Corada, M.; Candela, L.; Torres-Fuentes, N.; Pintado-Herrera, M.; Paniw, M.; González-Mazo, E. Science of the total environment Vol. 605-606, p. 770-783 DOI: 10.1016/j.scitotenv.2017.06.049 Data de publicació: 2017-12 Article en revista
This study is focused on the Guadalete River basin (SW, Spain), where extreme weather conditions have become common, with and alternation between periods of drought and extreme rainfall events. Combined sewer overflows (CSOs) occur when heavy rainfall events exceed the capacity of the wastewater treatment plants (WWTP), as well as pollution episodes in parts of the basin due to uncontrolled sewage spills and the use of reclaimed water and sludge from the local WWTP. The sampling was carried out along two seasons and three campaigns during dry (March 2007) and extreme rainfall (April and December 2010) in the Guadalete River, alluvial aquifer and Jerez de la Frontera aquifer. Results showed minimum concentrations for synthetic surfactants in groundwater (< 37.4 µg·L- 1) during the first campaign (dry weather conditions), whereas groundwater contaminants increased in December 2010 as the heavy rainfall caused the river to overflow. In surface water, surfactant concentrations showed similar trends to groundwater observations. In addition to surfactants, pharmaceuticals and personal care products (PPCPs) were analyzed in the third campaign, 22 of which were detected in surface waters. Two fragrances (OTNE and galaxolide) and one analgesic/anti-inflammatory (ibuprofen) were the most abundant PPCPs (up to 6540, 2748 and 1747 ng·L- 1, respectively). Regarding groundwater, most PPCPs were detected in Jerez de la Frontera aquifer, where a synthetic fragrance (OTNE) was predominant (up to 1285 ng·L- 1).
Candela, L.; Jiménez, J.; Valdes-Abellan, J.; Jacques, D.; Kohfahl, C.; Tamoh, K. Journal of hydrology Vol. 549, p. 114-124 DOI: 10.1016/j.jhydrol.2017.03.061 Data de publicació: 2017-06 Article en revista
The use of non-conventional water (e.g., treated wastewater, desalinated water) for different purposes is increasing in many water scarce regions of the world. Its use for irrigation may have potential drawbacks, because of mineral dissolution/precipitation processes, such as changes in soil physical and hydraulic properties (e.g., porosity, permeability), modifying infiltration and aquifer recharge processes or blocking root growth. Prediction of soil and groundwater impacts is essential for achieving sustainable agricultural practices. A numerical model to solve unsaturated water flow and non-isothermal multicomponent reactive transport has been modified implementing the spatio-temporal evolution of soil physical and hydraulic properties. A long-term process simulation (30 years) of agricultural irrigation with desalinated water, based on a calibrated/validated 1D numerical model in a semi-arid region, is presented. Different scenarios conditioning reactive transport (i.e., rainwater irrigation, lack of gypsum in the soil profile, and lower partial pressure of CO2 (pCO2)) have also been considered. Results show that although boundary conditions and mineral soil composition highly influence the reactive processes, dissolution/precipitation of carbonate species is triggered mainly by pCO2, closely related to plant roots. Calcite dissolution occurs in the root zone, precipitation takes place under it and at the soil surface, which will lead a root growth blockage and a direct soil evaporation decrease, respectively. For the studied soil, a gypsum dissolution up to 40 cm depth is expected at long-term, with a general increase of porosity and hydraulic conductivity.
The Campo de Cartagena (Eastern Spain) is one of Europe’s driest areas with a mean precipitation of around 300 mm. One of the main challengesin the region is to secure a reliable water supply in both quantity and quality terms, to provide a water supply and agricultural irrigation, while water desalination has become an extensively applied solution, and one of the most sustainable solutions to the water scarcity problem. As water availability is lacking and groundwater quality is poor, the agricultural sector in Campo de Cartagena has developed small private brackish groundwater desalination plants (15-20 m3/h) through already existing agricultural wells. Costs and benefits (C-B) for citrus cultivation (1 ha) in three such plants have been assessed. The results indicate that for the studied cases, current agricultural management is feasible and costs outweigh benefits, with a positive NPV and a cost/benefit ratio higher than 1. The internal rate of return is also positive and higher than 11%. The results evidence practical and theoretical implications as to how to increase water resources in areas where water is scarce by closing the loop, ensuring farmers’ profitability and encouraging private sector investments.
de Bustamante, I.; Cabrera, M.C.; Echegaray, M.; Candela, L.; Pérez-Barbón, A.; Martínez-Hernández, V. Congreso Hispano-Luso sobre las Aguas Subterráneas en el Segundo Ciclo de Planificación Hidrológica p. 1-8 Data de presentació: 2016-11-30 Presentació treball a congrés
A pesar del creciente aumento de la reutilización del agua a nivel mundial, su implementación y operación se enfrentan a grandes retos institucionales, regulatorios, económicos y sociales. Además, es un problema interdisciplinar e intersectorial que debe ser considerado mediante un enfoque integrador. Su regulación de esta práctica debe basarse en garantizar la protección de la salud y del medio ambiente, incluyendo objetivos de tratamiento y un seguimiento de la calidad del agua, adecuados y financieramente asequibles, ya que un coste alto puede ser un impedimento para su implantación. En este trabajo se revisan las características del ordenamiento jurídico comunitario y nacional y se exponen algunos casos de reutilización en España para riego y recarga de acuíferos, estudiados dentro del programa Consolider-Traguanet.
