Application of hydraulic insight obtained from the HYDRoSWOT data set to the estimation of high flows in large rivers

Abstract:

A comprehensive and publicly accessible U.S. Geological Survey (USGS) HYDRoacoustic dataset in support of Surface Water Oceanographic Topography (HYDRoSWOT) was derived from the USGS National Water Information System archive of acoustic Doppler current profiler river discharge measurements for a wide range of rivers throughout the United States (US). The data set summarizes the hydraulic characteristics of river cross sections in the US. Preliminary analysis of the data set, filtered for quality control, indicates that rivers tend toward consistent and predictable hydraulic characteristics as discharge increases, including the width to depth ratio, the Froude number, the ratio of maximum to mean depth, and ratio of the mean velocity to maximum velocity. The predictable characteristics of hydraulic cross-sections for relatively large river discharges, as inferred to be representative of a hydraulic reach, provide an opportunity to simplify the measurement of discharge of large river systems from remote platforms, including the upcoming Surface Water Ocean Topography mission. We have explored the application of these predictable relations to estimate high river discharge in several rivers in the US. The estimates demonstrate how river discharge in large rivers can be obtained from remote observations of width and stage, provided the elevation of the bottom relative to the elevation of the water surface in the channel is known or can be inferred from the observations. We also explore additional implications of the characteristic hydraulic relations not only from the standpoint of measurement applications, but also for basic research of the hydraulics of river flow.