The StopUP SuDS Tool

What are SuDS?

Sustainable Drainage Systems (SuDS) are a collection of drainage components designed to manage rainfall close to where it falls, to mimic natural drainage and encourage stormwater infiltration, evapotranspiration, reuse, storage, control and passive treatment. SuDS are designed to manage both the flood and pollution risks resulting from urban stormwater runoff and to contribute wherever possible to environmental enhancement and place making.  By reducing the rates and volumes of runoff from contributing urban surfaces, they can help improve receiving sewer capacity and lower risks of overflow spills.

What is the StopUP SuDS Tool?

The StopUP SuDS Tool has been built by HR Wallingford as part of the EC StopUP project. The tool is a simple web-based tool designed for non-technical users.
The tool allows users to create a representation of a SuDS network, to apply rainfall, and then to estimate and report on its hydraulic and water quality performance. In doing that, the StopUP SuDS Tool can assist users in the design and evaluation of planned SuDS schemes.

How to use the StopUP SuDS Tool?

To use the tool, you will need to follow these steps:


Build your scheme by defining each of your SuDS components (over a background map/image if you prefer)


Link your SuDS components together into a network


Add contributing urban areas


Define a suitable outfall


Select or input the rainfall you would like to use


Edit the runoff, evapotranspiration and pollutant values if you wish


Define any site information you would like to be displayed on the PDF reports


Run the model


Explore the results!

How does the StopUP SuDS Tool work?

The StopUP SuDS Tool is a simple volume balancing tool evaluating each SuDS component individually. The SuDS are represented as simple storage reservoirs which use up to three storage layers (‘drainage’, ‘soil’ and ‘surface’) and transfer water between the layers using simple rules. Unlike more complex drainage software, the hydraulic influence of downstream SuDS and the routing through the SuDS and connecting pipework are not represented. The water quality model is not physically based but uses a pollutant wash-off model combined with average event mean concentrations reflective of different land use types. The efficiency of SuDS to remove pollutants reflects observed removal rates for typical components (based on measured influent and effluent concentrations published in summaries of data held within the BMP database. (

Do you want to provide any feedback?

The StopUP SuDS Tool is undergoing further development between March 2024 and the end of the StopUP project in September 2025. If you have any feedback or undertake any testing of the Tool against other drainage models or observed data we would be grateful if you can share those with us at email address