The archetype of the unknown monster is certainly the Snark, which has been described by Lewis Caroll in his poem entitled The hunting of the Snark (Caroll, 1876). Here, we try to propose a strategy allowing the hunting of the unknown hydrological monster which we all try to deal with in this workshop. In particular we try to define: Which type of research team is needed to hunt the hydro-snark? Which kind of hydrological models may be of help to try to locate the hydro-snark? What kind of GIS devices may be useful to map hydro-snark breeding grounds?