Hydraulic performance of biofilter systems for stormwater management: Influences of design and operation

• Published in: Journal of hydrology (Amsterdam) Vol. 376; no. 1; pp. 16 - 23
• Main Authors: Le Coustumer, Sébastien, Fletcher, Tim D., Deletic, Ana, Barraud, Sylvie, Lewis, Justin F.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 30.09.2009; [Amsterdam; New York]: Elsevier; Elsevier
• Subjects: Best management practice; Biofiltration system; Clogging; Design engineering; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fluid dynamics; Fluid flow; Hydraulic conductivity; Hydraulics; Hydrology; Hydrology. Hydrogeology; Media; Reduction; Stormwater; Surface infiltration; Urban stormwater; Australia; Biofiltration system; Clogging; Best management practice; Hydraulic conductivity; Urban stormwater; Surface infiltration; urban environment; Australasia; clogging; urban areas; infiltration; surface water; drainage basins; hydraulic conductivity; hydraulics; water storage; water quality; water resource management; performances
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2009.07.012

In order to evaluate the long-term performance of stormwater biofilters, a study was undertaken to assess their hydraulic conductivity. Despite variability in conductivity (40% being below the recommended range of 50–200 mm/h, 43% within it, and 17% above), treatment performance is unlikely to be affected, as most systems are over-sized such that their detention storage volume compensates for reduced media conductivity. The study broadly reveals two types of systems: some with a high initial conductivity (>200 mm/h) and some with a low initial value (<20 mm/h). Significant reduction in conductivity is evident for biofilters in the former group, although most are shown to maintain an acceptably high conductivity. Those with initially low conductivity do not change greatly over time. Site characteristics such as filter area (relative to catchment area), age and inflow volume were not useful predictors of conductivity, with initial conductivity of the original media being the most powerful explanatory variable. It is clear therefore, that strict attention must be paid to the specification of original filter media, to ensure that it satisfies design requirements.