Blue-Green Infrastructure (BGI) in Dense Urban Watersheds. The Case of the Medrano Stream Basin (MSB) in Buenos Aires

Daniel Kozak,Hayley Henderson,Rodolfo Aradas,Alejandro De Castro Mazarro,Demián Rotbart

doi:10.3390/su12062163

Abstract

Conventional urban drainage approaches have historically focused on the volume of stormwater to be displaced with the aim of moving it as fast and as far as possible from the city. They have also been negligent regarding water quality and the inherent value of watercourses to distinct forms of life in cities, from maintaining biodiversity to providing recreational space for residents. Contemporary responses to these issues point to a paradigm change: They seek to replicate the natural mechanisms of absorption and retention, with the aim of addressing pluvial drainage needs closer to the site of origin. This article aims to explore the extent to which such an approach could be accommodated in one dense and highly impervious setting in the Global South. Specifically, it compares urban morphology, land value, hydraulic performance, and politico-institutional conditions of grey and Blue-Green Infrastructure (BGI) scenarios in Buenos Aires, Argentina. The findings suggest that even in very dense and impervious urban basins it is possible to implement BGI with a significant effect in achieving urban-sustainability goals. Furthermore, the results demonstrate that it is possible to deculvert watercourses in line with Compact City principles through the development of hybrid BGI/grey-infrastructure systems.

Highlights

There is a growing global consensus about the shortcomings of traditional hard-engineering solutions to tackle urban drainage [1,2,3,4,5,6,7,8,9,10]
This was operationalized through a scenario methodology that sought to give an account of different ways of combining possible answers to the same set of questions, with the aim of broadening debate about the advancement of Blue-Green Infrastructure (BGI) from a Global South perspective and aiding a future public-policy decision-making process locally [29]
Scenario 1 was based on the recent Urban Drainage Master Plan for the Medrano Stream Basin (UDMP-MSB) of CH2M Hill Argentina [26], financed with resources from the European Commission through the Spanish Agency for International Cooperation for Development (AECID) and the Inter-American Development Bank (IDB)

Summary

Introduction

There is a growing global consensus about the shortcomings of traditional hard-engineering solutions to tackle urban drainage [1,2,3,4,5,6,7,8,9,10]. Contemporary responses to these issues point to a change of paradigm in the design and management of urban drainage. They seek to replicate the natural mechanisms of absorption and retention, with the aim of solving pluvial drainage closer to the site of origin. They often include projects of “deculverting” or “daylighting” and the renaturalization of watercourses to different degrees. Adopting the terminology of a Source Pathway Receptor model to interpret the urban risk of flooding [5], the focus of contemporary approaches is on managing runoff at the source rather than the traditional approach of increasing the conveyance capacity of the transmission system

Objectives

Methods

Results

Discussion

Conclusion