Summary of the workshop
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to utilize distributed models to simulate its hydrological functions. However, this shows the
difficulties in applying these models: the current knowledge of internal processes of watersheds is
insufficient to make it possible to use data from remote sensing and DEM in a useful manner. In
fact, hydrology, which was developed before the introduction of technologies allowing for the
collection and processing of spatial information, is poorly adapted to the efficient use of the full
potential or remote sensing and GIS. The empirical methods development for the estimation of
peak (flood) discharge and annual contributions, barely use spatially distributed information, and
generally only in a statistical form. If the best possible use is to be made of georeferenced
information, it is important to undertake the development of new hydrological methods.
At the same time, there is the problem of choosing a model: a physical model based on
spatial data, difficult to calibrate and therefore basically unstable, or a conceptual parametric
model which is easier to calibrate but in which it is harder to explain the physical meaning of the
parameters.
All the results presented above have been positive and encouraging. However, the use of
spatial techniques also includes a series of bottlenecks, of failures even. Very important lessons
can be drawn from the analysis of these failures. They help to reflect and are very useful for the
identification of the various constraints. The different presentations and discussions have raised a
number of problems that could explain these difficulties:
Technical problems:
• vision limited to the ground surface
Problems related to inappropriate use of tools:
• attempts to develop universal tools that is in contrast with the impossibility of correctly
modelling natural phenomena in their geographical variability;
• underestimation of the role of validation and field measurements;
• use of one technique instead of another without verifying complementarity.
Problems related to methodological limitations:
• fast development of computers, associated with a slower development of methodologies and
thematic reflections;
• spatial approach that is based upon new ways of thinking that are not adapted to the
traditional calculation methods;
• problems of scale and change of scale not properly managed; high sensitivity of indicators to
spatial and temporal scales, improper combination of information at multiple scales;
• bad selection of the so-called useful indicators.
Operational results
The different presentations of the workshop cover on the one side operational results and on the
other some more general reflections on the methods for treating spatial information for the study
and management of water resources. Among the operational results, we can essentially find
simple cartographic applications, with remote sensing and DEM adding new, pertinent and
qualitatively measurable cartographic information. The enormous possibilities in terms of
24
to utilize distributed models to simulate its hydrological functions. However, this shows the
difficulties in applying these models: the current knowledge of internal processes of watersheds is
insufficient to make it possible to use data from remote sensing and DEM in a useful manner. In
fact, hydrology, which was developed before the introduction of technologies allowing for the
collection and processing of spatial information, is poorly adapted to the efficient use of the full
potential or remote sensing and GIS. The empirical methods development for the estimation of
peak (flood) discharge and annual contributions, barely use spatially distributed information, and
generally only in a statistical form. If the best possible use is to be made of georeferenced
information, it is important to undertake the development of new hydrological methods.
At the same time, there is the problem of choosing a model: a physical model based on
spatial data, difficult to calibrate and therefore basically unstable, or a conceptual parametric
model which is easier to calibrate but in which it is harder to explain the physical meaning of the
parameters.
All the results presented above have been positive and encouraging. However, the use of
spatial techniques also includes a series of bottlenecks, of failures even. Very important lessons
can be drawn from the analysis of these failures. They help to reflect and are very useful for the
identification of the various constraints. The different presentations and discussions have raised a
number of problems that could explain these difficulties:
Technical problems:
• vision limited to the ground surface
Problems related to inappropriate use of tools:
• attempts to develop universal tools that is in contrast with the impossibility of correctly
modelling natural phenomena in their geographical variability;
• underestimation of the role of validation and field measurements;
• use of one technique instead of another without verifying complementarity.
Problems related to methodological limitations:
• fast development of computers, associated with a slower development of methodologies and
thematic reflections;
• spatial approach that is based upon new ways of thinking that are not adapted to the
traditional calculation methods;
• problems of scale and change of scale not properly managed; high sensitivity of indicators to
spatial and temporal scales, improper combination of information at multiple scales;
• bad selection of the so-called useful indicators.
Operational results
The different presentations of the workshop cover on the one side operational results and on the
other some more general reflections on the methods for treating spatial information for the study
and management of water resources. Among the operational results, we can essentially find
simple cartographic applications, with remote sensing and DEM adding new, pertinent and
qualitatively measurable cartographic information. The enormous possibilities in terms of