Document Type

Conference Proceeding

Conference

World Environmental and Water Resources Congress 2009; May 17-21, 2009, Kansas City, Missouri, United States

Publication Version

Published Version

Publication Date

2009

Journal or Book Title

World Environmental and Water Resources Congress 2009: Great Rivers

First Page

3082

Last Page

3091

DOI

10.1061/9780784410363

Conference Title

World Environmental and Water Resources Congress 2009; May 17-21, 2009, Kansas City, Missouri, United States

Conference Date

May 17-21, 2009

City

Kansas City, Missouri

Abstract

This paper summarizes research from separate studies of fish passage over weirs (Larson et al., 2004; Litvan, 2006; Litvan, et al., 2008a-c) and weir hydraulics (Papanicolaou and Dermisis, 2006; Papanicolaou and Dermisis, in press). Channel incision in the deep loess region of western Iowa has caused decreased biodiversity because streams have high sediment loads, altered flow regimes, lost habitat, and lost lateral connectivity with their former floodplains. In-stream grade control structures (GCS) are built to prevent further erosion, protect infrastructure, and reduce sediment loads. However, GCS can have a detrimental impact on fisheries abundance and migration, biodiversity, and longitudinal connectivity. Fish mark-recapture studies were performed on stretches of streams with and without GCS. GCS with vertical or 1:4 (rise/run) downstream slopes did not allow fish migration, but GCS with slopes ≤ 1:15 did. GCS sites were characterized by greater proportions of pool habitat, maximum depths, fish biomass, slightly higher index of biotic integrity (IBI) scores, and greater macroinvertebrate abundance and diversity than non-GCS sites. After modification of three GCS, IBI scores increased and fish species exhibiting truncated distributions before were found throughout the study area. Another study examined the hydraulic performance of GCS to facilitate unimpeded fish passage by determining the mean and turbulent flow characteristics in the vicinity of the GCS via detailed, non-intrusive field tests. Mean flow depth (Y) and velocity (V) atop the GCS were critical for evaluating GCS performance. Turbulent flow measurements illustrated that certain GCS designs cause sudden constrictions which form eddies large enough to disorient fish. GCS with slopes ≤ 1:15 best met the minimum requirements to allow catfish passage of a flow depth of ≥ 0.31 m and a mean flow velocity of ≤ 1.22 m/s.

Comments

This proceeding is from World Environmental and Water Resources Congress 2009: Great Rivers (2009): 3082, doi:10.1061/9780784410363.

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Language

en

File Format

application/pdf

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