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At least 19 recordsLinked to original sources
USGS2005

Streamflow properties from time series of surface velocity and stage

Time series of surface velocity and stage have been collected simultaneously. Surface velocity was measured using an array of newly developed continuous-wave microwave sensors. Stage was obtained from the standard U.S. Geological Survey (USGS) measurements. The depth of the river was measured several times during our experiments using sounding weights. The data clearly showed that the point of zero flow was not the bottom at the measurement site, indicating that a downstream control exists. Fathometer measurements confirmed this finding. A model of the surface velocity expected at a site having a downstream control was developed. The model showed that the standard form for the friction velocity does not apply to sites where a downstream control exists. This model fit our measured surface velocity versus stage plots very well with reasonable values of the parameters. Discharges computed using the surface velocities and measured depths matched the USGS rating curve for the site. Values of depth-weighted mean velocities derived from our data did not agree with those expected from Manning's equation due to the downstream control. These results suggest that if real-time surface velocities were available at a gauging station, unstable stream beds could be monitored. Journal of Hydraulic Engineering ?? ASCE.

Journal of Hydraulic Engineering↗
USGS2005

Wash load and bed-material load transport in the Yellow River

It has been the conventional assumption that wash load is supply limited and is only indirectly related to the hydraulics of a river. Hydraulic engineers also assumed that bed-material load concentration is independent of wash load concentration. This paper provides a detailed analysis of the Yellow River sediment transport data to determine whether the above assumptions are true and whether wash load concentration can be computed from the original unit stream power formula and the modified unit stream power formula for sediment-laden flows. A systematic and thorough analysis of 1,160 sets of data collected from 9 gauging stations along the Middle and Lower Yellow River confirmed that the method suggested by the conjunctive use of the two formulas can be used to compute wash load, bed-material load, and total load in the Yellow River with accuracy. Journal of Hydraulic Engineering ?? ASCE.

Journal of Hydraulic Engineering↗
USGS2004

Flow resistance and suspended load in sand-bed rivers: Simplified stratification model

New methods are presented for the prediction of the flow depth, grain-size specific near-bed concentration, and bed-material suspended sediment transport rate in sand-bed rivers. The salient improvements delineated here all relate to the need to modify existing formulations in order to encompass the full range of sand-bed rivers, and in particular large, low-slope sand-bed rivers. They can be summarized as follows: (1) the inclusion of density stratification effects in a simplified manner, which have been shown in the companion paper to be particularly relevant for large, low-slope, sand-bed rivers; (2) a new predictor for near-bed entrainment rate into suspension which extends a previous relation to the range of large, low-slope sand-bed rivers; and (3) a new predictor for form drag which again extends a previous relation to include large, low-slope sand-bed rivers. Finally, every attempt has been made to cast the relations in the simplest form possible, including the development of software, so that practicing engineers may easily use the methods. ?? ASCE.

Journal of Hydraulic Engineering↗
USGS2003

Discharge rating equation and hydraulic characteristics of standard Denil fishways

This paper introduces a new equation to predict discharge capacity in the commonly used Denil fishway using water surface elevation in the upstream reservoir and fishway width and slope as the independent variables. A dimensionless discharge coefficient based only on the physical slope of the fishway is introduced. The discharge equation is based on flow physics, dimensional analysis, and experiments with three full-scale fishways of different sizes. Hydraulic characteristics of flow inside these fishways are discussed. Water velocities decreased by more than 50% and remained relatively unchanged in the fully developed flow downstream of the vena contracta region, near the upstream baffle where fish exit the fishway. Engineers and biologists need to be aware of this fact and ensure that fish can negotiate the vena contracta velocities rather than velocities within the developed flow region only. Discharge capacity was directly proportional to the fishway width and slope. The new equation is a design tool for engineers and field biologists, especially when designing a fishway based on flow availability in conjunction with the swimming capabilities of target fish species.

