Ben-Gurion University of the Negev

CWST - Center for Water Science and Technology

Summary reports on discussion/working group meetings and other activities


The National Facility of Experimental Hydrological Models (NFEHM)
  • The NFEHM , sponsored by The Ministries of Science of Israel and Germany and by BGU, was established at the campus of BIDS at Sde Boker, with the purpose of being an intermediate link between the laboratory scale exploration of processes in the soil zone to aquifer domain and the real field conditions. As a first step a box like model with dimensions of 1.0x1.0x1.5m was built, and filled with a quartz mix which mimics the hydraulic properties of the Israeli coastal plain aquifer.
    At this stage the following studies are planned:
    1. The transport of colloids in porous media and their effect on the mobility of contaminants;
    2. The testing of bio-remediation methods, both the degradation of an aquifer's native micro-organisms and the survival and activity of introduced bacteria for the purpose of degrading pollutants of aquifers.
    3. The testing of the possibility of introducing compaction waves for clean-up of local sites.


"Study program on the effect of drought on the ecology and eco-hydrology of the Negev"

Following the severe drought years of 1999 and 2000, the CWST in cooperation with BIDR sponsored a field program aimed at assessing the impact of drought on the eco-hydrological system of the Negev.
A first report on "The effects of drought on annual plant communities in the northern Negev of Israel" by Bertrand Boeken, Yarden Oren and Moshe Shachak.


Eco-hydrology of the drylands
  • 1st meeting - Sde-Boker (BIDR) - April 8, 1998
    The following memorandum summarizes the 1st meeting:
    Memorandum: Desert Eco-Hydro1ogy
    The inter-relationships between the hydrologic regime and the ecological structure and the feedback effects of one on the other, are nowhere of as much consequence as in the arid zone. Needless to say, the possibility of life in the desert depends on the availability of water. Indeed the very definition of a desert as an area with insufficient moisture to support widespread vegetation (Random House Dictionary of the English Language) emphasizes the control exerted by water on the desert biota. Furthermore, studies on the adaptation of desert plants to the varied and complex pattern of water shortage and the stratagems of the biota to cope with water stress and intermittence of the water supply, figure prominently in arid zone research.

    It is not as widely recognized that under the special situation of the arid zone and its precariously established hydrological balance, it is the ecological condition on the surface, which determines the partitioning of precipitation into the surface runoff{ infiltration, groundwater recharge and evaporation fluxes and thus holds the key to much of the hydrological development in the arid environment As an example, surface runoff is, in most instances, a necessary pre-requisite for obtaining a sufficient water depth for both sustained plant growth and groundwater recharge. Indeed the "runoff farming" practiced by the Nabeteans, which is nowadays developed for desert agriculture, utilizes this principle. The competition between the water use of these two processes dominates the large scale water balance and also affects water quality.

    The following is a partial list of points to discuss:

    • The intermittency (temporal and spatial) of rainfall events and their hydrological and ecological consequences.
    • Eco-hydrological niches, their water balance and sensitivity to climatic and anthropogenic changes. For example: oases, wadis, sabkhas, artificial leimans, runoff farms and naturally distributed runoff drenched plots.
    • The effect of the ecological pattern on water availability (balance) and quality (salinity).
    • Isotopic tracers (13C, 180, 2H) in water, plant and animal tissues, as possible monitors of the eco-hydrologic patterns.
    • Effect of biota, algal mats, etc. on hydraulic properties of the surface and soil.
    • Extraneous water in the arid environment and its eco-hydrological effect.

  • 2nd meeting - Sde-Boker (BIDR) - December 9, 1999
    Program:
    • Opening lecture: "ECO"-Hydrology? The UNESCO - IHP - V/2.3-2.4 Programme and ideas regarding theoretical concepts in limnology, landscape scale and necessary methodological strategies. (G. Janauer)
    • The interaction of water flow and vegetation structures in aquatic and terrestrial landscape units: a biologist's view.(G. Janauer)
    • The concept of "Desert Eco-Hydrology". (J. Gat)
    • Use of remote sensing for mapping distribution of microphytes in the Negev Dune area. (A. Karnielli)
    • On rainfall patterns. (D. Sharon)
    • Water balance in view of spatial variability of precipitation and variation of soil properties. (J. Ben-Asher)
    • Dew as a Eco-hydrological factor. (P. Berliner)
    • Water balance in Negev wadis. (A. Ben-Zvi)
    • Quantification of the relative amounts of ground and soil waters used by plants, using environmental isotopes. (I. Gev)
    • Water use pattern of desert plants; report on the GIF project. (J. Gat)
    • Surface Runoff formation, miscellaneous reports.

    List of participants
    Name Affiliation
    Alekperov ChingizBGU - BIDR
    Ben-Asher JiftachBGU - BIDR
    Ben-Zvi ArieIsrael Hydr. Service
    Berliner PedroBGU - BIDR
    Boeken BertrandBGU - BIDR
    Brenner AsherBGU - BIDR
    Droppelmann KlausBGU - BIDR
    Ephrath JonathanBGU - BIDR
    Figuenola PatriciaBGU
    Furshpan Avner BGU
    Gat JoelBGU - CWST
    Gev IsraelIsraeli Water Com.
    Janauer GVienna University
    Karnieli ArnonBGU - BIDR
    Nativ RonitHebrew University
    Ninari NuritBGU
    Sharon DavidHebrew University
    Sofer ZviBGU


  • Desert Urban Hydrology
    • 1st meeting - Beer Sheva - November 11th 2000
      Concept statement as background to the discussion:
      The hydrology of arid areas (drylands), differs considerably from that of more humid environments in that surface flows are a necessary prerequisite for the occurrence of groundwater recharge. This face has opposing consequences with regards to the effect of changes in land use, urbanization as its most extreme expression, on the quantity and quality of the groundwater recharge. Unlike the coastal area of Israel where the obstruction to direct rainwater infiltration by the urban development results in reduced recharge and increased surface flow, in the arid zone the surface flows may actually enhance the recharge provided they are prudently channeled. On the other hand, the system becomes very sensitive to contamination by surface accumulated materials, which are flushed by the surface runoff to the potential infiltration sites.
      The effect of development on the area's indigenous water sources depends on the type of activity and its scale. The immediate impact, when local water sources are utilized, is the stressing of the groundwaters by over-exploitation, often resulting in increased salinity. However, once the scale of the urbanization or development exceeds a critical value one utilized the supply of extraneous water, be it the import of water from beyond the region or desalinized or reclaimed sewage. The salient feature of such a situation is then an excess of water beyond the naturally available supply, mostly with high chemical loads, which may then overload the natural drainage capability and self-cleaning potential and resilience of the arid system.

      List of participants:
      Dr. E. Adar - BIDR
      Prof. D. Bahat - BGU
      Prof. Y. Ben-Asher - BIDR
      Dr. A. Ben-Zvi - Hydr. Surv.
      Dr. P. Berliner - BIDR
      Dr. A. Brenner - BIDR
      Arc. E. Erel - BIDR
      Dr. Y, Etzion - BIDR       		Prof. J. Gat - CWST
      Dr. I Gev Water Water Com.
      Prof. Y. Grados - BGU
      Dr. S. Netanyahu - BGU
      Dr. D. Ronen - Hydr. Serv.
      Prof. S. Sorek - BIDR
      Dr. A. Vengosh - BGU

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