Francisco Sánchez-Martos

• PhD
• University of Almería

The Campo de Dalías is a coastal plain, which has undergone a significant change in land use and intensive exploitation of groundwater. A series of diverse data has been analyzed: aerial and satellite images (1956–2013), evolution of the water table (1973–2019), and exploitation of different aquifers (1964–2017). The results indicate: (1) increase...

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 o...

Chemical and isotopic tracers are used to identify and discriminate the factors controlling the chemical characteristics of surface water in the Andarax River. Along the river, two areas are found to have distinct processes. In the Upper Andarax zone, the surface water (163–645 μS cm⁻¹) is influenced by the direct infiltration associated with preci...

This study proposes a multi-source data approach to estimating annual rates of floodwater recharge into the lower alluvial Andarax aquifer. The Andarax River catchment is about 2200 Km2, and although it is permanent in the upper part of the basin, the middle and lower catchment is ephemeral. The climate is Mediterranean with an annual average tempe...

El análisis de la temperatura del agua mediante series temporales es una herramienta que proporciona información útil para identificar la interacción entre el agua subterránea y la superficial en áreas heterogéneas de una manera rápida, fiable y de bajo coste, siendo una buena alternativa para la caracterización. El río Andarax presenta tramos de...

Identifying the groundwater-surface water interaction is fundamental to understand the dynamics of rivers in arid and semi-arid environments where river flow is discontinuous. At the head of the Andarax river, the waters are bicarbonated and have low salinity. The influence of groundwater in surface waters has been studied through the joint use of...

The identification of specific aquifers that supply water to river systems is fundamental to understanding the dynamics of the rivers' hydrochemistry, particularly in arid and semiarid environments where river flow may be discontinuous. There are multiple methods to identify the source of river water. In this study of the River Andarax, in the Sout...

In some hydrogeology applications, the only subsurface geological information available comes from a small number of boreholes from which hydrofacies have been intersected and identified. Geostatistical simulation is a widely used stochastic technique for generating a set of possible hydrofacies images that cover the range of the complexity and het...

Karstic landforms abound in the vicinity of the Uchucchacua mine (4,500–5,000 m a.s.l.). These help infiltration and the rapid inflow of water, which penetrates even the deepest working levels of the mine. These inflows affect mining operations and the mine has to be drained. In wet months, high volumes of mine water must be pumped, and these volum...

This paper presents a gravimetric study (based on 382 gravimetric stations in an area about 32 km2) of a nearly flat basin: the Low Andarax valley. This alluvial basin, close to its river mouth, is located in the extreme south of the province of Almería and coincides with one of the existing depressions in the Betic Cordillera. The paper presents n...

The Campo de Dalías (Almería, south-eastern Spain) was the backdrop for the development of intensive agricultural activity during the 1970s. Due to the poor natural soil development, the agriculturalists opted for a system that involved quarrying silt and clay deposits that could be used as soil in the greenhouses. In parallel, poor water quality i...

Water resources management in coastal wetlands requires knowledge of the degree of interdependence between groundwater and terrestrial ecosystems. This is especially so in semi-arid areas where surface inflows are restricted, marine influence is marked and the evaporation rate is high. In the Cerrillos-Punta Entinas wetland, the surface water quali...

Interactions between surface water and groundwater (SW-GW) in the Andarax catchment are complex and encourage a diversity of surface waters in the three longest watercourses. The headwaters of the river Andarax flow continuously, but it is temporal in its middle reaches and ephemeral in its lower reaches; these three reaches demonstrate the effect...

Water resources management in coastal wetlands requires the degree of interdependence between groundwater and terrestrial ecosystems to be known. This is especially so in semiarid areas where surface inflows are restricted, marine influence is marked and the evaporation rate is high. Thus, chemistry of surface waters is very variable in the Cerrill...

A significant thermal anomaly exists in the aquifer of the Lower Andarax (Almería, SE Spain), which is evidenced by the presence of several thermal springs as well as by elevated water temperatures (30–52 °C) recorded at various wells. Twelve vertical temperature logs were made to analyse these anomalies, and these yielded two-dimensional informati...

