Soakaways

Soakaways are used to collect surface runoff prior to being discharged into the surrounding soil. They are usually employed in areas where the surface run-off cannot be disposed into existing streams or ditches.

A conventional soakaway comprises a partially perforated cylindrical chamber, which allows the drainage of water into the surrounding soil.

Where the soakage must take place at depth a deep bored liner is used. Here the water is transported from a sealed storage chamber to the soakage medium by a small diameter plastic or steel pipe, again perforated in part.

There are a number of site investigation permeability tests for determining whether soakaways may work effectively. These range from small to large scale. Small-scale tests are only applicable to draining relatively small areas. We have our own ground investigation plant and equipment and can offer the following test methods:

• NHBC: Chapter 5.3; Percolation Test for Surface Water Soakaways (Small-scale)
• BS 6297: 2007; Percolation Test for Septic Tank Insulations (Small-scale)
• BS 5930: 1999; Falling Head Test in Boreholes (Small-scale)
• BRE Digest 365: 1991; Falling Head Test in Trial Pits (Large-scale)
• BS 5930; 1999; Constant Head Test in Boreholes (Large-scale)

Sustainable drainage systems (also known as SUDS) offer an alternative approach to traditional drainage. SUDS employ alternative techniques for the effective management of drainage at source including swales, detention/attenuation ponds, permeable pavements, rainwater harvestings and integrated constructed wetlands, all of which aim to detain run-off and release it slowly into watercourses or to ground.

We have developed our own specialist in-house software programs to assist our engineers in providing timely and cost effective design solutions.