Difference between revisions of "Water level - capacitive (Odyssey)"
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*The probe fits exactly on a 32 mm (ID) PVC pipe | *The probe fits exactly on a 32 mm (ID) PVC pipe | ||
*You can replace the batteries yourself | *You can replace the batteries yourself | ||
+ | *Log-interval can be event-controlled | ||
+ | *Very good support from the company (prompt answering emails). | ||
==Disadvantages:== | ==Disadvantages:== | ||
− | + | *Each sensor needs to be calibrated: | |
− | + | "median measurement error that ranged from 11 to 288 mm using the bucket calibration method and 12 to 81 mm using the PVC pipe calibration method" (Larson and Runyan, 2009) | |
− | + | *the sensor is not compensated for temperature or electrical conductivity. | |
+ | *manufacture state the accuracy to be -+ 5mm, but in practice it tends to be -+1cm. | ||
+ | *temperature dependency: "tests in water temperatures of 0°C - 20°C have shown a variation (under estimation) of approximately 5mm" (manufacture statement). | ||
+ | *electrical conductivity dependency: | ||
+ | **"If the conductivity of the water is above 5000µS/cm the sensor is largely unaffected by fluctuations in conductivity whereby large changes result in very small variations in the recorded data" (manufacture statement). | ||
+ | **"We suggest these probes only be used in water higher in conductivity than 4150 μS/cm" (Larson and Runyan, 2009). | ||
+ | **Larson and Runyan (2009) tested the influence of EC on the measurement by changing the EC. Here are the results (see study for details): | ||
+ | ***EC variations: from 590 μS/cm to 1600 μS/cm --> "observed" water level variations: 40 mm | ||
+ | ***EC variations: from 705 μS/cm to 1000 μS/cm --> "observed" water level variations: 15 mm | ||
+ | ***EC variations: from 670 μS/cm to 1200 μS/cm --> "observed" water level variations: 24 mm | ||
+ | ***EC variations: from 210 μS/cm to 620 μS/cm --> "observed" water level variations: 153 mm | ||
+ | ***EC variations: from 175 μS/cm to 1950 μS/cm --> "observed" water level variations: 240 mm | ||
==What to watch out for:== | ==What to watch out for:== | ||
Line 30: | Line 43: | ||
*After 2 years of use, two of my loggers would no longer connect to the computer. All others still worked fined. | *After 2 years of use, two of my loggers would no longer connect to the computer. All others still worked fined. | ||
*One of my loggers would only record data for a few seconds. Restarting the logger and letting it run until the storage was full seemed to take care of this. | *One of my loggers would only record data for a few seconds. Restarting the logger and letting it run until the storage was full seemed to take care of this. | ||
+ | *How do temperature/electrical conductivity influence the measurement. | ||
+ | |||
+ | ==Price:== | ||
+ | between 120 and 150 EURO (2010, Germany) depending on the length | ||
==Links== | ==Links== | ||
Projects that used the above equipment: | Projects that used the above equipment: | ||
− | + | * [http://teodoor.icg.kfa-juelich.de/overview-de TERENO] | |
Other related web sites: | Other related web sites: | ||
− | http://www.odysseydatarecording.com/odyssey_productsview.php?key=1 | + | *[http://www.odysseydatarecording.com/odyssey_productsview.php?key=1 odysseydatarecording] |
+ | *http://www.umbc.edu/cuere/BaltimoreWTB/pdf/TM_2009_003.pdf | ||
==References== | ==References== | ||
+ | *Bachmaier, S., Weiler, M., Troch, P. (2012): Intercomparing hillslope hydrological dynamics: Spatio-temporal variability and vegetation cover effects. WATER RESOURCES RESEARCH, VOL. 48, W05537, DOI: 10.1029/2011WR011196. | ||
+ | *Bachmair, S., Weiler, M. (2012): [http://www.hydrol-earth-syst-sci.net/16/3699/2012/hess-16-3699-2012.html Hillslope characteristics as controls of subsurface flow variability.] Hydrol. Earth Syst. Sci., 16, 3699–3715, DOI: 10.5194/hess-16-3699-2012. | ||
+ | *[http://www.umbc.edu/cuere/BaltimoreWTB/pdf/TM_2009_003.pdf Larson, P. and Runyan, C. (2009): Evaluation of a Capacitance Water Level Recorder and Calibration Methods in an Urban Environment, CUERE Technical Memo 2009/003] | ||
[[Category:Equipment]] | [[Category:Equipment]] | ||
[[Category:Water level]] | [[Category:Water level]] |
Latest revision as of 15:03, 25 October 2012
Parameter to be measured:
Water level
Method:
Capacitive
Equipment:
Odyssey
Advantages:
- Cheap
- Logging of 64k of data
- Logger start by starting start time
- The lack of an outer shroud makes it easy to transport the probes
- Available in different lengths
- Available with 2 sizes of brass weights
- The probe fits exactly on a 32 mm (ID) PVC pipe
- You can replace the batteries yourself
- Log-interval can be event-controlled
- Very good support from the company (prompt answering emails).
Disadvantages:
- Each sensor needs to be calibrated:
"median measurement error that ranged from 11 to 288 mm using the bucket calibration method and 12 to 81 mm using the PVC pipe calibration method" (Larson and Runyan, 2009)
- the sensor is not compensated for temperature or electrical conductivity.
- manufacture state the accuracy to be -+ 5mm, but in practice it tends to be -+1cm.
- temperature dependency: "tests in water temperatures of 0°C - 20°C have shown a variation (under estimation) of approximately 5mm" (manufacture statement).
- electrical conductivity dependency:
- "If the conductivity of the water is above 5000µS/cm the sensor is largely unaffected by fluctuations in conductivity whereby large changes result in very small variations in the recorded data" (manufacture statement).
- "We suggest these probes only be used in water higher in conductivity than 4150 μS/cm" (Larson and Runyan, 2009).
- Larson and Runyan (2009) tested the influence of EC on the measurement by changing the EC. Here are the results (see study for details):
- EC variations: from 590 μS/cm to 1600 μS/cm --> "observed" water level variations: 40 mm
- EC variations: from 705 μS/cm to 1000 μS/cm --> "observed" water level variations: 15 mm
- EC variations: from 670 μS/cm to 1200 μS/cm --> "observed" water level variations: 24 mm
- EC variations: from 210 μS/cm to 620 μS/cm --> "observed" water level variations: 153 mm
- EC variations: from 175 μS/cm to 1950 μS/cm --> "observed" water level variations: 240 mm
What to watch out for:
- Don’t damage the wire.
Problems/Questions:
- After 2 years of use, two of my loggers would no longer connect to the computer. All others still worked fined.
- One of my loggers would only record data for a few seconds. Restarting the logger and letting it run until the storage was full seemed to take care of this.
- How do temperature/electrical conductivity influence the measurement.
Price:
between 120 and 150 EURO (2010, Germany) depending on the length
Links
Projects that used the above equipment:
Other related web sites:
References
- Bachmaier, S., Weiler, M., Troch, P. (2012): Intercomparing hillslope hydrological dynamics: Spatio-temporal variability and vegetation cover effects. WATER RESOURCES RESEARCH, VOL. 48, W05537, DOI: 10.1029/2011WR011196.
- Bachmair, S., Weiler, M. (2012): Hillslope characteristics as controls of subsurface flow variability. Hydrol. Earth Syst. Sci., 16, 3699–3715, DOI: 10.5194/hess-16-3699-2012.
- Larson, P. and Runyan, C. (2009): Evaluation of a Capacitance Water Level Recorder and Calibration Methods in an Urban Environment, CUERE Technical Memo 2009/003