1. U.S. Geological Survey
Office of Surface Water

2. Partnership to Develop ADCP Standards
ERDC
Coastal and Hydraulics Laboratory
USGS
Office of Surface Water

3. ADCP 101 ADCP Conventional current meter Depth Cell
ADCP’s can be deployed from a boat or mounted on the streambed. This particular graphic shows an upward looking ADCP mounted on the stream bed. We mentioned the the ADCP measured a complete velocity profile. It is comparable to having a whole string of velocity meters deployed. It measures the velocity in discrete water layers by range gating the reflected acoustic energy. In other words it processes small parts of the entire echo individually thus producing multiple velocity measurements. The water layer is frequently referred to as a depth cell or bin. A measurement consisting of a single ping (burst of acoustic energy) can be made in less than a second. Typically a single profile measurement consist of several pings averaged together. Still the typical time for a profile measurement is 3-5 seconds.

4. Why ADCPs allow unprecedented data collection capabilities
ADCPs can collect inaccurate data if misapplied
USGS are using ADCPs in their operational program

5. Corps Data Collection Effort

6. Flow Homogeneity HOMOGENEOUS NONHOMOGENEOUS
Remember the Doppler shift is directional. The ADCP can only measure velocity parallel to the beams. To be useful we need to resolve those radial velocities into horizontal and vertical components. To do this, the assumption is made that all 4 beams are measuring a homogeneous volume of water. Remember the instrument is looking at four beams not the entire volume of water contained inside the boundary of the four beams.
What are the potential sources of error?
A vortex or eddy in one beam
Random errors
The error velocity gives a an indication or the flow homogeneity and is an indicator of the validity of the assumptions used to compute the horizontal and vertical velocity components.

7. Corps Data Collection Effort

8. Heave, Pitch, Roll Heave => Vertical Velocity
Pitch => Second Order Error
Roll => Second Order Error

9. Unmeasured Top and Bottom
The drawing shows the limitations of the measured velocity profile. Depth is lost near the water surface for the draft of the instrument and the blanking distance or dead band. All acoustic instruments have this dead band. It is the distance that sound travels while the ceramics of the transducer stop vibrating from having transmitted and reach a state that they can begin listening from a reflected acoustic energy.
Near the bottom the side lobe of the acoustic energy reflects of the stream bottom creating reflected acoustic energy that is of the same magnitude as the reflection of the main lobe off the scatterers in the water column near the bed. For most riverine systems this is 6% of the depth.

10. Who CHL USGS Michael Winkler Thad Pratt Terry Waller David Mueller
Chad Wagner
Kevin Oberg

11. Recommendations I Field Data Collection
Field crew needs to understand the use of the data
Compass must be calibrated
Slow boat speed
Collect single ping data
Field methods documented

12. Recommendations II Data Processing – ASCII Output
Review every transect in WinRiver
Set appropriate thresholds to filter data
Account for side lobe interference
Spatial averaging
must use vector averaging
Based on :
Instrument noise
Flow field
Desired spatial resolution
Account for unmeasured areas
Data processing methods documented

13. Recommendations III Data Processing – Raw Data Files Must apply
Boat speed
Compass heading/corrections
Side lobe interference
Generally not recommended unless you fully understand raw data files.

14. Test Plan Deliverables
What
Test Plan Deliverables
Technical Report on Discharge Measurements
Technical Report on Velocity Measurements
Processing Software (If Additional Funded)
Quick sheets for Discharge
Quick sheets for Velocity
Note Sheets for Discharge
Note Sheets for Velocity
Quick Sheets for Velocity Processing

15. When Oct 2006 Deliverables: TechNote (Study Plan)
Draft Discharge Sections:
Introduction
Predeployment
Field Procedures
Initiate Software Development (if funds are available).
Feb 2007
TechNote on Field Notes for Discharge
Quick sheets for Q measurements
Jul 2007
Velocity Software (if funding available)
Draft of remaining discharge report sections (less uncertainty)
Oct 2007
Uncertainty method for discharge (tentative)
Draft Discharge Measurement Guidance

16. POC’s
USGS, Mr. Dave Muelller
Corps, Mr. Michael Winkler

17. Corps Navigation Mission
Provide safe,reliable,efficient,effective and environmentally sustainable waterborne transportation systems for movement of commerce, national security needs, and recreation.

18. Lock and Dam 3 Barge sunk in dam gates August 1,1993
The outdraft current sweeps across the lock approach toward the gated part of the dam.
This makes downbound navigation very difficult during outdraft conditions, and has caused many navigation accidents.
Towboat pilots consider Lock and Dam 3 the most dangerous site on the upper river.
Only 4 roller gates
11 into-dam accidents since 1968

19. No Flow Entering Lock Approach
Outdraft
ETL Basham
Outdraft is defined as the flow in the upper lock approach that cannot be passed under or through the guard wall, and thereby moves across the upper lock approach or around the end of the guard wall and towards the dam. The outdraft, if severe, tends to move the head (bow) of the tow out of alignment with the guard wall and requires that the pilot increase maneuvering. EM
The effects on currents due to structures placed in a river depends principally on the configuration and alignment of the channel upstream and downstream therefrom and the amount of contraction and expansion in channel width produced by the obstruction.
The usual effect of the sudden channel contraction in the upper approach to the locks is an outdraft or crosscurrent that affects the movement of
a tow at a time when its rudder power is reduced because of reduced speed with respect to river currents. The intensity of the crosscurrents is
dependent on the total discharge affected by the structure and is a function of the velocity of currents approaching the structure, channel
depth, and width of channel affected by the structure, and, in some cases, by flow along the adjacent overbank. Since no two reaches of a
stream are identical, the intensity of the crosscurrents in the upper lock approach will vary according to the site selected and the orientation
of the structures with respect to the alignment of the channel and currents.
No Flow Entering Lock Approach

20. Tom Bevill Outdraft
Outdraft Currents

21. Tom Bevill – Confetti Picture
Can anyone locate the Outdraft Here??
Notice the Outdraft: Why we are here
Upstream View of the Model

22. Bull Nose Guard Wall

23. H-ADCP Doppler Unit
3 – Beam ADCP

24. H-ADCP Mount
H-ADCP Mounted

25. Separate Velocity Measurements - BINS
ADCP Measurements
Separate Velocity Measurements - BINS

26. Wind Meter

27. ADCP/Wind Control Station

28. Control Workstation

29. Current Vectors on IENC

30. Current Vectors on IENC