Pumping seawater from coastal aquifers for supplying desalination plants

The lack of water in the coastal areas demands an onerous search for an appropriate solution. One solution is that of water transfer from areas of surplus, but this is itself problematical. Technological developments have introduced the possibility of utilizing desalinated seawater as a drinking water source at a competitive price. Abstraction from coastal aquifers that are connected to the sea appears to be the cheapest means of supply. However, pumping poses some problems due to the corrosiveness of seawater. These problems include the difficulties of choosing suitable sites for the abstractions, drilling method, casing, filter pack, as well as the design of a monitoring system to assess aquifer behaviour as a result of the generally high exploitation rate. The 31 boreholes that have been drilled in the Andarax Delta near the city of Almeria are cited as an example of a real application

Consideraciones sobre la hidrogeología de la cuenca del río Almanzora (SE peninsular)

15 páginas, 10 figuras.[ES] Se analizan las características hidrogeológicas de los distintos sistemas acuíferos presentes en la cuenca del río Almanzora, de gran importancia por su posición estratégica en una región con recursos muy limitados, dadas las adversas condiciones climáticas a las que está sometida. Se establece una subdivisión en base a sus características litológicas, estructurales y piezométricas. Se analizan las características geométricas de las diferentes unidades, los principales puntos de agua relacionados con las mismas, su evolución piezométrica y la evaluación de los recursos. También se exponen las características fisicoquímicas de las aguas estudiadas.[EN] The hydrogeological characteristics of the aquifer systems existing in the Almanzora River basin are analyzed. Those aquifers are very important due to the climatological conditions -semiarid region- where water is a basical resource. The systems are identified from the lithologicaL structural and piezometrical characteristics. The geometrical characteristics, the numer of wells and springs, the piezometric evolution and the resources evaluation are established in each hydrogeological unit. Finally, the physical-chemical characteristics of the water are also studied.Esta investigación se realizó en el marco del proyecto «Dinámica del geoecosistema de la cuenca del río Almanzora: evaluación de los procesos de desertificación» (ICONA-CSIC).Peer reviewe

Características hidrogeológicas de un sector al SW de Aspe (Alicante)

Se exponen los resultados de las investigaciones hidrogeológicas llevadas a cabo en el acuífero que integran los materiales detríticos cuaternarios de Aspe, relativos a la geometría, parámetros hidráulicos y características físico-químicas de las aguas, para establecer finalmente el funcionamiento hidrogeológico. Los numerosos sondeos mecánicos recientemente realizados en los bordes permiten esbozar las relaciones de éstos con el acuífero principal.Les résultats des recherches hydrogéologiques effectuées dans l'aquifere intégré par les matériaux détritiques quaternaires d' Aspe sont exposés, relatifs a la géométrie, les parametres hydrauliques et les caractéristiques physico-chimiques des eaux, pour finalement établir le fonctionnement hydrogéologique. De nombreux sondages mécaniques récemment réalisés dans les bords, permettent de présenter une esquisse des relations entre ceux-ci et l'aquifere principal.Geometrical, hydraulic and hydrochemical data have been obtained in a hydrogeological research carried out in the quaternary detritic aquifer of Aspe. With these data and the information provided for a number of recently drilled boreholes located in the border of the system we can deduce the relationship between the main aquifer and its limits, as well as the general hydrogeological functioning of the system

Influencia de los materiales triásicos en la calidad del agua de algunos acuíferos kársticos del sur de Alicante (España)

Overexploitation of the aquifers of the Middle Vinalopó (SE Spain) has led to problems which, in many cases, are associated with groundwater salinization. The increase in salinity is considered to be due to the dissolution of mineral salts in the Triassic Keuper facies. Geophysical logging of various boreholes in three aquifers in this region confirms the presence of more mineralized waters at depth. The evidence suggests that the phenomenon of salinization results from mixing of these deep waters with more shallow ones. The fall in the ratio of freshwater to saltwater as overexploitation continues and the aquifer is emptied could explain the increased mineralization that has been observed at many boreholes that penetrate these aquifers.La fuerte presión sometida a los acuíferos del Medio Vinalopó (SE España) ha originado problemas de sobreexplotación, los cuales van asociados en un gran número de casos a la salinización del agua. El aumento de salinidad ha sido interpretado como debido a la disolución de sales provenientes de los materiales triásicos del Keuper. La testificación geofísica de diversos sondeos de tres acuíferos de esta región ha permitido constatar la presencia de aguas más mineralizadas en profundidad. Por tanto, todo indica que el fenómeno de la salinización se debe a la mezcla del agua más superficial con la profunda. La disminución de la relación agua dulce-agua salada, a medida que progresa la sobreexplotación y el vaciado del acuífero, podría explicar el aumento de la mineralización que han experimentado numerosas captaciones de estos acuíferos

Consideraciones sobre la hidrogeología de la cuenca del río Almanzora (SE peninsular)

