RESEARCH-AND-DEVELOPMENT IN METHODS OF SOAKAWAY DESIGN

Soakaways have been a traditional method of disposal of stormwater for decades, and their usage has mainly been determined by the absence of a convenient watercourse, drain, or sewer into which to discharge run off arising from roofs and paved surfaces. Today, soakaways are still being installed at a rate of tens of thousands per annum, despite the extensive storm-sewer systems in the UK. It is therefore surprising th at little systematic research and development has been undertaken into their design and performance, or into the appropriate forms of mainte nance to be conducted to extend operational life. The paper briefly de scribes the recent research into, and design approaches for, the sizin g of soakaways. An example is given of the use of Building Research Es tablishment Digest 365 to review alternative soakaway designs and to a ssess the cost implications. Some field data are reported which (a) il lustrate the seasonal variability and difficulties of determination of the soil infiltration rate, and (b) provide some insight into the pol lution issues from the use of soakaways.