Dewatering is a process that often must be done with projects that require excavation. It is the process of removing and relocating groundwater to allow excavation in a workable, more stable, and drier environment. This is done for a variety of reasons; for safety, when installing utilities or other underground infrastructure, for moving dirt more easily, or to make sure everything above-grade remains structurally sound. In a place like Florida, where we are inundated with major storms for a large portion of the year, dewatering becomes even more important in dealing with all the excess water.
Although each site is different, and you should design your specific dewatering system based on the specific site needs, there are 4 major methods of dewatering that typically get used:
- Wellpoint
- Sump pumping
- Eductor wells
- Deepwells
Dewatering may be a required part of major construction activities, but it is not without its impacts on the surrounding environment. Some factors that will control the impacts caused by dewatering activities include the scale and duration of the dewatering, surroundings, and the geological conditions. Potential impacts can include:
- Geotechnical impacts like ground settlement, which can cause damage or distress to above ground structures.
- Contamination can occur when dewatering draws in soil or water from a nearby contaminated site. A previously contained site may end up spreading contamination through dewatering.
- Groundwater often feeds surrounding water features, such as rivers, wetlands, and spring. Removing or displacing groundwater would have a direct impact on these areas.
- Dewatering may impact the availability of water that is sourced from underground aquifers. We often use these underground sources of water as drinking water or for industrial purposes.
Making sure to minimize impacts both on humans and on surrounding habitats is important when planning out your dewatering activities. Part of Environmental Compliance is ensuring that your dewatering activities are not damaging the surrounding environment. NPDES inspections also help to monitor whether sedimentation is occurring during the process. The proper inspection and reporting on site can catch issues early on and help to create a plan of action towards fixing any issues. Be sure to consult with a KCI stormwater professional if you need any assistance!