1 / 14

Teaching Geomorphology in the Field

Teaching Geomorphology in the Field. Channel Classification Karen Williams, PE Montana State University. Channel Classification Field Lab Goals. Exposure Familiarity with two prominent channel classification methods Skill

harrisshirley
Download Presentation

Teaching Geomorphology in the Field

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Teaching Geomorphologyin the Field Channel Classification Karen Williams, PE Montana State University

  2. Channel Classification Field Lab Goals • Exposure • Familiarity with two prominent channel classification methods • Skill • Ability to perform the field measurements needed to classify channels • Concept • Understand usage and limitations of channel classification

  3. Channel Classification

  4. Channel Classification Methods • Rosgen (1994) • form-based • embraced by federal and state agencies • limitation: commonly used to “predict a river’s behavior from its appearance” (Rosgen, 1994) • Montgomery and Buffington (1997) • process-based • widely used in PNW • limitation: most applicable in mountain settings

  5. Measurements for classification • Bankfull width • Bankfull depth • WS slope • Sinuosity http://www.stream.fs.fed.us/publications/videos.html

  6. Rosgen classification

  7. Planform

  8. Measurements for Rosgen classification • Entrenchment ratio: ratio of the flood-prone width to bankfull width 5-3 =2 2 x 2 =4 5-4 =1 3 5

  9. Montgomery & Buffington Classification • Cascade • Step pool • Plane bed • Pool riffle • Dune ripple Montgomery and Buffington, 1997

  10. Montgomery & Buffington Classification Montgomery and Buffington, 1997

  11. Real World E.g.:Reference/Impacted XS Surveys • Impacted Reaches – Plane Bed • transporting (not sorting or storing) all spawning gravel • Reference Reaches – Pool Riffle • sorting and storing spawning gravel • Goal of channel design and structures is to shift the channel into the sediment transport capacity limited regime

  12. NA indicates cross section did not conform to the Rosgen classification system, likely due to the geomorphic modifications caused by historic land use “classification and description are usually insufficient bases for extrapolation and thus for prediction.” Leopold, Luna B., and Langbein, W.B., 1963, Association and Determinacy in Geomorphology, in The Fabric of Geology, Geological Society of America, p.184-192.

  13. Annotated photos and map courtesy of Matt Kondolf

  14. References • Montgomery, D. and Buffington, J., 1997. Channel-reach morphology in mountain drainage basins. Geological Society of America Bulletin 109 (5), 596-611. • Rosgen, D., 1994. A classification of natural rivers. Catena 22, 169-199.

More Related