The hydrogeological characteristics of the aquifer systems existing in the Almanzora River basin are analyzed. Those aquifers are very important due to the climatological conditions -semiarid region- where water is a basical resource. The systems are identified from the lithologicaL structural and piezometrical characteristics. The geometrical characteristics, the numer of wells and springs, the piezometric evolution and the resources evaluation are established in each hydrogeological unit. Finally, the physical-chemical characteristics of the water are also studied.Se analizan las características hidrogeológicas de los distintos sistemas acuíferos presentes en la cuenca del río Almanzora, de gran importancia por su posición estratégica en una región con recursos muy limitados, dadas las adversas condiciones climáticas a las que está sometida. Se establece una subdivisión en base a sus características litológicas, estructurales y piezométricas. Se analizan las características geométricas de las diferentes unidades, los principales puntos de agua relacionados con las mismas, su evolución piezométrica y la evaluación de los recursos. También se exponen las características fisicoquímicas de las aguas estudiadas

Overexploitation and water quality in the Crevillente aquifer (Alicante, SE Spain)

The Crevillente aquifer is a karstic aquifer, situated in Alicante province in the SE of Spain. The aquifer basically comprises a series of Jurassic limestones and dolomites, belonging to the Betic Cordillera. Intense exploitation of the aquifer started in the early 1960s. Exploitation was initially concentrated in two sectors of the Sierra de Crevillente and, years later, extended to a third sector. As a consequence of abstractions that were much greater than recharge into the system, a continual drop in the water level persisted for several decades. These abstractions have occasionally caused local dewatering over depths of more than 300 m. From a hydrogeological point of view, the aquifer dewatering in one of the sectors was accompanied by increased mineralization and a fall in quality of the groundwater, and several boreholes had to be abandoned. In recent years, the degree to which the aquifer is overexploited has fallen considerably, and it appears to have entered a new hydrodynamic stage. New hydrogeochemical characterisations have been carried out, which indicate that the aquifer water is relatively strongly mineralised due, fundamentally, to the dissolution of evaporite rocks. On the other hand, deterioration in water quality as a consequence of the degree of overabstraction can also be confirmedDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEGeneralitat ValencianaUNESCOpu

Principales características hidrogeoquímicas del acuífero de Balerma-Las Marinas (Almería)

The Balerma-Las Marinas aquifer, which features mainly Pliocene calcarenite rocks, is one of the three distinct hydrogeological units that have been identified in the Campo de Dalías area of Almería. Its hydrogeochemistry has been established by analyzing one hundred and eight samples from different points along the aquifer. The high sodium chloride content of the water is put down to fairly recent relative changes in the sea and continent levels, which have left saline water trapped by a series of blocks that divide the aquifer into various separate compartments. This relative lack of hydraulic continuity between the aquifer and the sea, together with fact that its resources are not subject to overuse, make it very unlikely that marine intrusion is the cause of the high saline content of the water. The conclusion to be drawn is that these waters are not very suitable either for human consumption or for irrigation.El acuífero de Balerma-Las Marinas, esencialmente integrado por calcarenitas pliocenas, constituye una unidad hidrogeológica de las tres diferenciadas en el Campo de Dalías. Sobre la base de ciento ocho análisis químicos de muestras de agua recogidas en otros tantos puntos acuíferos se llega a establecer la hidrogeoquímica del acuífero; el predominio de aguas de facies clorurada sódica es interpretado como relicto de movimientos relativos mar-continente, recientes, unido a la existencia de una serie de bloques que compartimentan el acuífero y que han hecho posible que permanezca entrampada el agua salobre. La escasa explotación a que está sometido el acuífero y la baja continuidad hidráulica existente entre el acuífero y el mar descartan los procesos de intrusión marina como responsables del alto contenido salino de las aguas. Consecuentemente con lo expuesto, las aguas tienen calidad mediocre a mala, tanto para consumo humano como para su uso agrícola

Stochastic simulation of the spatial heterogeneity of deltaic hydrofacies accounting for the uncertainty of facies proportions

The spatial geological heterogeneity of an aquifer significantly affects groundwater storage, flow and the transport of solutes. In the particular case of coastal aquifers, spatial geological heterogeneity is also a major determining factor of the spatio-temporal patterns of water quality (salinity) due to seawater intrusion. While the hydraulics of coastal hydrogeology can be modeled effectively by various density flow equations, the aquifer geology is highly uncertain. A stochastic solution to the problem is to generate numerical realisations of the geology using sequential stratigraphy, geophysical models or geostatistical approaches. The geostatistical methods (two-point geostatistics, Markov chain models and multiple-point geostatistics) have the advantage of minimal data requirements, e.g., when the only data available are from cores from a few sparsely located boreholes. We provide an extension of sequential indicator simulation by including the uncertainty of the hydrofacies proportions in the simulation approach. We also deal with the problem of variogram estimation from sparse boreholes and we discuss the implicit transition probabilities and the connectivity of simulated realisations of a number of categorical variables. The variogram model used in the simulation of hydrofacies significantly influences the degree of connectivity of the hydrofacies in the simulated model. The choice of model is critical as connectivity determines the amount and extent of seawater intrusion and hence the environmental risk. The methodology is illustrated with a case study of the Andarax river delta, a coastal aquifer in south-eastern Spain. This is a semi-arid Mediterranean region in which the increasing use of, and demand for, groundwater is exacerbated by a transient tourist population that reaches its peak in the summer when the demand for the permanent population is at its highest. The work reported here provides a sound basis for designing flow simulation models for the optimal management of groundwater resources. This paper is an extended version of a presentation given at the 2012 GeoENV Conference held in Valencia, Spain.S. Jorreto-Zaguirre, P.A. Dowd, E. Pardo-Igúzquiza, A. Pulido-Bosch and F. Sánchez-Marto