Aparicio, J.O; Candela, L.; Alfranca, O. Congreso Hispano-Luso sobre las Aguas Subterráneas en el Segundo Ciclo de Planificación Hidrológica p. 1-7 Data de presentació: 2016-11-30 Presentació treball a congrés
El Campo de Cartagena (SE peninsular), cuenca sedimentaria constituida por materiales Neógenos y Cuaternarios, se caracteriza por un intenso desarrollo agrícola. El sistema hidrogeológico multicapa está constituido por la presencia de niveles profundos confinados y un acuífero somero libre; el agua presenta diversos grados de salinidad de origen natural y antrópica. La demanda hídrica está cubierta por agua subterránea, trasvase Tajo-Segura, agua desalada (mar) y desalobrada (acuíferos). Las pequeñas plantas desalobradoras (= 2200 m3/día) procesan el agua por osmosis inversa (OI) y tienen una importante participación en la aportación de recursos hídricos, pero existe escasa información del coste del agua asociado. Debido al gran número de plantas desalobradoras existentes, sus características específicas, la calidad de agua desalobrada, profundidad de pozo/sondeo, producción (m3), el análisis del coste final del agua se ha realizado solo para una muestra específica. El coste medio del m3 de agua desalobrada para nueve plantas elegidas, con una producción comprendida entre 120 m3/día y 2200 m3/día, oscila entre 0.17-0.24 €/m3, y resulta competitivo para usos agrícolas, donde la demanda de agua para riego agrícola en la región alcanza el 87% de los recursos hídricos disponibles, y la superficie regable es en promedio de unas 190 mil hectáreas.
Una de las amenazas a la calidad de los RRHH es la presencia de múltiples estresores, entre ellos que cabe destacar a los denominados contaminantes emergentes. Con el nombre de contaminantes o compuestos emergentes se define a una serie de compuestos químicos de origen diverso (fármacos, productos de diagnóstico, plaguicidas, detergentes, productos de uso personal, etc.) caracterizados por su continua y creciente producción y consumo. La información existente sobre su presencia en las aguas subterráneas no es abundante, sin embargo, fármacos como el ibuprofeno, cafeína, productos de diagnóstico RX, detergentes (LAS), retardantes de llama, drogas sociales, etc. (¿/l, ng/l) han sido detectados en acuíferos. Su presencia en el medio hídrico no es reciente, pero su distribución espacial, presencia, rutas de incorporación al medio y persistencia en el mismo todavía no son del todo conocidos, al igual que sus efectos sobre la salud humana y ecosistemas. Pueden ser nocivos, especialmente por la presencia generalizada de algunos compuestos y los limitados conocimientos sobre su toxicidad. La ausencia de normativa aplicable, a excepción de la primera lista de observación adoptada en 2015 (Decisión 2015/495) y el coste derivado de su control constituye un futuro reto en los programas de control y seguimiento.
Vadillo Pérez, I.; Candela, L.; Jiménez-Gavilán, P.; Urresti-Estala, B.; Corada, M. Congreso Hispano-Luso sobre las Aguas Subterráneas en el Segundo Ciclo de Planificación Hidrológica p. 1-6 Data de presentació: 2016-11-28 Presentació treball a congrés
Actualmente existe un creciente interés por los contaminantes emergentes, en especial por los productos farmacéuticos y de cuidado personal (PPCPs). Son contaminantes que han pasado inadvertidos a lo largo de los años debido a sus bajas concentraciones pero que presentan efectos perjudiciales para la salud y el medio ambiente. Estos compuestos, en su mayoría no regulados en la legislación, han sido hallados en aguas superficiales, subterráneas, sedimentos e incluso en aguas de abastecimiento. Este trabajo se centra en las aguas subterráneas de la cuenca del río Guadalhorce, determinando la distribución de los PPCPs, y la relación que presentan con las fuentes de contaminación existentes en el área de estudio.
In meeting water demand, many aquifers have been over-exploited by pumping in excess of recharge, leading to significant groundwater level decline and seawater intrusion in coastal areas. Water resources availability is going to be of the most important problems to face in the decades to come. To meet the growing water demand and also in response to water scarcity, measures to regulate demand and to increase supplies from new sources have been promoted. Among
the policies to be cited, recycling and reuse of treated wastewater (TWW) is gaining popularity due to: the constantly improving quality of TWW discharges in line with increasing technology, and the need of non-conventional water sources in the context of integrated water resources management (IWRM) to meet the water demand. Over the last decade there has been significant growth in the application of reuse, important advances in reuse technologies, and an increase in the number of states that have implemented either rules or guidelines for reuse EPA,2012; BOE, 2007). The two water reuse options currently gaining prevalence, direct potable reuse (DPR, defined through an integrated planning process) and indirect potable reuse (IPR, are considered as part of the water cycle increasing water resources, improving the IWRM and supply security. Agricultural irrigation and recreational facilities (ex. golf courses) and aquifer recharge (MAR) may be one the most well-known applications of reclaimed water. Successes, possible effects in groundwater and lessons learned are presented through specific case studies (De Bustamante et al., 2010; Candela et al; 2007; Candela et al., 2016; Teijón et al., 2016).
Himi, M.; Valdés-Abellán, J.; Lovera, R.; Queralt, I.; Tapias, J.; Candela, L.; Casas, A. European Meeting of Environmental and Engineering Geophysics p. 1-5 Data de presentació: 2016-09-05 Presentació treball a congrés
Desalinated brackish groundwater is becoming a new source of water supply to comply with growing water demands, especially in (semi) arid countries. Irrigation with desalinated or a blend of desalinated and ground/surface water, presents associated impacts on plants, soil and aquifer media. Mixed waters with different salinities can lead to the formation of unexpected chemical precipitates. The use of desalted
groundwater for irrigation counts with potential drawbacks, among them: changes of hydraulic properties of soil-aquifer systems (e.g. hydraulic conductivity, porosity) as a consequence of mineral precipitation; root growth blockage and plant uptake of pollutants; as well as leaching of contaminants to groundwater. An experimental plot located at SE Spain, covered by grass and irrigated by sprinklers with a blend of desalted and groundwater from a brackish aquifer has been monitored in order to characterize at field scale the possible impacts on soil hydraulic properties.
Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired.; In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils" were evaluated.; The direct analysis of a solid suspension using 20 mg of fine ground soil (<63 mu m) gave a 3.7 mg kg(-1) limit of detection for bromine which, in most cases, was suitable for monitoring total bromine content in soils (Br content range in soils = 5-40 mg kg(-1)). Information about bromide determination in soils is also possible by analyzing the Br content in water soil extracts. In this case, the TXRF analysis can be directly performed by depositing 10 mu L of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 mu g L-1.; Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide).; As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water.
Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired. In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils were evaluated. The direct analysis of a solid suspension using 20 mg of fine ground soil (<63 µm) gave a 3.7 mg kg-1 limit of detection for bromine which, in most cases, was suitable for monitoring total bromine content in soils (Br content range in soils = 5-40 mg kg-1). Information about bromide determination in soils is also possible by analyzing the Br content in water soil extracts. In this case, the TXRF analysis can be directly performed by depositing 10 µL of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 µg L-1. Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide). As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water.
Climate change impact on water resources (streamflow and deep natural recharge) based on the downscaled outputs from the ECHAM5 general circulation model (GCM) has been investigated in the Mediterranean basin (Fluvia, Spain) for the A2, B1 greenhouse scenarios and 2000-2024/2025-2050 time slices. The HEC-HMS 3.4 rainfall-runoff numerical model was the basic tool used to generate streamflow for the historical period, and deep natural recharge was calculated from Visual-BALAN 2.0, a water-soil-plant distributed model. The hydrologic and recharge models were employed to generate future climate change hydrographs and the deep recharge amount. Furthermore, the selected future climate scenarios, subject to possible changes in the land use/land cover forecast, were integrated into the models, and water resource impacts were assessed. The multiple combinations of climate model, time slices, greenhouse scenarios, land use/land cover scenarios and hydrological estimation methods resulted in six scenarios. The obtained results estimate an increase in temperature (1.5 degrees C), a decline in precipitation (17%) and a maximum decrease of 49.5% and 16.8% in runoff and groundwater recharge, respectively, for 2050 (A2) compared to the historical values. Planned land cover scenarios, implying small changes of agricultural and forested land, show no major contribution to future water resource changes. According to the results, the most sensitive parameters conditioning future water resources are changes in temperature and precipitation.
Climate change impact on water resources (streamflow and deep natural recharge) based on the downscaled outputs from the ECHAM5 general circulation model (GCM) has been investigated in the Mediterranean basin (Fluvià, Spain) for the A2, B1 greenhouse scenarios and 2000–2024/2025–2050 time slices. The HEC-HMS 3.4 rainfall-runoff numerical model was the basic tool used to generate streamflow for the historical period, and deep natural recharge was calculated from Visual-BALAN 2.0, a water-soil-plant distributed model. The hydrologic and recharge models were employed to generate future climate change hydrographs and the deep recharge amount.
Furthermore, the selected future climate scenarios, subject to possible changes in the land use/land cover forecast, were integrated into the models, and water resource impacts were assessed. The multiple combinations of climate model, time slices, greenhouse scenarios, land use/land cover scenarios and hydrological estimation methods resulted in six scenarios. The obtained results estimate an increase in temperature (1.5 C), a decline in precipitation (17%) and a maximum decrease of 49.5% and 16.8% in runoff and groundwater recharge, respectively, for 2050 (A2) compared to the historical values. Planned land cover scenarios, implying small changes of agricultural and forested land, show no major contribution to future water resource changes. According to the results, the most sensitive parameters conditioning future water resources are changes in temperature and precipitation.
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
Páez, G.; Muñoz, F.; Candela, L.; Tamoh, K.; Valdes-Abellan, J. Science of the total environment Vol. 539, p. 410-419 DOI: 10.1016/j.scitotenv.2015.08.153 Data de publicació: 2016-01 Article en revista
Extensive application of vinasse, a subproduct from sugar cane plantations for bioethanol production, is currently taking place as a source of nutrients that forms part of agricultural management in different agroclimatic regions. Liquid vinasse composition is characterised by high variability of organic compounds and major ions, acid pH (4.7), high TDS concentration (117,416-599,400 mg L-1) and elevated EC (14,350-64,099 ¿S cm-1). A large-scale sugar cane field application is taking place in Valle del Cauca (Colombia), where monitoring of soil, unsaturated zone and the aquifer underneath has been made since 2006 to evaluate possible impacts on three experimental plots. For this assessment, monitoring wells and piezometers were installed to determine groundwater flow and water samples were collected for chemical analysis. In the unsaturated zone, tensiometers were installed at different depths to determine flow patterns, while suction lysimeters were used for water samples chemical determinations. The findings show that in the sandy loam plot (Hacienda Real), the unsaturated zone is characterised by low water retention, showing a high transport capacity, while the other two plots of silty composition presented temporal saturation due to La Niña event (2010-2011). The strong La Niña effect on aquifer recharge which would dilute the infiltrated water during the monitoring period and, on the other hand dissolution of possible precipitated salts bringing them back into solution may occur. A slight increase in the concentration of major ions was observed in groundwater (~5% of TDS), which can be attributed to a combination of factors: vinasse dilution produced by water input and hydrochemical processes along with nutrients removal produced by sugar cane uptake. This fact may make the aquifer vulnerable to contamination.
The naturally high microbiological and chemical quality of groundwater, captured at springheads and in shallow galleries and dugwells, has been vital for human survival, wellbeing and development from our earliest history – and remains so today. The purity of groundwater, coupled with its mineral content, is such that many springs historically have been attributed medicinal value.
Strategic overview series of the International Association of Hydrogeologists-IAH. This Series is designed both to inform professionals in other sectors of key interactions with groundwater resources and hydrogeological science, and to guide IAH members in their outreach to related sectors.
