Impact of Rainwater Harvesting on the Drainage System: Case Study of a Condominium of Houses in Curitiba, Southern Brazi...Published: 18 August 2018 by MDPI in Water
The objective of this work is to assess the impact of rainwater use in single-family houses on drinking water consumption and on the urban drainage system by means of a case study of a condominium of houses in the city of Curitiba, southern Brazil. A quantitative evaluation of the rainwater volume used and spilled in the recovery system was carried out using two methods for sizing the rainwater tank capacity. Using daily rainfall data and three demand scenarios of water consumption, it was possible to verify the efficiency and reliability of the adopted systems. Furthermore, in order to verify the impact on drainage, the greatest rainfall in the series was assessed and then it was possible to measure it by comparing the hydrograph peak flows with and without the rainwater harvesting systems in the watershed outfall, corresponding to the storage tanks (concrete boxes) in the condominium. It was concluded that there was a decrease in the peak flow of 4.9% and 4.4%, respectively, in the two storage tanks evaluated when the rainwater tank capacities were estimated using the method based on the German Practical Method.
<p>The rainwater use in buildings provides a number of benefits, such as securing water supply, resilience to climate change, reducing runoff in cities and potable water savings. This article presents a literature review about the use of rainwater in Brazil. A state of the art theme was presented focusing on economic, environmental and social impacts. The legislation related to rainwater harvesting ‒ including the cities that have made such a practice mandatory ‒ was also assessed. The potential for water savings is directly related to the amount of precipitation, and inversely to the potable water demand. Despite the variation in the availability of water in the country and the differences between the design and the use of the projected systems, it was concluded that there is a high potential for potable water saving when using rainwater in buildings in Brazil. The systems are efficient to supply the rainwater demands, both quantitatively and qualitatively. Some new topics are suggested, such as the study of the benefits and impacts of the large-scale rainwater harvesting use, the study of new methodologies and the effects on the drainage systems. Finally, the need for financial investments in experimental research and innovative technologies was apparent, in order to improve rainwater management, depending on user needs and environmental impacts.</p>