5 Critical Questions to Ask Before the Start of a Dewatering Project.

Industry literature / 26 April 2024 by Griffin Dewatering
Credit : Griffin Dewatering

Before you create a dewatering plan, you have to know your current situation. Here we will discuss the information needed to create a seamless and cost-effective approach to Construction Dewatering.
Let’s dive into the five critical questions to determine the potential impacts of groundwater on your project.

1. What is the project scope?

This sounds easy, right? It’s all outlined in your project plan sheets – take a look at the few pages and take into account the goal and timeline for each step of the project. From the dewatering perspective, you will need to focus on how much work will take place below the current site grade.

2. What structures are being installed?

  • Do the structures require compaction of the subgrade?
  • Do they require a base layer of gravel?
  • Will they be pre-cast or cast-in-place?

3. What is the depth of the excavation?

Knowing the depth of all excavations from the plan sheets will help determine which will be impacted by groundwater. 

For multiple excavations determine the following:

  • How will you phase each excavation?
  • Which can be combined into one larger excavation?

Don’t forget to include any specified over-excavation in your calculations!

4. Do you have a geotechnical report with soil borings & water table information?

A geotechnical report is the single most helpful document when determining the need and best method for dewatering. 

The report includes:

  • Representative soil borings & water level information
  • Regional geological information
  • Sieve analyses
  • Slug tests results used to determine hydraulic conductivity

5. Is there an identified discharge point?

In many cases, the specifications will provide a discharge point for any water that is generated. 

Flow limitations or water quality guidelines can determine:

  • How many structures can be dewatered at the same time?
  • Most effective method of dewatering where you need to limit TSS (total suspended solids) or turbidity
  • Contamination is expected when there are identified contaminants in the discharge limits

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