Fluviageny refers to the history of river segment lineages as they change through time. For example, when considering fish populations, the introduction of dams into a river network disrupts movement of fish across the dams, creating segments of rivers between dams in which a given fish population that was once ubiquitous throughout the river network begins to evolve independently within each portion of the river network between a set of dams. This concept is similar to and derives its name from phylogeny in biology, i.e., the Tree of Life.

Numerical codes can be assigned to river segments to represent fluviageny. The convention we use here is as follows. Consider a river network with no dams. When the first dam is built, all river segments upstream of the dam are assigned a fluviageny code of 1. All river segments downstream of the dam are assigned a fluviageny code of 2. When the second dam is built, upstream river segments between the new dam and any upstream dams or river terminations have ".1" appended to their fluviageny code. Likewise, the uninterrupted portion of the river network downstream of the dam will have ".2" appended to its fluviageny code. 1.

For example, consider five dams (a through e) built in five different years (from 1920 to 1952). The figure below shows an example river network with those dams, and the corresponding fluviageny codes that would be assigned.

Fluviageny Example

The Fluviageny toolbox contains tools to compute fluviageny in a river network using ArcGIS. The toolbox is accompanied by a document, Computing Fluviageny with ArcGIS.pdf, with background information about fluviageny, data preparation, and how to use this toolbox.

Software Requirements:

ArcGIS for Desktop 10.1 (or higher), with a Standard or Advanced license (does not work with Basic license).
Arc Hydro Tools (optional, but recommended for data preparation)

Credits: Tools and documentation authored by Dr. Tim Whiteaker, The University of Texas at Austin. Concepts of fluviageny were introduced to Dr. Whiteaker by Andrew Gordon.