Barologger 5

The Barologger 5 uses algorithms based on air pressure only.

It measures and logs changes in atmospheric pressure and temperature, which are then used to compensate water level readings recorded by a Levelogger.

Leveloggers measure absolute pressure (water pressure + atmospheric pressure) expressed in feet, meters, centimeters, psi, kPa, or bar.

The most accurate method of obtaining changes in water level is to compensate for atmospheric pressure fluctuations using a Barologger 5, avoiding time lag in the compensation. The Barologger 5 is set above the high water level in one location on site. One Barologger can be used to compensate all Leveloggers in a 30 km (20 miles) radius and/or with every 300 m (1000 ft.) change in elevation.

The Levelogger Software Data Compensation Wizard automatically produces compensated data files using the synchronized data files from the Barologger and Leveloggers on site.

The Barologger 5 uses pressure algorithms based on air rather than water pressure, giving superior accuracy. The recorded barometric information can also be very useful to help determine the barometric lag and/or barometric efficiency of the monitored aquifer.

The Barologger 5 records atmospheric pressure in psi, kPa, or mbar. When compensating submerged Levelogger 5, Edge, Gold, or Junior data, Levelogger Software can recognize the type of Levelogger and compensate using the same units found in the submerged data file (e.g. feet or meters). This makes the Barologger 5 backwards compatible.

Why Use a Barologger?

Submersed absolute Leveloggers measure total pressure (water column equivalent + barometric pressure). In order to accurately determine the true changes in water level only, barometric pressure fluctuations must be removed from the data. The simplest method to accomplish this is by the use of a Barologger suspended above a high water level in one well on site. The approximate site compensation coverage is 20 miles (30 km). This records ambient barometric fluctuations over time and allows quick and accurate barometric compensation using the data files from both the Barologger and any Leveloggers in the area.

Manual Barometric Compensation

If an on-site Barologger is not available, your data can be compensated using alternate barometric data (e.g. from a local weather station).

To accomplish an accurate manual barometric compensation, the atmospheric pressure station should not be greater than 20 miles (30 km) away and within an elevation change of 1000 ft (300 m). In addition, the date and time of the barometric data should cover the range of data collected by the Levelogger.

To begin manual compensation, your Levelogger data and barometric data must be in the same units and assure that any offsets or normalization values are accounted for. Previous Levelogger and Barologger models (e.g. Gold) produce data with an offset of 31.17 ft or 9.5 m (lowest expected pressure at mean sea level) removed from the level values. Levelogger Edge data does not contain this offset. Although not shown in our examples, it is also important to remember that weather station barometric data will often contain a different offset or normalization. Manual data conversation and barometric compensation should account for any variation of the normalization or offset used between the barometric data sourced and Solinst Leveloggers.

Examples:

1.Conversion from psi to feet of water column equivalent: Example: 15 psi (for Levelogger Edge):

15 psi x2.30666 ft/psi = 34.60 ft head

2.Conversion from kPa to meters of water column equivalent: Example: 101.40 kPa (for older Levelogger):

101.4 kPa x 0.101972 m/kPa = 10.34 m - 9.50 m offset = 0.84 m head

* Values in green denote pressure conversion factors; consult the table above to obtain common pressure conversions

Once the final calculated barometric pressure values are obtained, they are subtracted from the Levelogger data set. Since the Levelogger data can be easily exported as a .csv or .xml file using Levelogger Software, all manual corrections can be performed in external programs.

In an example where the uncompensated Levelogger Edge data is a water level of 41.17 ft, from the calculation above, the manual compensation would be: 41.17 ft – 34.60 = 6.57 ft.

In an example where the uncompensated older Levelogger data is a water level of 3 m, from the calculation above, the manual compensation would be: 3 m – 0.84 = 2.16 m.

Applications

• Pump and slug tests
• Reservoir and stormwater runoff management
• Watershed and drainage basin monitoring
• Stream gauging, lake, and wetland monitoring
• Tank level measurement
• Monitoring water levels in wells and surface water

Barologger Installation

The Barologger is a Levelogger with a small range adequate to monitor the fluctuations that occur in barometric pressure. The Barologger's readings are used to barometrically compensate Levelogger readings. As a rule of thumb, a Barologger can be used to compensate all the Leveloggers in a 30 km (20 mile) radius and/or with every 300 m (1000 ft) change in elevation.

Note:

The Barologger should not be used to monitor water, as the internal mathematics for temperature compensation are based on air rather than water.

To monitor barometric pressure correctly, the Barologger should never be submerged. In well installations, it is recommended that the Barologger be suspended in one of the monitored wells above the high water point (the well must be vented). For best reading accuracy, the Barologger should be installed in a similar thermal environment to that of the Levelogger. In groundwater wells, the Barologger should be suspended beyond the frost line and deep enough to avoid large temperature fluctuations. In surface water applications, the Barologger is best deployed in a dry well – a well embedded in the bottom of the water body, but sealed at the base from water entry and vented to the atmosphere. If a dry well cannot be installed, the Barologger can be installed on a float in the stilling well.