Delivering and Evaluating Multiple Flood Risk Benefits in Blue-Green Cities
University of Nottingham

WP2b. Sediment, Debris and Habitats

There is potential, through informed integrated design and decision making, to achieve multiple flood risk benefits through the use of Sustainable Urban Drainage Systems (SuDS) and Blue-Green infrastructure. Nonetheless, effective designs may be hampered by the limited understanding of sediment transport and debris dynamics in emerging vegetated and naturalized urban drainage systems. 


  • Assess sediment transport and debris dynamics within Blue-Green urban drainage networks and develop improved approaches to accounting for the risks and benefits associated with Blue-Green infrastructure

View the WP2b summary of research activities PDF file icon 



Key messages

  • SuDS/Blue-Green assets provide sediment detention, but not necessarily in the way, or to the level, that existing manuals suggest
  • SuDS/Blue-Green assets provide water quality improvement, with differing levels of benefits provided by different types of assets
  • SuDS/Blue-Green assets can change the particle size distribution in stormwater by removing the larger sediment, but again each asset acts differently
  • Field data shows the benefits of individual SuDS/Blue-Green assets: this is a step towards detention and pollutant remediation ranking of studied SuDS
  • Research has illustrated the benefit of SuDS/Blue-Green networks, and that the composition of the network is more important than the number of assets in the network

This research has been drafted into new CIRIA guidance on SuDS Asset Performance, as well as helping inform the 2015 SuDS Manual.

Tagged debris to illustrate transfer pathways in urban watercourses

 Antenna used to detect tagged debris in urban watercourse

Fluorometer used to calculate discharge (flow rates) of the urban watercourse


Pathway – receptor field data collection and analysis

Photograph of the SuDS treatment train at the J4M8 Business Park, Edinburgh, UK.

Photograph of the SuDS treatment train at the J4M8 Business Park, Edinburgh, UK.  Photograph of a storage pond at the end of the SuDS treatment train, J4M8 Business Park, Edinburgh, UK

          SuDS treatment train                               Storage pond

Using novel and innovative trace technology, debris and sediment transport monitoring was undertaken across established SuDS treatment trains and small urban watercourses. 

Tagged debris and sediment incorporating Passive Integrated Transponder (PIT) technology was released across representative urban surfaces.  

The conveyance, deposition and re-suspension of the sediment highlights the efficiency of the multi-element urban drainage network to detain or convey sediment and pollutants from the source (urban surfaces) to receptor (receiving water body).

See Allen et al., (2015) Provision, transport and deposition of debris in urban waterways, International Journal of Sediment Research.



The WP2b team comprised Scott ArthurHeather HaynesDeonie Allen, (Heriot-Watt University), Jenny Mant, Ian Holman and Sue White (Cranfield University). 

WP2b is also linked with Jenny's work at the  River Restoration Centre (RRC).

Blue-Green Cities Research Project

Sir Clive Granger Building,
University of Nottingham,
University Park,
Nottingham, NG7 2RD.

Tel. 0115 8468137