Water Framework Directive (WFD) legislation requires the definition of both surface and groundwaters as a coherent set of hydrological units which could be monitored and managed. Certain parcels of land situated between river water bodies and transitional or coastal water bodies did not warrant classification as a river water body. Such parcels of land are defined as coastal interbasins and have not formed part of the 1st or 2nd cycle classification process. The European Water Framework Directive was transposed to national legislation through the Water Environment (Water Framework Directive) Regulations (Northern Ireland) 2017. The Water (Amendment) (Northern Ireland) (EU Exit) Regulations 2019 ensures that the Water Framework Directive (WFD) (as transposed) and the various supporting pieces of water legislation remain implemented in Northern Ireland as National legislation.