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D.M. Bjerklie

Publications and source records attributed to D.M. Bjerklie.

2 recordsLinked to original sources

Estimating the bankfull velocity and discharge for rivers using remotely sensed river morphology information

A method to estimate the bankfull velocity and discharge in rivers that uses the morphological variables of the river channel, including bankfull width, channel slope, and meander length was developed and tested. Because these variables can be measured remotely from topographic and river alignment information derived from aerial photos and satellite imagery, it is possible that the bankfull state of flow can be estimated for rivers entirely from remotely-sensed information. Defining the bankfull hydraulics of rivers would also provide a reference condition for remote tracking of dynamic variables including width, stage, and slope, and for quantifying relative change in flow conditions of rivers over large regions. This could provide a more efficient method to inventory and quantify river hydraulic attributes and dynamics.

Journal of Hydrology

Estimating discharge in rivers using remotely sensed hydraulic information

A methodology to estimate in-bank river discharge exclusively from remotely sensed hydraulic data is developed. Water-surface width and maximum channel width measured from 26 aerial and digital orthophotos of 17 single channel rivers and 41 SAR images of three braided rivers were coupled with channel slope data obtained from topographic maps to estimate the discharge. The standard error of the discharge estimates were within a factor of 1.5-2 (50-100%) of the observed, with the mean estimate accuracy within 10%. This level of accuracy was achieved using calibration functions developed from observed discharge. The calibration functions use reach specific geomorphic variables, the maximum channel width and the channel slope, to predict a correction factor. The calibration functions are related to channel type. Surface velocity and width information, obtained from a single C-band image obtained by the Jet Propulsion Laboratory's (JPL's) AirSAR was also used to estimate discharge for a reach of the Missouri River. Without using a calibration function, the estimate accuracy was +72% of the observed discharge, which is within the expected range of uncertainty for the method. However, using the observed velocity to calibrate the initial estimate improved the estimate accuracy to within +10% of the observed. Remotely sensed discharge estimates with accuracies reported in this paper could be useful for regional or continental scale hydrologic studies, or in regions where ground-based data is lacking. ?? 2004 Elsevier B.V. All rights reserved.

Journal of Hydrology