Since installation of its first deep well system in the mid-1950s, Moretrench 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 construction of Lock & Dam 26 across the Mississippi River. This depth of experience and engineering expertise is unmatched by any other dewatering contractor.
A deep well is, quite simply, a dewatering device equipped with its own submersible pump. Deep wells can vary from 3 to over 24 inches in diameter, 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 wellpoints, 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 that extend well below the bottom of the excavation.
In addition to pre-drainage for large open excavations, Moretrench has designed and installed deep well systems for such diverse applications as TBM launch box excavation for subway tunnel mining; pressure relief for dry dock repair and rehabilitation; dividing wall pressure relief to maintain dividing wall stability during water supply reservoir drainage and cleaning; and dam rehabilitation.
Deep well dewatering in conjunction with wellpoints is also proving to be 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. See more about Moretrench’s ash pond services here.
Deep Wells can be constructed by a number of different methods including jetting with pressurized water, direct rotary drilling, bucket drilling and duplex drilling. Moretrench determines the best installation method based on site geology and other project specifics.