The preparatory process for the Second Assessment allowed for a discussion of the existing differences in monitoring and assessment systems, the deriving problems regarding comparability of data and the lessons learned from those riparian countries which have harmonized or made compatible their monitoring and assessment systems. The Convention takes a holistic approach, based on the understanding that water resources play an integral part in ecosystems as well as in human societies and economies. Its commitment to integrated water resources management (1WRM) replaces an earlier focus on localized sources of pollution and management of separate components of the ecosystem.