BeST (Benefits of SuDS Tool)


W045 BeST (Benefits of SuDS Tool) provides guidance to help practitioners estimate the benefits of Sustainable Urban Drainage Systems (SuDS).  Estimates are based on overall drainage system performance without the need for full scale economic input. It uses ecosystem services to understand the overall benefits that SuDS provide over conventional piped drainage.  Using values input by the user, it provides support to quantify and monetise the benefits of a SuDS scheme for a given area over a specified time period. The benefits are presented as a series of graphs and charts that are based on the ecosystem service and Triple Bottom Line (accounting) frameworks.  


SuDS scheme data in an Excel spreadsheet.

Tables / statistics / reports
Site scale
Local scale
Cost of the tool (and guidance): 
Open access (free)
A range of land uses, generally urban.
Resource requirement (software): 
Microsoft Excel
Level of technical expertise required: 
Excel skills
Types of ecosystem service included: 
Habitat type (UK NEA habitats): 
How does it work?: 

BeST is based on research evidence from the ecosystem services and Triple Bottom Line (accounting) frameworks, which consider the social, financial and environmental bottom line.  The tool uses an ‘impact-pathway’ approach.  This looks at which ecosystem services are affected by the SuDS scheme and how these changes impact on the environment and contribute to human welfare, and where possible it estimates the economic value of the changes. The tool can be applied for new developments (i.e. to compare the benefits of a SuDS option versus a conventionally drained option) or for retrofitting existing infrastructure (i.e. to compare the benefits that could be achieved with a SuDS design versus an existing baseline).

The tool is run using site-specific information input into an Excel spreadsheet. The user must answer a set of screening questions to qualitatively assess which benefit categories or 'models' should be run. Based on the choices made, the user will complete the relevant benefit assessment sheets and may need to supply information about the SuDS used (e.g. green roofs, trees, swales). The accompanying 'W045b BeST Options Comparison' tool also enables the user to compare simulations from more than one BeST model.