Improved Water Resource Management Using an Acoustic Pulsed Doppler Sensor in a Shallow Open Channel

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26 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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Improved Water Resource Management
Using an Acoustic Pulsed Doppler
Sensor in a Shallow Open Channel

MIKE COOK, PHD

Irrigation Australia

July
-

2012

Background



Less than 1% of freshwater worldwide is accessible to
humans


-

Climate change, drought


-

Water scarcity



Agriculture represents 70% of freshwater use


-

Efficient use essential for
ag

production & water savings


-

Irrigation upgrades


flow matters


-

Flow data is often “good enough”



Many governments are mandating flow monitoring


-

Australia Bureau of Meteorology


-

California Water Resources Act



Accurately measuring flow is increasingly important


2

Development Goals



Understand shallow and complex flow

-
Turnout or irrigation ditch



Leverage SonTek expertise in pulsed Doppler
technology

-
Better measurement for end users


Reduce high cost of instrument hardware


Including installation with minimal or no earthworks



An accurate flow measurement

-
International requirements (Australia and California)

-
Better delivery information


save water



Work in as shallow water as possible

-
Low flows add up over time


3

Development


Data Collection

Phase 1 of SBIR from the USDA



More than 100 FlowTracker
measurements in small channels

-
Understand complex flow conditions

-
In many cases more than 100 points

-
Isovel

maps



Data used to determine

-
Beam angles

-
Proprietary flow algorithms


4

Disclaimer:
This material is based upon work supported by the Cooperative State Research, Education, and Extension Service, U.S.
Department of Agriculture, under Agreement No. 2008
-
33610
-
19458.


Any opinions, findings, conclusions, or recommendations
expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agri
cul
ture


Development


Hardware

Phase 2 of SBIR




Relies on Pulsed
-
Doppler technique using timing
controllers to profile water velocity in discrete layers



Newly developed High Definition feature can profile cells 2
cm apart (SmartPulse
HD
)



Low profile designed to operate in 8 cm of water



Beam geometry selected based on Phase I work



Profiles the vertical and horizontal distribution of velocities



Flow tested against known USGS ratings



5

End Product


SonTek IQ

6



Bottom mounted / up
-
looking pulsed Doppler profiler (3MHz)

-
Measures water level

-
Measures water velocity


Calculates flow and total volume

-
Measure temperature



Adaptive velocity sampling via SmartPulse
HD



Communications via RS232, SDI
-
12, Modbus



External power source 8
-
15 VDC



Developed with a grant from the USDA and significant
feedback from California Polytechnic University and the
University of Illinois

SonTek IQ Attributes

7

Skew Beam

Skew Beam

Along Axis Beam
(upstream)

Along Axis Beam
(downstream)



Velocity profiling beams (4)


3MHz


-

Along axis beams (2), 25
°

off vertical axis


Profiles velocity along channel axis


-

Skew beams (2), 60
°

off vertical axis & 60
°

off center axis


Profiles velocity in shallow water and off central axis

Profiles the horizontal and vertical distribution of velocities

SonTek IQ Attributes

8

Temperature Sensor

Water Level Measurement


-

Vertical Beam


-

Pressure Sensor


(flow through cell)


Water level measured by vertical beam and pressure sensor


-

Work in tandem to provide best possible water level data


-

Calculates cross
-
sectional area of flow from area rating



High resolution temperature sensor


-

Provides data for speed of sound correction


-

More accurate velocity = more accurate flow data


SonTek IQ Attributes

9

Mounting
Bracket

Power and
Communications
connector



Five conductor cable (connector
not

wet mateable)


-

Communications: RS232, SDI12, ModBus


-

Power requirements: 8
-

15 VDC



Mounting brackets


-

Allows for easy installation, two screws 5" (12.7 cm) apart


-

Additional options for mounting
-

underside of the instrument (3
-

brass inserts)


