Hydraulics of High-Gradient Streams
01 Nov 1984-Journal of Hydraulic Engineering (American Society of Civil Engineers)-Vol. 110, Iss: 11, pp 1519-1539
TL;DR: In this article, a simple and objective method was employed to develop an equation for predicting the Manning roughness coefficient of high-gradient streams by using multiple regression techniques and measurements of the slope and hydraulic radius.
Abstract: Onsite surveys and 75 measurements of discharge were made on 21 high-gradient streams (slopes greater than 0.002) for the purpose of computing the Manning roughness coefficient, n, and to provide data on the hydraulics of these streams. These data show that: (1) n varies inversely with depth, (2) n varies directly with slope, and (3) streams thought to be in the super-critical flow range were actually in the subcritical range. A simple and objective method was employed to develop an equation for predicting the n of high-gradient streams by using multiple-regression techniques and measurements of the slope and hydraulic radius. The average standard error of estimate of this prediction equation was 28% when tested with Colorado data. The equation was verified using other data available for high-gradient streams. Regime-flow equations for velocity and discharge also were developed.
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TL;DR: In this paper, a classification system for natural rivers is presented in which a morphological arrangement of stream characteristics is organized into relatively homogeneous stream types, and morphologically similar stream reaches are divided into 7 major stream type categories that differ in entrenchment, gradient, width/depth ratio, and sinuosity in various landforms.
Abstract: A classification system for natural rivers is presented in which a morphological arrangement of stream characteristics is organized into relatively homogeneous stream types. This paper describes morphologically similar stream reaches that are divided into 7 major stream type categories that differ in entrenchment, gradient, width/depth ratio, and sinuosity in various landforms. Within each major category are six additional types delineated by dominate channel materials from bedrock to silt/clay along a continuum of gradient ranges. Recent stream type data used to further define classification interrelationships were derived from 450 rivers throughout the U.S, Canada, and New Zealand. Data used in the development of this classification involved a great diversity of hydro-physiographic/geomorphic provinces from small to large rivers and in catchments from headwater streams in the mountains to the coastal plains. A stream hierarchical inventory system is presented which utilizes the stream classification system. Examples for use of this stream classification system for engineering, fish habitat enhancement, restoration and water resource management applications are presented. Specific examples of these applications include hydraulic geometry relations, sediment supply/availability, fish habitat structure evaluation, flow resistance, critical shear stress estimates, shear stress/velocity relations, streambank erodibility potential, management interpretations, sequences of morphological evolution, and river restoration principles.
1,642 citations
Cites background from "Hydraulics of High-Gradient Streams..."
...Another recommended application to roughness estimation is to develop specific relations of roughness and associated velocity as recently developed for “mountain streams” by Jarrett (1984, 1990)....
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...Another recommended application to roughness estimation is to develop specific relations of roughness and associated velocity as recently developed for “mountain streams” by Jarrett (1984, 1990) ....
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TL;DR: In this paper, an overview is given of empirical relationships that can be used to estimate the most important parameters of debris-flow behavior, including peak discharge, the mean flow velocity, the total travel distance, and the runout distance on the fan.
Abstract: The assessment of the debris flow hazard potential has to rely on semi-quantitative methods. Due to the complexity of the debris-flow process, numerical simulation models of debris flows are still limited with regard to practical applications. Thus, an overview is given of empirical relationships that can be used to estimate the most important parameters of debris-flow behavior. In a possible procedure, an assessment of a maximum debris-flow volume may be followed by estimates of the peak discharge, the mean flow velocity, the total travel distance, and the runout distance on the fan. The applicability of several empirical equations is compared with available field and laboratory data, and scaling considerations are used to discuss the variability of the parameters over a large range of values. Some recommendations are made with regard to the application of the presented relationships by practicing engineers, apart from advocating field reconnaissance and searching for historic events wherever possible.
662 citations
01 Jan 1996
TL;DR: HEC-RAS (River Analysis System) is an integrated system of software, designed for interactive use in a multi-tasking environment, that is the successor to the current steady-flow HEC-2 (HEC, 1991) Water Surface Profiles Program.
Abstract: HEC-RAS (River Analysis System) is an integrated system of software, designed for interactive use in a multi-tasking environment. The system is comprised of a graphical user interface (GUI), separate hydraulic analysis components, data storage and management capabilities, graphical and tabular output, and reporting facilities. HEC RAS (HEC, 1996) is the successor to the current steady-flow HEC-2 (HEC, 1991) Water Surface Profiles Program. The capabilities of the current version of HEC-RAS will be described.
