This publication provides guidance to water-sector decision makers and planners on how to deal with the quality dimension of groundwater resources management in the World Bank's client countries. There is growing evidence of increasing pollution threats to groundwater and some well-documented cases of irreversible damage to important aquifers. This guide has been produced in the belief that groundwater pollution hazard assessment must become an essential part of environmental best practice for water supply utilities. The guide is particularly relevant for the World Bank's Latin American and Caribbean Region, where many countries have initiated major changes to modernize their institutional and legal framework for water resources management, but may not yet have considered groundwater at the same level as surface water, because of lack of awareness and knowledge of groundwater issues and policy options.

RESUMEN : La microcuenca Río Arenal ubicada en el municipio de San Rafael-Antioquia representa una importante área para el desarrollo económico de esta región. Esta microcuenca se ha visto afectada por la presión ambiental (vertimiento de aguas residuales, cambios del uso del suelo, etc) derivada del manejo turístico del río. Con el objetivo de diagnosticar la calidad del agua y proporcionar una base para futuros procesos de gestión ambiental, control y regulación, se realizó una caracterización fisicoquímica, microbiológica e hidrobiológica mediante el uso de macroinvertebrados acuáticos, además de conocer la percepción de la comunidad sobre la calidad y gestión del río. Para ello se realizaron dos campañas de muestreo en 6 estaciones sobre el cauce del río, se registraron variables in situ y se tomaron muestras de agua para ser analizadas en laboratorio, además se encuestaron 45 habitantes de la microcuenca. Los resultados fisicoquímicos y microbiológicos presentaron variaciones leves entre estaciones; la temperatura, pH y turbidez presentaron diferencias estadísticamente significativas entre los muestreos. Se recolectaron 2136 individuos de macroinvertebrados acuáticos clasificados en 111 morfotipos, que comprenden 66 géneros, 51 familias y 14 ordenes; las familias más representativas fueron Baetidae, Elmidae, y Simuliidae; con la mayor diversidad en la estación E2 y abundancia en la estación E5. El índice BMWP/Col estuvo en los rangos 77-179 indicando aguas de calidad buena. Se concluye que el Río Arenal presenta una condición ecológica buena. Las encuestas indicaron que la comunidad reconoce la vulnerabilidad de la microcuenca y la necesidad de implementar políticas de control y regulación del recurso hídrico. | ABSTRACT : The Arenal River micro-basin located in the municipality of San Rafael-Antioquia represents a key area for economic development. This micro-basin has been affected by environmental pressures (wastewater discharge, changes in land use, etc.) derived from tourism management of the river. To diagnose water quality and provide a basis for future environmental management, control and regulation processes, a physicochemical, microbiological and hydrobiological characterization was carried out using aquatic macroinvertebrates, as well as the community's perception of the river's quality and management. For this purpose, two sampling campaigns were carried out in 6 stations on the riverbed, variables were recorded in situ and water samples were taken for laboratory analysis, and 45 inhabitants of the micro-watershed were surveyed. The physicochemical and microbiological results showed slight variations between stations; temperature, pH and turbidity showed statistically significant differences between campaigns. A total of 2136 individuals of aquatic macroinvertebrates were collected, classified into 111 morphotypes, comprising 66 genera, 51 families and 14 orders; the most representative families were Baetidae, Elmidae, and Simuliidae; with the highest diversity at station E2 and abundance at station E5. The BMWP/Col index was in the ranges 77-179 indicating a good water quality. It is concluded that the Arenal River presents a good ecological condition. The surveys indicated that the community recognizes the vulnerability of the micro-watershed and the need to implement water resource control and regulation policies. | Pregrado | Ingeniero Ambiental

Nitrate is found in groundwater due to natural and anthropic processes. Nitrate content in groundwater is associated with factors such as human activities, soil type, climate, geology and chemistry of groundwater. Some of these factors (climate and geology) coincide with those that determine the type of groundwater flow system (local, intermediate or regional) present in an area which, in turn, is influenced by climate, stratigraphy, and type of subsoil and surface rocks; therefore, it is expected that the concentration of nitrate is related to the type of groundwater flow. The relationship between the concentration of nitrate in groundwater samples and the type of flow was analyzed in an aquifer system located in the Trans-Mexican Volcanic Arc, within the Michoacán-Guanajuato volcanic complex. The system is composed of two hydrogeological units, one volcanic and the other sedimentary, with the presence of geological faults, in a context where there is agricultural activity and deficient domestic wastewater management. To improve understanding of the overall aquifer system, 34 groundwater samples (28 wells, 6 springs) were analyzed. The results indicate that each flow system presents characteristic patterns of nitrate concentration and groundwater chemical composition. A high nitrate concentration was found in local and local-intermediate flow systems. Nitrate concentration decreased from local to intermediate and regional flows. The nitrate concentration decreased depending on groundwater flow direction, so it is possible to use nitrate as a parameter to differentiate groundwater flow systems.