Natural Resources, School of

 

Date of this Version

Fall 12-3-2010

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Natural Resources Sciences, Under the Supervision of Professor Steven A. Thomas. Lincoln, Nebraska: December, 2010
Copyright 2010 Christopher M. Pracheil

Abstract

Reduced ecological complexity, decreased water quality, and accelerated stream bank erosion are common disturbances in rivers with agriculturally dominated watersheds. Massive bank failures, increased sediment loads, and decreased riverine habitat are current problems in the agriculturally dominated Cedar River of central Nebraska. In an effort to slow erosion and prevent further ecological degradation, 20 reach scale stream bank stabilization projects were installed on the Cedar River from 2001 to 2004. The objective of this study was to determine the impact of the Cedar River stream bank stabilization projects on the ecological conditions within the Cedar River. Stream bank erosion, suspended sediment load, aquatic chemistry, in-stream metabolism, riparian macrophytes, macroinvertebrates, and fish data from seven stabilized and three unstabilized reaches were monitored from the spring of 2007 through to fall of 2008 to assess the ecological condition of each site. Stabilized sites experienced significantly less stream bank erosion than unstabilized sites. Suspended sediment and dissolved nutrient concentrations general increased in the downstream direction, irrespective of treatment. Riparian macrophyte diversity and density was significantly higher at stabilized sites. Stabilized sites were found to have greater numbers of macroinvertebrate families and individuals, as well as greater numbers of the sensitive EPT families and individuals. More fish species and native fish species were captured at the stabilized sites, and a greater number of fish per m2 were captured at the stabilized sites. The results of this study demonstrate that stream bank stabilization projects can positively impact plant, invertebrate, and fish communities, while not impacting water quality parameters.