SuDS in the Thames : suitability of the ground for infiltration

Following large-scale flooding in 2007, the Pitt Review (Pitt, 2008) established that surface water was a primary cause of flooding. In response, the Floods and Water Management Act, enacted in 2010, includes the provision for sustainable drainage systems (SuDS), which aim to tackle this problem as well as improve water quality in rivers. A key sustainable drainage technique is infiltration to the ground; these systems utilise the storage capacity of the subsurface to attenuate rainfall and include, for example, soakaways, infiltration basins, infiltration trenches and free-draining permeable pavements (Figure 1). In the UK, the subsurface in many areas provides effective and practical opportunities for the attenuation of rainwater, however a number of considerations must be taken into account during the planning, design and installation process. To promote these techniques, the British Geological Survey is developing a national dataset that incorporates a wealth of subsurface data necessary for preliminary desk-based site assessment.