fieldprotwkshp temperature 20160503 - acwi
TRANSCRIPT
Jen Stamp, Tetra Tech, Inc.
Temperature Protocols
Office of Research and DevelopmentAir, Climate and Energy Program, National Center for Environmental Assessment
The views expressed in this presentation are those of the author and they do not necessarily reflect the viewsor policies of the U.S. Environmental Protection Agency or other collaborating agencies
May 4, 2016
National Water Quality Monitoring ConferenceField Protocols Workshop
• Equipment• Sensor placement• Installation techniques
Temperature - outline
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Temperature = the ‘lowhanging fruit’ at RMN sites
• Inexpensive sensors• Low maintenance• Less error prone/require
fewer corrections
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RMN sites:• At least one water and air temperature sensor
should be deployed at each site
Equipment
Simple, inexpensive sensors are beingused at RMN sites
Many differentsensoroptions!
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In addition to the sensor, you should also have a radiationshield to -
• Prevent direct solar radiation from hitting the sensorsand biasing the readings
• Serve as a protective housing
Radiation Shields
Examples of radiation shields forwater temperature sensors
Several holes are drilled into the canister to make it neutrally buoyantand to facilitate water circulation.
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Air Temperature - challenging!
Unbiased measurements can bedifficult to obtain.
Most effective radiation shieldsare mechanically aspirated.
Small fan located within theshield that maintains air flow inlow wind conditions.
Require power which makesthem unsuitable for remotedeployment.
Can also be expensive.
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Passive Air TemperatureRadiation Shields
Many RMN partners havemade their own low-costpassive shields.
www.youtube.com/watch?v=LkVmJRsw5vs
Zack Holden (USFS) hasdocuments and a You-Tube video withinstructions on how toconstruct the shield thathe designed and hassuccessfully used atthousands of sites
Sensor Placement
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Depends on objectives of your study and site-specificconsiderations.
At RMN sites
• Sensors should be deployed in the same locationsover time
• Air and water temperature sensors should be locatedin close proximity (if possible)
• The location should be representative of thecharacteristics of the reach from which the biologicaldata are being collected
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Water temperature sensorsshould be placed in locations that are:
• Well-mixed horizontally and vertically• Of sufficient depth to keep the sensor submerged year
round• Stable, safely accessible during different flow conditions,
and easy to relocate• Protected from physical impacts associated with high flow
events (e.g., the downstream side of a large landmark rockor log; this also helps to hide it)
• Low human activity to reduce vandalism and accidentalsnagging
• Are areas of high use, visibility, or fishing access• Have heavy beaver activity• Have backwater pools, eddies, or standing water
that might stratify during low flow conditions• Are influenced by localized warm or cool water
sources, such as• a tributary confluence• an impoundment (including beaver ponds)• a lake outlet• point-source discharges
• Have a very high gradient (>7%). Sensor retentionrates are inversely related with slope (Isaak et al. 2013).
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Water temperature sensorsshould NOT be placed in locations that:
• Should be placed approximately 6 inches above thestream bottom (per Schuett-Hames et al. 1999).
• What about in small, shallow streams?• You may have no choice but to place a sensor near
the stream bottom to ensure that it remainssubmerged during low flows. If this happens, note onthe field form because:• Measurements could be influenced by
groundwater and subsurface flow;• Sensors on or near the streambed are more
susceptible to burial by moving substrates(sensors should never be intentionally buried).
Depth
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If the riparian zone is forested, mount the air temperaturesensor to the tree that is:
1) nearest the water temperature sensor; and
2) large enough to support the radiation shield andsensor (ideally >12 inches (0.305 meters) in diameter).
Placement of air temperaturesensors at RMN sites
For our purposes, trees generally make the bestattachment points because they provide stability,some degree of shade, and can help hide the sensorfrom potential vandals.
If a suitable tree is present, attach the radiation shieldand sensor to its north side, out of direct sunlight(see ‘Best Practices’ report for a simple process for doing this).
