Abstract
The ANR 11 MONU 14 Fresqueau project is an interdisciplinary project involving computer scientists and hydroecologists. Its aim is to collect a large dataset about watercourses, in two large french watersheds; and then to explore it with data mining methods for answering scientific questions. The collected data are numerous and have various origins and characteristics: they have spatial or temporal characteristics, they can be quantitative or qualitative, sparse or dense, their precision and validity are variable. Due to all these characteristics, mining this big dataset appeared a complex task.