Strahler number

The river atomic number ( floz ) water or ordinal number is in geomorphology and hydrology is a positive integer that indicates the degree of branching in a river network.

There are different approaches to the topological order of rivers or river sections according to their distance from the source or from the confluence ( confluence of two rivers, see: mouth ) into the sea, and their hierarchical position in the aquatic environment.

The classical flow order

The classic river divides the order into the sea opens out flow ( current) to order one. Tributaries get a larger by one order than the river, in which they each open.

This emanates from the mouth of the river atomic number indicates the position on the grid. It is appropriate for general cartographic purposes, but raises problems because it must be decided at each confluence, at which the branches of the river continues, or whether it is the confluence of two other rivers has its ( hydrological ) source here. In the application, one does not speak of the river, but by strand, and the strand of order 1 is the one that is on each river association, whichever is greater, relatively water-rich, which the outdated, very old nomenclature of most rivers largely reflects. Also in connection with this Flussordungssystem searching the geographers of the 19th century for the "true " source is to be understood. In the course of further criteria were discussed, after which the main line can be defined. The interest was adjacent to the flow path with the greatest length ( source with maximum distance to the mouth ) and the sizes of each to compare partial catchment areas particularly the larger direction of Constance at the point of confluence, also with regard to merely roll call, subordinated in the volume of capital flows (such as Rhine / Elbe River Aare / Moldova; see also: Creek ).

River ordinal number on lamp

After spotlights first-order rivers are the extreme inflows. Two rivers of the same order together, the confluence receives an atomic number that is one higher, flowing waters, together with two different Floz to transmit the higher the resulting waters.

The spotlights order is designed for the morphology of a river area, and the basis of important hydrographic indicators to its structure, such as branching ratio, flux density and flow rate. Its base is the watershed line of the catchment area. However, it is scale- dependent, depending on the scale of the flow detection caused other ordinal numbers. A general lower bound is obtained by defining a body of water " flow " over the mouth width, or the card detection based on minimum extent. The system itself can also be used for smaller-scale structures.

River atomic number by Shreve

After Shreve the outermost inflows will also receive the order one. At confluence, however, add up the atomic numbers.

The system according to Shreve found primarily in hydrodynamics application: it sums the numbers of sources in each catchment area above a level / effluent, and roughly correlates with the runoff and entries. As the spotlight method is dependent on the accuracy of the detected sources, but less scale- invariant. It can also be made ​​relatively scale independent by suitable normalization, and is then largely independent of the precise knowledge of the upper and lower reaches of an area.

Application

Classic application of water systems is the general hydrological mapping. In the systematic detection of a water system flow classification systems also give important clues for the unique identification and allocation of waters.

Significance of the methods of radiator and Shreve especially for modeling and morphometric analysis of water systems because they do not assign a string, but a section of the river a number. This allows the network disconnect at each level or discharge in headwater and underwater, and classify these points. Which is applied as the basis for the representation of the water balance on memory models, or time-based rainfall-runoff models and the like.

Also in the GIS-based geoscience latter two models are used because they represent the " graphical thickness " of a flow object. By choosing a lower threshold to fine structures of the tree can be blanked.