title: Determination of pollution and recovery time of karst springs, an example from a carbonate aquifer in Israel.
abstract: This work combines the monitoring of two incidents of spring water pollution in the Western Galilee region of Israel, together with artificial tracer tests that provided valuable information regarding karst system connections and direct estimation of groundwater velocities. Almost simultaneous contamination of seven springs endangered the water supply for the region. The variations over time in contaminant concentration in the different springs were not similar, indicating more than one contamination source. Tracer tests revealed two different pollution sources that contributed to two different conduit pathways in the karst system. Breakthrough data for the tracers were modeled by a two-region non-equilibrium transport model, which provided the transport parameters of the karst conduit. Groundwater velocities in the conduits were found to be in a range of 2-3 km/day. The rapid response of the system was also demonstrated by the short recovery time of the springs, where, after the elimination of the pollution source, most water quality parameters reverted to their background concentrations in less than 3 months. The coexistence of highly polluted springs and uncontaminated groundwater in boreholes penetrating into the same aquifer demonstrates the complexity of groundwater flow in karst systems. In such systems, the fast groundwater flow in localized karst conduits seems to coexist with a slower flow within other portions of the aquifer.
authors.affiliation: Ministry of Energy and Water Resources, Government of Israel, Yaffo 234, 13106, Jerusalem 91130, Israel. EinatM@energy.gov.il
authors.forename: Einat
authors.initials: E
authors.lastname: Magal
authors.forename: Yuval
authors.initials: Y
authors.lastname: Arbel
authors.forename: Sarit
authors.initials: S
authors.lastname: Caspi
authors.forename: Hilel
authors.initials: H
authors.lastname: Glazman
authors.forename: Noam
authors.initials: N
authors.lastname: Greenbaum
authors.forename: Yoseph
authors.initials: Y
authors.lastname: Yechieli
mesh_terms: D004784:Environmental Monitoring; D019793:Fluorescein / Q000032:analysis; D060587:Groundwater / Q000032:analysis; D007557:Israel; D008962:Models, Theoretical; D060985:Natural Springs / Q000032:analysis* / Q000737:chemistry; D014876:Water Pollution / Q000032:analysis*
chemical_list: D019793:Fluorescein