It is the task of the engineer, as of any other professional person, to
do everything that is reasonably possible to analyse the difficulties
with which his or her client is confronted, and on this basis to design
solutions and implement these in practice. The distributed hydrological
model is, correspondingly, the means for doing everything that is
reasonably possible - of mobilising as much data and testing it with as
much knowledge as is economically feasible - for the purpose of
analysing problems and of designing and implementing remedial measures
in the case of difficulties arising within the hydrological cycle. Thus
the aim of distributed hydrologic modelling is to make the fullest use
of cartographic data, of geological data, of satellite data, of stream
discharge measurements, of borehole data, of observations of crops and
other vegetation, of historical records of floods and droughts, and
indeed of everything else that has ever been recorded or remembered, and
then to apply to this everything that is known about meteorology, plant
physiology, soil physics, hydrogeology, sediment transport and
everything else that is relevant within this context. Of course, no
matter how much data we have and no matter how much we know, it will
never be enough to treat some problems and some situations, but still we
can aim in this way to do the best that we possibly can.