Soakaway Design

A reoccuring request we receive is to design a soakaway for a proposed small development. This request normally comes in the form of a Further Information request from planning permission applications. The Soakaway design is normally requested to be carried out as per the BRE Digest 365. This is the industry norm for such soakaway designs.                                                                                                                                                                                               Upon receiving a requst to carry out the Soakaway design our first task is to visit the site to carry out the Infiltration tests. These are similar to percolation test. The results are the prepared in the format of a small report and the size of the Soakaway determined. This report is then provided to the Council for the Further Information responce.

What is a Soakaway? 

In its simplest form a Soakaway is a large hole dug in the soil and filled with stone. Rainwater runoff from the impervious surfaces (driveways, roofs etc.) is collected by a pipe and allowed to flow into this large hole. The stone filled hole is then covered with soil and a covering such as grass/driveway etc. The Soakaway prevents flooding of the surrounding areas by allowing the large pit fill with water during times of heavy rain fall and then infiltrate into the ground slowly.

Why have the planners asked me for a Soakaway Design?

Request from the councils for Soakaway Designs have become more and more common in recent years. This is due to the increased amount of flooding in built up areas. By implenting Soakaway designs the rainwater runoff from the proposed development is curtailed within the site in question and does not put any extra pressure on the mains runoff water system thus reducing the risks of flooding.

How can D O' Sullivan Consulting Engineers help me?

Our typical request for a Soakaway comes from someone seeking planning permission for an extension/driveway/new dwelling. The local County or City Council may then request a Soakaway Design in the form of a Further Information (FI). Upon recieving instruction we then call to the site to carry out soil tests (similar to percolation tests) to determine the infiltration of the soil. This simply involves digging small holes and measuring the rate of soakage of the ground in question. These results are then used to design the size of the Soakaway. This is normally carryout out to BRE Digest 365 (the code used to size Soakaway). A diagram is also provided showing the contractor the size of the Soakaway to be constructed. Everything is prepared in report format and can be emailed directly to our client.