Jiménez-Martínez, J.; García-Aróstegui, J.L.; Hunink, J.; Contreras, S.; Baudron, P.; Candela, L. Environmental Reviews Vol. 24, num. 4, p. 377-392 DOI: 10.1139/er-2015-0089 Data de publicació: 2016 Article en revista
Hydrological processes and water resources are increasingly modified by anthropogenic actions, leading to multiple pressures on the environment and related ecosystems. A better understanding of the interactions between the anthroposphere and the hydrosphere is necessary to shape more sustainable societies. The pressure of human activities on the environment is specially high along the circum-Mediterranean area due to a combination of biophysical and economic factors.The Campo the Cartagena coastal plain together with the Mar Menor lagoon is one of the most exemplary areas in this aspect. This work analyzes this system at the basin level by providing a synthesis of the state of knowledge of each hydrological compartment and the links between them
El agua subterránea constituye un recurso natural clave para el medio ambiente y el desarrollo económico de la cuenca del río Segura, que satisface entorno al 35% de la demanda total para riego. En la cuenca del Campo de Cartagena-Mar Menor, el recurso subterráneo desempeña además un papel estratégico especialmente en periodos de sequía, al amortiguar en un rango del 30-75%, las variaciones de los recursos procedentes del Trasvase Tajo-Segura. Las interrelaciones
de los acuíferos del Campo de Cartagena con la laguna costera del Mar Menor y las implicaciones ambientales derivadas de su uso intensivo ha incrementado el interés científico, a la vez que emerge la necesidad de cumplir con las obligaciones legales derivadas de la Directiva Marco del Agua. En la actualidad la adopción efectiva de diferentes medidas de adaptación y mitigación encaminadas a mejorar la gestión de la cuenca y del Mar Menor precisa de Sistemas de Soporte a la Decisión basados en un mayor conocimiento hidrogeológico del acuífero multicapa y de los patrones y dinámicas de uso y consumo de agua.
Vadillo Pérez, I.; Candela, L.; Gambero-Sedeño, L.; Urresti-Estala, B.; Jiménez-Gavilán, P.; Corada-Fernández, C. International Association Hydrogeologists Congress p. 370 Data de presentació: 2015-09 Presentació treball a congrés
This research is focused in the Guadalhorce porous aquifer (Malaga, south of Spain), to study the distribution of EC and the interaction with the hydrogeochemistry. 14 EC (Ibuprofen, Hydrochlorothiazide, Salicilic Acid, Triclosan, Menfenamic Acid, Carbamazepine, Trimethoprim, Ofloxacin, Cafeine, Metotrexato, Metronidazole, Sulfadiazine,
Sulfamethazine and Sulfamethoxazole) and 36 paramaters including electrical conductivity, T, pH, DO, major ions (Cl-, SO42-, HCO3-, NO3-, Ca2+, Mg2+, Na+, K+), metals (B, Al, Fe, Mn, Cd, Pb, Zn, As and Se) and isotopes (d2H-H2O, d18O-H2O, d34S-SO42-) were controlled in a single field sampling (June 2012). Relationships between certain
pollutants by its focus of origin are studied.
Irrigation with slightly saline water is becoming a normal practice in water-scarce regions to increase the available water resources. Although in many areas its use has been proved sustainable, assessment of possible longterm impacts due to its application are scarce due to lack of real field experiences. To overcome this barrier,
numerical simulation of variable-saturated flow and reactive transport is an efficient tool to assess the long-term irrigation impacts on soil and aquifer caused by non-conventional water use. A multicomponent reactive transport model, HP1, to simulate long term salt leaching to groundwater has been applied to an experimental site developed in a semi-arid region (SE Spain). The model is based on a previously
validated and calibrated flow model based on several years of observation data: soil pressure head (at 20 and 60 cm depth) and volumetric water content (at 20, 40, 60, 90 and 120 cm depth). Aquifer media dispersivity for the reactive model was obtained from a field tracer test and inverse modelling. Among the obtained results processes related to salt dynamics in the non-saturated zone of the aquifer, and accumulative waterborne salt recharge under different agricultural and water management strategies are shown.
Since the 1960's the coastal aquifer overlying the irrigated plain of Korba El Mida (East coast of Cap-Bon) has been under intensive exploitation leading to groundwater degradation quality by seawater intrusion and irrigation return flow. Also, the main coastal sabkhas (wetlands) are no longer the natural outlets of the aquifer, due to a
reversal of the hydraulic gradient jointly with groundwater depletion. Since 1962 geophysical surveys, use of environmental isotopes and tracers, and groundwater monitoring campaigns for sampling and level measurements of existing piezometers and surrounding wells, have been carried out in order to assess origin of salinity, extent and evolution along time. Since 2008, artificial recharge groundwater with reclaimed water through three infiltration basins is taking place to increase groundwater resources, restore the piezometric levels, and improve water quality. Values of Electric Conductivity may range between 0.3 and 10.6 dS/m in the surroundings of Korba and El Mida;
most piezometers and some wells had essentially sodium-chloride facies but some wells present a calcium-sulfate facies. High nitrate concentration (up to 300 mg/L), potassium and sulphate increase due to mineral fertilizers and manure application are observed in some areas of the aquifer, fact supported by the Cl-NO3 diagrams. The high
heterogeneity of the salinity distribution, due to geological and hydrodynamic conditions, generates complex groundwater mixing of different origins: seawater intrusion, irrigation return flow, natural recharge besides the existing induced aquifer recharge in the area. The spatial variability of concentrations in the Korba-El Mida aquifer
reveals the complexity of the groundwater contamination by salinization and anthropogenic activities.
Candela, L.; Valdés-Abellán, J.; Jiménez, J.; Tamoh, K. Spanish journal of agricultural research Vol. 13, num. 1, p. e1201-e1201-15 DOI: 10.5424/sjar/2015131-6323 Data de publicació: 2015-06-10 Article en revista
Irrigated agriculture is usually performed in semi-arid regions despite scarcity of water resources. Therefore, optimal irrigation
management by monitoring the soil is essential, and assessing soil hydraulic properties and water flow dynamics is presented as a
first measure. For this purpose, the control of volumetric water content, ¿, and pressure head, h, is required. This study adopted two
types of monitoring strategies in the same experimental plot to control ¿ and h in the vadose zone: i) non-automatic and more timeconsuming;
ii) automatic connected to a datalogger. Water flux was modelled with Hydrus-1D using the data collected from both
acquisition strategies independently (3820 daily values for the automatic; less than 1000 for the non-automatic). Goodness-of-fit
results reported a better adjustment in case of automatic sensors. Both model outputs adequately predicted the general trend of ¿
and h, but with slight differences in computed annual drainage (711 mm and 774 mm). Soil hydraulic properties were inversely
estimated from both data acquisition systems. Major differences were obtained in the saturated volumetric water content, ¿s, and
the n and a van Genuchten model shape parameters. Saturated hydraulic conductivity, Ks, shown lower variability with a coefficient
of variation range from 0.13 to 0.24 for the soil layers defined. Soil hydraulic properties were better assessed through automatic
data acquisition as data variability was lower and accuracy was higher.
