There are many considerations when determining the best dewatering method for a construction project. Variables such as the ground water table, the job site’s soil makeup, and the scope of the work being performed are all considered when choosing the most effective method.
According to MWI Pump’s Steven von Gontard, who has nearly two decades of experience selling, installing, and servicing construction dewatering projects in Central Florida, the process of choosing the best dewatering method begins with asking the contractor five critical questions:
- What is the scope of the project?
- What structure(s) are being installed?
- What is the depth of your excavation?
- Do you have a geotechnical report that provides soil borings and existing groundwater table? (This is critical to developing a successful dewatering plan.)
- Where is your discharge point and what precautions need to be taken for county/municipal/permit compliance?
Once these questions are answered, one of these five primary dewatering methods can be selected to effectively remove surface water and/or groundwater from a construction site.
- Open Pumping
Open pumping is a simple method that consists of utilizing a centrifugal or submersible pump to pull water out of your jobsite. A suction hose and strainer or submersible pump are set in the lowest area where water collects and discharges the water to the desired area. The suction screen/submersible pump must remain free from debris or mud to avoid clogging the system. The preferred pumps to use in this application are a DD004 MWI 4” Double Diaphragm Pump, an MWI Primerite™ Self Priming Centrifugal Pump, or an MWI Duraflo™ Hydraulic Submersible Pump.
- Kelly Well
A Kelly well is a piece of pipe (larger than a centrifugal pump hose/strainer or submersible dewatering pump being used) with slots cut into it. The pipe is installed into a sump at a depth greater than the required excavation and backfilled with stone as a filter media to keep the sump/Kelly well from silting. A centrifugal pump suction hose or a submersible pump is installed into this pipe and dewaters the area surrounding the Kelly well.
Water will take the path of least resistance into the Kelly well allowing for a dry area to perform the desired task. The preferred pumps to use in this application are a DD004 MWI 4” Double Diaphragm Pump, an MWI Primerite™ Self Priming Centrifugal Pump, or an MWI Duraflo™ Hydraulic Submersible Pump.