The construction of desalination plants along the Mediterranean coast that are supplied with seawater via pumped boreholes in coastal aquifers has given rise to novel hydrogeological situations. At the experimental site on the Andarax delta (SE Spain), a monitoring system has been set up, consisting of piezometer clusters. Piezometric level and ele...

Introducción El agua desalada es uno de los recursos hídricos no convencio-nales que más auge está to-mando en los últimos tiempos en zonas áridas y semiáridas, sobre todo en los litorales de las provincias de Almería, Murcia y Alicante, en los que existe un Las diagrafías y la caracterización de la influencia de los bombeos de agua de mar sobre el...

The three aquifer units differentiated in the Low Andarax-detritic, carbonated, and deep aquifers-present problems in water quality. This is made worse during the course of economic development as a result of the appearance of processes of marine intrusion, dissolution of saline rocks present in the stratigraphic series, overexploitation with consi...

The salinity of the waters of the detritic aquifer of Bou Ahmed (Morocco) is very diverse. Based on their hydrogeochemistry, two types of water have been differentiated. The less saline group of waters (electrical conductivity less than 1.500 μS/cm) is directly related to the surface waters of the two rivers that feed the aquifer. The more saline g...

Recently, the Junta de Andalucia (Autonomous Regional Government of Andalusia) has taken on the financing of the research project given by the title of this communication. The project represents an ambitious proposal to determine, as precisely as possible, the operation of the hydrogeological system that underpins large part of the economy of Almer...

Use of δ11B provides a solid tool for discriminating hydrogeochemical processes in complex coastal aquifers. Its efficiency increases markedly when it is applied along with other major or minor constituents. Nevertheless, various factors may affect its interpretation: the presence of clays, which favour adsorption and desorption, the influence of w...

Karst caves exhibit a wide range of hydrological and hydrochemical responses to infiltration events, due to their physical heterogeneity space and dynamic variability over time, and due to non-Gaussian inputs (rain) and outputs (discharge). This paper reviews different approaches of studying seepage water in caves, in order to understand the infilt...

The climatic variability of southeastern Spain recently produced one of the driest periods of the 20th century, which provoked a marked decrease in river flows. A study of trends was applied to four representative rainfall stations (Granada, Almeria, Murcia and Alicante) and showed that the downward trend is generalised. Three of the stations regis...

A study of drip water from a stalactite in the Cueva del Agua (Granada, southern Spain) over four hydrological years has enabled a detailed characterization of infiltration through the non-saturated zone of this cave. The most significant aspects are: (1) The drip water regime is not seasonal, but is linked instead to slow infiltration. Sudden chan...

Air temperature in several galleries of the Covadura System (Sorbas Gypsum Karst, Almería) was measured at monthly intervals over a period of 1 year. The spatial temperature distribution for each month was modeled in a geostatistical framework. The mean trend of the air temperature and the difference between each experimental temperature measuremen...

We recorded the air temperature and carbon dioxide concentration within the Cueva del Agua, a cave in Spain, under natural conditions prior to the cave being opened to tourists. Geostatistical tools are useful techniques for characterizing microclimate parameters with the aim of adopting measures to ensure the conservation and sound environmental m...

The contact between freshwater and seawater in coastal aquifers is studied using a relatively simple model for homogeneous aquifers. However, for real aquifers it is not so simple. The desalination plant built to supply water to the city of Almería is situated over the aquifer in the southern part of the River Andarax Delta. Its design capacity is...

The giant Geode of Pulpí (Almería, Spain) can be considered as one of the most significant recent mineralogical discoveries in terms of geological heritage. Any tourist exploitation of this mining environment should be sustainable, and the first step is to determine the feasibility of opening the interior of the geode to visitors. To achieve this o...

Abstract— Automated time-Lapse Electrical Resistivity Tomography (ALERT) is employed for the permanent monitoring of the coastal aquifer system in the Andarax delta in SE Spain. Innovative technology has been designed that allows the near real-time measurement of geoelectric, hydrologic and hydrochemical properties, virtually "on demand", thereby g...

The Andarax river is characterized by the variability of its flow, which is dependent upon the rainfall regime of the area. This work presents a study of the chemical composition of the surface waters of the Andarax river over an annual cycle. It analyses the relationship between ground water and surface waters using a hydrogeochemical methodology....

