Construction dewatering, the temporary lowering of the groundwater, has been practiced by Keller for more than 90 years, and we are recognized as the industry's preeminent dewatering contractor and an innovator in the field.
Process
Under some circumstances, artificial recharge can be used to minimize the potential side effects of excessive groundwater lowering during construction.
Groundwater control can also be provided by installing subsurface barrier walls or ground modification methods. In addition to construction applications, groundwater control methods can be used for environmental containment and structural seepage control or stabilization of waste products such as coal combustion residuals.
Primary dewatering systems
Since its first deep well system was installed in the mid-1950s, Keller has successfully engineered numerous dewatering projects to allow excavation in the dry, including the largest single dewatering effort ever accomplished in the United States for the construction of Lock & Dam 26 across the Mississippi River. This depth of experience and engineering expertise is unmatched by any other construction dewatering contractor.
A deep well is a dewatering device equipped with a submersible pump. Deep wells can vary from 3 to over 24 inches in diameter, can be installed from 20 feet to hundreds of feet deep, and pump from a fraction to thousands of gallons per minute. Deep wells are best suited where permeable soil extends well below the bottom of the excavation. Deep wells are equipped with individual submersible pumps. Unlike well points, deep wells are not limited by suction and can be installed from 20 feet to hundreds of feet deep. Since each deep well involves a higher unit cost than other pre-drainage systems, deep wells are best suited to homogeneous aquifers extending well below the excavation's bottom.
Deep well dewatering with well points is also proving successful in stabilizing wet fly ash and bottom ash ponds at existing or former coal-fired generating stations for fast, safe, and effective clean closure in compliance with EPA regulations.
Deep wells can be constructed by several methods, including jetting with pressurized water, direct rotary drilling, bucket drilling, and duplex drilling. Keller determines the best installation method based on site geology and other project specifics.
The wellpoint system is the oldest method of predrainage. Over the last 90 years, Keller has completed numerous wellpoint dewatering projects and is recognized as North America's leading wellpoint contractor.
The basic wellpoint system consists of well points, header piping, and a centrally located pumping station serving the whole system. Wellpoint systems are very cost-effective where close spacing is required. However, as a vacuum-type system, their effectiveness is limited by depth, and available suction lift to 15-20 ft.
Well points are typically installed around the perimeter of the excavation by self-jetting methods, with a hole puncher used to penetrate coarse gravels, cobbles, and boulders. In difficult ground, penetration can be facilitated by various drilling methods.
An ejector system is a hybrid system between well points and deep wells. Ejectors are typically used where the groundwater must be lowered more than 15 feet and the soil is of low hydraulic conductivity, so vacuum application is beneficial to improve soil drainage.
Unlike deep wells, which are equipped with individual submersible pumps, an ejector system (also called an eductor system) allows multiple wells to be powered by a single pumping station. Single-pipe and two-pipe ejector systems are available. The single-pipe system is typically used when the well casing is less than three inches in diameter, while the two-pipe system requires a minimum 4-inch well screen and casing. The two-pipe ejector is the simplest to install and can be easily removed for maintenance.
However, ejectors are inherently inefficient, and their application requires accurate knowledge of site conditions and practical restraints.
Since they are not limited to suction lift and have a lower unit cost than deep wells, ejectors are well suited for deep excavations in stratified soils where close spacing is required. Single-pipe ejectors are installed using methods similar to well points, while two-pipe ejectors are typically installed by mud rotary drilling techniques.
Specialist contacts
Andrew Buttitta, PE is an Area Manager for Dewatering/Treatment at Keller North America.
Andrew is based in Colorado and serves as Area Manager for Keller’s dewatering services in the Rocky Mountain and Midwest Region. This includes the states of Colorado, Wyoming, Montana, Idaho, Utah, North and South Dakota, Kansas, Nebraska, Minnesota, Iowa, Missouri, New Mexico, Oklahoma, and Texas.
In this capacity, his primary roles include proposal development; design input; cost estimating and budget oversight; project implementation; scheduling, and overall management of the regional projects. Although experienced in a variety of geotechnical construction techniques, he is currently focused on construction dewatering systems which include wellpoints, deep wells, and ejector wells. He covers all markets including dams, power, tunneling, infrastructure and environmental.
He holds a BS in Civil Engineering from Rensselaer Polytechnic Institute in Troy, NY. He is a Registered Professional Engineer in New Jersey. Since joining Keller in 2007, his career has progressed from Staff and Project Engineer to Project Manager, Senior Project Manager to his current position of Area Manager.
Donald Young is an Area Manager for Dewatering/Treatment at Keller North America.
Donald oversees dewatering and groundwater control projects throughout Southern California. He brings more than 20 years of local dewatering experience, supporting projects that include deep excavations, pipeline installations, dam remediation, and infrastructure construction. In his current role, Donald is involved in all phases of project delivery, including estimating and bidding, dewatering system design, crew management, materials coordination, and client relations.