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To be consistent with typical meteorological observations,air sensors should be placed at a height ofapproximately 4-6 feet off the ground.
Placement of air temperaturesensors at RMN sites
Try to minimize the amount of othervegetation near the sensor.
Why? The ground, vegetation andother objects can create radiationmicroenvironments that bias readings.
Other techniques are being used as well.
Site-specific conditions will dictate which installationtechnique is most appropriate.
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In the report, we cover the following techniques:
• Underwater epoxy method (Isaak et al. 2013)• Attaching sensors to stable instream structures or rebar
Installation techniques for watertemperature sensors
Attaching sensors to stableinstream structures
If there is a large rock or boulder, root, woody debris or other stableinstream structure, you can attach the sensor and housing to the structureusing heavy-duty materials like plastic-coated galvanized steelcable/wire rope, metal clamps, and heavy-duty cable ties.
If you think the structure might move during high flow events, considercabling or chaining the structure to an object on the nearest bank (or toanother stable instream structure).
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Use heavy-duty materials!
Cable and rebar set-up for alarge stream in Maryland MDDNR
If conditions permit, attach cableties at two points.
If a site lacks stable instream structures and the streambottom is such that a metal stake can be driven into it, driverebar (generally 2–4 feet) into the streambed, deep enoughto stay in place during high stream flow events. Considerusing bent rebar – it is more secure and poses lesssafety risk for people wading in the stream.
The sensor and its protective housing are attached to therebar via heavy-duty materials like metal clamps, heavy-duty cable ties and galvanized steel cable/wire rope.
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Rebar installations
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Underwater epoxy installations
Isaak et al. 2013. A simple protocol using underwater epoxy to installannual temperature monitoring sites in rivers and streams. USFSGeneral Technical Report, 314.
YouTube video:http://www.youtube.com/watch?v=vaYaycwfmXs&feature=youtu.be
Dan Isaak, Dona Horan, Sherry WollrabFisheries Biologists, USDA Forest Service, Rocky Mountain Research Station
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Underwater epoxy installations
Use epoxy to attach the sensor to the structure
Equipment: (a) two-part FX-764 epoxy from Fox Industries, (b) PVCsolar shield, (c) temperature sensor, (d) cable ties, (e) plumber’stape, (f) rubber gloves, (g) plastic viewing box, (h) wire brush, and (i)metal forestry tree tag (Isaak and Horan 2013)
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Underwater epoxy installations
Examples of good attachment points. Arrows pointto the solar shield containing a sensor; circleshighlight metal forestry tags epoxied above thesensor to monument the site (photos from Isaak etal. 2013).
Select a suitable anchor point:
• Protrudes ≥ 1 foot above the water surface at lowflows
• Wide enough to protectsensor from movingrocks/debris during floods
• Flat attachment site ondownstream side andrelatively deep water withflow
• Small substrate ondownstream side and 8inches of space for shuttleattachment
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CT DEEP hasused windowweights, angleirons, andtethering tosecurestructures
Other installation techniques arebeing used as well…
Photosprovided byCT DEEP
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Acknowledgments
• Dan Isaak, Dona Horan, Sherry Wollrab & ZackHolden (USFS)
• Michael Kashiwagi & MD DNR• Chris Bellucci, Meghan Lally & CT DEEP• Drew Miller & VA DEQ• Debbie Arnwine & TN DEC
Plus other RMN partners and collaborators…
QUESTIONS? COMMENTS?
Britta Bierwagen ([email protected])
Jen Stamp ([email protected])
Anna Hamilton ([email protected])
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Why collect air temperature?
To gain a better understanding of the ‘thermalsensitivity’ of streams (e.g., how does the air-watertemperature relationship vary across sites from differentregions, size classes, gradients, with differing levels ofgroundwater influence, etc.).
Air temperature data, which are more readily availablethan stream temperature data, can be used to model(historic and future) stream temperature, and toimprove or validate models that predict streamtemperature.