Groundwater/surface-water interaction is receiving increasing focus in Africa due to its importance to ecologic systems and sustainability. In South Africa’s 1998 National Water Act (NWA), water-use licenses, including groundwater, are granted only after defining the Reserve, the amount of water needed to supply basic human needs and preserve some ecological integrity. Accurate quantification of groundwater contributions to ecosystems for successful implementation of the NWA proves challenging; many of South Africa’s aquifers are in heterogeneous and anisotropic fractured-rock settings. This paper reviews the current conceptualizations and investigative approaches regarding groundwater/surface-water interactions in the context of South African policies. Some selected pitfall experiences are emphasized. The most common approach in South Africa is estimation of average annual fluxes at the scale of fourth-order catchments (∼500 km2) with baseflow separation techniques and then subtracting the groundwater discharge rate from the recharge rate. This approach might be a good start, but it ignores spatial and temporal variability, potentially missing local impacts associated with production-well placement. As South Africa’s NWA has already been emulated in many countries including Zambia, Zimbabwe and Kenya, the successes and failures of the South African experience dealing with the groundwater/surface-water interaction will be analyzed to guide future policy directions.

Uno de los mayores problemas para obtener agua potable es la remoción de hierro en aguas de aljibes y pozos de agua subterránea. En este artículo se presentan los resultados del tratamiento del agua de un manantial con un contenido de hierro de 7,27 mg/L. Se encontró que la combinación óptima de tratamiento para hierro fue la de la coprecipitación con cloruro férrico y cal, aunque el tratamiento con alumbre y cal, con cloruro férrico, con permanganato de potasio y cal, y con cloro, también permiten la remoción requerida. | One of the main problems for obtaining drinking water is the removal of iron in springs and wells of groundwater. This article presents the results of the treatment of the water from spring with a content of 7,27 mg Fe/L. It was observed that the best combination of treatment for iron was the coprecipitation with ferric chloride and lime, although the treatment with alum and lime, with ferric chloride, with potassium permanganate and lime, and with chloride, also achieves the required removal.

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.

La adopción de un enfoque de economía circular para la gestión de aguas superficiales y/o subterráneas permite a los sectores y agentes mundiales encargados del agua lograr suministros seguros, sostenibles y de calidad para el futuro. La economía circular ha surgido como una herramienta y un marco que alinea los resultados económicos y ambientales. Dado esto, el presente estudio busca comprender la reutilización del agua bajo el prisma de la economía circular e investiga las oportunidades y los riesgos en el desempeño durante esa transición. Es un análisis cuyo método utilizado en la fase de investigación es el inductivo; en la fase de procesamiento de datos, el cartesiano, y en el informe, se emplea el método deductivo-inductivo. El argumento económico para adoptar enfoques circulares en la gestión de aguas subterráneas queda demostrado por el beneficio potencial de sus principios rectores, que retienen más valor en productos, componentes y materiales, manteniéndolos en uso por más tiempo y proyectando el tratamiento de los desechos desde el principio. La economía circular acontece, por tanto, como herramienta para alcanzar la sostenibilidad. | Adopting a circular economy approach to surface and/or groundwater management enables the global water sector to achieve safe, sustainable and quality water supplies for the future. Circular economics has emerged as a tool and framework that aligns economic and environmental outcomes. Given this, the present study seeks to understand the form of water reuse from a circular economy perspective and investigates opportunities and risks for water reuse with the transition to this economy. It is a research whose method used in the investigation phase is the inductive; in the data processing phase, the Cartesian, and in the report, that is, the deductive-inductive method is employed. The economic argument for circular groundwater approaches has been demonstrated by the potential benefit of its governing principles, which retain more value in products, components and materials, keeping them in use longer and planning waste from the start. Circular economy emerges, therefore, as a tool to reach sustainability.

Abstract: A coastal karstic aquifer highly exposed to anthropogenic pollution and seawater intrusion is the main water supply source for Merida-Progreso inhabitants (Yucatan, Mexico). In this investigation fresh/ brackish water interface changes linked to precipitation events were identified and correlated with the Ghyben-Herzberg principle. Water level elevations and electrical conductivity values were manual and automatic recorded in a 26 wells monitoring network. Results indicate a fast water level increase (hours) to precipitation events, for example a 19 cm water level increase and 570 µmhos·cm-1 decrease measured at the fresh/brackish water interface were recorded in an observation well located west of Merida city less than 24 hours after a 60 mm rainfall. Predictions using the Ghyben-Herzberg principle do not correlate with in-situ measurements. Actual thickness of the freshwater lens change from rainy (33 m) to dry (31.5 m) season below Merida city, minor thickness changes along the year were identified north to Merida city (26 m freshwater lens thickness). | Resumen: La población en la región Mérida-Progreso, Yucatán, México, depende totalmente del agua subterránea que es obtenida de un acuífero kárstico costero, vulnerable a la contaminación antropogénica y natural por los efectos de la intrusión salina. El objetivo de estudio fue describir, espacial y temporalmente, el comportamiento de las interfases de agua dulce y agua salobre ante eventos de precipitación, y proponer alternativas que ayuden a explicar la respuesta observada y su relación con el principio de Ghyben-Herzberg. Se utilizó una red de 26 pozos de observación para determinar elevaciones del nivel del agua y cambios en la conductividad eléctrica en las interfases mediante mediciones manuales y una red automatizada. Los resultados indican que en general existe una respuesta rápida (del orden de horas) del nivel freático a la precipitación, por ejemplo un incremento de 19 cm en la elevación del nivel del agua al occidente de Mérida y un comportamiento irregular de las elevaciones de las interfases de agua salina (decremento de 570 µmhos·cm-1) y salobre ante eventos de precipitación (60 mm). De acuerdo con los resultados obtenidos, el principio de Ghyben-Herzberg no es aplicable para la determinación de la posición de la interfase de agua salina en la región. Finalmente, se definieron espesores de agua dulce bajo la zona urbana de Mérida para las temporadas de lluvia (33 m) y estiaje (31.5 m), y un espesor promedio de 26 m al norte de Mérida a 15 km de la línea de costa donde no hay una variación entre ambos periodos.

This study examines how environmental issues have been addressed in the water sector in Brazil, within the context of activities of the Federal Government, generally, and those implemented under Bank sector operations, in particular. The core focus of the study lies in the management of water quality, as it affects both the users of raw water, and those who are primarily concerned with the disposal of wastewater. The report considers the following three sectoral areas concomitantly - water resources management, water supply and sanitation, and, the environment - thus limiting its review, and focus to those themes which are key to the over-arching issue of water quality. Water resources management in the country relied upon heavy investments in medium, and large scale projects that provided basic infrastructure for water uses. However, these have produced questionable impacts in terms of reducing poverty, and inequality. One of the reasons for this, has been the poor infrastructure management, which despite its importance, has been largely underestimated. While improvements in the utilization of existing infrastructure in the water sector remain critical, it needs to be complemented by incentives to both service providers, and water users. Moreover, low economic, environmental, and social returns from investments in the water sector, reflect the tendency to distract attention from the objectives in the design, and implementation of projects. Thus, an assessment of water quality goals is required, which should be based on systematic evaluations of the costs, and benefits of reaching alternative standards, and explicit social objectives.