Classification Systems for Rivers More Complementary Than Expected

Mar 18, 2016

Scientists who study rivers debate how to classify them, but a new study suggests the different approaches are not so different.


The Elwha River in Washington
Credit / NPS

  A rushing stream, a babbling brook, and a lazy river might be enough for most people, but river ecologists around the world have devised several different systems for distilling the complex geomorphic, hydrologic, and ecological features of rivers into simple descriptions of their channels and floodplains.

“There’s a number of different ways that you can go about classifying rivers, or basically assigning a name to the way that they look. River managers have relied on these for a number of years, because measuring different processes, you know, measuring the rate of bank erosion or the rate of sediment transport through a stream is notoriously difficult.”

Alan Kasprak and Nate Hough-Snee led a team of USU researchers at the Intermountain Center for River Rehabilitation and Restoration who tested whether streams in Oregon’s Middle Fork John Day River Basin were classified the same way under four popular systems for doing so. The study is in today’s issue of the journal PLoS ONE.

“River classification serves a lot of different purposes. Some of these purposes are simply just educating the public, lay-folks, or non-expert scientists who work in natural resource capacities, as to what range of possibilities may be within a given watershed. What different types of channels occur within the Logan River watershed, or the Bear River watershed?”

Hough-Snee and Kasprak’s team found that the classifications agreed 80 percent of the time, a finding which might settle the lively debate over which classification framework is ‘the best’. The classifications tended to disagree in areas with a lot of human disturbance, because the ways in which people modify rivers tend to disconnect them from their surrounding landscape. Hough-Snee and Kasprak hope that their research findings will help land managers and researchers agree upon appropriate methods to rapidly identify high-quality fish habitat, compare watersheds, or estimate rates of bank erosion.