The Hydrological Behaviour of an Eco-Productive Green Roof in Bogota, Colombia

This paper responds to a very real need in Colombia. In peri-urban areas of Bogota, people harvest and use untreated rainwater. Initial research indicates that water collected from roofs contains high turbidity values, as well as high concentrations of TSS, BOD5, and heavy metals (Torres et al., 2013). Moreover, these areas do not generally have access to public sewer systems. Recently, a number of green roofs have been proposed to prevent flooding for large construction projects. Our task here is to quantify and analyse the efficacy of the eco-roofs laid out in Forero et al. (2011), which are made with easily and cheaply attainable materials such as recycled plastic bottles. The experimental set-up consists of six independent eco-roof modules and a reference roof to serve as a sort of control device. The results obtained in this study show that: (i) the crop type employed on green roofs has significant influence over the results of both hydrological behaviour and pollutants concentrations measured on the water runoff from roofs; (ii) the eco-roof can retain up to 38% of the runoff volume and can reduce the runoff peak up to 20%; (iii) the eco-roof helps retaining high concentrations of zinc (Zn).