A new type of small diameter monitoring wells are capable of providing the support for a large variety of devices designed to measure the groundwater elevation, the presence and thickness of an eventual contaminant phase and to sample the soil gas and the groundwater. The probe rods with an expandable drive point are driven into the subsurface. At final depth, a certain type of screen and casing is installed as a permanent well and the probe rods are retracted to allow the groundwater to flow in.

Installing innovative DP wells is possible in a variety of internal diameters (0,5“, 0,75“, 1“ and 2“). In either of the options, one can use several installing alternatives:

• HDPE screens are optionally protected by a permeable geo-membrane with mesh size of 60 µm to fight against clogging.
• Prepacked screens with various diameters (0,5” and 1,5”) allows a quick and simple installation through the Direct Push casing and offers an well-executed sampling interval.
• Continuous multi-channel tubing allows a rapid multilevel (3 or 7 channels) sampling of the desired intervals. A 7 channels tubing allows for example a quick and efficient sampling of up to 6 different intervals and a simultaneous groundwater level monitoring.

A great advantage of installing a monitoring well through a cased hole like geo-log proposes is that there is no side slough to contend with. In addition, the casing effectively seals the well hole when advancing through contaminated deposits. These factors mean that installation of the well till the desired depth is guarantied and cross contamination is eliminated.

Fully (continuously) screened wells are the most required type. They can be sampled either integral or in a multilevel way by use of double displacement mini-pumps and packer-systems. The sampling systems can be permanently installed (fixed with bentonite packers) or can be employed in a mobile way (with inflatable packers). Dedicated depth differentiated screened wells can be built based on at the surface prepaired sampling ports with multilevel sampling intervals delineated by either bentonite or rubber separators. All of the sampling systems make use of a flow-through cell unit where the standard on site measurements (pH, temperature, redox potential, oxygen content, electrical conductivity) are carried out.

The maximal depth and the drilling velocity depend strongly on the local lithology and the chosen well diameter.  geo-log was able to reach 52 m bgl for installing an 1“ and 25 m for a 2“ monitoring well. In installing monitoring wells, the DP technology has some important advantages over conventional drilling methods: small machines and small diameter tools enable penetration rates in a range of meters per minute with a fast and economical mobilization and moving between locations. One usual working day could mean to finalize about four wells till an end depth of around 15-20 m bgl.

Another great advantage of the DP method stays, besides the economical efficiency, into the small time gap from the decision stage till the well is ready to be exploited. As a result, the DP assisted methodology to deal with monitoring wells provides a h

High numbers of samples translated into a high volume of data and deliver reliable data for 2-D / 3-D imaging (Fig. 10) with minimal surface disturbance, due to the no soil cuttings generated and no waste disposal needed. They assure a quicker, economically more efficient and detail-reach investigation in comparison to the conventional ways of assessing a site.