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COMBINATIONS OF FLUTe METHODS

While FLUTe’s several methods are useful by themselves, they are more commonly used in combination. The combinations can be very cost effective. Here are some of the combinations:


The Blank liner, NAPL FLUTe and FACT

A common question is “where is the contaminant?” This combination uses the Blank liner covered with the color reactive NAPL detection covering (NAPL FLUTe) plus the activated carbon felt strip (FACT) for wicking the dissolved phase of a variety of contaminants. The covered liner is install immediately after the borehole is drilled to prevent cross connection. Two weeks later the liner is removed. Any stains on the cover are photographed with an adjacent tape measure to locate NAPL sources. The FACT carbon felt is cut from the cover, rolled, and stored in DI water for future assessment as desired for identification of the dissolved contaminants. The blank liner is immediately installed back into the borehole to seal against cross contamination. Sometimes, geophysical measurements are made in the open hole before the liner is reinstalled.
Whereas the NAPL FLUTe system can be installed without the FACT, the FACT system is always installed in the NAPL FLUTe cover.

The Blank liner, NAPL FLUTe, FACT and Transmissivity profile

This is the same as the above sequence, but when the blank liner is reinstalled, it is done while performing the high resolution transmissivity profile of the formation. When completed, the borehole is sealed. Sometimes, geophysical measurements are made in the open borehole before the liner is reinstalled. The transmissivity profile is very helpful in detection of the active flow zones in the formation and in guiding the selection of sections of the FACT to be analyzed.

The Blank liner, NAPL FLUTe, FACT, transmissivity profile, and Water FLUTe

This is the same as the above measurements followed by the construction of the Water FLUTe multi-level system. The blank liner is then removed and the Water FLUTe liner is installed in the same day for water quality and head measurements.
In some cases, the combinations above are reduced to a popular
FLUTe Trio which includes the sealing Blank liner, the transmissivity profile for each borehole after they are all sealed (sometimes following the geophysics measurements in each hole as the blank is removed) and the Water FLUTe installation in all the boreholes in a later single campaign.

The advantages of the combinations

The combination of the several methods, sometimes including various geophysics measurements, in a single fielding campaign can be very cost effective and provide a wide range of hydrologic information. The ability to consider the results from the measurements in all boreholes before selecting the monitoring intervals in each hole allows the best use of the resources without the need to make a snap judgment of the completion of each well as it is being drilled.
With the transmissivity profiling results in hand, one can also select the minimum sections of the FACT activated carbon from each borehole for the relatively expensive analysis with the GCMS technique. The activated carbon felt can be stored in DI water with little concern about loss of contaminants for many days based on tests done by the Danish Technical University.
The uncertainty of straddle packer seals in an open hole in fractured rock makes the dependence on those measurements problematic. This is especially true if the objective is to determine the depth of contamination in the formation. The uncertainty of the packer seal is also compounded by the time the borehole is open to cross connection during the straddle packer testing.
The power point presentation
“The Full Use of FLUTe Technology in Fractured Rock” describes the potential efficiencies of combinations of the flexible liner methods for a wide variety of hydrologic assessments.