[Watershed of the Gelbressee river [Belgium]. Second part]

agricultura agriculture aquatic communities aquatic organisms aquatic plants bassin versant belgique belgium biocenose biocenosis biocoenosis conservation de la nature environmental impact hidrogeologia hidrografia hydrogeologie hydrogeology hydrographie hydrography impact sur l'environnement impacto ambiental industria industrie industry nature conservation organisme aquatique plante aquatique watershed management watersheds