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EBMUD Flow Monitoring Technologies Evaluation
Study Presentation
BACWA Collection Systems Committee
MeetingFebruary 25, 2009
Kevin Krajewski, P.E.
V&A
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Acknowledgements
Sponsoring Agency -
Technical Assistance and Field Work -
Represented Companies
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Project Overview
Flow Monitoring Technologies Evaluation Study
• 31 Sites Monitored for Flow Monitoring and I/I Study– Pipe Sizes ranged from 8-inch diameter to 105-inch diameter
– Varying types of hydraulic conditions
• 5 Types of Open-Channel Flow Monitoring Technologies
• 10 Flow Meter Models made by 6 Manufacturers
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Site Locations
• 10 test site locations to allow for
direct comparison of flow data
• Site 27
• EBMUD District MH S45
• 84-inch RCP
• 6 different flow meters
installed and evaluated
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• Area-Velocity Flow Metering
– Q = V x A, whereQ = flowV = average velocityA = wetted cross sectional area
• Primary Devices (Weirs and Flumes)– Devices that alter flow in a predictable manner so that a known
relationship between flow and measured depth can be utilized
Requirements for Measuring Flows
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Types of Metering Technologies Evaluated
Technology Manufacturer Flow Meter Model# of Meters
installed
Continuous Wave Doppler
Teledyne IscoHachADS
2150Sigma 910FlowShark
16123
Pulse DopplerTeledyne IscoTeledyne Isco
ADS
ADFM AccQMin FlowShark Pulse
121
Radar Hach Marsh-McBirney Flo-Dar 6
Transit-Time ADS Accusonic 1
Custom Compound Weir
SFE Global SFE Global 2
Transit-Time with Flume
Accuron FlowScope 1
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Hach Sigma 920
Continuous – Wave Doppler
Field ofVelocity Measurement
Teledyne Isco 2150+ 2110
ADS Flow Shark
$6,000 - $7,000 $5,500 - $6,500 $6,500 - $7,500
O&M requirements – planned periodic (every 2 – 4 weeks)
Typical for temporary efforts.
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Pulse – Wave Doppler
Teledyne Isco ADFM Teledyne Isco AccQMin ADS Flow Shark Pulse
$17,000 - $19,000 $10,000 - $12,000 $10,000 - $14,000
O&M requirements – planned periodic (every 2 – 4 weeks)
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Radar
Hach Marsh-McBirney Flo-Dar
$10,000 - $12,000
O&M requirements -- responsive to questionable data and surcharge events
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Transit-Time
Accusonic Accuron FlowScope
>$20,000 $5,500 - $6,500
O&M requirements – planned periodic (every 2 – 4 weeks)
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Custom Compound Weir (CCW)
SFE Global
O&M requirements – planned periodic (every 2 – 4 weeks)
$16,000 - $17,000 Installed
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Flow Level and Submerged Pressure Transducers
• Submerged pressure transducer: measures the hydrostatic
pressure of the liquid above the transducer (proportional to
liquid level)
– Subject to fouling or “drift”
• Ultrasonic level meters transmit a pulse to the surface of the
liquid and measure the time it takes for the pulse to be
reflected back to the meter.– Down-looking (non-submerged) or Up-looking (submerged)
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Site 27 Level Data
15
20
25
30
35
40
45
25-Apr 26-Apr 27-Apr
Leve
l (in
)
SIGMA FlowSharkFloDar ADFM
Level Data
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• Accuracy and repeatability
• Uptime
• Installation/removal maneuverability
• O&M maintenance
• User-Friendliness (hardware & software)
• Compatibility (to Remote monitoring options)
• Connectivity
• Cost
Evaluation Criteria
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Analysis: Site 27
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
20-Mar 21-Mar 22-Mar
Velo
city
(fp
s)
ADFM FlowShark Pulse
SIGMA FloDar
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1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
18 20 22 24 26 28 30 32 34 36 38 40
Level (in.)
Vel
oci
ty (
fps
)
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
18 20 22 24 26 28 30 32 34 36 38 40
Level (in.)
