Direct-push multilevel sampling system for unconsolidated aquifers

Abstract

An economical multilevel groundwater monitoring system has been developed that can be rapidly installed with a direct-push machine, yet is suitable for sampling across large permeability contrasts. This sealed multiport sampling (SMPS) system consists of up to five lengths of PVC tubing (12mm OD), each with a screen at a specific depth created by drilling 2.5-mm holes. Above and below each screen, round elastomer pieces, with peripheral holes (to clip in the sampling tubes) and a central hole (to hold a discontinuous piece of central tubing at the height of the screen), are emplaced. Cement-bentonite grout is injected via a tremie tube inserted through the discontinuous centre tube into each interval between the sampling screens. The elastomer pieces and central tube prevent grout from reaching the screened interval. A textile wrapped around the system holds the arrangement in place and at the same time serves to filter the groundwater at the level of the sampling screens. The SMPS system was tested at a tetrachloroethene (PCE) contaminated site. The seals effectively separated the sampling intervals even in heterogeneous formations. Furthermore, concentration profiles agreed well with a reference system. The system should be suitable for a wide range of hydrogeological conditions.

Using environmental tracers to determine the relative importance of travel times in the unsaturated and saturated zones for the delay of nitrate reduction measures

“…2). These were installed using the direct-push technique of the sealed multiport sampling system (SMPS, Ducommun et al, 2013). Thereby, the individual levels are isolated from each other by an injected mixture of cement and bentonite.…”

A Permanent Multilevel Monitoring and Sampling System in the Coastal Groundwater Mixing Zones

“…With regard to multilevel samplers, lots of pioneering work has been done, as summarized in Table (Hesslein ; Puls and Paul ; Ronen et al ; Beck et al ; Ducommun et al ). However these methods are mainly applicable in terrestrial environments.…”

“…The main restraint of the field studies is the sampling difficulty within the CGMZs (Charette and Allen 2006). With regard to multilevel samplers, lots of pioneering work has been done, as summarized in Table 1 (Hesslein 1976; Puls and Paul 1997;Ronen et al 1987;Beck et al 2007;Ducommun et al 2013). However these methods are mainly applicable in terrestrial environments.…”

A Simple and Affordable System for Installing Shallow Drive Point Piezometers

“…Drive point systems have been used for installing piezometers for more than 30 years (Desaulniers 1983). As they can be relatively inexpensive to construct and install (compared to traditional installation using drilling rigs), they have been widely used where detailed spatial networks of piezometers are required, such as for delineating contaminant plumes (Ducommun et al 2013) and for studies of surface water-groundwater interaction (Baxter et al 2003;Rivett et al 2008). Small diameter drive point piezometers are particularly useful in situations where the water table is within suction lift of the land surface, where submersible pumps are not required to obtain groundwater samples.…”

“…The outer casing (and the inner rod, if used) is subsequently removed to expose the screen. Some of these systems are designed to accommodation multilevel sampling tubes, although this requires either smaller diameter piezometers or larger diameter outer casing (Ducommun et al 2013;Rivett et al 2008).…”