Benchmarking for using an acoustic Doppler current profiler for bathymetric survey

Area of Science:

• Geosciences
• Hydrography
• Environmental Engineering

Background:

• Acoustic Doppler Current Profilers (ADCPs) are valuable for measuring water currents but often require post-processing for accurate bathymetric data.
• Existing methods for ADCP depth data may lead to significant errors in volume estimations, necessitating improved techniques.

Purpose of the Study:

• To develop and validate a post-processing methodology for ADCP data to enhance depth accuracy and bathymetric results.
• To significantly reduce discrepancies in reservoir volume calculations compared to standard methods.

Main Methods:

• Applied a robust local regression method to remove outliers from raw ADCP data.
• Developed a linear regression model to adjust ADCP beam depths for improved accuracy.
• Validated the adjusted data using a scaled rod, Real-Time Kinematic (RTK) positioning, and a single beam echo sounder (SBES) in a control area.

Main Results:

• The proposed post-processing significantly reduced volume calculation discrepancies from 30% to under 1% when compared to SBES data.
• The standard deviation of depth measurements decreased from an average of 0.15 m to 0.03 m after applying the adjustment techniques.
• Statistical hypothesis tests confirmed the validity and improvement of the processed ADCP depth data.

Conclusions:

• Post-processing is essential for improving the quality of depth data obtained from ADCPs for bathymetric surveys.
• The developed methodology offers a reliable and accurate approach for estimating reservoir volumes using ADCP data.
• This technique enhances the utility of ADCPs in hydrographic surveys, particularly for volumetric assessments.