Ve
loc
ity
(fp
s)
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
18 20 22 24 26 28 30 32 34 36 38 40
Level (in.)
Vel
oci
ty (
fps)
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
18 20 22 24 26 28 30 32 34 36 38 40
Level (in.)
Ve
loc
ity
(fp
s)
Sigma 910 ADFM
Flo-Dar Flow Shark Pulse
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A Marsh-McBirney Flo-Mate Portable Velocity Meter was used for velocity profiling. Multiple
point velocity readings were measured throughout the flow stream to create an accurate
velocity profile so as to determine average velocity. This is necessary with the Marsh-
McBirney Flo-Dar.
Velocity profiling was conducted multiple times at various times of the day (high flow, low flow,
etc.)
Flow
Velocity Profiling
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Analysis: Site 27
*velocity taken from period 3/20/2008 to 4/26/2008
Meter TypeAverage Velocity*
(fps)
Hach Sigma 910: 2.87
Teledyne Isco 2150: 2.61
Teledyne ADFM: 3.05
ADS FlowShark Pulse: 2.61
Hach Marsh-McBirney Flo-Dar: 2.95
Accusonic: 2.63
Average Velocity per Velocity Profiling:
2.91
Minimum/Maximum % Difference:
±8%
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• Regardless of manufacturer’s specifications, it cannot be assumed that
velocity measurements for any meter will be accurate within ±2%. Velocity
profiling should be conducted with any meter selected for use in a large
diameter pipe.
• Continuous-Wave Doppler flow meters are not appropriate for long term
installations in large (39” or greater) diameter pipes with flow depths of the
magnitude measured in Site 27.
Conclusions for Site 27
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Continuous – Wave Doppler
Limitations
Low Flow (~14-18”)
Sensor penetrates most of flow, most accurate velocity
Medium Flow (~24-36”)
Sensor less than half of flow, does not pick up peak velocity.
High Flow (36”+)
Sensor minimal portion of flow, velocity not representative of actual flow
Velocity Sensor Range (~16”)
Velocity Sensor – offset at 5:30
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Meter Summary: % Usable in Study Locations
74%74%74% 3%
45%
58%
87% 16% 10%16%
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Meter Summary: Continuous Wave
- Best used in 8-inch to 42-inch pipe (generally – depends on site conditions)
- Good flexibility in most situations
- Good for surcharged conditions
- Cost effective option
- Isco and Sigma: more user friendly, slightly less expensive
- ADS Flow Shark slightly better data, expect connectivity issues
- Required periodic maintenance
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Meter Summary: Pulse-Doppler
- Best used in larger diameter pipe meeting minimum flow conditions.
- More expensive (generally)
- ADFM and AccQMin: Slightly better data, but expect issues in pipe with sediment. More expensive than ADS.
- ADS Pulse: Can handle sediment, less expensive, user friendly
- Required periodic maintenance
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Meter Summary: Radar
- Can be used on nearly all sized pipelines
- Good flexibility for most situations
- Sometimes only option, especially high velocity, small pipe diameter sites, or dangerous confined space entry situations
- Questionable for surcharged conditions
- More expensive
- Expect connectivity issues for DC powered sites (AC power okay)
- Requires responsive maintenance (surcharge events)
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Meter Summary: Transit-Time Accusonics
- Best used in larger diameter pipe
- Requires commitment for metering site (difficult to remove)
- Accurate Velocity Data
- Required periodic maintenance: Most O&M to clean sensors
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Meter Summary: Transit-Time Flow-Scope
- Only for smaller diameter pipe with tight tolerances.
- (will be) Cost-Effective
- Emerging technology. Not ready just yet.
- Best for 8 to 12 inch pipe with low velocity, low level flows.
- Required periodic maintenance
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Meter Summary: Custom Compound Weir
- Best for specific applications: high turbulence, convergence of two lines, or extremely low flows
- Expensive
- Dedicated permanent site, each site custom built.
