In-Situ TROLL 9500 Operators Manual - Manual (Page 53)

46
Multi-Parameter
Water Quality TROLL ®
TROLL 9500 Operator’s Manual 0095110 rev. 007 01/09
7 MONITORING PRESSURE (WATER LEVEL)
Pressure sensor
WHY MONITOR PRESSURE?
Water level or pressure head readings are taken for a number of
reasons. In aquifer characterization, this type of data will help the user
determine important hydrologic parameters of an aquifer, including
hydraulic conductivity, transmissivity, permeability, storage coefficient,
dispersivity, and porosity. Some or all of these parameters are impor-
tant in the design of wells and well fields for various purposes.
In the design of a remediation system, the proper placement of wells
for monitoring or extraction is of paramount importance if the system
is to function effectively. Accurate data from slug and pump testing is
one of the primary tools employed for aquifer characterization in the
design process.
Step testing and constant-rate pump testing yield significant data in
determining proper pumping rates. Improper rates can lead to aquifer
depletion, salt water intrusion, and several other problems. Accurate
data in designing the system and monitoring the system is essential
for long-term success of the well and the proper maintenance of the
aquifer.
The collection and use of water level measurements in the mining
and coal bed methane industries are essential for the success of
the mines and wells. Data derived from pilot testing of water wells
constructed for coal bed methane extraction provide necessary
information on bottom-hole pressure and appropriate pumping rates
to accomplish the de-watering necessary to release the methane gas.
Monitoring of water levels assures efficient produc-
tion.
Water level measurements of
surface water by pressure
measurements yield significant
data about the overall health
of the hydrologic cycle. This
information is also useful to government, agriculture, and industry as
well as the scientific community when planning water use and when
adjudicating water rights issues.
THE PRESSURE SENSOR
The optional pressure sensor of the Multi-Parameter TROLL 9500, if
included, is permanently-installed and factory-calibrated. If your MP
TROLL 9500 was ordered without a pressure or turbidity sensor, there
will be a permanently installed plug in the pressure sensor slot. A
pressure sensor can be added at the factory.
Do not try to remove the pressure sensor or permanently
installed plug.
FACTORY CALIBRATION
The pressure sensor is calibrated across full pressure over a range of
½
From a two-dimensional data set of tem-
perature A/D versus reference temperature,
and a three-dimensional data set of pressure
A/D versus temperature A/D and reference
pressure, numerical coefficients are gener-
ated to equations that map the MP TROLL
performance across all temperatures and
pressures.