Multiple event analysis of fine sediment pollutant transport through Sustainable urban Drainage Systems

Deonie Allen, Scott Arthur, Heather Haynes, Valerie Olive

Thursday 2 july 2015

15:20 - 15:35h at Asia (level 0)

Themes: (T) Hydro-environment, (ST) Impacts of pollutants on the water environment

Parallel session: 12G. Environment - Impact

There is a research gap in the analysis of this multiple event sediment deposition, distribution and pollutant flushing efficiency through Sustainable urban Drainage Systems (SuDS). Past study of SuDS efficiency in urban pollutant conveyance has focused on event and snapshot analysis. Recent studies have assessed event based suspended solid mitigation by SuDS assets, while sedimentation research considers deposition over multiple annual periods within wet (blue) assets. The functionality of ephemeral or ‘green’ SuDS assets and treatment trains comprised of both blue and green systems is less well understood over the longer term. The novel tracing technique was an in-house developed REO La tag. Field data collected were rainfall, tag concentration, TSS and deposition mass. Conclusions specific to the case study are: (i) resuspension and transport of material within the SuDS treatment train occurs for a minimum of 16 weeks; (ii) linear wetland assets general outperform alternative SUDS assets in terms of TSS mitigation and deposition; (iii) using a multiple event analysis highlights significant under-performance of SuDS assets against design capacities.