Ground Dewatering

There are often occasions when you find yourself working below the natural ground water level or in an area that is affected by the tide, ground types such as running sand are both dangerous from a Health & Safety point of view and damaging to your fixed price quotation if you have not had the foresight to add a disclaimer with regard to ground de-watering.

The last time i had call to use this system we were installing a treatment plant and due to ground levels we needed to excavate down to around 3.8mtrs to accommodate the tank and a reinforced concrete base and of course at 2.2mtrs we hit running sand.

The ground was like quick sand and as quickly as the excavator dug, the ground would just level out. The de-watering guys came in and installed a system and within 24hrs it was like playing on Blackpool beach, you could have bagged the bone dry sand and sold it.

As the animation to the right show a series of well points are installed around the working area in this case a septic tank, the well points extend down to a depth beyond that required to work in and a pump draws the water up and lowers the water level in that immediate area.

Of course the difficulty is that you do not know the size of area you are draining but on the jobs i have been involved with we were able to start work within 24 hours of the system installation

Once the ground was de-watered we were able to install the treatment plant, anchor it to a reinforced base before surrounding it in concrete to ensure it didn't`t pop up out of the ground as soon as the de-watering unit was turned off.

The system is basic, simple and effective, you will however need an outlet point for the pumped water to discharge, if this is into a storm or combined sewer system a silt trap tank will be required.