Inference of fault and fracture systems beneath the Matatlan waste dump basement, a VLF study

AbstractWe used the VLF technique to infer fault or major fracture zones that might serve as path for contaminant waste fluids in the Matatlan dumpsite, in Guadalajara, western Mexico. To interpret the data we used the Fraser, and Karous-Hjelt filters.Profiles were interpreted with 2D direct modeling based on Karous-Hjelt modified filter (K-H). The Fraser and Karous-Hjelt conjugated filter were applied to the entire data. The results of both techniques show similarities in the directions and positions of anomalous features, which are assumed fault or fracture zones. We observed one fault zone at the centre of the site, with a NEE-SWW strike. Other important inferred structures have NW-SE directions at the western part of the site.The cooperative use of both techniques, based on K-H filter and the Fraser filter give results as an N-S inferred structure in the westernmost part of the zone, as well as NW-SE linear anomalies, mainly in the western half of the site. The N-S structure has the same direction as that of Rio Grande de Santiago Canyon. The NW-SE features coincide with the directions of the Tepic-Zacoalco rift. Others NE-SW lineaments are located towards the centre of the area. These facts coincide strongly with the predominance of fracture groups show in the fracture analysis. The inferred structures could serve as conduits for the leachates to migrate towards the Coyula canyon as well as towards the Rio Grande de Santiago Canyon.Statistic analysis of fracture orientations showed N-S (A), N75-80E (B), N60-65W (C), and N25-30W (D) main directions, and N45-55E (E), and 90E (F) secondary directions. Group A coincides with the direction of the Rio Grande de Santiago Canyon, whereas pattern F have the same direction as Coyula Canyon

Transferencia de los ODS 2030 a través del proyecto redes: “Red de empatías sociales - plataforma digital WEBGIS para el mapeo de iniciativas ciudadanas”

Los ODS 2030 nos llevan a cuestionar el papel que tienen las nuevas tecnologías para favorecer la partici-pación ciudadana cuando pensamos en construir la ciudad sostenible. Son muchos los colectivos sociales que trabajan de forma colaborativa para mejorar la vida de los barrios. Estas iniciativas son emergentes y, en muchos casos, no aparecen inscritas formalmente. El proyecto Red de Empatías Sociales: Plataforma digital webGIS tiene por objeto el estudio comparado de estas iniciativas a partir del análisis y mapeo de sus redes de relación, tanto en el espacio físico como en el digital. Se caracterizan estos procesos partici-pativos locales implicados en la vida de las comunidades para poner en valor y empoderar a la ciudada-nía en la construcción de las ciudades sostenibles. Se presenta el diseño de los cuestionarios que se utili-zan como modelo para llevar a cabo entrevistas con agentes locales en tres ámbitos de estudio: Málaga capital, Benalmádena y los pueblos del Valle del Genal. Los resultados obtenidos de estas entrevistas permiten identificar y caracterizar las iniciativas locales. Éstos revelan que el uso de las TIC favorece la consolidación de su red de empatías y la creación de nuevas sinergias conforme a los ODS 2030

Mapping of social initiatives as a model of local development against depopulation in rural areas. The Valle del Genal case (Andalusia, Spain)

The cultural heritage of many rural areas, such as the villages of Valle del Genal in Andalusia, is endangered. Factors such as the depopulation suffered in the last 25 years have prevented the knowledge transfer from the elderly to the young. This paper focuses on mapping the social, economic and habitat resources as a preliminary step to the implementation of measures and policies against the abandonment of these areas. The aim is to create a map regarding the cultural identity and idiosyncrasy of each village in the valley. The mapping of these local entities is carried out through a combination of participatory work with the communities in the area and the data tracking from geo-positioning and social networks applications. During the identification and inventory process, the relationship between different citizen initiatives and social groups are analysed. This cartography pretends to offer a base of accessible knowledge for inhabitants and visitors.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