Journal of Hydraulic Engineering↗
USGS2023

Discharge estimation using video recordings from small unoccupied aircraft systems

Measurement of river discharge during flooding events has especially been a challenging and dangerous task in the southwestern US, where flows can be flashy, laden with sediment, and at high velocity. Small unoccupied aircraft systems (sUAS) can be deployed to access unsafe field sites and capture imagery for measuring surface flow velocity and discharge. This paper compares flow discharge estimation at eight field sites—located at or near USGS gauging stations—using time-averaged surface velocities and the turbulence dissipation rate (TDR) derived from large-scale particle image velocimetry (LSPIV) analysis of sUAS videos with conventional measurement techniques conducted by professional USGS hydrographers. Sites characteristics include both natural and engineered channels. The conventional measured discharges were treated as the reference discharges for evaluating the accuracy of the LSPIV discharge estimates. This study evaluated four approaches to estimate the depth-averaged or cross-sectional averaged velocity: constant-velocity index, logarithmic law, power-law, and the entropy method. Results showed the discharges can be accurately calculated by using any of these methods, and that choice of method depended on width to depth ratios.

Journal of Hydraulic Engineering↗
USGS1983

Mixed-station extension of monthly streamflow records.

Monthly streamflow records at a site are sometimes extended by exploiting interstation correlation of streamflow, often through simple linear regression with a base station having a long-term record. An approach is presented which selects a base station from among several in a region for filling in missing data. It differs from traditional approaches in that different stations can be selected as the base station to fill in different values. Application of the approach demonstrated large reductions in the streamflow prediction error for two sites in Colorado.-from ASCE Publications Information

Journal of Hydraulic Engineering↗
USGS1983

Rainfall intensity-duration-frequency formulas.

A new general rainfall intensity-duration-frequency formula is presented, utilizing a method similar to, but more accurate than one previously developed. The previously developed formula was based on the average depth-duration ratio of about 40% and the mean depth-frequency ratio of 1.48. It is shown that this formula is only a particular form of the writer's more general formulation. -from Author

Journal of Hydraulic Engineering↗
USGS1984

Flash flood in Tangue Verde Creek, Tucson, Arizona.

The flood of July 26, 1981, in Tanque Verde Creek east of Tucson, Arizona, that killed eight people near Tanque Verde Falls was just a small one for this stream. Dangerous floods are not necessarily large ones; two much larger floods occurred there within a week. Floods can travel for miles at rates of rise and speeds too great for a person to escape from rough stream channels. -from ASCE Publications Information

Journal of Hydraulic Engineering↗
USGS1984

Potential flow through channel constriction.

Potential flow through an eccentric, normal constriction of zero thickness in an infinitely long, straight channel of constant width and unit depth is studied by use of a Schwarz-Christoffel transformation. The transformation is integrated by a direct approach. Parametric equations for streamlines are obtained and used to compute an average streamline length for a potential-flow field. -from ASCE Publications Information

Journal of Hydraulic Engineering↗
USGS1988

Generalized viscoplastic modeling of debris flow

Various concepts have been proposed or used in the development of Theological models for debris flow. The earliest model developed by Bagnold was based on the concept of the “dispersive” pressure generated by grain collisions. Bagnold's concept appears to be theoretically sound, but his empirical model has been found to be inconsistent with most theoretical models developed from non‐Newtonian fluid mechanics. Although the generality of Bagnold's model is still at issue, debris‐flow modelers in Japan have generally accepted Takahashi's formulas derived from Bagnold's model. Some efforts have recently been made by theoreticians in non‐Newtonian fluid mechanics to modify or improve Bagnold's concept or model. A viable rheological model should consist both of a rate‐independent part and a ratedependent part. A generalized viscoplastic fluid (GVF) model that has both parts as well as two major rheological properties (i.e., the normal stress effect and soil yield criterion) is shown to be sufficiently accurate, yet practical, for general use in debris‐flow modeling. In fact, Bagnold's model is found to be only a particular case of the GVF model. Analytical solutions for (steady) uniform debris flows in wide channels are obtained from the GVF model based on Bagnold's simplified assumption of constant grain concentration.

Journal of Hydraulic Engineering↗
USGS1988

General solutions For viscoplastic debris flow

Theoretical velocity profile and theoretical pressure and concentration distributions for (steady) uniform debris flow in wide channels are derived from a generalized viscoplastic fluid (GVF) model without imposing R. A. Bagnold's assumption of constant grain concentration. Good agreement between the theoretical velocity profile and the experimental data of Japanese scientists strongly supports the validity of both the GVF model and the proposed method of solution from the model. It is shown that both E. C. Bingham and Bagnold versions (or submodels) of the GVF model can be used to simulate debris flow at the dynamic state. Although Bagnold's dilatant submodel appears to fit the Japanese data better than the Bingham submodel for flow of noncohesive grains, the choice between them is by no means clear-cut.

