BeST (Benefits of SuDS Tool)


BeST (Benefits of SuDS Tool) provides guidance to help practitioners estimate the benefits of Sustainable Drainage Systems (SuDS) without the need for specialist economic input.  Estimates are based on the performance of the whole drainage system rather than individual components. BeST uses the ecosystem services approach 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.

Quantitative data on ecosystem services
Tables / statistics / reports
Economic assessment
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 which looks at which ecosystems services are affected by the SuDS scheme and how these changes impact on the environment and contribute to human welfare. 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 accompanying 'W045b BeST Options Comparison' tool also enables the user to compare simulations from more than one BeST model. It was last updated in early 2019.

The tool is based on an Excel spreadsheet. The user answers a set of screening questions to qualitatively assess which benefit categories or 'models' should be run. Based on the choices made, the user will enter site-specific data onto the relevant benefit assessment sheets for the SuDS options used (e.g. green roofs, trees, swales).