ESTIMATION OF HYDRAULIC CONDUCTIVITY AND CONTENT OF FINES FROM EXPERIMENTAL LAWS THAT CORELATE HYDRAULIC AND ELECTRIC PARAMETERS

Hydraulic conductivity is a basic element in the advancement of knowledge of a geological environment in both the flow and transport processes of pollutants for conservation projects, managementand environmental management and also for the development of public policies for protection of ecosystems, among others. The aim of this paper is to obtain the hydraulic conductivity (K) and the finescontent (C) of saturated granular half using two empirical laws. One correlates the electrical conductivity of saturated granular media σo and water saturated σw which depends on the formation factor(F), cation exchange capacity (CEC) and the fines content in the saturated soil. Using data obtained from materials of 18 samples from 6 wells the relationships between F-C and CEC-C were obtained,so the equation reduces to a σo function in terms of σw and C, with a correlation coefficient of R = 0.97. A second experimental law is the one that results from the experimental relationship between K and C,being 1.4054 K 0.1804.C with a correlation coefficient of R = 0.96. From both experimental expressions relationships between K and C, a and C,and C are created so from every pair knowing one of them you get to know the other one. Under the scheme outlined electrical conductivity sections for the saturated medium and fines content are obtained,finding that the groundwater in the study area consists of a thin top layer and beneath it there is a predominantly sandy environment

Calidad y aptitud de uso agrícola y doméstico del agua del acuífero del río Sinaloa, porción costera

The Guasave valley, Sinaloa is mainly agricultural. There are rural communities that supply water for domestic use from local wells. Economic and social activities occurring on this valley demand water, so that water extraction has shifted to the coastal zone. For this reason, it is important to know the natural mechanisms that control the water chemical composition, its quality, its impact on the ground and its temporal variation in response to its suitability for agricultural or domestic use. To determine the mechanism controlling the water chemistry, the Gibbs diagram was used and it was found that the dominant mechanism is evaporation-weathering. Regarding the domestic use of water, PHASECH quality index was used, finding that water quality is only acceptable near the Sinaloa river. Concerning the suitability for agricultural water use, Wilcox diagram was employed and only 48% the water in the area was classified from good to admissible. Regarding the risk of soil salinization or sodification, the salinity diagram of the U. S. Department of Agriculture was used and it was observed that 35% of the water was located in the C3S1 area. The interrelationship between total dissolved solids and electrical conductivity of water was EC = 1.65 TDS. In addition, it is concluded that the Sinaloa river aquifer is highly sensitive to salinity due its coastal character and the presence of evaporitic bodies far away from the coastline, therefore the threat of saltwater intrusion during a dry period is latent. The presence of the Sinaloa river is an important recharging element that keeps groundwater in suitable conditions for agriculture and very close to those required for domestic use.El valle de Guasave, Sinaloa, es eminentemente agrícola y cuenta con comunidades rurales que se abastecen de agua para su uso doméstico mediante pozos ubicados en sus predios. La actividad económica y social de dicho valle demanda agua para ambas actividades, por lo que su extracción se ha desplazado hacia la zona costera, siendo importante conocer los mecanismos naturales que controlan la composición química del agua, su calidad, su variación temporal atendiendo a la aptitud de uso agrícola o doméstica. Para determinar el mecanismo que controla la composición química del agua se utilizó el diagrama de Gibbs, encontrándose que el mecanismo dominante es por evaporizaciónmeteorización. Respecto al agua para uso doméstico se utilizó el índice de calidad PHASECH, encontrándose que el agua cumple con el mismo sólo en las proximidades del río Sinaloa. En cuanto a la aptitud de uso agrícola del agua se utilizó el diagrama de Wilcox, encontrándose que sólo el 48% del agua de la zona se clasifica como buena a admisible. En cuanto al riesgo de salinización o sodificación del suelo por el uso del agua de riego, se usó el diagrama de salinidad del Departamento de Agricultura de Estados Unidos de Norteamérica, encontrándose que el 35% del agua se ubica en la zona C3S1. La relación obtenida entre los sólidos totales disueltos y la conductividad eléctrica del agua, fue EC = 1.65 STD. Se concluye además, que el acuífero del río Sinaloa es altamente sensible a la salinización por su carácter costero y presencia de cuerpos evaporíticos alejados de la línea de costa, por lo que, el peligro de intrusión salina ante un periodo de sequía es latente. La presencia del río Sinaloa es un elemento relevante de recarga que permite mantener el agua subterránea en condiciones aptas para la agricultura y muy cercanas a las requeridas para uso doméstico

