Abstract
Flooding and overflow are recurring problems in several Brazilian cities, which usually face disorderly development. The causes vary, and include increased impervious surface areas, deficiency/inefficiency of drainage structures and lack of maintenance, siltation of rivers, channel obstructions, and climatic factors. In this paper, we present an analysis of mitigation measures to minimize flooding in a watershed located in the core of the city of São Paulo, the biggest city with the highest gross domestic product (GDP) in Brazil. Observed rainfall records and existing intensity duration frequency (IDF) curves for the region are used to obtain design storms. To account for climate change, the equidistance quantile matching method for updating IDF curves under climate change, a well-known procedure, was applied to the existing historical data. Several different global climate models (GCMs) and one regional model were applied to obtain and update rainfall design storms. The GCMs and future scenarios used were from Intergovernmental Panel on Climate Change—IPCC Assessment Report 5 (AR5) and two future projections—representative concentration pathway (RCP) 4.5 and 8.5. Spatially distributed reservoirs combined with low-impact development (LID) measures were used to evaluate different design storm scenarios combined with return periods of 25 and 100 years as well as the updated IDF under climate change for RCP 4.5 and RCP 8.5. Results show that the proposed changes to the drainage system can help reduce the risk and damage of flooding. The climate change scenarios, however, impose a significant threat and need immediate attention from city planners and stakeholders.
Highlights
The Anhangabau watershed lies in the central portion of the city of São Paulo, Brazil, emptying into the Tamanduatei River, which arises from other municipalities in the metropolitan region
The objective of this study is to evaluate a new alternative applied to the region of the case study, based on modern concepts of water resource management such as distributed reservoirs and low-impact development (LID)
The results are presented in terms of water surface levels, hazard indices, and impact on buildings for the current drainage system, the proposed retention system, LID controls, and climate
Summary
The Anhangabau watershed lies in the central portion of the city of São Paulo, Brazil, emptying into the Tamanduatei River, which arises from other municipalities in the metropolitan region. São Paulo was established in a flat area between the Tamanduatei and Anhangabau rivers. 300 years, life in São Paulo existed only because of these two rivers: The Anhangabau was smaller, with clean drinking water, while the larger Tamanduatei served for navigation. In the late 1930s, a city road plan was proposed, aiming to use valley bottoms for the construction of new avenues. This plan started a practice that was established as a model in city structuring, where water routes gave way to cars. Floods in the Anhangabau watershed have become a critical and chronic problem, an issue that has been studied for
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
