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| Titel |
Potentials and limits of urban rainwater harvesting in the Middle East |
| VerfasserIn |
J. Lange, S. Husary, A. Gunkel, D. Bastian, T. Grodek |
| 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 ; 16, no. 3 ; Nr. 16, no. 3 (2012-03-06), S.715-724 |
| Datensatznummer |
250013206
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| Publikation (Nr.) |
 copernicus.org/hess-16-715-2012.pdf |
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| Zusammenfassung |
| In the Middle East, water is scarce and population growth causes a rapid
rise of urban centers. Since many towns of the Palestinian Authority (PA)
suffer from water shortage, the use of rainwater harvesting (RWH) as an
alternative to conventional water supply has gained increasing interest
among water resources planners. This study quantifies actual volumes of
urban RWH to be expected from highly variable Mediterranean rainfall. A
one-parameter model uses measured potential evaporation and high resolution
rainfall data as input to calculate RWH volumes from rooftops inside
Ramallah, a traditional Arab town. While during average seasons a 87%
runoff harvest (480 from 550 mm of rainfall) can be expected, this value
decreases to about 75% (190 from 250 mm of rainfall) during drought
seasons. A survey comprising more than 500 questionnaires suggests that
approximately 40% of the houses are equipped with RWH systems from which
one third are out of use. Although water quality is perceived to be
favourable, only 3% of the active RWH systems are actually used for
drinking and only 18% for domestic purposes. All active RWH systems
investigated may harvest approximately 16 × 103 m3 of rooftop
runoff during an average season and 6 × 103 m3 during droughts.
When these numbers are extrapolated to all houses in Ramallah, theoretical
maximum potentials increase to approximately 298 × 103 m3 during
average seasons and 118 × 103 m3 during droughts. A part of this
potential can easily be exhausted by rehabilitation of installed RWH
systems. The use of RWH for emergency water supply should be advocated,
although care is needed because of hygienic risks. Regional estimates for
the entire Lower Jordan River Basin yielded RWH potentials of 20 × 106 m3
during the average season 2002/2003 but only 3 × 106 m3
during the drought season 1998/1999. Thus, urban RWH is a relatively small
contribution to overcome water scarcity in the region and decreases
significantly during droughts. Yet it is a sustainable water resource, which
is available on spot for everybody. Due to population growth and ongoing
urbanization it will be more important in future. |
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