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| Titel |
Screening of sustainable groundwater sources for integration into a regional drought-prone water supply system |
| VerfasserIn |
T. Y. Stigter, J. P. Monteiro, L. M. Nunes, J. Vieira, M. C. Cunha, L. Ribeiro, J. Nascimento, H. Lucas |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 13, no. 7 ; Nr. 13, no. 7 (2009-07-15), S.1185-1199 |
| Datensatznummer |
250011939
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| Publikation (Nr.) |
 copernicus.org/hess-13-1185-2009.pdf |
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| Zusammenfassung |
This paper reports on the qualitative and quantitative screening of
groundwater sources for integration into the public water supply system of
the Algarve, Portugal. The results are employed in a decision support system
currently under development for an integrated water resources management
scheme in the region. Such a scheme is crucial for several reasons,
including the extreme seasonal and annual variations in rainfall, the effect
of climate change on more frequent and long-lasting droughts, the
continuously increasing water demand and the high risk of a single-source
water supply policy. The latter was revealed during the severe drought of
2004 and 2005, when surface reservoirs were depleted and the regional water
demand could not be met, despite the drilling of emergency wells.
For screening and selection, quantitative criteria are based on aquifer
properties and well yields, whereas qualitative criteria are defined by
water quality indices. These reflect the well's degree of violation of
drinking water standards for different sets of variables, including toxicity
parameters, nitrate and chloride, iron and manganese and microbiological
parameters. Results indicate the current availability of at least 1100 l s−1 of high quality groundwater (55% of the regional demand),
requiring only disinfection (900 l s−1) or basic treatment, prior to
human consumption. These groundwater withdrawals are sustainable when
compared to mean annual recharge, considering that at least 40% is
preserved for ecological demands. A more accurate and comprehensive analysis
of sustainability is performed with the help of steady-state and transient
groundwater flow simulations, which account for aquifer geometry, boundary
conditions, recharge and discharge rates, pumping activity and seasonality.
They permit an advanced analysis of present and future scenarios and show
that increasing water demands and decreasing rainfall will make the water
supply system extremely vulnerable, with a high risk of groundwater
salinization and ecosystem degradation. |
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