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| Titel |
Source detection by chemical and isotopic means - the Lower Jordan River |
| VerfasserIn |
Noa Hillel, Stefan Geyer, Saed Khayat, Tobias Licha, Jonathan B. Laronne, Christian Siebert |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250125066
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| Publikation (Nr.) |
 EGU/EGU2016-4595.pdf |
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| Zusammenfassung |
| During the past several decades the volume of freshwater carried by the Lower Jordan River
(LJR) has been reduced by 90% due to damming of its main tributaries, leaving a mixed flow
of polluted and brackish to saline water from anthropogenic and partly known geogenic
sources. Since the river represents the highly secured border between Jordan, Israel and the
West Bank, neither systematic nor long-term measurements were conducted in it. Only vague
knowledge exists about the amount and composition of natural contributors and no
knowledge concerning their temporal dynamics. However, since the river water is intensely
used for irrigation along its course and represents the major source of water to
the Dead Sea, the spatio-temporal variation of water discharge and chemistry are
required for water resource assessment in the Lower Jordan Valley and the Dead
Sea.
To monitor the temporal variations of water discharge and hydrochemistry, an automatic
sampler, including water level and EC sensors with real time transmission were installed at
the Baptism site, a few kilometers upstream of the delta. Major ions are analyzed on a daily
basis, while stable isotopes of sulfate (δ34S, δ18O), nitrate (δ15N, δ18O) and water (δ2H,
δ18O) are analyzed on an event basis. A general inverse correlation between EC and water
level was found although extreme high conductivity values relate to flood events during the
wet period. Due to the high-resolution monitoring, a series of flood events could be
observed, some having unusually high saline water. Results from Cl/Br, Na/Cl, Mg/Ca,
δ34S allow separation and identification of sources: (i) the dissolution of evaporite
minerals, abundant in the surrounding geological strata, (ii) sewage and (iii) brine
springs.
The continuous monitoring is an essential tool for understanding long-term
processes and changes in such a dynamic system, and is crucial for identifying rarely
occurring extreme flow events. However, a single sampling location is not sufficient for
locating the sources responsible for the changes in water composition over time. |
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