Services

TerraFirma Earth Technologies, Ltd. specializes in the installation, maintenance, and operation of dewatering systems and equipment. We offer several services to help owners and contractors maintain acceptable groundwater levels for both temporary projects and permenant installations. We offer several services to meet this goal:

Based on a projects, we will provide proposals based on one or more of the above services, employing whichever service is best suited to the task specifications.

 

Wells

TerraFirma uses several different well designs to achieve efficient dewatering results. The most commonly used well is the deepwell. A deepwell consists of a borehole into which a well assembly (made up of casing and well screen) has been placed, the annular space between the two is filled with filter media. Within this well assembly is installed an electrically driven submersible pump and discharge column pipe, which ties into a discharge manifold after it exits the seal at the top of the well. Usually valves are placed between the well head and discharge manifold to ensure minimal downtime if an individual well need servicing.

Deepwells are often used in conjunction with relief wells. These wells consist only of the borehole, filter media, and the well assembly. The purpose of these wells is aid in the draining of the soils, thereby making the integrated deepwell system more efficient at a lower cost.
Sump wells are used if standing water is anticipated. Sump wells are installed within the base of the excavation, which allows for standing water


Wellpoint systems

Wellpoints are a common method of dewatering. They are cheaper than other methods, install quickly, and have rapid draw down times. However, they are not capable of handling excavations over about 25’ without benching in several levels. A typical wellpoint system includes a series of wellponts (usually 1-2” pvc with a slotted portion at its base) connected to a vacuum header via a swingarm. The header is attached to a vacuum pump which applies a vacuum to the system, and pulls in water from the wellpoints.

 

Eductor systems

While not as common as the previous methods, eductors are very effective at dewatering clayey and silty formations. Eductors consist of the well assembly, into which an eductor body is placed above the screen. A high pressure supply line pumps water into the eductor body, which creates a venture effect, pulling water from the surrounding soils.

 

System Maintenance and Operation

TerraFirma provides contractual maintenance and operation of both systems we install, and existing systems. Our maintenance and operations solutions ensure that dewatering systems operate as they should, and that they produce the results as originally intended.

We will evaluate your current dewatering systems and propose a maintenance program based on our initial investigations.  We work with our clients to find cost effective solutions to bring neglected systems back online, and to prevent future deterioration.