Date of Award:

5-2013

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Watershed Sciences

Committee Chair(s)

Joseph M. Wheaton

Committee

Joseph M. Wheaton

Committee

Nicolaas W. Bouwes

Committee

Christopher M. U. Neale

Abstract

The Bonneville Power Administration (BPA) Fish and Wildlife Program (FWP) mitigates impacts, including mortality, from hydroelectric dams in the Columbia River Basin for ESA-listed salmon and steelhead populations and other species of special concern. Given the extensive economic resources invested in mitigation and the incredible diversity of in-stream habitat across the Columbia River basin, questions have arisen about which sampling strategies are most tractable across the entire Columbia River Watershed, but also produce datasets that allow researchers to answer meaningful questions about salmonid populations and trends in habitat. In response to these issues, the NOAA Integrated Status and Effectiveness Monitoring Program (ISEMP) was initiated in 2003 to develop and test strategies for determining the status and trend of salmonid populations and their habitat in the Columbia River basin. This thesis study was funded by ISEMP and designed to answer questions related to the accuracy, precision, and efficiency of using available surveying techniques to characterize stream and near channel topography. The primary objectives were: i) to assess the relative quality and efficiency of ground-based and airborne techniques for characterizing wadeable stream topography, and ii) to quantify the magnitude and effect of observer variability on ground-based total station surveys.

To better understand the relative strengths and weakness of using different ground-based and airborne surveying techniques to characterize wadeable stream topography (Objective i), we used a case study from the Lemhi River Basin, Idaho. Separate and complete total station (TS), real-time kinematic GPS (rtkGPS), terrestrial laser scanning (TLS), and airborne laser scanning (ALS) topographic surveys were conducted over the summer of 2010 at six sample sites of varying complexity. Analysis methods included both basic statistical and advanced spatial analysis approaches including residual error analyses, digital elevation model (DEM) pairwise comparison analyses, and estimating spatially variable errors. The primary findings were:

  • TS and rtkGPS are most reliable for characterizing wadeable wetted channel topography.
  • rtkGPS surveys are limited at sites with dense vegetation making TS a more universal technique.
  • TLS is unreliable and inefficient in-channel unless the channel is un-vegetated, water depth is extremely shallow, or the channel is dry.
  • ALS is unreliable in the wetted channel but produces a more comprehensive representation of floodplain topography.

To quantify the effect of observer variability on ground-based topographic surveys (Objective ii), we used a case study from the Upper Grande Ronde River Basin, Oregon where seven field crews sampled the same six sites using total stations. Analysis methods included both basic statistical and advanced spatial analysis approaches including decomposing metric variance, identifying systematic surveying and post-processing errors, and estimating spatially variable DEM errors. Our primary conclusions were that:

  • Ground-based survey techniques are viable tools for monitoring programs.
  • Most errors can be fixed post-hoc or minimized with improvements to training and quality assurance measures.
  • In the context of geomorphic change detection crews must be give adequate guidance on how far to extend survey extents into areas of the active floodplain that the channel could possibly migrate to.
  • Protocols should be regularly evaluated with variability studies to identify crew sources of error.

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