Scientific Investigations Report 2009-5080
ABSTRACTSt. Clair River is a connecting channel that transports water from Lake Huron to the St. Clair River Delta and Lake St. Clair. A negative trend has been detected in differences between water levels on Lake Huron and Lake St. Clair. This trend may indicate a combination of flow and conveyance changes within St. Clair River. To identify where conveyance change may be taking place, eight water-level gaging stations along St. Clair River were selected to delimit seven reaches. Positive trends in water-level fall were detected in two reaches, and negative trends were detected in two other reaches. The presence of both positive and negative trends in water-level fall indicates that changes in conveyance are likely occurring among some reaches because all reaches transmit essentially the same flow. Annual water-level fall in reaches and reach lengths was used to compute conveyance ratios for all pairs of reaches by use of water-level data from 1962 to 2007. Positive and negative trends in conveyance ratios indicate that relative conveyance is changing among some reaches. Inverse one-dimensional (1-D) hydrodynamic modeling was used to estimate a partial annual series of effective channel-roughness parameters in reaches forming the St. Clair River for 21 years when flow measurements were sufficient to support parameter estimation. Monotonic, persistent but non-monotonic, and irregular changes in estimated effective channel roughness with time were interpreted as systematic changes in conveyances in five reaches. Time-varying parameter estimates were used to simulate flow throughout the St. Clair River and compute changes in conveyance with time. Based on the partial annual series of parameters, conveyance in the St. Clair River increased about 10 percent from 1962 to 2002. Conveyance decreased, however, about 4.1 percent from 2003 to 2007, so that conveyance was about 5.9 percent higher in 2007 than in 1962. |
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Holtschlag, D.J., and Hoard, C.J., 2009, Detection of conveyance changes in St. Clair River using historical water-level and flow data with inverse one-dimensional hydrodynamic modeling: U.S. Geological Survey Scientific Investigations Report 2009–5080, 39 p.
Abstract
Introduction
Study Area
Problem
Purpose and Scope
Data and Models Provided by Other Agencies
Flow Data
Conventional Current-Meter Measurements
Acoustic Doppler Current Profiler Measurements
Water-Level Data
The Standard 1-D Hydrodynamic Model of the St. Clair River
Model Schematization
Model Geometry and Parameterization
Approach
Water Levels at Gaging Stations
Water-Level Fall between Gages
Reach Conveyance
Conveyance Ratios
Inverse 1-D Hydrodynamic Modeling of the St. Clair River
1-D Hydrodynamic Model of the St. Clair River
Inverse Modeling
Nonlinear Regression
Parameter Convergence
Parameter Magnitudes and Uncertainties
Parameterization Strategy
Simulation of Flow under Annual Parameterizations Derived from Inverse Modeling
Results of Conveyance Analyses
Inferring Reach-Conveyance Changes from Water-Level Measurements
Water-Surface Fall
Conveyance Ratios
Inferring Changes in Reach Conveyance from 1-D Hydrodynamic-Model Parameters
Time-Varying Parameter Estimation
Effective Channel Roughness Estimated from Conventional Measurements
Effective Channel Roughness Estimated from Acoustic Doppler Current
Profiler Measurements
Fixed-Parameter Estimation
Scenario 1962 to 1968
Scenario 1981 to 1985
Scenario 1996 to 2007
Integration of Time-Varying and Fixed-Parameter Estimation Results
Effective Channel Roughness Ratios and Conveyance Ratios
Inferring Changes in River Conveyance from 1-D Hydrodynamic Simulations
Summary and Conclusions
Acknowledgments
References Cited