Find further information on the Conservation of Freshwater Ecosystem Values (CFEV) Program and its data at www.dpipwe.tas.gov.au/cfev.
TitleStrahler stream order
References
Strahler, A.N. (1957). Quantitative analysis of watershed geomorphology. Transactions of the American Geophysical Union 38: 913-920.
Column headingRS_ORDER
Input data
Type of dataCategorical
Number of classes9
Assigning values to ecosystem spatial units
Strahler stream ordering is an internationally recognised stream ordering classification for stream networks which rates each stream segment according to the orders of the incoming upstream segments.
The Strahler stream order (Strahler 1957) was derived from the rivers spatial data layer, where headwater reaches were assigned a stream order of 1 through to reaches entering estuaries, which could attain a maximum stream order of 9 (in Tasmania).
Each time two or more stream segments with order ‘n’ merge, the downstream order increases to ‘n+1’. See Figure 1 for a diagrammatic explanation of Strahler stream order.
Figure 1. Diagram of the stream order procedure used by the CFEV Project (after Strahler (1957)).
CFEV assessment framework input