Dewatering for reducing groundwater level to be able to execute infrastructure and building works.
Dewatering is a technique used to control groundwater on a jobsite. In layman’s terms, it’s the nontoxic process of separating solid waste from sludge and temporarily lowering groundwater levels for drier and more stable working conditions. The unpredictability of storms and rainfall makes dewatering tanks an essential piece of equipment for any outdoor project. Without them, jobsites flood, work stalls and projects get delayed.
The benefits of dewatering
Dewatering can refer to draining underground water, which helps dry the soil to make it more suitable for construction or draining retention ponds and other bodies of water. Water can damage construction equipment or slow down operations. Dry soil reduces the risk of sediment being carried off by water and helps to stabilise the landscape. The presence of water can also obstruct certain site tasks, such as pouring concrete.
Having water on the worksite can also produce unsafe working conditions. Not only is groundwater a slipping hazard for workers, but standing water is a breeding ground for mosquitoes and other pests. Dewatering tanks help eliminate these issues, safeguard your workers' health, follow environmental regulations and keep your project on track.
Which common dewatering methods can you use?
Generally, there are four different procedures used for construction dewatering. Each method is used for a specific application, so choosing the right technique for the job is vital.
- Sump pumps: Sump pumping is considered the most simple and common dewatering method. You allow groundwater to flow into the excavation area, where it is collected in sumps to be pumped out. Sump pumping is best applied in shallow excavations containing a high gravel or sand content.
- Wellpoint: The wellpoint method includes hooking up a series of wells via a riser pipe, which are then connected to a header pipe and vacuum pump. The liquid is then suctioned offsite and treated to remove contaminants. Since this dewatering system uses suction, it is most suitable for depths of up to 6 metres.
- Deep wellpoint: This procedure uses boreholes in tandem with submersible pumps, lowering the groundwater level beneath the excavation. Small wells are drilled all around the excavation, where liquid naturally flows with gravity. This lowers the water table and drains groundwater from the excavated area.
- Eductor wells: This practice is similar to the wellpoint method, except it uses high-pressure water instead of a vacuum. This method can be used at depths of up to 45 metres and is ideal for materials like clay with low permeability.
United Rentals can support with dry installed and subs for a variety of dewatering challenges.
Dewatering helps the environment
Environmental protection plays a key role in most markets and industries these days, including construction. With the government imposing stricter laws around wastewater disposal, it is more important than ever that we find environmentally friendly solutions for its elimination. Dewatering is an eco-friendly and economical solution for many companies.
It makes sense that dewatering helps clean up the environment since it removes harmful waste and toxins from the water. But one thing you may not have considered is that this filtered water could be reused on the site itself or for other purposes. This saves on the cost of using water from mains or other sources such as rivers. We can offer many purification technique solutions when water needs to be cleaned for unsolved and dissolved contaminants. All this while lowering the labour and transportation costs of freshwater to the jobsite. Don’t let the rainy weather get the best of your construction site.