Ruddlesden geotechnical


Soakaway Drainage

Soakaway testing, assessment and recommendations in accordance with BRE DG 365 (2016) form a key service provided by Ruddlesden geotechnical.

In addition to providing soil infiltration rates for soakaway design, other geological and geotechnical aspects are considered and assessed to ascertain how the baseline ground conditions may affect the use of soakaways and how any proposed soakaways could affect the baseline conditions, including changes in seasonal groundwater levels, slope stability and the risk of creating new contamination migration pathways.

Case Study

Soakaway Drainage Feasibility Assessment, Cornwall

Soakaway drainage, combined with sustainable drainage systems (SuDS), was proposed as a means of surface water drainage at a proposed residential development site in Cornwall.

Soakaway testing and assessment was as a pre-commencement planning requirement.

In order to provide soil infiltration rates for preliminary design, in-situ soakaway testing was undertaken in accordance with BRE DG 365. Close liaison with the consulting engineer ensured that the test locations were targeted at key locations and depths across the site.

In addition to considering the infiltration characteristics at the site, as parts the site were relatively steeply sloping, a slope stability assessment was undertaken, to assess how soakaway drainage might affect slope instability; soakaways had to be carefully sited as a result of this.

Long-term groundwater level monitoringwas also undertaken to demonstrate that the seasonal high groundwater table would not rise above the base of the soakaway.

  • AGS
  • Constructionline
  • CSCS
  • SMAS
  • ECFC trust