The Model 403 CMT Multilevel System consists of continuously extruded polyethylene tubing with three or seven separate channels running the length of the tubing. Monitoring zones are manually constructed, sealed-off, and screened, one in each channel, at different vertical intervals. This allows the System to monitor up to seven depth discrete zones in a single groundwater monitoring well. Designing these systems is very flexible; construction of monitoring ports can be done right at the drilling site.
Typical 3 or 7-Channel CMT Installation
using layers of bentonite
and sand backfilled from surface
The narrow 3-Channel System is 1.1"(28 mm) in diameter; the 7-Channel System is 1.7" (43 mm) in diameter. Backfilling around these single tube systems is simple, compared to multiple clustered or nested wells at various depths.
The 3 and 7-Channel Systems can be backfilled with standard methods of bentonite seals and sand packs. The 3-Channel System has the option of using pre-formed bentonite and sand cartridges, which can be positioned on the CMT and installed using direct push methods.
CMT Systems can be used to accurately measure water levels and take water samples. Solinst offers narrow diameter, portable Water Level Meters and samplers that can be used in the CMT. A wellhead seal is available to allow vapour sampling.
The CMT System provides many benefits to site assessors.
- Inexpensive and easy to install and use
- No joints - smooth surface for easy sealing
- Up to 7 depth-discrete monitoring zones
- Locate ports and seals exactly where needed
- Installs quickly using direct push methods or in boreholes
- Lowers risk of cross contamination and new contaminant pathways
- Provides a 4D view of groundwater flow and distribution of contaminants in the subsurface
Solinst offers courses for CMT construction and installation. Contractors who complete the course are "Trained CMT Contractors" and can be listed on the Solinst website.