| 1. |
- Mendoza, J. A., et al.
(författare)
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Assessment of groundwater vulnerability in the Rio Artiguas basin, Nicaragua
- 2006
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Ingår i: Environmental Geology. - : Springer Science and Business Media LLC. - 0943-0105 .- 1432-0495. ; 50:4, s. 569-580
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Tidskriftsartikel (refereegranskat)abstract
- The Rio Artiguas basin in central Nicaragua shows a distinctive case of environmental deterioration due to anthropogenic activities. Heavy metals used in gold mining and other wastes are continuously released into the rivers, representing a threat to the water quality. This article aims to evaluate the groundwater intrinsic vulnerability in the Rio Artiguas basin and to provide information for sustainable use of water resources. The DRASTIC and GOD methods were used to analyse the relative pollution potential within the basin. DRASTIC was modified to include the degree of influence that geological structures have on the vulnerability. Moderate vulnerability areas cover most of the basin along stream valleys and lowlands, increasing downstream in the basin. The resulting vulnerability maps show that the limited groundwater resources are susceptible to surface water pollution as high vulnerability areas converge along the river valleys.
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| 2. |
- Corriols, Marvin, et al.
(författare)
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Geophysical characterization of the Leon-Chinandega aquifer, Nicaragua
- 2008
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Ingår i: Hydrogeology Journal. - : Springer Science and Business Media LLC. - 1431-2174 .- 1435-0157. ; 16:2, s. 349-362
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Tidskriftsartikel (refereegranskat)abstract
- Electrical geophysical surveys in the mode of vertical electrical soundings (VES) and continuous vertical electrical soundings (CVES) were conducted in the Leon-Chinandega plains, northwestern Nicaragua, in order to obtain detailed information about the geometry of the different hydrogeological layers in the aquifer and depth to the basement. A total of 51 VES were carried out within the plains. The results show a complex structure towards the north east of the area, and the southwestern part of the plains presents a smoother stratification. The geoelectrical measurements and borehole information indicate that the basement topography is characterized by hills and deep valleys with highly variable basement depths. Fifty CVES where done in a smaller area in the center of the plain. The resistivity data yielded considerable information revealing the existence of two main geo-electrical units. The combined interpretation of geological and geophysical data shows an environment typical of sedimentary volcanic coastal plains. The information collected during this investigation provides valuable data for estimating the fresh-water resources of the Leon-Chinandega aquifer system and for development of a groundwater management plan.
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| 3. |
- Mendoza, J. A., et al.
(författare)
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Hydrogeological and hydrochemical features of an area polluted by heavy metals in central Nicaragua
- 2006
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Ingår i: Hydrogeology Journal. - : Springer Science and Business Media LLC. - 1431-2174 .- 1435-0157. ; 14:5, s. 777-784
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Tidskriftsartikel (refereegranskat)abstract
- Geophysical and hydrochemical surveys were used to investigate the hydrogeological conditions in one of the Rio Sucio microbasins, in central Nicaragua. Zones of vertical structures (i.e. fractures and quartz veins) and weathering were mapped using Continuous Vertical Electrical Soundings (CVES), as such zones are of major importance for groundwater transport. Water from the springs was analysed to determine concentrations of major ions and heavy metals. Low ion concentrations and 180 analyses indicate that the springs occur close to their recharge areas and there is a relatively rapid groundwater circulation. Mercury (Hg) content in the springs was low, while comparatively high amounts of lead (Pb) were found. The results presented here demonstrate the important function of weathering and tectonics in the occurrence of groundwater systems in the basin. Hg and Pb found in the springs' water reveal the existence of an increase in pollution sources disseminating in the area. More than 100 years of using mercury in the gold-mining industry and releasing wastes into rivers has affected water quality and ecosystems. Further investigations are needed in this area to determine the groundwater vulnerability to this pollution as this resource may be needed in the future.
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| 4. |
- Mendoza, Jose Alfredo, et al.
(författare)
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Aquifer interactions with a polluted mountain river of Nicaragua
- 2008
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 22:13, s. 2264-2273
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between a stream and nearby shallow aquifers were investigated in a mountain basin being polluted by mercury released during mining in central Nicaragua. Hourly data series of water levels and temperatures were analysed using cross-correlation. Resistivity imaging was used to map the subsurface and to complement the hydrological data interpretation. The results show the complex hydrogeological conditions that characterize the region, with weathering and fractured rock as main contributors to groundwater transport. The resistivity images suggest the presence of two vertical dykes perpendicular to the stream, and zones rich in clay. The data series indicate a rapid response from the aquifers to recharge events, followed by immediate discharge on a yearly basis. Furthermore, alternating periods of stream infiltration and aquifer discharge were identified. This work demonstrates that surface water pollution is a threat to groundwater quality in the area.
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| 5. |
- Korsak, Larisa, et al.
(författare)
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Wastewater treatment in Nicaragua
- 2003
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Ingår i: Proceedings of the 9th Annual IWA Specialised Conference "Design, Operation and Economics of Large Wasewater Treatment Plants".
