas
No full textEl auge del petróleo y del gas no convencionales, así como de las energías renovables están transformando la concepción tradicional de los recursos energéticos mundiales.
Hoy día, a pesar de que los recursos de gas son abundantes, su futuro está ligado al desarrollo del shale gas el cual, a su vez, está supeditado a dos restricciones: una de caracter político y social, que tiene que ver con la seguridad medioambiental inherente al proceso de extracción; y otra, puramente técnico-económica relacionada con la rentabilidad del citado proceso de extracción, así como con la disponibilidad de infraestructuras de transporte y transformación en el país de origen
Insuring water: a practical risk management option in water-scarce and drought-prone regions?
No full textRecurrent water deficits in various arid and semi-arid Mediterranean basins are largely covered by illegal groundwater abstractions uncontrolled by the water authorities. Aquifers thus play the role of buffer stocks and are used by farmers as a reliable, though informal, insurance system. This has led to continuous groundwater depletion and increased scarcity and drought risk over the last few decades. An effective solution to this problem requires the replacement of this spontaneous, informal and uncoordinated insurance scheme with a formal and planned system that can be coordinated with the objective of reducing overexploitation. In this paper we develop a methodology to estimate the fair risk premium and the potential water savings associated with drought insurance for irrigated agriculture. This method is illustrated with its application to the Campo de Cartagena Agricultural District in the Segura River Basin (Spain). Results show that although the potential for illegal abstractions is high (9.5 hm3/year), the cost of the insurance system is ten times lower than the amount that risk-averse farmers are willing to pay for water security. This information may serve as the starting point for the design of a drought insurance system able to cope with other relevant institutional challenges
Seasonal dynamics and sedimentation patterns of Microcystis oligopeptide-based chemotypes reveal subpopulations with different ecological traits.
No full textThe patchy distribution of oligopeptide production abilities in cyanobacterial populations enables the
classification of strains into different oligopeptide-based chemotypes. In order to evaluate the ecological
significance of chemotypes in natural systems, we tracked the seasonal dynamics and sedimentation losses of
Microcystis chemotypes in the eutrophic Valmayor reservoir (Spain). Fifty-three distinct chemotypes were
identified throughout the season, six of them only present as benthic colonies. There was no correlation between
chemotype affiliation and taxonomic morphospecies or colony size. The succession of chemotypes in the water
column occurred synchronically in pelagic and littoral habitats and at different depths. Shifts in chemotype
assemblages successfully explained temporal fluctuations in biomass-standardized microcystin contents of the
bloom. The dynamics of chemotypes were driven both by asynchronous proliferation in the water column and
significantly different sedimentation rates among chemotypes. While differential settling was the most important
loss process shaping chemotype succession, the existence of alternative processes selectively inflicting massive
losses to individual chemotypes was observed. Together, the significant differences in sedimentation and pelagic
net growth rates among chemotypes, their segregation among pelagic and benthic habitats, as well as the existence
of chemotype-selective loss processes, show that Microcystis oligopeptide chemotypes interact differently with
their environment and represent commonly overlooked ecologically functional intraspecific linages
Application of a porous composite hydrophobic/hydrophilic membrane in desalination by air gap and liquid gap membrane distillation: A comparative study
No full textA first attempt was carried out comparing the two membrane distillation (MD) configurations, liquid gap (LGMD) and air gap (AGMD), using a porous composite hydrophobic/hydrophilic membrane, the same system and the same MD operating parameters. The surface modified membrane was prepared by the phase inversion technique in a single casting step using a fluorinated surface modifying macromolecule (SMM). Different membrane characterization techniques were applied. MD experiments were performed at different feed temperatures and sodium chloride aqueous solutions. The permeate fluxes were found to be slightly higher (2.2–6.5%) for LGMD compared to that of AGMD although the resistance to mass transfer in LGMD is higher due to the presence of the liquid permeate layer between the membrane and the cooling solid surface. This observed enhancement is attributed partly to the small established distance between the liquid/vapor interfaces at both side of the hydrophobic thin top-layer of the membrane in LGMD configuration, and the higher thermal conductivity of water, which is an order of magnitude higher than that of air, resulting in higher heat transfer coefficient of the permeate in LGMD. The salt rejection factors were found to be almost similar for both MD variants and higher than 99.61%. Compared to AGMD, the thermal efficiency is higher for LGMD, whereas the specific internal heat loss is lower. A linear increase of the thermal efficiency with the feed inlet temperature was observed for both MD configurations. The global heat transfer coefficient and the heat transfer of the permeate membrane side were also found to be greater for LGMD. The temperature polarization effect was found to be slightly higher for AGMD, whereas the concentration polarization effect was slightly higher for LGMD due to its higher permeate flux. In general, the LGMD proved to be more attractive than AGMD for desalination when using bi-layered hydrophobic/hydrophilic membranes
Pb–Zn–Cd–As Pollution in Soils Affected by Mining Activities in Central and Southern Spain: A Scattered Legacy Posing Potential Environmental and Health Concerns
No full textIn this chapter, published geochemical data for soils from several Pb–Zn mine sites and districts from Spain are reviewed. Although most of the mines have closed down, a legacy of highly polluted soils still remains throughout the sites constituting a potential hazard for the environment and human health. The fate of the studied metals and metalloids in these soils is mainly controlled by factors such as mining methods, concentration and metallurgical operations, mineralogy of the ore, gangue and host rock, fracturing of the host rocks, physiography, climate, and soil types (pedogenic evolution). It can be concluded that the most polluted soils (identified on the basis of an enrichment factor) are those of the Sierra Minera (La Unión District – SE Spain), at more than 488 (Pb), 163 (Zn), 99 (Cd), and 98 (As) times the background values from non-contaminated soils. Pb is usually related to As, which in turn is bound to Fe oxides and oxyhydroxides. Metal bearing jarosite and other soluble phases also play a relevant role in the studied soil–water systems, because these minerals are dissolved during intense rainy events, thus resulting in high rates of metal leaching and mobilization by runoff
Approaching water management at watershed scale using distributed water balances in the Yanuncay River basins (Ecuador)
No full textIn this study, the excess water generated during a 10-year period (1998–2008) in the upper and middle Yanuncay River basins is estimated. The distributed water balance method, which analyses the interaction between all the different parameters that form part of the water cycle in nature, was developed. To create the model, basic parameters such as rainfall, temperature, soil type and surface cover are required. Moreover, by using computer software such as Microsoft Office Excel and geographic information systems, it is possible to obtain monthly data showing the water excess and generate thematic maps which allow for an effective monitoring of the behaviour of the middle and upper Yanuncay River basins. This study takes the spatial variability of the various factors that influence the behaviour of a basin into account. This allows determining zones with greater water excess, which are areas that would need to be protected. The model can easily incorporate new data such as land use and surface cover (based on time frames) which would facilitate the comparison of different scenarios