Ground Water Flow Meter

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The Cypress Groundwater Flow Meter (GWFM) in use at the L31N and L30 groundwater monitoring stations is similar to the heat-pulse groundwater flowmeter used by Krupa et al. (2001) in their preliminary assessment of velocity at the Miami-Dade wellfield. The GWFM equipment used initially by the SFWMD Hydrogeology Department (Kerfoot Technologies GeoFlow) was intended for short term installations and required control by a laptop computer.
For the L31N project, J. Brock (Rapid Creek Research) developed a controller for the heat pulse probe designed for long-term deployment that was capable of data collection with a datalogger. The original probes used at L31N are similar to the Model 200 (Kerfoot Technologies) except they are equipped with four pairs of thermistors instead of two pair. (See How the Heat Pulse Flow Meter Works).
The eight wells at L31N (four at north site and four at south) were instrumented with flowmeters that became operational during 2006 and continue to collect data at present (2014). Originally configured for operation with a CR23X datalogger (Campbell Scientific), the Cypress GWFM was upgraded in 2009 for use with Campbell Scientific’s CR1000 datalogger. Six monitoring wells at the USACE L30 project were equipped with the CR1000-based GWFM measurement systems during 2010.
The probe’s sensing end has a porous packer that fits tightly in either a 4” (left) or 2” (right) monitoring well. The packer is positioned into the screened section of the well using hang rods.
The hanger rod is perforated to allow adjustment of elevation. The green stripe indicates north.
At the well head, the hang rod is secured with a removable pin that ensures proper compass orientation. Starting with the 2010 installation at L30, we began using 4” risers (left) as they provide more space for other sensors, including pressure transducer and conductivity. The older wellhead (right) at L31N is more cramped and difficult to work in.
J.Brock removes a flowmeter from a 100 ft deep monitoring well along L31N. The 10 ft hang rods are shown to the right.