Irrigated agriculture is usually performed in semi-arid regions despite scarcity of water resources. Therefore, optimal irrigation management by monitoring the soil is essential, and assessing soil hydraulic properties and water flow dynamics is presented as a first measure. For this purpose, the control of volumetric water content, ¿, and pressure head, h, is required. This study adopted two types of monitoring strategies in the same experimental plot to control ¿ and h in the vadose zone: i) non-automatic and more time-consuming; ii) automatic connected to a datalogger. Water flux was modelled with Hydrus-1D using the data collected from both acquisition strategies independently (3820 daily values for the automatic; less than 1000 for the non-automatic). Goodness-of-fit results reported a better adjustment in case of automatic sensors. Both model outputs adequately predicted the general trend of ¿ and h, but with slight differences in computed annual drainage (711 mm and 774 mm). Soil hydraulic properties were inversely estimated from both data acquisition systems. Major differences were obtained in the saturated volumetric water content, ¿s, and the n and a van Genuchten model shape parameters. Saturated hydraulic conductivity, Ks, shown lower variability with a coefficient of variation range from 0.13 to 0.24 for the soil layers defined. Soil hydraulic properties were better assessed through automatic data acquisition as data variability was lower and accuracy was higher.
Candela, L.; Tamoh, K.; Olivares, G.; Gomez, M.; Valdes-Abellan, J. Aqua-LAC: revista del Programa Hidrológico Internacional para América Latina y el Caribe Vol. 7, num. 13, p. 1-10 Data de publicació: 2015-03 Article en revista
Se presentan los efectos del cambio global en la cuenca del río Tordera (España) para el periodo 2000-2050, escenarios climáticos A2 (medio-alto) definidos por el Panel Intergubernamental del Cambio Climático (IPCC, 200) y escenarios socioeconómicos (cambios previstos en la cuenca) denominados estable y tendencial. Los efectos sobre los recursos hídricos se han analizado de forma conjunta superficial-subterránea mediante una metodológica de tipo acoplado. Para establecer los impactos futuros sobre los recursos hídricos se ha seleccionado el Modelo de Circulación Global ECHAM5 (Max Planck Institute). Los resultados obtenidos indican una disminución de la precipitación del 11.3% y un aumento de la temperatura de 1ºC, respecto a los valores históricos de la zona. De acuerdo a la proyección futura (2050) sobre cambios en los recursos hídricos, la escorrentía superficial obtenida mediante simulación con el código HEC-HMS 3.4 experimenta una reducción del 31.8% respecto al valor histórico y la recarga natural, estimada mediante VISUAL-Balan, se reduce en un 11.7%. El balance en el acuífero deltaico simulado mediante MODFLOW 2009.1 Pro muestra igualmente una disminución de los parámetros del balance. Los cambios del uso del suelo previstos de acuerdo a la legislación vigente (escenarios socioeconómicos) no conducen a la generación de un impacto apreciable en los recursos hídricos; según los escenarios definidos la variación de precipitación y temperatura son los parámetros fundamentales del cambio previsto.
To satisfy water demand in the arid climate area (SE Spain), small private desalination plants (more than 1000) of brackish groundwater are in operation. This
process has led to an increase of groundwater salinity as a consequence of aquifers connection, uncontrolled
subsurface injection of brines and pitfalls of the brines conveyor network. Measures being taken, including the
economic efficiency of the small private desalination plants with regard to groundwater, and obtained results are presented.
Corada-Fernández, C.; Jiménez, J.; Candela, L.; González-Mazo, E.; Lara-Martín, P. Chemosphere Vol. 119, num. Supplement, p. S131-S137 DOI: 10.1016/j.chemosphere.2014.04.098 Data de publicació: 2015-01 Article en revista
Irrigation with reclaimed water is becoming a common practice in arid- and semi-arid regions as a consequence of structural water resource scarcity. This practice can lead to contamination of the vadose zone if sewage-derived contaminants are not removed properly. In the current work, we have characterized soils from the Guadalete River basin (SW Spain), which are often irrigated with reclaimed water from a nearby wastewater treatment plant and amended using sludge. Physico-chemical, mineralogical and hydraulic properties were measured in soil samples from this area (from surface up to 2 m depth). Emerging contaminants (synthetic surfactants and pharmaceutically active compounds, or PhACs) were also determined. Synthetic surfactants, widely used in personal care products (PCPs), were found in a wide range of concentrations: 73–1300 µg kg-1 for linear alkylbenzene sulfonates (LAS), 120–496 µg kg-1 for alkyl ethoxysulfates (AES), 19–1090 µg kg-1 for alcohol polyethoxylates (AEOs), and 155–280 µg kg-1 for nonylphenol polyethoxylates (NPEOs). The presence of surfactant homologues with longer alkyl chains was predominant due to their sorption capacity. A positive correlation was found between LAS and AEOs and soil organic carbon and clay content, respectively. Out of 64 PhACs analyzed, only 7 were detected occasionally (diclofenac, metoprolol, fenofibrate, carbamazepine, clarithromycin, famotidine and hydrochlorothiazide), always at very low concentrations (from 0.1 to 1.3 µg kg-1).
