{{Unreferenced, date=May 2019, bot=noref (GreenC bot) A waterbody number, waterbody index number or waterbody ID is used for the hydrographic classification of waterbodies. Where classification only covers bodies of flowing water such as rivers, it may be called a watercourse number. Many different systems are used in limnology to number waterbodies such as lakes, rivers and streams, ranging from basic index numbers representing their location in the river system, such as serial numbers for the major catchment areas of the rivers, or numbers indicating their hierarchical position in the system. On the basis of such numbers the aim is to give waterbodies, river sections or catchment areas a clear identification number. As a result of the systems used in various specialist fields there may even be different national and regional waterbody index numbers for the same body of water.

Stream order

A general geographical and hydrographical classification uses

Strahler number In mathematics, the Strahler number or Horton–Strahler number of a mathematical tree is a numerical measure of its branching complexity. These numbers were first developed in hydrology by and ; in this application, they are referred to as the ...

s to determine the: *

Stream order The stream order or waterbody order is a positive whole number used in geomorphology and hydrology to indicate the level of branching in a river system. There are various approachesKoschitzki, 2.3, pp. 12ff to the topological ordering of riv ...

– the level of the waterbody in the hydrographical hierarchical classification system (there are several different systems)

National terminology or systems

* ''

Gewässerkennzahl The ''Gewässerkennzahl'' (GKZ, rarely GWK or GEWKZ) or "waterbody index number/waterbody number" is an identifier with which all watercourses in Germany are numbered, together with their catchments and precipitation areas. It is also referred ...

'' ("watercourse index number"), Germany * ''

HZB Code HZB may refer to: * Helmholtz-Zentrum Berlin, a German research institute * HZB, the IATA code for Merville–Calonne Airport Merville – Calonne Airport is a regional airport in France. It is located south of Merville, in northern France. T ...

'' ("waterbody index number"; legally defined, HZB code, OWK No., WRRL codes), Austria * River basin number (järvinumero), Finland * '' Sandre'', France * Watercourse number, Pakistan *

State Water Register State Water Register (russian: Государственный водный реестр) is a systematized collection of documented information on water bodies owned by the Russian Federation, subjects of the Russian Federation, municipalities, ind ...

, Russia * '' Gewässerlaufnummer'' ("waterbody serial number"),

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

* '' Čislo hydrologického pořadí'' ("hydrological order number"), Czech Republic * Waterbody number, waterbody ID, United Kingdom * Waterbody number, waterbody index number, Geographic Names Information System, United States

Stream order

National terminology or systems

See also