The Taxa Watermanagement the Netherlands (TWN) checklist consists of several lists of species that are relevant for the proper management of Dutch inland water bodies. The lists contain aquatic, semi-aquatic as well as terrestrial organisms. Nomenclature of the taxa is consequent binominal with references to authors and identification literature. At a regular base the lists are being updated and improved by specialists from the Rijkswaterstaat laboratories. The lists are part of the official Aquo-standard, used by all Dutch water managing organisations. The TWN checklist accommodates over 16.000 species and is sub-divided in lists on amphibians, birds, butterflies, diatoms, macroalgae, macroinvertebrates, mammals, macrophytes, nematodes, phytoplankton, reptiles and zooplankton.