A method is evaluated for estimating the longitudinal dispersion coefficient K from velocities and bathymetry measured with an acoustic Doppler current profiler (ADCP). If shear controls mixing, can be estimated measurements of velocity depth in a cross section. The has typically been by costly time-consuming tracer studies because field could not resolved sufficiently before flow changed. However, ADCP transects, which now are routinely used to measure discharge, provide detailed data...

First posted August 25, 2020 For additional information, contact: Director, Dakota Water Science CenterU.S. Geological Survey821 East Interstate AvenueBismarck, ND 585031608 Mountain View RoadRapid City, SD 57702 Streamflow estimates for floods with an annual exceedance probability of 0.001 or lower are needed to accurately portray risks critical infrastructure, such as nuclear powerplants and large dams. However, extrapolating flood-frequency curves developed from at-site systematic...

Many hydrologic and hydraulic (H&H) engineering applications require spatial rainfall distribution over a watershed, but point precipitation frequency estimates, such as those provided by NOAA Atlas 14, are only applicable for relatively small areas. For larger areas, areal reduction factors (ARFs) commonly used to transform estimate of given duration corresponding estimate. The most common source ARFs the United States is Technical Paper 29 (TP-29), published in 1958, although there have...

Estimating the storm surge magnitude and annual exceedance probability is a key element in siting design of coastal nuclear power plants both U.S. France. However, differences climatology, specifically relative importance tropical cyclones (TCs) versus extratropical storms (XTCs), have driven estimation method development. This work compares purely statistical modeling with combined numerical simulation approaches for extreme applied to North Atlantic coast which subject storms. Two...

A numerical model was used to better understand ice-related scour processes at a large lock and dam. Large holes in front of Melvin Price Lock Dam, the largest navigation structure on Mississippi River, present unique opportunity explore this effect because has been so severe well documented. Likely scenarios for river ice accumulation passage were identified based historical flows observations. For all simulations, accumulated upstream gates as observed field thicknesses found match with...

Multimechanism floods (MMFs) are caused by the simultaneous occurrence of more than one flood mechanism such as storm surge, precipitation, tides, and waves. MMFs can lead to severe or differing impacts single-mechanism floods. As a result, comprehensive risk assessments require ability assess multivariate probabilistic behaviors hazards from MMFs. This study introduces novel Bayesian-motivated approach for assessment hurricane-induced combination river antecedent flow. A Bayesian network...

In designing flood control projects, engineers must show that the proposed project provides a damage reduction benefit in economic terms. For ice structures, however, cost benefits have rarely been calculated at time of construction because uncertainty associated with ice-affected flooding. This work presents quantitative method for assessing financial such structures since installation. Oil City, located confluence Allegheny River and Creek Pennsylvania, experienced frequent jam flooding...

We evaluate the use of river velocity and bathymetry data measured with an acoustic Doppler current profiler (ADCP) to estimate longitudinal dispersion coefficient K. If shear controls mixing, can be estimated from a theoretical formula involving measurements in cross section. The has typically been by costly time consuming tracer studies rather than evaluating because field could not resolved sufficiently before flow changed. However, ADCP transects, which now are routinely used measure...

McMurdo Station watershed in Antarctica is one of the southernmost basins that annually experiences active water flow during austral summer. This runoff, primarily from snowmelt, has daily and seasonal fluctuations. The fluctuation variation depend on air temperature many other factors. At times, extreme runoff occurred at such overflows across roads bypasses culverts, creating disruption massive erosion. Knowing when peak occurs critical for operation maintenance channels. We conducted an...

We evaluate the use of river velocity and bathymetry data measured with an acoustic Doppler current profiler (ADCP) to estimate longitudinal dispersion coefficient K. Whenever mixing is controlled by shear dispersion, can be estimated from a theoretical formula that relies on measurements in cross section. The relative ease detail which ADCPs measure velocities allows greater frequency spatial coverage U.S. rivers. conducted simultaneous ADCP tracer Kissimmee River South Florida under...