Green roofs for comprehensive water management: Case study in Chapinero, Colombia

Abstract

The city of Bogotá (Colombia) has been immersed in flooding problems caused by rainwater, and issues from the increase in average temperature and air pollution. Green technologies are a mechanism that can mitigate these problems. This research analyzes the behavior of urban flooding in the northern sector of the Chapinero locality when replacing the existing roofs with green roofs through computer modeling. Additionally, its develops a green roof prototype, which analyzes the quality of rainwater before and after being filtered through different substrates (mixtures of garden soil, rice husk, humus, sand and/or sawdust) and plants (Sedum, Asparagus plumosus and Soleirolia), in order to determine the materials with which the conditions of rainwater quality are controlled once it filters through said roofs. The increase in the amount of green roofs contributes to mitigating flooding, as well as to the capacity of the area’s storm drain pipes to transport rainwater. In turn, laboratory results indicate that sawdust is 46% more efficient than the other analyzed materials in controlling the rainwater’s pH. Sedum plants demonstrated a satisfactory resistance to the conditions of frequent rainfall. Using green technologies not only decreases urban vulnerability to flooding, but also creates mechanisms for comprehensive water management.