PRIVATE LOT FLOOD PEAK ATTENUATION BY STORMWATER DETENTION TANKS

Changes in the hydrological cycle due to climate change and urbanization augment and accelerate runoff and flooding, degrade the urban environment, and cause human and material losses. Thus, it is important to implement measures that ensure urban hydrological conditions are kept as close as possible to pre-urbanization conditions, preventing floods. In addition to the conventional major and minor systems, cities may establish criteria for percentage of permeable area as well as stormwater management practices such as stormwater detention tanks, a type of low impact development technology (LID). The present study evaluates the adequacy of current practices in private lot detention tank design. It analyses time to empty, total detention time and flood peak abatement provided by detention tanks designed according to Curitiba’s (Brazil) Bylaw 176/2007. Based on the results obtained, modifications were suggested to existing legislation to increase the efficiency of the detention tanks and, thus, reduce urban flooding and adapt to climate change. The proposed methodology can be applied elsewhere to guide detention tank design.