Geochemical processes controlling the groundwater transport of contaminants released by a dump in an arid región of México

The Vado Carranza dump, located in the Mexicali Valley, Baja California, northwest Mexico, was operated for more than 15 years receiving about 30 tons/ day of solid wastes. The disposed wastes were periodically burned in open air. The presence of a shallow aquifer in the area makes the groundwater vulnerable to contamination processes. The purpose of this study was the evaluation of heavy metals content (Cu, Cd, Ni, Pb and Zn) in soil and groundwater in the vicinity of this dump. The results indicate high content of metals in soil, mainly at a superficial level, with the highest concentrations in the areas where burning of wastes occurred. Elevated concentrations of cadmium and copper were detected in groundwater with the highest concentrations occurring in monitoring wells located in the north side of the dump, downward of groundwater flow. Although the high content of metals in soil can be attributed to the burning of waste, other sources of pollution could be the agricultural irrigation in the vicinity of the dump. The program PHREEQC was used to model the geochemical evolution of groundwater. Results suggest that evaporation of the contaminated waters circulating below the landfill is one of the key processes that explain the increased concentration of contaminants in groundwater and its seasonal variations. As groundwater flows away from the dump, evaporation can concentrate the chemicals making the water more toxic. These results are important because they illustrate processes that are likely to occur in landfills located in other desert areas of the world

Simulación del movimiento de partículas contaminantes sobre zonas de vulnerabilidad en el acuífero de los valles centrales de Oxaca

This study is an approach combined with the use of two indices and overlap methodologies: Matus for potential recharge zones and DRASTIC for aquifer vulnerability. In addition, an aquifer model of the Central Valleys made with MODFLOW software, together with a particle simulation method with the MODPATH package. It was found that the most vulnerable zones are: the cultivation area located 1.5 km northwest of San Lucas Quiavini, the body of water at 2.5 km northwest of San Miguel Tlanichico,agricultural land between Guadalupe and San Sebastián Etla and the urban area of San Francisco Telixtlahuaca. These areas are not only a danger for the water quality in the site, but can also affect nearby wells or distant communities, so that require special protection.El presente trabajo integra el uso de dos metodologías de índices y superposición: Matus para definir zonas potenciales de recarga hídrica y DRASTIC para reconocer la vulnerabilidad del acuífero. Además, se hizo una modelación del acuífero de los Valles Centrales de Oaxaca con MODFLOW, aunado a una simulación de partículas con el módulo MODPATH. Se encontró que las zonas más vulnerables a contaminantes son: el área de cultivo localizada a 1.5 km al noroeste de San Lucas Quiavini, el cuerpo de agua localizado a 2.5 km al noroeste de San Miguel Tlanichico, terrenos de cultivo entre Guadalupe y San Sebastián Etla y la zona urbana de San Francisco Telixtlahuaca. Estas áreas no solo son un peligro para la calidad de agua en el sitio, sino que podrían afectar a pozos o comunidades a kilómetros de distancia, por lo que requieren especial protección

Characterization of a leachate contaminated site integrating geophysical and hydrogeological information

