Hydrologic performance assessment of regulated and alternative strategies for flood mitigation: a case study in São Paulo, Brazil

ABSTRACT

This study examines the hydrologic performance of conventional and low-impact development (LID) stormwater approaches when implemented as retrofit measures in a highly urbanised catchment (10.23 km²). A hydrologic-hydrodynamic model was proposed to simulate different implementation scenarios. Rainfall data and downstream water level observations between 01/2016 and 02/2019 were used to calibrate and validate (0.77$\le$NSE$\le$0.97) the model for the current situation. The simulation of stormwater control, as indicated in the municipal regulation, involving on-site retention tanks at a lot scale, led to peak flow reductions of 5% for a 10-year design storm event. When the number of dwelling owners subjected to comply with the control measures was increased, a peak flow reduction of 18% for the same event was reached. Modelling tools can guide policy and rule-making processes from a catchment management perspective, supporting the evaluation and improvement of strategies adopted in urban stormwater management.

KEYWORDS:

• Watershed management
• hydrological modelling
• low-impact development
• flood mitigation
• stormwater management
• sustainable development

Acknowledgements

The authors are grateful to the São Paulo Flood Warning System (SAISP) for the data provided.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This study was financed in part by the São Paulo Research Foundation (FAPESP) under Grant number 2018/19222-7 and by the Coordination for the Improvement of Higher Education Personnel (CAPES, Brazil), Finance Code 001.