394 citations
TL;DR: A complex sequence of pyroclastic flows and surges erupted by Nevado del Ruiz volcano on 13 November 1985 interacted with snow and ice on the summit ice cap to trigger catastrophic lahars (volcanic debris flows), which killed more than 23,000 people living at or beyond the base of the volcano.
361 citations
TL;DR: In this paper, a non-dimensional hydraulic geometry equation with different parameters for deep and shallow flows, and a variable power resistance equation that is asymptotic to roughness-layer formulations for shallow flows and to the Manning-Strickler approximation of the logarithmic friction law for deep flows are proposed.
Abstract: [1] Alternative general forms are considered for equations to predict mean velocity over the full range of relative submergence experienced in gravel- and boulder-bed streams. A partial unification is suggested for some previous semiempirical models and physical concepts. Two new equations are proposed: a nondimensional hydraulic geometry equation with different parameters for deep and shallow flows, and a variable-power resistance equation that is asymptotic to roughness-layer formulations for shallow flows and to the Manning-Strickler approximation of the logarithmic friction law for deep flows. Predictions by existing and new equations using D84 as roughness scale are compared to a compilation of measured velocities in natural streams at relative submergences from 0.1 to over 30. The variable-power equation performs as well as the best existing approach, which is a logarithmic law with roughness multiplier. For predicting how a known or assumed discharge is partitioned between depth and velocity, a nondimensional hydraulic geometry approach outperforms equations using relative submergence. Factor-of-two prediction errors occur with all approaches because of sensitivity to operational definitions of depth, velocity, and slope, the inadequacy of using a single grain-size length scale, and the complexity of flow physics in steep shallow streams.
310 citations
References
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Book•
01 Jan 1959
TL;DR: This book discusses the development of Uniform Flow and its applications, as well as the theory and analysis of open channel flow, and the design of channels for Uniform Flow.
Abstract: Chapter 1: Basic PrinciplesChapter 2: Open-Channel Flow and its ClassificationsChapter 3: Open Channels and Their PropertiesChapter 4: Energy and Momentum PrinciplesChapter 5: Critical Flow: Its Computation and ApplicationsChapter 6: Uniform FlowChapter 7: Development of Uniform Flow and Its FormulasChapter 8: Computation of Uniform FlowChapter 9: Design of Channels for Uniform FlowChapter 10: Theoretical Concepts of Boundary LayerChapter 11: Surface RoughnessChapter 12: Velocity Distribution and Instability of Uniform FlowChapter 13: Gradually Varied FlowChapter 14: Theory and AnalysisChapter 15: Methods of ComputationChapter 16: Practical ProblemsChapter 17: Spatially Varied FlowChapter 18: Rapidly Varied FlowChapter 19: Flow Over SpillwaysChapter 20: Hydraulic Jump and its Use as Energy DissipatorChapter 21: Flow in Channels of Non-Linear AlignmentChapter 22: Flow Through Nonprismatic Channel SectionsChapter 23: Unsteady FlowChapter 24: Gradually Varied Unsteady FlowChapter 25: Rapidly Varied Unsteady Flow Flood RoutingAppendices
5,013 citations
TL;DR: In this paper, the size of material on the bed of a stream is determined based on an analysis of the relative area covered by particles of given sizes, which is applicable to those rivers which flow on coarse material and may be waded during periods of low water.
Abstract: This determination of the size of material on the bed of a stream is based upon an analysis of the relative area covered by particles of given sizes The method is applicable to those rivers which flow on coarse material and may be waded during periods of low water Sampling consists of measuring the intermediate axis of 100 pebbles picked from the bed of the channel on the basis of a grid system From this sample a frequency distribution is drawn from which the desired size parameters are read The advantages of the areal sampling procedure over bulk sampling are (1) that it is applicable to very coarse materials, and (2) that it provides a more representative sample of an entire reach of a stream
2,300 citations
TL;DR: In this article, the shape and roundness of sedimentary particles are determined from the long, intermediate, and short diameters of the particles, and their roundness is measured by a rapid visual method.
Abstract: Methods are described for the rapid measurement of shape and roundness of large sedimentary particles. Shape is determined from the long, intermediate, and short diameters of the particles, and roundness is measured by a rapid visual method. The importance of distinguishing between these properties is discussed. Shape and roundness behave differently during abrasion and selective transport, and hence are important in evaluating the effects of these processes during the formation of the deposit.
1,075 citations