La caracterización de las propiedades hidráulicas del suelo es fundamental para estudios relacionados con la agronomía, hidrología y ciencias ambientales. No todos los equipos son igualmente aplicables para dichas caracterizaciones, siendo clave el conocimiento previo del tipo de suelo para elegir la técnica más adecuada. Este trabajo compara los resultados obtenidos para la determinación en laboratorio de las curvas de retención de agua del suelo, pF, y la conductividad hidráulica saturada, KS, mediante diferentes equipos. La conductividad hidráulica fue calculada con una cámara triaxial (GDS Instrument®) y con el equipo KSAT (UMS®). La curva de retención se obtuvo mediante la cámara de Richards (Soil Moisture Equipment Corp.) y el equipo HYPROP (HYdraulic PROPerty analyzer de UMS®), que mide directamente el potencial mátricial en función de la pérdida de contenido de humedad por evaporación. Los resultados obtenidos se evaluaron mediante técnicas estadísticas.
The TWAP Groundwater Component Project for the European region focuses on three subregions, defined by taking into account the similarities of water management issues by UNECE: Western and central Europe, South-Eastern Europe, Eastern and Northern Europe. The region is characterised by a great diversity in water resources availability, pressure status and responses in Transboundary Aquifers (TBA).
Teijón, G.; Candela, L.; Šimunek, J.; Tamoh, K.; Valdes-Abellan, J. Soil and sediment contamination Vol. 23, num. 7, p. 736-750 DOI: 10.1080/15320383.2014.869194 Data de publicació: 2014-10-03 Article en revista
Naproxen-C14H14O3 is a nonsteroidal anti-inflammatory drug which has been found at detectable concentrations in wastewater, surface water, and groundwater. Naproxen is relatively hydrophilic and is in anionic form at pH between 6 and 8. In this study, column experiments were performed using an unconsolidated aquifer material from an area near Barcelona (Spain) to assess transport and reaction mechanisms of Naproxen in the aquifer matrix under different pore water fluxes. Results were evaluated using HYDRUS-1D, which was used to estimate transport parameters. Batch sorption isotherms for Naproxen conformed with the linear model with a sorption coefficient of 0.42 (cm3 g-1), suggesting a low sorption affinity. Naproxen breakthrough curves (BTCs) measured in soil columns under steady-state, saturated water flow conditions displayed similar behavior, with no apparent hysteresis in sorption or dependence of retardation (R, 3.85-4.24) on pore water velocities. Soil sorption did not show any significant decrease for increasing flow rates, as observed from Naproxen recovery in the effluent. Sorption parameters estimated by the model suggest that Naproxen has a low sorption affinity to aquifer matrix. Most sorption of Naproxen occurred on the instantaneous sorption sites, with the kinetic sorption sites representing only about 10 to 40% of total sorption.
We studied the transport of a pesticide at field scale, namely carbofuran molecule which is known for its high mobility, especially in sandy soils with high hydraulic conductivity and low organic matter. To add to our knowledge of the future of this high-mobility molecule in this type of soils, we developed a mechanistic numerical model allowing the simulation of hydric and solute transfers (bromide and carbofuran) in the soil. We carried out this study in an agricultural plot in the region of Mnasra in Morocco. Confrontation of the measured and simulated values allowed the calibration of the parameters of hydric transfer and carbofuran. The developed model accurately reproduces the
Despite a weak irrigation and precipitation regime, carbofuran was practically leached beyond the root zone. Prospective simulations show that under a more important irrigation regime, carbofuran reaches 100cm depth, whereas it does not exceed 60cm under a deficit regime.
Pascual, J.; Pérez-Foguet, A.; Codony, J.; Raventós, E.; Candela, L. International journal of water resources development Vol. 30, num. 3, p. 572-587 DOI: 10.1080/07900627.2013.843410 Data de publicació: 2014-09-01 Article en revista
This article assesses the relation between water management, environmental degradation and poverty through a stakeholder analysis focused on the status and management of water resources. It draws from the situation observed in the Ethiopian Central Rift Valley, an endorheic basin south of Addis Ababa where human activities have resulted in the degradation of most freshwater ecosystems and where the vast majority of the population lives in poverty. It proposes a shift in water governance that focuses on improving economic and social welfare and enhancing environmental sustainability. This shift can help overcome some of the problems affecting the Central Rift Valley, namely: (1) the overexploitation of water resources; (2) poor water quality; and (3) the high dependency of the population on water resources to sustain their livelihoods.
This article assesses the relation between water management, environmental degradation and poverty through a stakeholder analysis focused on the status and management of water resources. It draws from the situation observed in the Ethiopian Central Rift Valley, an endorheic basin south of Addis Ababa where human activities have resulted in the degradation of most freshwater ecosystems and where the vast majority of the population lives in poverty. It proposes a shift in water governance that focuses on improving economic and social welfare and enhancing environmental sustainability. This shift can help overcome some of the problems affecting the Central Rift Valley, namely: (1) the overexploitation of water resources; (2) poor water quality; and (3) the high dependency of the population on water resources to sustain their livelihoods
Determination of reliable solute transport parameters is an essential aspect for the characterization of the mechanisms and processes involved in solute transport (e.g., pesticides, fertilizers, contaminants) through the unsaturated zone. A rapid inexpensive method to estimate the dispersivity parameter at the field scale is presented herein. It is based on the quantification by the X-ray fluorescence solid-state technique of total bromine in soil, along with an inverse numerical modeling approach. The results show that this methodology is a good alternative to the classic Br-determination in soil water by ion chromatography. A good agreement between the observed and simulated total soil Br is reported. The results highlight the potential applicability of both combined techniques to infer readily solute transport parameters under field conditions.