Journal of Hydraulic Engineering↗
USGS1988

General two‐point method for Determining velocity in open channel

The generally accepted procedure is to average velocity measurements at 0. 2D and 0. 8D, measured vertically from the water surface,or alternatively to measure velocity at a position equal to 0. 6D, where D is the total depth of flow. In some situations, one may wish to measure at depths other than 0. 2D and 0. 8D. For instance, a temporary stream gage may be continuously monitoring velocity with two probes located at fixed vertical positions. As the total depth changes, the relative measurement position changes. This paper presents a general two-point method that can be used to determine the depth-averaged velocity when measurements at two arbitrary but known depths are available.

Journal of Hydraulic Engineering↗
USGS1988

Groundwater velocity magnitude in radionuclide transport calculations

Analytical solutions have been developed for many conceptual models of solute transport in groundwater (Bear 1979). Although these models usually rely on assumptions too restrictive for accurate description of actual field situations, they are useful in understanding groundwater transport and in evaluating the relative importance of the subsurface processes affecting transport. In addition, these simple models are often used for generic and screening-type analyses of groundwater contamination problems (Kent et al. 1985). For example, the Nuclear Regulatory Commission assesses potential doses resulting from the disposal of very slightly contaminated material in the ground using analytical solutions for one- and two-dimensional groundwater transport (Codell and Schreiber 1979; Codell et al. 1982; Goode et al. 1986). This note presents a method for determining a "worst-case" groundwater velocity value for two conceptual models of decaying radionuclide transport, resulting in maximum calculated point concentration.

Journal of Hydraulic Engineering↗
USGS1988

Comprehensive method of characteristics models for flow simulation

The use of the specified time interval (STI) numerical schemes has been popular in applying the method of characteristics (MOC) to unsteady open‐channel flow problems. Studies and analyses of several variants of the STI schemes have led to the derivation of a new scheme, referred to herein as the multimode scheme, which combines implicit, temporal reachback, spatial reachback, and classical schemes into one. Three numerical models have been developed to implement the implicit and multimode schemes. The IMOCDS model uses an implicit scheme, with which the time step is no longer subject to the Courant constraint. The remaining two models, NEWMOC and SPRMOC, are two versions of the multimode scheme. The NEWMOC and SPRMOC models demonstrate all the advantages previously provided by individual STI schemes, cover the combined flow range of the various schemes involved, and, in addition, display newly acquired benefits such as robustness. Numerical analyses, numerical experiments, and field applications that verify, support, and demonstrate the enhanced model capabilities are presented.

Journal of Hydraulic Engineering↗
USGS1989

Comparison: US P-61 and Delft sediment samplers

The Delft Bottle (DB) is a flow-through device designed by the Delft Hydraulic Laboratory (DHL), The Netherlands, to sample sand-sized sediment suspended in streams. The US P-61 sampler was designed by the Federal Interagency Sedimentation Project (FISP) at the St. Anthony Falls Hydraulic Laboratory, Minneapolis, Minnesota, to collect suspended sediment from deep, swift rivers. The results of two point-sampling tests in the United States, the Mississippi River near Vicksburg, Mississippi, in 1983 and the Colorado River near Blythe, California, in 1984, are provided in this report. These studies compare sand-transport rates, rather than total sediment-transport rates, because fine material washes through the DB sampler. In the United States, the commonly used limits for sand-sized material are 0.062 mm to 2.00 mm (Vanoni 1975).

Journal of Hydraulic Engineering↗
USGS1989

Mass conservation: 1-D open channel flow equations

Unsteady flow simulation in natural rivers is often complicated by meandering channels of compound section. Hydraulic properties and the length of the wetted channel may vary significantly as a meandering river inundates its adjacent floodplain. The one-dimensional, unsteady, open-channel flow equations can be extended to simulate floods in channels of compound section if it is assumed that the lateral velocities are negligible, the water surface is level across the section, and the effects of turbulence and friction may be adequately described by resistance laws used for uniform flow. It is shown that the equations derived from the addition of differential equations individually describing flow in main and overbank channels do not conserve mass when overbank and main channels are of different lengths. Equations derived through the use of appropriate integral relations, however, do conserve mass and momentum in the general case and are not limited to the specification of one main and two overbank channels.

Journal of Hydraulic Engineering↗