Have you ever wondered why construction companies often take their time to ensure that they get the details right and go about every step of each project correctly? The reasons are not so far-fetched and are mainly because substandard structures are very risky and can collapse at any time. You can see why each step in construction is crucial, as they all contribute to making the structure stable.

Talking about structure stability, many factors contribute to determining how solid a project can be, including the preparation of the site. One critical aspect to preparing a site for construction is removing excess water from the soil in a process called dewatering. This article will explain this concept and highlight why it is essential to dewater a site, especially in water-logged areas, before construction.

The Concept of Dewatering

Dewatering is an essential part of getting any site ready for construction, and it involves removing excess water from the ground to ensure a straightforward and uncomplicated construction process. But since dewatering is a process that extracts excess water.

You must use the necessary means to remove any ground water as even a minor amount ground water will weaken the soil and possibly weaken the soils possibly causing slumping and cave ins. However, you must use the necessary means to ensure that the soil does not contain excess water, as even the slightest excess water can prove very detrimental to both the project and the process.

Why is Dewatering Necessary in Construction?

The importance of dewatering is quite numerous and crucial, especially during excavation or foundation laying. Here are some significant reasons to dewater a construction site.

  1. Safer Working Conditions: A wet site can be dangerous to work on, but a dewatered site provides a safe working space for them
  2. Increased Performance: Muddy sites are difficult to work on, slowing down overall performance. Dewatering helps eliminate this issue and ensures work continues as planned.
  3. Environmental Care: Excess groundwater may not be environmentally friendly as it can be a breeding place for insects and bacteria. Dewatering extracts excess groundwater and helps to eliminate this environmental threat.

Dewatering Techniques for Construction Sites

Many dewatering techniques have been introduced in previous years, but only four are valid for construction processes. Here is a breakdown of each.

Wellpoint system: The wellpoint system of dewatering is very efficient, and it involves the drilling of several wells on the construction site. Wellpoint installation involves the pre-drilling of 225mm diameter holes and jetting the wellpoint to depth. Pre- drilling is not always necessary in reasonably hormogeneous sandy conditions. The wellpoints are connected to a central header pipe that leads to a collection point. A dewatering pump attached to the header pipe is then used to extract the water from each well through the pipes.

Eductor Wells: This method is similar to the wellpoint system, but it typically uses high pressure/ flow water to create vacuum through a venturi resulting in ground water recovery with motive water and recovered ground water discharging above ground.

Sump Pumping: Sump pumping is the most used dewatering method because it is effortless and more economical than the other methods. It is also very efficient for extracting groundwater. Sumps must be created below the trench or excavation invert and screened to allow unimpeded ground water flows to the sumps.

Deep Wellpoint: This procedure is used where ground conditions will allow sub surface drainage to a deeper recovery point where excavations are greater than 4-5m deep especially in small with restricted working areas.


It has been established that dewatering is an essential part of construction for reasons beyond the construction process. But it is equally necessary for construction because it facilitates better projects and ensures workplace safety, among others. First class dewatering equipment is necessary to ensure favourable project outcomes. This article has discussed the top things you should know about the concept and why it is necessary.