Levelogger User Guide - Software Version 3.4.0 or Higher
Page 46
11.1.2 Fixed Installations
Artesian Monitoring
Monitoring of artesian conditions in which the piezometric surface is above
ground surface or more particularly above the top of well casing elevation using
Leveloggers can be quite straight forward.
Continuous artesian conditions infer that the piezometric surface never drops
below the level the ground surface or particularly the top of casing elevation and
the casing is sealed with a sealed wellhead. In this case, where freezing is not a
concern, the Levelogger need only be installed on the wellhead itself by means
of a large compression fitting with a 1/4" NPT connector, as illustrated in Figure
11-6. Solinst can supply a 7/8" nylon compression fitting for this purpose. First,
a 1/4" NPT hole is tapped into the wellhead. The user slides the Levelogger into
the compression fitting, leaving about 1/4 of the logger body exposed above the
fitting. The compression fitting nut is tightened around the Levelogger. The 1/4"
NPT connector on the bottom of the pressure chamber of the fitting threads into
the hole in the sealed wellhead. The user can communicate with the logger
simply by removing the logger cap and attaching the optical reader. Ensure that
the logger and sealed wellhead are enclosed within an outer protective well cap
or enclosure. This method should only be used in low pressure conditions (less
than 30 psi or 66 ft (20 m) of water column).
When conducting artesian monitoring with Leveloggers a number of considerations
must be kept in mind. First, ensure that the maximum hydraulic pressure the
Levelogger will encounter within the well at its installation point will not exceed
the hydraulic range of the logger. Second, artesian conditions do not preclude the
necessity for barometric compensation of Levelogger data. Artesian conditions
are caused by aquacludes forming confined aquifers. Confined aquifers, while
not acted on by barometric pressure to the same extent as unconfined aquifers,
are typically subject to barometric pressure at some barometric efficiency (See
Section 11.1.3). Finally, bear in mind that the total pressure and subsequent
water column equivalent depth measured by the Levelogger after barometric
compensation may not represent the actual water level within the artesian well.
Sealed intermittent artesian wells can be pressurized when artesian, but can also
be de-pressurized when non artesian. The Levelogger’s reading after barometric
compensation represent the height of the piezometric surface.
Note:
The Levelogger
NPT Adaptor is
not recommended
for pressures in excess of
30 psi (66 ft (20 m) of water
column).
Figure 11-7
7/8” Nylon Compression Fitting
with 1/4" NPT Connector
Levelogger Cap
Levelogger Body
Compression
Fitting Nut
Ferrule
Pressure
Chamber
1/4" NPT
Connector
