VAHMPIRE: Validation hydrological models using process studies and internal data from research basins

• Research unit: EU RFP
• Project number: 95.0449

Key words (English)

Hydrological processes; environmental tracing; uncertainty analysis; hydrological models; model validation

Alternative project number (English)

EU project number: ENV4-CT95-0134

Research programs (English)

EU-programme: 4. Frame Research Programme - 3.1 Environment

Short description (English)

See abstract

Partners and International Organizations (English)

CSIC/IJA (E), CSIC/IPE (E), ESAB/UCSCA (E), UB/GPPG (E), UNEWIWRSRU (UK), ADAS/CRD (UK), UNIBO/DISTGA (I), TUBS (D)

Abstract (English)

The research conducted by the Soil and Water Institute (IATE) in the context of the VAHMPIRE project has two main objectives: the study of hydrological processes and the validation of hydrological models.
Concerning the study of the first topic, two kinds of approach are adopted. First an experiment of environmental tracing is conducted in three watershed at the same time. The aim of this experiment is to determine the hydrological behaviour at the basin scale and to identify which parameters control it (e.g. geology, topography, soil occupation...). This analysis is based on the application of the three-component geochemical mixing model developed for the particular case of the Haute-Mentue watershed. During this application, it appears that the uncertainty of chemical component definition may be important and its consideration could moderate the interpretation of hydrograph separations. So, both a method and a computer software are proposed in order to estimate the uncertainty of mixing model.
The second approach for this study of hydrological processes combines environmental tracing with hill slope measurements (Time Domain Reflectometry, piezometric measurements, rainfall simulator). The hydrometric measurements are conducted to the contributing areas, identified during the environmental tracing experiment, in order to study specific mechanisms. The application of hill slope measurements first allows to confirm the important contribution of subsurface flows to flood generation observed during the environmental tracing experiment. Finally this analysis seems to indicate that the important contribution of soil water is due to macropores flows.
The validation exercise of hydrological models in the VAHMPIRE project has focused on three main areas:
process representation, calibration - validation and scale problem in hydrological modelling. The approach adopted in this study for the calibration and the validation uses field measurements rather than the classical methods. First pedotransfert functions are developed on the base of data obtained by the analysis of small soil cores in order to characterise the general hydraulic properties of soil. The methodology would improve the use of pedotransfert function at the model mesh scale and so it could be related to the scale problem. In order to analyse the coherence and the validity of processes in hydrological models, the IATE institute has developed two types of approaches. The first one is conceptual and tests the importance of some hypotheses such as the role of geomorphology and topography in runoff production and the second one is physically based and focuses on the role of distributed parameterisation on the watershed hydrological behaviour.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 95.0449