| Sufficient freshwater availability in the water scarce environment of the
Upper Jordan Catchment (UJC) is a central prerequisite for peaceful
agricultural and industrial development. Hydrological modelling is required
to understand terrestrial water balance and to provide scientifically sound
estimates on water availability.
This article aims at two related objectives: First the water balance of the
UJC, a hydrogeologically complex catchment located at the borders of Israel,
Syria and the Lebanon, is investigated. It is for the first time that a
physically based model is set up for this region that accounts both for the
entire terrestrial water balance and in particular for the
groundwater-surface water interaction. It is shown that the model is able to
describe observed river discharges satisfactorily.
Secondly, it is investigated if observed and simulated runoff components can
be explained by simple lumped approaches based on 1) linear filter theory
and 2) neural networks and what the number of degrees of freedom for the
runoff components is. It is exemplary shown for the Ayun subcatchment of the
UJC that the simulated river discharge, the direct runoff component and the interflow
runoff component as modelled by the physically based distributed
hydrological model WaSiM can be described by simple effective equations with only
3 to 5 degrees of freedom. Application of simple lumped approaches to
observed river discharge values showed much weaker performance. |