Impact of an Extreme Flood Event on Streambank Retreat: Cedar River, Nebraska, USA

Naisargi Dave, Aaron Mittelstet, Jesse Korus, Michele Waszgis

Research output: Contribution to journalArticlepeer-review

Abstract

The 2010 dam breach and consequent anomalous flood event on the Cedar River in Nebraska, USA provided an opportunity to study the following objectives: (1) evaluate the impact of an extreme flood event on streambank retreat along a 45 km stretch relative to the average annual retreat; (2) quantify the changes in streambank retreat for each km segment downstream of the breach; and (3) examine the influence of riparian vegetation and radius of curvature on meander bank erosion rate. During the hydrologic event, discharge peaked at nearly three times greater than the next highest recorded rate and equated to a return period of 2,000 years. Aerial images and ArcGIS were utilized to calculate the average annual streambank retreat for each year during the preflood (2006–2010), flood (2010), and postflood (2010–2016) periods. The 2010 flood period had a significantly higher average annual streambank retreat of 2,820 m2/km/yr than the preflood and postflood periods, which, respectively, measured 576 and 384 m2/km/yr. From 2006 to 2016, 29% of all streambank erosion was from this one extreme flood event, thus demonstrating the impact that one extreme flood event can have on streambank retreat and the geomorphology of a stream system.

Original languageEnglish (US)
Pages (from-to)528-541
Number of pages14
JournalJournal of the American Water Resources Association
Volume56
Issue number3
DOIs
StatePublished - Jun 1 2020

Keywords

  • extreme flood event
  • riparian vegetation
  • stream power
  • streambank erostion/retreat

ASJC Scopus subject areas

  • Ecology
  • Water Science and Technology
  • Earth-Surface Processes

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