Following an intensive training programme, on the use of the unique Sennebogen large diameter drill rig, held in Germany with the Project Dewatering Ltd parent company Hölscher Wasserbau, drilling works have now begun on site at the Marlow Flood Alleviation Scheme.
The scheme is a series of improved flood defence walls and large bunded water storage areas, together with four separate groundwater pumping systems. The groundwater pumping systems, being installed by Project Dewatering Ltd for the main contractor Galliford Try, are designed to prevent the rising of groundwater levels in critical areas during significant flood events.
The groundwater abstraction system is designed around 16 large diameter abstraction wells installed to the base of the underlying gravels. Once installed, the systems will automatically pump groundwater to nearby large area bunded lagoons. Integral to PDL’s activities, is a programme of pump testing and commissioning that will give the EA assurances that the system is installed as per the specification.
It is the use of this unique drilling method that allowed Project Dewatering Limited to keep costs low during the tender process, and critically, to meet the specification provided by the Environment Agency where others we only able to offer smaller diameter wells as alternatives.
In addition, the drilling method had a number of important advantages:
- No requirement for large volumes of recirculation water or additive polymers (quite specific);
- The method of spoil generation leads to a cleaner, drier more manageable work area and
- With large pneumatic tyres rather than tracks, disturbance of sensitive surfaces, including Marlow cricket pitch, was reduced.
Project Dewatering Limited have already identified a number of follow on sites where this unique method will add value to clients projects. If you are interested to find out more information, please contact us through the contact details on the home page.