How to effectively lower the water level
Most construction projects require an effective plan to lower the water table so that the job site maintains its safety and that all structures are strong. Dewatering is especially necessary for projects that involve digging deep pits as well as in wetland areas.
It is necessary to control how the water level drops below the ground because water can easily accumulate in trenches under the ground and pits. There are special pumping methods, which we will discuss in this article. Let's also look at the most basic factors to consider in creating an effective water level lowering plan:
1. Preliminary survey
Before you start developing a dewatering plan, first have a good survey of the area where the work is taking place. Examine the condition of the soil and other factors. Typically, water pumps are used to lower the water table.
It is very important to study the soil, as well as understand the condition of the groundwater in the area where the construction is planned. Sometimes the groundwater is closer to the surface and you can use another method to dewater the site.
2. Other factors before dewatering
Before you choose how you will lower the water level, first look at some of the factors:
- The location of your project.
- The type, size, and depth of the excavation.
- Solidity, thickness and type of soil.
- Geological conditions.
- The level of ground water in the areas where you plan to lower the water.
- Harmful effects as a result of the selected method of lowering the water level.
- Depth of the area where the lowering of water from the upper ground takes place.
- The impact of lowering the water table on the structures on the site.
- Cost of all works.
- Requirements and permits to be obtained prior to commencing work.
- A comparison of other methods and dewatering.
- Volume of water in the ground and the ability of each method to lower the water volume.
- How much space do you have to implement the dewatering method.
- How long do you need to use the dewatering system.
Once all factors have been carefully considered, engineers can understand which strategy should be the priority and most effective given the nature, scale and size of the entire project.
3. The Right Method of Water Level Lowering
Lowering the water table at a construction site can be accomplished by a variety of methods. Some are more complicated and some will prove to be quite simple. Let's take a look at the most popular methods that engineers most often use:
- Open sump pumping: This is one of the most popular methods; it works by gravity. A hole is made in a specially dug area so that water from nearby areas flows into this hole, this will make it much easier to pump out the water. This method is especially effective when the water level is not too high.
- Depth wells: The method is also based on the principles of gravity. A deep well is made near a construction preocct and water accumulates in it. The water level in the upper layers drops noticeably. If there is a lot of water on the site - this method will be especially effective.
- Compaction of the ground by chemical methods.
The soil around the site can be made more stable with the help of special chemical compounds consisting of soda silicates or calcium chloride. This method can be particularly costly, so if the project is not particularly extensive, do not use this option:
- Cement grout: Grout is made from sand, cement and water. This compound is injected into the ground through several holes. With this method, cracks and soil become more solid and less permeable.
- Well system: In this method, several wells must be installed, and it is one of the best and most effective methods to lower the water table noticeably.
If you choose to use any of these methods, it is important to think about keeping erosion on the site to a minimum. Fences and ditches should be lined, especially in areas where water should be lowered. There are some simpler methods:
- Gravity drainage: This method of dewatering uses special channels to transport water from where the work is being done to special water discharge areas.
- Draining: The simplest method from a technological point of view. Sometimes to get rid of unnecessary water - just use construction buckets.
4. Precautions during water level lowering
In areas where there is a high risk of soil erosion - problems are especially common during the lowering of the water level. To get rid of such a problem, use dewatering bags that will filter out sediment. Such special bags are made of geotextile fabric. The bags will easily remove sediment and filter out water.
For slurry pumps, these bags can be especially useful, so if you are using one, consider using these bags as well. When you choose where you will dump unwanted water, consider a few basic factors:
- It's best to drain to some wooded area.
- You don't want to drain on a slope.
- If the place for water discharge has erosive soil, it is better to choose another site.
- It is important that the channels to lower the water level are stable.
- No need to dewater during rains.
- It is important to be more careful if water begins to discharge toward any reservoirs (rivers, lakes, swamps, and even sewers).
Before you decide to do water dewatering, workers should thoroughly inspect the work area, survey every factor and make sure there are no risks. There are pros and cons to each method of lowering water levels. In some conditions, it will be easier to use ordinary buckets, and sometimes you will have to try hard not to spoil the soil and get rid of unnecessary water. The main thing is to balance all the major factors so that you have a safe construction site, for the best execution of the project.
Was this article helpful?24 Posted by: 👨 Joshua C. Molina