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The effect of depth-velocity correlations on aquatic physical habitat usability estimates

dc.contributor.authorPrewitt, Charles G., author
dc.contributor.authorCarlson, Clarence A., committee member
dc.contributor.authorStalnaker, Clair B., committee member
dc.date.accessioned2016-02-19T18:31:40Z
dc.date.available2016-02-19T18:31:40Z
dc.date.issued1982
dc.description.abstractRecent developments in instream flow evaluations have resulted in a variety of assessment methodologies. Of these, the Instream Flow Incremental Methodology permitted consideration of both physical habitat parameters (e.g., depth, velocity, substrate and temperature) and preferences for certain values of these parameters by selected organisms. This methodology was based on the PHABSIM (Physical HABitat SIMulation) computer system, which allowed 1) prediction of depths, velocities and associated substrates at a stream reach; 2) determination of weighting factors for the predicted values from preference curves constructed for each organism or group of organisms; and 31 application of a joint weighting factor (obtained by multiplying the individual weighting factors) to the surface area of the stream reach to obtain weighted usable area (WUA) for that reach. WUA is an indicator of the extent of available preferred physical habitat and a valuable tool in streamflow assessments. Calculation of joint preference factors by multiplication was statistically permissible only if the variables were uncorrelated. Using the original calculation approach, variable correlations were assumed to be zero, but might actually be quite high. To test the hypothesis that two variable (depth-velocity) correlations greater than zero did not significantly affect WUA results, a study was designed to account for effects of increased levels of correlation upon WUA calculated using various preference curves in a variety of stream types and channel characteristics. In the entire data set, the hypothesis was supported only to a correlation level of .2, a level unlikely to occur. However, results were more consistent in medium and large streams than in small streams. Further, in medium and large streams with complex channel configuration, users could expect independent depth-velocity curves to give results similar to correlated curves even if the actual correlation level was 0.4 or in many cases 0.6. Indicators of simple and complex channel conditions and discharge ranges of small, medium and large streams were given. Ecological (niche and guild theory) inferences related to habitat requirements and impact analysis were briefly discussed, and hypotheses regarding habitat diversity and stability presented. Definition of a fundamental niche using a multivariate statistical approach was suggested as a tool in predicting effects of environmental changes upon usable habitat.
dc.format.mediumdoctoral dissertations
dc.identifier.urihttp://hdl.handle.net/10217/170676
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relationCatalog record number (MMS ID): 991003807579703361
dc.relationSH173.5.P74
dc.relation.ispartof1980-1999
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subject.lcshFishes -- Habitat
dc.subject.lcshFishes -- Effect of water levels on
dc.subject.lcshStreamflow velocity
dc.titleThe effect of depth-velocity correlations on aquatic physical habitat usability estimates
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineFishery and Wildlife Biology
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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