Geoscience Reference
In-Depth Information
10
Beyond the Primer: Predictions in
Ungauged Basins
PUB requires the development of new predictive approaches that are based on a deep
“understanding” of hydrological functioning at multiple space-time scales. Indeed, PUB
will herald a major change of paradigm in surface hydrology from the present one based
on “calibration” to a new exciting one based on “understanding”.
PUB Science Plan, 2003
Through its sharp focus on predictive uncertainty, PUB will therefore adopt and foster a
self-critical approach to hydrologic predictions by addressing what is not known or not
understood, and emphasizing the need for empirical exploration and explicit attempts to
generate, falsify and validate new ideas and new forms of knowledge. Also, the focus on
predictive uncertainty will enable hydrologists to go beyond quick fixes, to search for new
and innovative solution approaches, and to seek knowledge and understanding of natu-
ral processes beyond the immediate problem-solving needs of construction, environmental
management or regulation.
PUB Science Plan, 2003
10.1 The Ungauged Catchment Challenge
One of the great unsolved challenges in hydrology is the accurate simulation of a catchment without
any observational data with which to calibrate a hydrological model, i.e. an ungauged basin (Wagener
et al.
, 2004; Vogel, 2005; Bl oschl, 2005). This is also called the
regionalisation problem
in hydrological
modelling. It is so much easier to get reasonable predictions if some discharge data are available to give
an indication, at least, of the response of a catchment and to allow the calibration of model parameter
values. Even if the hydrological modeller has experience of applying a particular model in many different