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Mendoza, Alfredo
(författare)
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Groundwater occurrence and risk of pollution in a mountain watershed of Nicaragua
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hydrogeological and geophysical methods were applied in the Río Artiguas watershed, a mountain basin located in central Nicaragua. This area is under environmental stress from anthropogenic activities like gold mining using mercury and waste disposal into the streams. The aim of this work was to characterise the hydrogeological conditions in the basin with emphasis on understanding the possible connections between streams and groundwater. It was also important to evaluate the vulnerability and risk of groundwater pollution. Hydrogeological mapping, resistivity imaging, hydrological measurements and hydrochemical surveys were combined to meet the aims of the work. The hydrogeological characterisation permitted identification of a) recharge areas, b) geological units that contribute to the formation of the groundwater system and c) a mechanism of discharge through springs and streams. The geophysical surveys allowed mapping the extension of weathering and tectonic features with hydrogeological significance, e.g. faults, dykes and fractures. A total of 99 perennial springs were documented and classified according to their mechanism of formation. Isotopic data indicate that the recharge occurs very close to the sites where the springs are formed. This is also supported by the relatively low ion concentrations found in the water of the springs. The weathering layers together with fractures and dykes form shallow aquifers that commonly discharge in a spring or along the streams. The high precipitation regime is an immediate source of water to the system, and in conjunction with the geology and steep topography it generates a constant and rapid circulation of water from recharge areas to discharge zones. The natural implication of this hydrogeological framework is that the formation of large or regional flows is not evident at the current state of knowledge. The same factors that influence groundwater occurrence are to some extent responsible for the degree of groundwater vulnerability to pollution. The vulnerable areas are situated along the steep valleys of the basin, where the interactions between subsurface and surface water can facilitate the spreading of pollutants. Since the pollution sources are located near the streams the risk of groundwater pollution is concentrated there. The pollutants disposed into the streams are rapidly removed by the river flow, which has a high contribution from precipitation. The pollutants are then transported far away from the sources. The urgent need to end the pollution of Río Artiguas is obvious. The tools to prevent further deterioration are not only to be found in the hydro geosciences and mining technology sphere, but they are also located in the socio?political arena. In this respect, the research presented in this thesis will gain importance as it reaches and informs local decision makers about the vulnerability and risks of pollution that the current anthropogenic activities represent for the groundwater resources.
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| 7. |
- Stephansson, Ove
(författare)
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Swedish research co-operation with developing countries : Nicaragua as an example
- 1985
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Ingår i: Raw Materials Report : Journal of Mineral Policy, Business and Environment. - : Informa UK Limited. - 0349-6287. ; 3:1, s. 46-47
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Tidskriftsartikel (refereegranskat)abstract
- Examines the current programme of the Swedish Agency for Research Co-operation with Developing Countries, with emphasis on the co-operation with Nicaragua
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| 8. |
- Korsak, Larisa, et al.
(författare)
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Alternatives of Sludge Use in Nicaragua
- 2005
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Ingår i: Proceedings of the 27th Annual HWEA Conference "New Technical Knowledge for Clean Water".
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Rivera, Claudia
(författare)
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Integrating Climate Change Adaptation into Disaster Risk Reduction in Urban Contexts: Perceptions and Practice
- 2014
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Ingår i: PLoS Currents. - : Public Library of Science (PLoS). - 2157-3999. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- This paper analyses the perceptions of disaster risk reduction (DRR) practitioners concerning the on-going integration of climate change adaptation (CCA) into their practices in urban contexts in Nicaragua. Understanding their perceptions is important as this will provide information on how this integration can be improved. Exploring the perceptions of practitioners in Nicaragua is important as the country has a long history of disasters, and practitioners have been developing the current DRR planning framework for more than a decade. The analysis is based on semi-structured interviews designed to collect information about practitioners’ understanding of: (a) CCA, (b) the current level of integration of CCA into DRR and urban planning, (c) the opportunities and constraints of this integration, and (d) the potential to adapt cities to climate change. The results revealed that practitioners’ perception is that the integration of CCA into their practice is at an early stage, and that they need to improve their understanding of CCA in terms of a development issue. Three main constraints on improved integration were identified: (a) a recognized lack of understanding of CCA, (b) insufficient guidance on how to integrate it, and (c) the limited opportunities to integrate it into urban planning due to a lack of instruments and capacity in this field. Three opportunities were also identified: (a) practitioners’ awareness of the need to integrate CCA into their practices, (b) the robust structure of the DRR planning framework in the country, which provides a suitable channel for facilitating integration, and (c) the fact that CCA is receiving more attention and financial and technical support from the international community.
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| 10. |
- Rosberg, Jan-Erik
(författare)
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Pneumatic slug testing in large-diameter wells
- 2010
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Ingår i: Hydrogeology Journal. - : Springer Science and Business Media LLC. - 1431-2174 .- 1435-0157. ; 18:5, s. 1291-1300
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for an alternative method to conventional pumping tests that is logistically easier and faster to use and which can be handled by only one person. The well known slug test fulfils those requirements if the equipment is properly designed. The applicability of small-diameter slug-test equipment using pneumatic initiation in large-diameter wells, up to 12aEuro(3) (0.3 m), is discussed. In wells with 36 times greater cross-sectional area than the slug-test equipment, it will take a long time for casing depressurization after slug initiation. The casing-depressurization time was measured for each slug test and is presented as a part of the results. The small-diameter equipment was found to be applicable and the long casing-depressurization times did not generally affect the transmissivity estimates. The series of slug tests yielded transmissivity estimates that were in good agreement with each other and also when compared with estimates from pumping tests. However, the slug-test results from wells completed in more permeable formations were harder to interpret, and may be an effect of long casing-depressurization times; further investigations are needed. There is a description of the design of several airtight couplings between the slug-test equipment and the casing.
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