Welcome to Project Dewatering, the UK’s leading specialists in Dewatering and Water Control Systems.
What is Dewatering?
Many civil engineering or smaller projects involve excavations below groundwater level. Dewatering is a term to describe the removal of groundwater from within a soil material and is carried out to ensure excavations are undertaken in dry and stable conditions. The risk of not controlling groundwater can have catastrophic effects by groundwater ingress and instability, or excessive groundwater pore pressures resulting in heave or quick conditions.
Construction Dewatering is a common term used to describe the temporary lowering of groundwater level within an aquifer or depressurising a sub-artesian or artesian head. Permanent Dewatering covers the installation of continuing groundwater control system. Ground conditions and objectives dictate dewatering requirements and appropriate method can be determined by pumping testings. The dewatering mechanism can encompass gravity drainage such as deepwells using submersible borehole pumps or applying a vacuum to a soil material using ejectors or vacuum wellpoint systems.
A deep well typically consists of a borehole fitted with a slotted liner and an electric submersible pump. As water is pumped from a deep well, a hydraulic gradient is formed and water flows into the well forming a cone of depression around the well in which there is little or no water remaining in the pore spaces of the surrounding soil. Deep wells work best in soils with specific permeability profiles with the amount of drawdown that a well can achieve is limited only by the size of the pump. Deep Wells are typically drilled using cable percussive or rotary drilling methods, terminating typically in a 300mm or 250mm bore.
Wellpointing or vacuum wellpoints are a very versatile and economic method of groundwater control and have an advantage of being installed relatively quickly and at close centres are very effective in fine grained or stratified soils. Wellpoints consist of small diameter tubes with a filter intake at the bottom, they are typically installed around the perimeter of an excavation or parallel to a pipeline by jetting or auguring techniques. Vacuum and flow is generated by a dewatering pump, which in turn limits drawdown to ~5-6m depth. For greater depths a second stage wellpointing system can be installed at a lower level. Project Dewatering can offer stainless steel ‘self-jetting’ wellpoints as well as conventional disposable wellpoints.
Ejectors or Eductors are very effect in soils of low to medium permeability where the pumping water level is too deep for wellpoints but yields too small to allow the use of a electric submersible borehole pump. Ejectors are commonly used up to depths of 50m, can run at times of zero water entry into the well and if sealed can generate a vacuum in the well to increase efficiency.
In conjunction with dewatering, Project Dewatering has one of the UK’s best drilling capabilities of any groundwater control company. We offer other services such as pumping tests, pressure relief wells groundwater remediation, grey water treatment, water recycling and ground source heat systems.
Why Project Dewatering are the Natural Choice for your Dewatering Needs.
Practice and experience, along with a firm understanding of the underlying principles of dewatering, are the best tools for designing a successful dewatering system and this is something that the Project Dewatering team can deliver to any dewatering project.
Our team members consist of highly-qualified industry professionals and leading authorities on dewatering and these combined with many years of project experience in this specialist area, ensures that the client always receives the best results combined with cost-effective project delivery.
Our expertise in the dewatering arena has given us the opportunity to work on some very high profile and mission-critical projects where on-budget, on-time and precise delivery are key to the project success.
Projects such as the prestigious Tyne Tunnel 2 project and Belfast Sewers Project, where we collaborated with an international workforce to deliver the highest quality results illustrate just how our expertise is regarded and sought within this specialist industry sector.
For information and advice on dewatering solutions,
please call our office on +44 (0) 1473 658 807.
Our experienced, friendly staff will be delighted to discuss your specific needs.