Browsing by Subject "River Regimes"

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    Church and Rood Alluvial River Channel Regime Data [1983]
    (2024-04-22) Church, Michael; Rood, Kenneth; ctn@umn.edu; Nguyen, Charles; National Center for Earth-Surface Dynamics (NCED)
    Investigation of downstream hydraulic geometry in rivers in order to seek a rational basis for river behavior requires that data be properly comparable. Comparisons should be restricted to measurements that have been obtained by similar means: consistent river behavior should be sought only along reaches or amongst rivers that are homogeneous with respect to the main governing conditions of hydrology, sediment supply and alluvial materials. Data reported in the literature are usually insufficient to allow investigator assuredly to meet these criteria. This catalogue defines a set of consistent criteria for description of river channels. Although more or less arbitrary, they conform with usually preferred field practices. Ten river channel morphological types are defines as a basis for discriminating channels that may be compared meaningfully. About 500 sets of data are compiled that met the criteria and are drawn from a wide search of the literature. Almost all are located in humid or semi-arid temperature environments. At the minimum, discharge, gradient, section mean geometry, and bed material size must be given the basis of the data must be known. For many data sets, additional information is referred to in a "dictionary" of sources. Many River stations have more than one entry, since data sets may be available for more than one discharge.
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    William Brownlie Alluvial Channel Data [1981]
    (2024-05-23) Brownlie, William R; ctn@umn.edu; Nguyen, Charles; National Center for Earth-Surface Dynamics (NCED)
    In recent years, attempts have been made to develop numerical models for unsteady flows in channels with sediment transport. This work was conducted to analyze two essential ingredients of any numerical model: the relationship between the hydraulic variables (slope, depth, and velocity), and the predictor of sediment concentration. Report KH-R-43A (not in this archive) presents a detailed analysis of the two components and examines their role in numerical modeling. Six hydraulic relationships and 13 sediment concentration predictors are examined and compared. New relationships are then developed which appear to be more accurate than the existing techniques. Finally, the new relationships are utilized in a numerical unsteady flow, moveable bed model which uses a four-point implicit finite difference solution scheme. The data base associated with this report (presented originally as Report KH-R-43B) contains 7,027 records (5,263 laboratory records and 1,764 field records), in 77 data files. The data are provided here as two spreadsheets – field data and laboratory data. Not all records were used in the final analyses, but they have been included in an attempt to provide a historically complete set of alluvial channel observations. The material presented in these reports is essentially the same as the thesis submitted by the author in partial fulfillment of the requirements for the degree of Doctor of Philosophy. A common list of references, with data sources separated from other references, has been included in both reports.