One of the most important issues for water resource management is developing strategies for groundwater modelling that are adaptable to data scarcity. These strategies are particularly important in arid and semi-arid areas where access to data is poor and data collection is difficult, such as the Lake Chad Basin in Africa. In the present study, we establish a numerical groundwater flow model and evaluate the effects of dry and wet periods on groundwater recharge in the Chari–Logone area (96¿000¿km2) of the Lake Chad Basin. Boundary conditions, flow direction, sources, and sinks for the Chari–Logone local model were obtained by revising and remodelling the Lake Chad Basin regional hydrogeological model (508¿400¿km2) developed by the BRGM (Bureau de Recherches Géologiques et Minières) in the 1990s. The simulated aquifer water level showed good agreement with observed levels. Aquifer recharge is primarily determined by river–aquifer interactions and mostly occurs in the southern section of the study area. In wet years, groundwater recharge also occurs in the N'Djamena area. The approach we adopted provided relevant results and was useful as an initial step in more detailed modelling of the area. It also proved to be a useful method for groundwater modelling in large semi-arid and arid regions where available data are scarce.
Poch, R.; Jiménez, J.; Wallis, K.J; Ramírez de Cartagena, F.; Candela, L. Agricultural water management Vol. 134, p. 1-13 DOI: 10.1016/j.agwat.2013.11.017 Data de publicació: 2014-03 Article en revista
Agriculture constitutes a major source of non-point pollution (e.g., nitrates) where overall water resources are affected, in particular, aquifers. Intensive agricultural practices take place in regions with appropriate weather conditions that are usually deficient in water resources. The preservation of water resources in these types of regions depends on the evaluation of the efficiency of agricultural practices for specific crops and conditions. Although water scarcity is a characteristic feature in the Western Mediterranean, it is one of the most appropriate regions in the world for intensive agriculture development for climatic reasons. In the current work, percolation and N leaching from different crops (corn, potato, and rotation of lettuce and melon) under different irrigation methods (surface, sprinkler and drip) were evaluated through experimental plots. Water (irrigation + precipitation) and fertilizer inputs were accurately controlled. Soil water content and nitrate concentration were monitored from time domain reflectometry measurements, and cup lysimeters and destructive sampling, respectively. Percolation and nitrate leaching was simulated from different numerical codes (STICS and GLEAMS, tipping bucket method; HYDRUS-1D, Richards’ equation), which were chosen based on the available information and the specific purposes of each experiment. For the studied periods, the obtained results showed high percolation values: 34, 58 and 37% of total applied water for corn, potato, and rotation of lettuce and melon, respectively. Also, high N leaching values across all experiences were observed, even higher than the applied doses in some periods as consequence of remobilizing mineralized N, despite following the recommended agricultural management practices. Percolation and N leaching were mostly controlled by the precipitation regime, namely, unevenly distributed intensive rainfall events, mainly in autumn and spring, which have a great impact in irrigated agriculture due to the permanent high soil water content. In detail, irrigation water applied for frost prevention on potato crops and plastic cover for melon crops, played a very important role for both percolation and N leaching. Whilst for the corn crop, N leaching mainly took place in the fallow period (autumn and winter), where the rain leached N present in soil from previous crops.
Gaaloul, N.; Candela, L.; Chebil, A.; Soussi, A.; Tamoh, K. Desalination and water treatment Vol. 52, num. 10-12, p. 1997-2008 DOI: 10.1080/19443994.2013.821026 Data de publicació: 2014 Article en revista
During the last few decades, the Grombalia shallow, an unconfined aquifer, had been under stress by groundwater pumping due to the increasing population and development of agricultural activity. Recently, the aquifer has displayed an important decline in the water level of boreholes and wells, and considerable deterioration of groundwater quality due to saltwater intrusion. A groundwater numerical model for the Grombalia aquifer has been developed based on the Visual Modflow 3.1 code to simulate the groundwater changes under steady state regime and transient conditions. The results of the model show reasonable agreement between observed and estimated groundwater levels in the observation wells. Sebkaht Soliman wetland aquifer connection has been identified. This paper presents the effect of different groundwater management scenarios and pumping discharge on groundwater resources in the Grombalia aquifer (Cap-Bon peninsula, Tunisia).
Corada-Fernández, C.; Lara-Martín, P.; Jimenez, J.; Candela, L.; González, E. International Conference on Environmental Science and Technology p. 436 Data de presentació: 2013-09-06 Presentació treball a congrés
Corada-Fernández, C.; Lara-Martín, P.; Candela, L.; González, E. Science of the total environment Vol. 461-462, p. 568-575 DOI: 10.1016/j.scitotenv.2013.04.100 Data de publicació: 2013-09 Article en revista
This manuscript deals with the presence and degradation of the most commonly-used surfactants, including anionic (linear alkylbenzene sulfonates, LAS, and alkyl ethoxysulfates, AES) and non-ionic (alcohol polyethoxylates, AEOs, and nonylphenol polyethoxylates, NPEOs) compounds, in sediments and pore water from several aquatic environments (Southwest, Spain). Different vertical distributions were observed according to the respective sources, uses, production volumes and physicochemical properties of each surfactant. Levels of nonionics (up to 10 mg kg- 1) were twice as high as anionics in industrial areas and harbors, whereas the opposite was found near urban wastewater discharge outlets. Sulfophenyl carboxylic acids (SPCs), LAS degradation products, were identified at anoxic depths at some sampling stations. Their presence was related to in situ anaerobic degradation of LAS in marine sediments, whereas the occurrence of these metabolites in freshwater sediments was attributed to the existence of wastewater sources nearby. No significant changes in the average length of AEO and NPEO ethoxylated chains were observed along the sediment cores, suggesting that their biodegradation was very limited in the sampling area. This may be directly related to their lower bioavailability, as their calculated sediment–pore water distribution coefficients (log Ksw), which showed that non-ionic surfactants examined in this study had greater sorption affinity than the anionic surfactants (e.g., 2.3 ± 0.3 for NPEOs).