Donald earned a Bachelor of Arts in Geology from California State University, San Bernardino.
Mark Farkas is a Project Manager at Keller North America.
Mark manages dewatering and groundwater control projects throughout Southern California. His experience includes temporary and permanent dewatering systems, deep wells, groundwater management, system installation, testing, commissioning, and project delivery for municipal, infrastructure, and industrial clients. In his current role, he oversees project planning, estimating, procurement, field operations, and client coordination for complex groundwater control projects.
Mark earned a Bachelor of Science degree in Civil Engineering from California State University, Long Beach.
George A. King, Jr. is a Pre-Construction Manager at Keller North America.
George has more than 40 years of experience in construction dewatering and groundwater control, including the design, installation, operation, and troubleshooting of temporary and permanent groundwater management systems. He has extensive experience in the geology of Washington DC and Baltimore, particularly for deep buildings and tunnels. His current responsibilities include project management, scheduling, and inventory management as well as design, estimating, project management, and contract negotiations. His project experience includes major infrastructure and urban development projects such as The Wharf in Washington, D.C., and the DC Clean Rivers Project.
George studied Civil Engineering at Anne Arundel Community College and Delaware Technical and Community College and has completed coursework in groundwater and hydrology through the National Ground Water Association.
Matthew DeGregoris is an Area Manager for Dewatering at Keller North America.
Matthew leads groundwater control and dewatering operations throughout the Northeast, including New York, New Jersey, Connecticut, Pennsylvania, and New England. He has more than 25 years of industry experience and has been with Keller since 2000, progressing through roles including Accountant, Project Administrator, Assistant Project Manager, Project Manager, Division Manager, and Area Manager. Matthew specializes in construction dewatering and groundwater control systems, with expertise in wellpoint, deep well, and ejector well systems, as well as landfill gas extraction well drilling.
Matthew holds a BS in Business Administration from Montclair State University in Montclair, NJ.
Greg Landry, PE, LEED AP, is Chief Engineer – Dewatering at Keller North America.
Greg has over 20 years of geotechnical contracting experience with a specific emphasis on construction dewatering. His current responsibilities include supervising the engineering team and other professionals who perform design and analysis, cost estimation and proposal preparation, client interface, and implementing QA/QC programs for Keller’s dewatering services. Greg has a deep background in designing innovative dewatering solutions for various dams, levees, and coal ash ponds across a range of geologic conditions, depths, configurations, and project objectives.
He holds a M. Eng.Sc., Groundwater Studies, from the University of New South Wales, in Sydney, Australia and a B.A.Sc., Civil Engineering from the University of Waterloo in Ontario, Canada. Licensed as a Professional Engineer in New Jersey, he has authored and co-authored numerous technical papers and has been the Co-instructor for ASCE’s annual short course ‘Construction Dewatering and Groundwater Control - Design and Application,’ since 2009.
Matthew Zabawa, G.I., is a Design Engineer II with Keller North America.
Matthew specializes in groundwater control and dewatering systems. He has more than seven years of experience in the design and installation of groundwater control techniques, including deep wells, wellpoint systems, and ejector wells. He is currently based in Rockaway, New Jersey, and supports dewatering projects throughout the United States. Matthew holds a Bachelor of Science degree in Geology and Geography from the University of Nebraska at Omaha.
Bob Lawlor is a Pre-Construction Manager at Keller North America.
Bob supports the company’s groundwater control and dewatering business across North America. He brings more than 30 years of experience in specialty construction, with expertise spanning dewatering systems, groundwater control, estimating, business development, operations, and project execution.
In his current role, he leads preconstruction strategy, proposal development, and client engagement for complex groundwater management projects. Bob earned a Bachelor of Science degree in Civil Engineering from New Jersey Institute of Technology (NJIT).
Common uses
- Groundwater control
- Pre-drainage for excavations
- Dam rehabilitation
- Expansion of existing structures
- Stabilizing wet fly ash and bottom ash ponds
Advantages
- Use in a wide range of soils including sands, gravels, silts, soft clays and stratified soils
- Cost-effective system
Related projects
Infrastructure
South Brooklyn Marine Terminal
Sports and entertainment
Atlantic Park – Surf Park
Keller provides dewatering and earth retention solutions at a new wave park, located just two blocks from where the Atlantic Ocean and Chesapeake Bay converge.
Infrastructure
Pipestem Dam Spillway Modification
To protect the Pipestem Dam, Keller installed a dewatering solution to stabilize the spillway.
Infrastructure
New Madrid Power Plant Units 1 & 2
Keller installed, operated and maintained a deep well dewatering system for a very deep excavation at a power plant in the Mississippi River flood plain.
Commercial
World Trade Center Bathtub Rehab
Keller initiated a chemical grouting program to address groundwater leakage and potential ground loss through the damaged perimeter slurry wall “bathtub” area located 75-ft below street level, 66-ft below the water table.
