Shallow Water FLUTe™
The Shallow Water FLUTe is an economical version of the Water FLUTe for use in environments with shallow water tables (<25 FT).
System Overview: The system consists of a continuous borehole liner, spacers defining the sampling intervals, and tubing directly to the surface from each sampling interval (see the drawing). The SWF depends on the ability to pump the water sample to the surface using a peristaltic pump, so the maximum water table depth at any sampling interval is < 25 ft. The SWF is shipped on a small plastic reel and hence the shipping and installation is similar to a blank FLUTe liner.
Installation: The Shallow Water FLUTe can be installed in the overburden and unstable rock formations through sonic casing and everted into open bedrock wells. For installation specifics in open boreholes, click here.
Sampling Intervals: All samples collected from the Shallow Water FLUTe are drawn directly from the formation, with no potential for cross contamination or leakage as possible with packer based multi-level systems. The Shallow Water FLUTe is capable of up to 10-20 ports per borehole depending on the hole diameter from 4 inches to greater and all intervals can be sampled and purged simultaneously.
Head Measurements: The water table depth at each port can be measured with a FLUTe vacuum water level meter system. For continuous head measurements at each port, an air couple transducer (ACT) system can be used with a simple surface connection. The transducers are located in the surface casing for easy access for reuse, replacement or repair. Click here for more information on the ACT system.
Well Completion: There is no need for an exterior seal with grout, sand or bentonite. The liner seals the entire hole and the water is drawn directly from the formation. As such, there is no concern about the seal of granular materials in a slender annulus.
Warranty and Removability: The SWF system is fully warrantied and removable for other use of the borehole or easy abandonment by grouting the borehole. The system can be used for artesian situations with a heavy mud fill. Whereas the system can be used for a variety of borehole depths, the Standard Water FLUTe system is better suited for boreholes more than 200 ft deep or for deeper water tables.
The SWF is well suited for detection of tracer arrivals in that the purge volumes are minimal and the sample is drawn directly from the formation. Because there is not an interior tubing bundle, a transparent liner version allows one to watch for the arrival of strongly dyed injections, such as potassium permanganate, using a borehole camera. That option requires a special polyester liner instead of the standard nylon liner.
A FLUTe method called a precise gradient measurement is available in order to measure vertical gradients within ~ 1mm between any two ports in the liner.
Because there is no field assembly and no annular sealing materials needed, and the system is fully removable by inversion from the borehole, the overall cost of the Shallow Water FLUTe system is often the least expensive multi-level sampling and head measurement option of the multi-level monitoring systems.