Sampling spatial sediment variation in gravel-bed streams

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dc.contributor.authorCrowder, David W.en
dc.contributor.committeechairDiplas, Panayiotisen
dc.contributor.committeememberCampbell, James B. Jr.en
dc.contributor.committeememberCox, William E.en
dc.contributor.departmentCivil Engineeringen
dc.date.accessioned2014-03-14T21:47:03Zen
dc.date.adate2005-10-07en
dc.date.available2014-03-14T21:47:03Zen
dc.date.issued1995-07-05en
dc.date.rdate2005-10-07en
dc.date.sdate2005-10-07en
dc.description.abstractA gravel-bed stream's grain size distribution plays an important role in determining a river's depth, sediment transport rates, and stream bed stability as well as the survival rates of mussels and salmonids. Unfortunately, the material found in gravel-bed rivers exhibits vertical stratification as well as spatial variation in the horizontal direction and is difficult to sample. Previous research has largely dealt with the ability of grid, areal, and bulk sampling techniques to sample a single spot within a river. Little has been done in characterizing an entire river reach. Of the methods suggested, none is adequate because they are either inherently biased or are incapable of describing the spatial variations within a sampled region. The present research proposes a method that overcomes these problems. It shows that a single large grid sample, or composite grid sample, can be used to obtain an unbiased estimate of an area's overall grain size distribution at a known accuracy level. It then suggests that the arithmetic mean is a suitable parameter to characterize the coarseness of individual sediment deposits within a sampled area. Thus, by recording the size and location of each stone taken in the composite grid sample one can use statistical hypothesis testing to systematically analyze local means throughout the sampled area and locate sediment boundaries. Once the boundaries are located, stones from the composite grid sample falling within the boundaries of a particular deposit can be analyzed as separate grid samples representative of the individual deposits present and describe the local variability.en
dc.description.degreeMaster of Scienceen
dc.format.extentxv, 220 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-10072005-094830en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10072005-094830/en
dc.identifier.urihttp://hdl.handle.net/10919/45064en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1995.C768.pdfen
dc.relation.isformatofOCLC# 34390989en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectsediment samplingen
dc.subjectspatial variationen
dc.subjectgravel-bed riversen
dc.subjectgrid samplingen
dc.subject.lccLD5655.V855 1995.C768en
dc.titleSampling spatial sediment variation in gravel-bed streamsen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineCivil Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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