NSW Hydro Point defines point hydrographic feature types. It represents points of standard bodies of inland water where flow is minor and is defined as either natural water body or man-made water body. The dataset also indicates whether a hydro point is perennial, non-perennial or mainly dry.

NSW Hydro Line defines the centreline of a water course. It includes features such as natural water course, canal-drain, race, spill way and tunnel-siphon. It includes key attributes such as hydro line name, perennially and flow direction.

NSW Named Water Course defines the centreline of a named water course as a single feature. It is an aggregation of Hydro Line parts.

The Water theme is based on hydrology which is the study of the movement, distribution and quality of water. This includes the hydrologic cycles, water resources and environmental watershed sustainability. Hydrology includes surface hydrology, hydrogeology, drainage basin management and water quality where water plays the central role. Water (surface water and groundwater) is concerned with information as aligned with the definitions under the Water Act 2007. This theme includes Hydrology elements which are described as: Surface Water • Water in a watercourse, lake or wetland. • Any water flowing over or lying on land, either: • after having precipitated naturally after having risen to the surface naturally from underground. Groundwater • Water occurring at a place below ground that has been pumped, diverted or released to that place for the purpose of being stored there • Does not include water held in underground tanks, pipes or other works.

NSW Ancillary Hydro Point data represents a location that has unique hydrology characteristics or monitors or controls stream flow or manages hydrographical spatial data integrity. Features within an ancillary hydro point class include: bore, lock, rapids, spring, tidal limit marker, waterfall, dissipation point, regulators, barriers, river gauge, and sink.

NSW Coastline data is linear feature class defining the line of contact between a body of water and the land. In particular, the line delineating the interface between land, internal waters and the “Territorial Sea” as defined by the Seas and Submerged Lands Act - No. 161 of 1973. The coastline defining Mean High Water Mark (MHWM) does not include MHWM within estuaries. Features within coastline feature class include: mean high water mark and mean low water mark.

NSW Fuzzy Extent Water Area is polygon feature class representing the approximate extents of formally named water features that have relatively indistinct name extent. Fuzzy extent water areas are divided into Bay like, River like and Sea like sub types. Bay like class is defined as bay-like features, which includes Bays, Bights, Coves, Entrances, Gulfs, Harbours, Inlets, Ports and River Mouths. River like is defined as a named river-like feature of indefinite name extent which includes Anabranch, Arm, Bend, Canal, Channel, Cowal, Passage, Reach, River Bend, River Feature, and Strait that have not been represented by another hydrographic feature class. A sea like water body includes sea and ocean.