An Integrated Water Resources Management (IWRM) shall be applied to achieve a sustainable development, to increase population incomes without affecting lives of those who are highly dependent on the environment. First step should be to understand water dynamics at basin level, starting by modeling the basin water resources. For model implementation, a large number of data and parameters are required, but those are not always available, especially in some developing countries where different sources may have different data, there is lack
of information on data collection, etc. The Ethiopian Central Rift Valley (CRV) is an endorheic basin covering an area of approximately 10,000 km2. For the period 1996-2005, the average annual volume of rainfall accounted for 9.1 Mm3, and evapotranspiration for 8 Mm3 (Jansen et al., 2007). From the environmental point of view, basin ecosystems are endangered due to human activities. Also, poverty is widespread all over the basin, with population mainly living from agriculture on a subsistence economy. Hence, there is an urgent need to set an IWRM, but datasets required for water dynamics simulation are not too reliable. In order to reduce uncertainty of numerical simulation, two semi-distributed open software hydrologic models were implemented: HEC-HMS and ArcSWAT. HEC-HMS was developed by the United States Army Corps of Engineers (USACoE) Hydrologic Engineering Center (HEC) to run precipitation-runoff simulations for a variety of applications in dendritic watershed systems. ArcSWAT includes the SWAT (Soil and Water Assessment Tool, Arnold et al., 1998) model developed for the USDA Agricultural Research Service into ArcGIS (ESRI®). SWAT was developed to assess the impact of land management practices on large complex watersheds with varying soils, land use and management conditions over long periods of time (Neitsch et al., 2005). According to this, ArcSWAT would be the best option for IWRM implementation in the basin. However, considering data uncertainty and model complexity a previous hydrologic assessment of the basin based in HEC-HMS simulation is advisable. As a first approach HEC-HMS was implemented for basin modeling in order to get physical parameters of interest, results from HEC-HMS calibration were used to setup the accuracy of the ArcSWAT numerical modelling.
For monitoring the vadose zone, different strategies can be chosen, depending on the objectives and scale of observation. The effects of non-conventional water use on the vadose zone might produce impacts in porous media which could lead to changes in soil hydraulic properties, among others. Controlling these possible effects requires an accurate monitoring strategy that controls the volumetric water content, Ø, and soil pressure, h, along the studied profile. According to the available literature, different monitoring systems have been carried out independently, however less attention has received comparative studies between different techniques. An experimental plot of 9x5 m2 was set with automatic and non-automatic sensors to control Ø and h up to 1.5m depth. The non-automatic system consisted of ten Jet Fill tensiometers at 30, 45, 60, 90 and 120 cm (Soil Moisture®) and a polycarbonate access tube of 44 mm (i.d) for soil moisture measurements with a TRIME FM TDR portable probe (IMKO®). Vertical installation was carefully performed; measurements with this system were manual, twice a week for Ø and three times per week for h. The automatic system composed of five 5TE sensors (Decagon Devices®) installed at 20, 40, 60, 90 and 120 cm for Ø measurements and one MPS1 sensor (Decagon Devices®) at 60 cm depth for h. Installation took place laterally in a 40-50 cm length hole bored in a side of a
trench that was excavated. All automatic sensors hourly recorded and stored in a data-logger. Boundary conditions were controlled with a volume-meter and with a meteorological station. ET was modelled with Penman-Monteith equation. Soil characterization include bulk density, gravimetric water content, grain size distribution, saturated hydraulic
conductivity and soil water retention curves determined following laboratory standards. Soil mineralogy was determined by X-Ray difractometry. Unsaturated soil hydraulic parameters were model-fitted through SWRC-fit code and ROSETTA based on soil textural fractions.
Simulation of water flow using automatic and non-automatic date was carried out by HYDRUS-1D independently. A good agreement from collected automatic and non-automatic data and modelled results can be recognized. General trend was captured, except for the outlier values as expected. Slightly differences were found between hydraulic
properties obtained from laboratory determinations, and from inverse modelling from the two approaches. Differences up to 14% of flux through the lower boundary were detected between the two strategies According to results, automatic sensors have more resolution and then they’re more appropriated to detect subtle changes of soil hydraulic properties. Nevertheless, if the aim of the research is to control the general trend of water dynamics, no significant differences were observed between the two systems.
Adsorption/desorption processes (sorption isotherms) of Naproxen in a sandy aquifer matrix sediment were investigated using batch tests to compare Naproxen sorption behavior at 15°C and 25°C. Both temperatures are representative of the aquifer media and environmental conditions. Adsorption was well described by linear isotherms with low sorption affinity to aquifer material (Kd of 0.4 µg kg-1) at both temperatures (15°C and 25°C). Desorption isotherm coefficients at 15°C and 25°C were 5.0 and 4.9, respectively. Naproxen hysteresis indices were between 9.98 and 10.8, indicating that a Naproxen fraction may be irreversibly fixed in the aquifer media, being higher at 25°C (10.88) compared to 15°C, showing a decreasing trend with increasing compound concentration at 15°C. The low sorption of Naproxen leads to potential leaching to groundwater if present in irrigation water, and its prevalence in an aquifer media when directly injected in wells for groundwater recharge.
Valdés-Abellán, J.; Candela, L.; Jiménez- Martínez, J.; Saval, J. Desalination and water treatment Vol. 51, num. 10-12, p. 2431-2444 DOI: 10.1080/19443994.2012.747506 Data de publicació: 2013 Article en revista
Desalinated brackish groundwater is becoming a new source of water supply to comply with growing water demands, especially in (semi-) arid countries. Recent publications show that some chemical compounds may persist in an unaltered form after the desalination processes and that there is an associated risk of mixing waters with different salinity for irrigation. At the university of Alicante campus (Spain), a mix of desalinated brackish groundwater and water from the existing aquifer is currently applied for landscape irrigation. The presence of 209 emerging compounds, surfactants, priority substances according to the 2008/105/EC Directive, 11 heavy metals and microbiological organisms in blended water and aquifer samples was investigated. Thirty-five compounds were detected (pesticides, pharmaceuticals and surfactants) among them two priority substances a-endosulfan and Ni were found above the permitted maximum concentration. Blended water used for landscape irrigation during the summer period is supersaturated with respect to carbonates, which may ultimately lead to mineral precipitation in the soil-aquifer media and changes in hydraulic parameters.