Porto Alegre, Brazil

(Case Studies)

Porto Alegre, Brazil is an example of the difficulties surrounding the implementation of stormwater management plans in an urban setting. The major issues that the city encountered were weak technical information, data deficiency, lack of decision makers, and inadequate institutional arrangements. The goal of the case study was to make officials aware of the need for more institutional improvements and better knowledge transfer. After the case study, the use of conventional methods of stormwater management was not recommended because of the rapid expansion of the town and the previous failures of these methods. Conventional methods that involved channels for water flow failed because they soon filled with solid waste, sediments, and sewage, thus contributing to a rise in water-borne diseases (Figure 1.1) (Allasia, 2007).

Figure 1.1: Interferences and Abstractions in Drainage Networks

In order to tackle the issue of stormwater runoff, the city developed an Urban Master Drainage Plan, which further posed difficulties such as data deficiency, uncontrolled migration of people into the city, lack of legal documents, lack of water storage devices, and water quality problems. The plan also encountered resistance from project managers and the general public, rendering it unsuccessful (Allasia, 2007).

The lack of data was a major hindrance to the success of the Urban Master Drainage Plan. The flow of creeks that ran through the city was not adequately recorded, and the data that was collected was often inconsistent with the actual conditions. Moreover, the city was unable to record occupied and free areas further inhibiting planning of a successful stormwater management system. Furthermore, the frequent change of government created a scenario where each new government would question the work of the previous government, effectively putting a halt on all the progress that was previously made. Another barrier to the plan was the water quality in the city. Sewage water was mixing into the drainage systems, and the large amounts of sediment and human waste matter not only decreased the performance of the systems, but also polluted the water. All of the polluted water finally dispersed to different detention ponds, which subsequently clogged with solid waste (Figure 1.2). Despite all the above mentioned setbacks, the most substantial inhibition to the development of a Master Drainage Plan came in the form of the general population’s rejection of the detention ponds. Based on previous experiences with unclean water, the people were not interested in investing their time and energy into poorly maintained detention ponds that would eventually end up mixed with sewage water and solid waste (Allasia, 2007).

Figure 1.2: Solid Waste in a Detention Reservoir

The case study in Brazil portrays some of the important problems that arise when dealing with sustainable drainage in an urban setting. In Monwabisi Park, the VPUU will be assisting us with institutional improvements, and we will be working closely with the city to allow for a better transfer of knowledge. This case study also further demonstrates the importance of community involvement.

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