- Required periodic maintenance
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Results Summary
[1] Pipe Size Definition: Small = 15” and below, Medium = 18” to 36”, Large = 39” and above.[2] This category was defined by the number of flow monitoring sites within the EBMUD project (31 sites total, pipe diameters ranging from 8 inches to 105 inches, and all types of hydraulic conditions) wherein the given type of meter could have been appropriately used for obtaining good flow monitoring results. Most = >80%, Several = 60% - 80%, Many = 40% to 60%, Unique = <40%. Note – these results will vary depending on the characteristics of the collection system being evaluated.[3] $ = $5,000 - $9,000, $$ = $9,000 - $14,000, $$$ = $14,000 - $19,000, $$$$ = greater than $19,000.
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General Decision Treedepth < 1 inch 1 < depth < 3 3 < depth < 12 12 < depth < 24 depth > 24
vel < 0.5 fps
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar,
CCW1, FlowScope1
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
0.5 < vel < 4.0
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar,
CCW1, FlowScope1
Sigma4, Isco4,
FlowShark4, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
4.0 < vel < 8.0
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar,
CCW2, FlowScope2
Sigma3, Isco3,
FlowShark3, AccQMin, ADFM, Accusonics, Flo-
Dar, CCW2, FlowScope2
Sigma3, Isco3,
FlowShark3, AccQMin3, ADFM, Accusonics, Flo-
Dar, CCW2, FlowScope2
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar,
CCW1,2, FlowScope1,2
Sigma4, Isco4,
FlowShark4, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
vel > 8.0
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar,
CCW2, FlowScope2
Sigma3, Isco3,
FlowShark3, AccQMin, ADFM, Accusonics, Flo-
Dar, CCW2, FlowScope2
Sigma3, Isco3,
FlowShark3, AccQMin3, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma4, Isco4,
FlowShark4, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope (also see note 6)
vel > 18 fps5
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma3, Isco3,
FlowShark3, AccQMin3, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma, Isco, FlowShark, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope
Sigma4, Isco4,
FlowShark4, AccQMin, ADFM, Accusonics, Flo-Dar, CCW, FlowScope (also see note 6)
Legend: Black = Meter can be considered, Grey = Meter may be considered, GreyStrikeThrough = Meter should not be considered
Notes: 1 Depends on depth relative to pipe size. May not be recommended if depths exceed recommended range of weir/flume.2 Velocities may exceed the weir/flumes abilities to accurately alter hydraulics -- evaluated on a site-by-site basis, possibly post-installation3 High velocities may hit submerged sensor(s) and cause a hydraulic jump ("fish-tail effect"). In this case, this type of meter should not be used.4 As depths increase > 24 inches, the accuracy of the velocity may decrease for these meters5 Velocities > 18 fps may not be able to be metered accurately with any meter6 Velocities > 8 fps with Depths > 24 inches -- Safe entry into the pipe channel for mounting a submerged sensor may not be possible (effects all meters except Flo-Dar)
Flo-Dar General Note: It is advisable to run an in-situ velocity profile for all installationsFlo-Dar's, Sigmas, Iscos, FlowSharks not recommended when Vel < 0.5 fpsSigma's, Isco's, FlowSharks not recommended when Depth < 1 inchAccQMin not recommened when Depth < 3 inchesADFM's not recommended when Depth < 12 inches
, Pulse
, Pulse , Pulse
, Pulse , Pulse
Pulse
Pulse
Pulse
Pulse
, Pulse
, Pulse
, Pulse
Pulse
Pulse
Pulse
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Decision Tree (cont.)
Output from Depth/Velocity Matrix
Sediment > 2 inches?
ADFM and AccQMin Meters must be mounted at the pipe invert and may not be
appropriate.
Permanent vs. Temporary Installation:Meter Maintenance
Submerged sensor meters (all meters except the Flo-Dar) are prone to fouling and may require a confined space entry for
sensor maintenance.
Required Accuracy vs. Cost
What are the overall requirements for accuracy? Are the flow results to be used for billing purposes (high accuracy required)? To monitor for potential surcharge situations (high
accuracy not required)?
Pipelines known to have repeated surcharging?
Submerged sensor meters perform better in surcharge situations than Radar, Weir and
Flume meters
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Q & A