Multi
-
beam profiling with SmartPulse
HD

10


Multiple profiling beams sample more or the water


Maps horizontal and vertical distribution of velocities


Adaptively samples velocity using three acoustic
techniques


Pulse coherent, Pulse incoherent and Broadband


Selects acoustic technique based on:


Water depth


Water Velocity


Turbulence


Benefit for end
-
users


Reduces noise in the data


Provides best possible flow data

SonTek IQ Data


Velocity Profile

11

IQ SmartPulse
HD

Technology

30 Second Average

Velocity profiles below are the same test facility
in
similar flow
conditions


more data & less noise = better measurement



Older Doppler Technology

60 Second Average

1
1.2
1.4
1.6
1.8
2
2.2
0
0.5
1
1.5
2
2.5
Velocity (ft/s)
Depth (ft)
0.8
1
1.2
1.4
1.6
1.8
2
0
0.5
1
1.5
2
2.5
Velocity (ft/s)
Depth (ft)
Application/Concept

12

The SonTek IQ minimizes earthworks


in many cases decision makers are
building a section for a magmeter or installing a control section made of
concrete (weirs, ramp flumes, etc.).

Cocopah Test Site

13



Site near Yuma, AZ



Cooperation of USGS (Yuma)



Upstream


culvert outlet (15m)



Downstream


ramp flume (10m)



IQ installed in trapezoidal canal



Cleaned cross
-
section (important)



Custom mounting frame



Comparison data



Rating curve (water level via radar)



FlowTracker measurements


Complex site due to backwater effect

Cocopah Test Site


Instrument Configuration

14



USGS uses water
level as a surrogate
for flow (radar) with
periodic gagings
(15/3)




5 minute
Sampling interval, 3
minute Averaging
interval




IQ installed on
custom railing,
elevated from
bottom (0.31 ft)

Cocopah Test Data

15

1

2

3

Cocopah Test Results

16

Water
Level (ft)

IQ Flow
(cfs)

Reference
(cfs)

% Error

Comparison

1

1.89

13.84

13.48


2.6

Comparison

2

2.12

17.80

18.49*

-
3.7

Comparison

3

2.06

16.48

16.85*

-
2.2

*FlowTracker comparison data


USGS Gage data

Average error =
-
2.8%

Ypsilanti Test Site Information

17



Site near
Winterhaven
, AZ



Cooperation of USGS (Yuma)



Upstream


culvert outlet (10m)



Downstream


broad crested weir (20m)



IQ installed just under walkway



Traditionally a difficult site



Broad crested weir


small changes in
level means large changes in flow



Cleaned cross
-
section (important)



Comparison data



Rating curve (water level via bubbler)



FlowTracker measurements

Ypsilanti Test Site


Instrument Configuration

18



USGS uses water
level as a surrogate
for flow with
periodic gagings
(15/3)




3 minute
Sampling interval, 3
minute Averaging
interval




IQ Installed with
weighted mount,
slightly raised

Ypsilanti Test Data

19

1

2

3

4

Ypsilanti Test Results

20

Water
Level (ft)

IQ Flow
(cfs)

Reference
(cfs)

%

Error

Comparison

1

1.81

18.73

19.01


1.1

Comparison

2

1.58

8.36

8.45


1.4

Comparison 3

1.90

23.85

24.33


1.6

Comparison

4

2.19

43.70

43.25*

1.0

* FlowTracker comparison made measured 42.07 cfs

Average error = 1.28%


USGS gage data

IQ Data Summary and Conclusions

21



SonTek
-
IQ

was installed at traditional irrigation sites



Compared to rating curves and discreet measurements



Sites were traditionally good for monitoring water level



Typically not ideal for a velocity sensors



SonTek
-

IQ performance



Flow rate was within 2.8% at Cocopah



Flow rate was within 1.3% at Ypsilanti



Average error for the two sites was 1.9%



Better data means better decisions and save water



Reliable data immediately after install



No indexing was required



Velocity data is crucial for irrigation monitoring