Horizontal wells for dewatering are of two principal types:
- Horizontal drains installed by specialist trenching machines
- Horizontally directionally drilled (HDD) wells.
Horizontal drains installed by specialist trenching machines
This technique uses a horizontal flexible perforated pipe, pumped by a wellpoint pump, to lower groundwater levels. The perforated pipe is installed by a special trenching machine. One end of the pipe is unperforated and is brought to the surface and connected to a wellpoint suction pump. The method can be very effective for dewatering long pipeline excavations.
Horizontally directionally drilled (HDD) wells.
HDD wells are used where groundwater must be abstracted from beneath inaccessible areas or from areas where the disruption associated with surface drilling is undesirable. Applications for HDD wells include:
- Installation of permanent dewatering systems beneath existing built up (urban) environments.
- Pumping for remediation of contaminated groundwater without the risks of cross-contamination associated with vertical drilling
- Dewatering for tunnel construction
- Recharge wells to re-inject water as part of artificial recharge schemes.
Groundwater Engineering provides complete horizontal well dewatering solutions:
- Design of dewatering systems
- Well drilling and installation
- Pumping tests
- Equipment sales and rental
- Monitoring systems
- On-site operation and maintenance