The Meaning of Dewatering and its construction site methods
Introduction
Water is removed from a construction site and moved to another location, such as a detention pond or forest so that the site can be worked on safely. Construction sites require dewatering before work can begin.
The depth of the drawdown and the amount of water table lowering required are the major determinants of which the dewatering technique should be used.
What do you mean by Dewatering?
As a construction site is dewatered and the water is moved to a pond, tank, or another location, depending on local regulations, construction work can begin or continue. Dewatering can be done in a variety of ways, but evaporation or pumping are usually the two most common methods.
Dewatering: Why Is It Needed?
Depending on the location of a construction site, dewatering may be necessary, especially if it is in an area prone to flooding or holds stormwater after heavy rains.
As a result of dewatering activities, the work site stays safe, prevents slippery mud from forming, provides stabilization, and promotes erosion control.
It is important to pump water to help in the following ways:
- Ensure that the construction site is prepared
- Safety on the job site should be promoted
- Ensure efficient project management
Dewatering methods: why it matters
When there is undesired water present on a construction site, it can lead to a number of potential safety risks, increased costs, and delays to your project.
The right technique must be used to control, manage and remove water from the site during the preparation and excavation of the surface or the completion of dry site construction work on the site.
Taking into consideration that the geology and hydrology of each location will be different, this becomes even more important.
What are the common methods of Dewatering Methods?
A dewatering system can be categorized into four types: the wellpoint, the sump pumping, the eductor well, and the deep well. Depending on the type of soil and the type of excavation, different types of dewatering methods will work best.
Wellpoint
In order to dewater an excavation effectively, wellpoint dewatering systems use small, individual well points located around the excavation, which are connected to a central, centrifugal header pipe with a vacuum function that is installed at the top of the excavation.
Construction work can then begin in a stable, dry area and groundwater levels will be lowered as a result. An advantage of this system is that it can be utilized in shallow excavations or in sites with fine-grained soils that are less permeable. The cost effectiveness and ease of installation make it a great option.
Educator
The at grade pumping station for the educator dewatering method is made up of a number of tiny wells. The foot-valve and pipe systems in the wells are fitted with nozzles, also known as educator bodies, that creates a vacuum zone and suck groundwater in.
An educator dewatering system is very low-maintenance once it has been installed and is very cost-effective. Additionally, an educator dewatering system can reach significant depths, it isn't restricted by a suction lift, so it works well for use in deep excavations.
This method is particularly useful in low-permeability soils, as well as when it is necessary to space wells closely or vacuum them. Despite its ability to handle a large volume of water, it is not capable of handling a large amount of it.
Sump Pump
It has been proven that sump pumping is the most cost effective and simplest method of dewatering.
In such a system, sumps are used as reservoirs for collecting water, which is then pumped out to an area to be discharged by solids-handling pumps. These pumps are located in the drainage area.
In general, shallow excavations that do not require a lot of surface water removal are ideal for this technique, as well as soils with a low level of permeability. Although sump pumping can have many advantages, it can also pose risks such as erosion and collapse and can produce water that contains a high level of total suspended solids.
Deepwell
A deep well dewatering system lowers groundwater by drilling a sequence of wells, each with a submersible pump. The wells in this gravity-based system are bigger and deeper than those in wellpoint systems. It is frequently applied to drain water from older buildings that extend below the present excavation.
Although it can manage different excavation depths, this dewatering technique is best suited for project sites that need to pump out a lot of groundwater or require major drawdowns. It also functions effectively in soils with high permeability.
Bypass dewatering
When sewer lines require maintenance, dewatering pumps are used to pump water around damaged sections of the pipes in order to prevent sewage from backing up into the pipes.
It is important to note that the pumps are installed upstream of the maintained pipe section. Irrigation and construction projects also make use of bypass techniques on a regular basis.