A study of the boron content alongside Cl -, SO 4 2-, and NO 3 - ions has enabled the factors that determine its origin to be distinguished. In carbonate rocks, with their higher saline content, boron is associated with marine intrusion. In the Plioquaternary aquifer, its origin is complex and is associated with three processes: marine intrusion, w...

Cave temperature monitoring was carried out in the Cueva del Agua de Iznalloz, Granada, Spain, a cave that has great tourist potential and which has been maintained under natural conditions for over 30 years. The cave temperature under natural conditions was used to identify possible anthropogenic influences, in order to distinguish these from the...

Groundwater temperature and electrical conductivity logs were applied in this study to gain an understanding of the hydrogeological behaviour of a complex system. This system, compartmentalized by a large number of fractures, which may even cause geothermal anomalies, is that of the Campo de Dalías in the south-east of the Iberian Peninsula. In add...

The Kohonen neural network was applied to hydrochemical data from the Detritic Aquifer of the Lower Andarax, situated in a semiarid zone in the southeast of Spain. An activation map was obtained for each of the sampling points, in which the spatial distribution of the activated neurons indicated different water qualities. To extract the information...

The study of salinization of groundwater in the Detrital Aquifer of the Lower Andarax is highly complex due to the semiarid climate, the presence of evaporites, proximity to the sea and localized geothermal manifestations in the area. The salinization has been characterized by jointly studying the content of various minor ions (B, Br and Li) and a...

A case study is presented for the application of statistical and geostatistical methods to the problem of estimating groundwater quality variables. This methodology has been applied to the investigation of the detrital aquifer of the Bajo Andarax (Almería, Spain). The use of principal components analysis is proposed, as a first step, for identifyin...

INTRODUCCIÓN El recorrido a realizar transcurre a lo largo Campo de Dalías y el Bajo Andarax, (figura 1). Estas dos áreas presentan rasgos diferenciales en lo relativo a naturaleza dominante de los sis-temas acuíferos; en el Campo de Dalías los materiales carbonatados constituyen los acuíferos principales, mientras que en el Bajo Andarax son los ma...

In the Lower Andarax river basin 3 aquifer units have been defined, namely the Carbonate Aquifer, the Deep Aquifer and the Detrital Aquifer, which between them contain a wide variety of water types. Identification of hydrogeochemical processes has been performed by studying a series of ionic ratios, comprising the principal constituents together wi...

The analysis of the occurrence of boron in relation to other ions (Cl− and SO42−) in the groundwaters of the Lower Andarax river reveals that this element is basically derived from the dissolution of evaporite sediments and geothermal processes. This study confirms that the geothermal anomalies favour the mobilization of boron although this factor...

The Agua Cave karst system, wich is about 6.7 km long, is the most important gypsum cave in Spain. It is in relation with a dol ine of about 1.5 km 2 with one hundred sink-holes of access inside. The system is controled by fractures N150º-160ºE and N40º-50ºE. We have recognize a diferential geomorphological evolution in accordance with the presence...

The three aquifer units differentiated in the Low Andarax—detritic, carbonated, and deep aquifers—present problems in water quality. This is made worse during the course of development as a result of the appearance of processes of marine intrusion, dissolution of saline rocks present in the stratigraphic series, overexploitation with considerable i...

The delta of the Andarax river, situated at the sou- thern end of the Detritic Aquifer of the Bajo Andarax, is composed of detritic deltaic, fluviodeltaic and marine deposits. Its vertical lithology varies from silts and clays, through intermediate sands of various sizes. to gravel. It shows frequent and abrupt changes in the horizontal plane. The...

The lack of water in the coastal areas demands an onerous search for an appropriate solution. 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. Howe...

There is a significant thermal anomaly in the Lower Andarax aquifer (Almería, SE Spain), which is evidenced by the presence of several thermal springs as well as by the elevated water temperature (30 - 52ºC) recorded at various aquifer sampling points. Sixteen vertical temperature logs were recorded to analyse these anomalies, and these supplied in...

RESUMEN En la ciudad de Almería se ha construido una planta desaladora en la que la captación del agua de mar se realiza mediante sondeos. Ante la explotación tan intensa que se tiene prevista se han construido tres grupos de piezómetros en las proximidades de los sondeos de abastecimiento, con objeto de analizar la evolución espacial y temporal de...