Analysis of the use of rainwater for non-potable purposes in the square of conc?rdia city, Santa Catarina

The increase in paved areas in cities is directly related to flooding, concentrating runoff volumes in areas with low infiltration rates. In search of actions that allow the dampening of the drained volume and with the possibility of using this water, compensatory drainage techniques are employed, alternatives whose functions may be storage, and/or infiltration. In this context, this work aimed to design a rainwater harvesting system for non-potable purposes for Praca Dogello Goss, belonging to the municipality of Concordia, Santa Catarina. For this, at first, a survey was carried out of the volume of runoff produced in the square, considering the precipitation of 2018. Subsequently, based on the literature, the volume of water needed for watering gardens and lawns, as well as for washing of sidewalks. And finally, a rainwater storage and pre-treatment system was designed, consisting of a cistern followed by a stone filter. According to the results obtained, it was identified that with the waterproofed area available in the square, rainfall greater than 5 mm h-1 generates drainage in which it allows the storage of rainwater. This volume of precipitation is frequent in the region. Considering the use of water in the square for non-potable purposes (watering gardens and washing sidewalks), the square's weekly demand was 14.6 m3. In view of this demand, the dimensioned cistern had a useful volume of 30 m3, and this volume is linked to a water storage time of at least 15 days. Finally, it should be noted that the use of a storage and pre-treatment system associated with the reuse of water for non-potable purposes in the studied square, decreased an average of 8% of the runoff volume generated in the impermeable area of the square, indicating that it is a good alternative to contribute to the urban drainage of urbanized cities.