GEOMORPHIC CLASSIFICATION OF INTERMITTENT RIVERS AND EPHEMERAL STREAMS IN DIFFERENT ECOREGIONS OF THE CONTINENTAL UNITED STATES

In order to fully understand stream and river channels, there must be a classification system in place. A classification system would make it easier to monitor stream and river functions and any anthropogenic impacts taking place. Specifically, a comprehensive classification for Intermittent Rivers and Ephemeral Streams (IRES) has yet to be developed. Generally defined, IRES have flow that occurs during or after rainfall or seasonally and thus, flow naturally ceases at some points along their network.

This research project will examine geomorphic features of IRES across different Environmental Protection Agency (EPA) Ecoregions in the continental United States to be able to better classify IRES. Five United States Geologic Society (USGS) gages along intermittent or ephemeral streams will be chosen per Level One EPA Ecoregion as field sites. A Geographic Information System analysis will be done which involves reviewing the National Hydrography Dataset, USGS streamflow data, land cover, Digital Elevation Models, and ecoregion data. This study will look for broad patterns recognizable across North America and applicable to the identification of IRES. The importance of these variables will be identified using a Principal Component Analyses. Properties of IRES that will be considered are width, stream slope/gradient, location in stream network, longitudinal profile, mean annual discharge, and landcover classification. This research is still in its preliminary investigations, but a broad pattern of geomorphic properties that are most consistent in importance to IRES identification should emerge during this study.