Tips for Choosing a Jobsite Dewatering System

Dewatering systems for construction sites aren’t one size fits all. Choosing the most appropriate dewatering system for the job will yield the best results in the least amount of time.

What is dewatering? It’s removing groundwater or surface water in order to lower the water table to the desired level and establish a workable excavation area. In a recent webinar, experts from United Rentals’ Fluid Solutions Group highlighted several common dewatering methods and explained when they might be most appropriate. Here are some considerations:

Wellpoint systems

Wellpoint dewatering systems are the most popular dewatering method for excavations up to 18 feet deep. They consist of a shallow well, or a series of wells, placed at strategic locations around the site. Water is pumped to the surface through a connected pipeline.

Wellpoint systems:

• Work for excavations up to 18 feet
• Are fast to install
• Draw down water quickly
• Are widely available
• Offer pinpoint dewatering for specific small areas (around utilities, for example)
  
   

Deep well systems

Deep well dewatering systems consist of drilled wells, usually twice the depth of the excavation. The soil on the site helps determine the appropriate depth. Electric submersible pumps move the water out of the work area.

Deep well systems:

• Work at depths below 26 feet
• Can remove large volumes of groundwater
• Take longer to draw down water
• May obstruct areas of the jobsite at grade
  
   

Sock dewatering systems

Sock dewatering systems consist of perforated pipes installed with a specially designed trenching machine that lays the socks at a depth of around 20 feet.

Sock dewatering systems:

• Are used on excavations 5 to 15 feet deep
• Draw down water fast
• Are effective for larger sites
• Present less ground obstruction
  
   

Open pumping systems

Open pumping systems include sump dewatering, which is appropriate for shallow excavations and moving large amounts of water, and rim ditch dewatering systems, which can be built for minimal cost and work well for removing large amounts of water and redirecting discharge.

Open pumping systems:

• Are used for excavations 5 to 15 feet deep
• Draw down water fast
• Catch laterally flowing and upward flowing water
• Are best for eliminating above-ground obstructions
  
   

Groundwater filtration systems

With any type of dewatering system, filtering systems can treat the pumped-out water before it is released. Filtration can reduce or eliminate turbidity and VOCs so contractors can remain compliant with environmental regulations.

Installing dewatering systems

Contractors can rent dewatering equipment and self-perform the installation. Another option is to rent the equipment and work with a technical adviser on installation and operation.

The easiest and most time-efficient method of installing a dewatering system, however, is relying on a turnkey provider that rents the equipment, offers technical expertise and performs the installation. Look for a dewatering provider that has:

• Proven engineering and design expertise
• Trained, knowledgeable installation advisors
• A variety of dewatering equipment available
• Installation equipment designed for dewatering solutions
• A good safety record
• Service after installation, including maintenance and refueling
• Wide coverage areas to serve many jobsite locations
• A reputation for reliability and accountability

United Rentals is one of the few companies in the United States that meets all of these criteria.