Se reporta en este estudio la caracterización de una zona contaminada por lixiviados, siguiendo una metodología que integra datos geofísicos y geohidrológicos para proponer un modelo hidrogeológico del fenómeno. La caracterización del sitio (la estructura del subsuelo, y las características del suelo) incluyó seis perfiles sísmicos de refracción, tres líneas electromagnéticas (FDEM), dos perfiles eléctricos (ERT), cinco sondeos eléctricos verticales (SEV), y una serie de pruebas geohidrológicas para delimitar la pluma contaminante. El área de estudio corresponde a la laguna de lixiviados del relleno sanitario de la ciudad de Oaxaca, sur de México. El modelo hidrogeológico que se presenta constituye un ejemplo del potencial de la integración de varios métodos aplicados con el mismo objetivo; reduciendo así la ambigüedad de la respuesta geofísica. Los resultados indican que los valores de baja resistividad (1.5 a 2.5 Ohm-­m) se relacionan con un suelo contaminado subyaciendo a la laguna de lixiviados y al medio fracturado. También se detectó un desplazamiento de la pluma contaminante hacia el SW de la laguna. La calidad del agua es buena, pero la actividad humana del área de estudio confiere un riesgo para el acuífero superficial de Zaachila. doi: https://doi.org/10.22201/igeof.00167169p.2012.51.4.122

Relationship between chloride concentration and electrical conductivity in groundwater and its estimation from vertical electrical soundings (VESs) in Guasave, Sinaloa, Mexico

Soils in arid or semi-arid areas often have salinity problems, so the quality of irrigation water plays an important role in agricultural production. Groundwater quality analysis includes the determination of chloride ions, which are toxic to plants in high concentrations. A total of 1358 groundwater samples were collected and analyzed in the period 1980-2008. Water electrical conductivity [EC] and chloride ion concentration values were related by the linear equation [Cl-] = 4.928 EC (R> 0.94), to estimate the concentration of chloride ions as a function of the electrical conductivity of water in the study area. A geophysical survey was conducted through 34 Vertical Electrical Soundings (VESs) to calculate the water electrical conductivity from the interpretation of the apparent resistivity data. Twenty-nine VESs were used to relate the resistivity of the saturated formation (Ro) with that for the groundwater (Rw) by the linear equation Rw = 0.427 Ro + 1.987. Then, EC was estimated as the inverse of Rw. Finally, the chloride ion concentration was determined by the equation mentioned above. Following the same procedure for the five remaining VESs, which were acquired in places where there are no wells, the chloride ion concentration and the electrical resistivity of the saturated formation (Ro) and groundwater (Rw and its inverse EC) were obtained without requiring a destructive technique.Los suelos de zonas de clima árido o semiárido a menudo tienen problemas de salinidad, por lo que la calidad del agua para riego juega un papel importante en la producción agrícola. Los análisis en agua subterránea incluyen la determinación del ión cloruro, el cual en grandes concentraciones es tóxico para las plantas. Se analizaron en laboratorio 1358 muestras de agua subterránea tomadas en el periodo de 1980 - 2008 con lo que se determinó la conductividad eléctrica y la concentración del ión cloruro. Estos resultados sirvieron para obtener la ecuación de correlación lineal [Cl4.928 = [- EC (R>0.94), con el propósito de estimar la concentración del ión cloruro en función de la conductividad eléctrica del agua en el área de estudio. Se realizó la prospección geofísica a través de 34 Sondeos Eléctricos Verticales (SEV), para calcular la conductividad eléctrica del agua a partir de la interpretación de los datos de resistividad aparente. Con 29 SEV se relacionó la resistividad del medio saturado con la resistividad del agua subterránea mediante la ecuación lineal: Rw = 0.427 Ro + 1.987 Posteriormente, se calculó la conductividad eléctrica del agua, como inversa de su resistividad, por último, la concentración del ión cloruro mediante la ecuación expuesta anteriormente para el área de estudio. Siguiendo el mismo procedimiento, en los cinco SEV restantes efectuados en lugares donde no hay perforaciones, se pudo estimar la resistividad eléctrica de la capa saturada (Ro), la resistividad eléctrica del agua del acuífero (Rw, y su inverso EC) y la concentración del ión cloruro, sin requerir el uso de una técnica destructiva