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| Titel |
Source detection in the Lower Jordan River - How to monitor the impossible |
| VerfasserIn |
Noa Hillel, Christian Siebert, Tobias Licha, Jonathan B. Laronne |
| 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 |
250125113
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| Publikation (Nr.) |
 EGU/EGU2016-4646.pdf |
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| Zusammenfassung |
| The Lower Jordan River (LJR) is a major ecosystem in the semi-arid to arid Jordan-Dead Sea
Graben, the backbone of abundant farming activities in the Lower Jordan Valley and
the major inflow to the dying Dead Sea. During the 1960’s the Sea of Galilee and
the Yarmouk River, the main sources of the river, were dammed, decreasing its
annual flow from ∼1.2×109 m3 to less than 0.2×109 m3, leaving a mix of point and
non-point sources composing its base flow. Beside natural saline springs along its
course, current day anthropogenic sources (e.g. sewage, agricultural return flow and
fishpond effluents) have a negative impact on the water quality and the ecosystem,
contributing high salinity and causing overall pollution. To enable an environmental
assessment of the river and to satisfy the regulations of LJR international treaties, the
temporal dynamics of water quantity and quality must be observed on a regular
basis.
As the LJR forms the highly secured border between Jordan, Israel and the
Palestinian Authority, nearly the entire river course is physically inaccessible. To
overcome that situation, considerable efforts have been made to install a network of 7
sampling stations along the LJR to identify and separate the different contributing
sources. Automatic water samplers in three of the stations collect water daily in
addition to continuous measurement of stage, EC, pH and temperature. Sensors at all
locations transmit online real-time data. During monthly campaigns a total of 14
sites are manually sampled along the river and some tributaries. Water samples
are analyzed for major ions, trace elements and stable isotopes. While the sensor
network allows separating events occurring in different reaches along the river
course and calculating travel time between stations, water sample analyses enable
fingerprinting and separating the actual sources. By doing so, an unusual and very
local event was recorded by the most southern station (5.5 km north of the Dead
Sea). Here, the water level rose by ∼3 m for nearly 20 minutes. Dubious enough,
there was no sign of that event at the closest station 6.5 km upstream. This example
clearly stresses the necessity of the station network. Furthermore, it demonstrates that
previous discharge estimations to the Dead Sea are only vague and based on random
measurements at very few locations, providing meagre understanding of the river system. |
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