Improved Water Resource Management Using an Acoustic Pulsed Doppler Sensor in a Shallow Open Channel MIKE COOK, PHD Irrigation Australia July

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 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 Agriculture

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 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: 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

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

Cocopah Test Results 16 Water Level (ft) IQ Flow (cfs) Reference (cfs) % Error Comparison † 2.6 Comparison *-3.7 Comparison *-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

Ypsilanti Test Results 20 Water Level (ft) IQ Flow (cfs) Reference (cfs) % Error Comparison † 1.1 Comparison † 1.4 Comparison † 1.6 Comparison *1.0 * FlowTracker comparison made measured 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