Dewatering On Construction Sites: What You Need To Know

Safety and practicality should be at the top of your priority list for any construction project. Prior to works commencing, you’ll have several crucial tasks to organise so that engineers and builders can arrive on site on schedule, including dewatering.

We consider what you need to consider when approaching dewatering at construction sites.

What is Dewatering in Construction?

Dewatering is an efficient process where solid waste is separated from sludge to temporarily lower groundwater levels. It’s often used where water has accumulated in trenches and excavations, and in areas with a steep slope or high water table.

This ensures conditions are dry and stable before construction goes ahead.

Why is Dewatering Important?

There are a few reasons why dewatering may be an essential part of the construction process, across a range of projects.

Prepares the Soil

Before construction starts, you want to ensure you have firm foundations on which to build a solid structure. As dewatering removes any excess water, the dry soil stabilizes the ground and reduces the risk of erosion.

Ensures Safety

Wet or muddy ground can create unsafe working conditions for people on site, resulting in accidents and injuries. Standing water can also be a target for toxins and pests, such as mosquitos.

Helps You Stay on Schedule

Weather – particularly here in the UK – is notoriously temperamental. During the winter months, the abundance of rain can quickly lead to flooded sites and pockets of standing water; which can damage equipment. Dewatering at the very start will reduce this risk and keep your project on track.

How Does Dewatering Work?

Dewatering is usually achieved by using a combination of wells and pumps. The pumps pull the water from the wells to be stored or disposed of. There are several different kinds of well systems that may be used, depending on the requirements and conditions of the site.

Dewatering Methods

Well Points

Suitable for most ground conditions, well points are a series of shallow wells which are aligned along the excavated area and connected to pipes. Pumps draw out the groundwater to be discharged via a settlement tank.

Deep Wells

The deep well system consists of boreholes with submersible pumps that work to lower the groundwater level, as well as the water table, across the desired area. This method is suited to projects where large volumes need to be removed.

Eductor Wells

Utilising the “venturi effect”, eductor wells use a small volume of water at a high pressure to drive the flow. This technique is particularly effective in deep excavations with low permeability soils.

Precautions to Take When Dewatering

Dewatering is needed on most construction sites, so it’s important to consider some precautions you should take before getting started.

• Never pump water directly into sloped areas
• Avoid dewatering during periods of heavy rainfall
• Never pump water into areas that are showing signs of erosion
• Make sure the dewatering surface is surrounded by grass or vegetation
• Water that has been contaminated should never be discharged

Industrial Liquid Storage Tanks For the Dewatering Process

Keeping your site safe is essential to protecting your employees and keeping your project on track. If you’re looking for a robust and easy-to-use tank solution for your dewatering processes, our fleet of industrial water storage and sludge tanks is ideal.

To find out more about your options, please get in touch with our expert team at 01264 243116.

For more advice on dealing with excess water, see our guide on managing and storing stormwater.