Time to re-evaluate urban drainage models: assessing the potential benefits of soil water measurements

Nature-based solutions (NBS) are cited in Sweden’s recent UN Climate Adaptation report and are the preferred option for urban stormwater management in the proposal for a revised EU Urban Wastewater Treatment Directive.

Planning of reliable and affordable stormwater systems typically involves use of computer models to simulate urban drainage systems under different rainfall and climate conditions.

Implementation of NBS requires inclusion of infiltration processes within models and development of methods to integrate soil water content (SWC) measurement data.

To address these two needs, this project combines two extensive field monitoring campaigns with multiple modelling approaches to investigate: influence of the number and location of SWC on levels of modelling uncertainty and which modelling approach (conceptual, mechanistic or machine learning) are most suitable for SWC in urban catchments.

Further, the specific role of using SWC in calibrating catchment models will be evaluated together with interrogation of the completely novel concept: can SWC provide a simpler and cheaper surrogate for flow measurement in predicting catchment drainage hydrology?

The project will lead to recommendations for researchers and practitioners on how to account for and utilize SWC in urban drainage modelling.

In this way, the project can contribute to the development of sustainable urban drainage systems around the world and achieving UN SDG 11 (Sustainable Cities).