What is the primary function of retention basins?

The primary function of retention basins is to retain storm water and allow for evaporation or infiltration. These basins are designed to hold excess storm water runoff, which can help manage and control flooding in urban areas. By allowing the water to slowly evaporate or seep into the ground, retention basins play a significant role in recharging groundwater supplies and reducing the volume of water that flows into local waterways, thereby mitigating potential pollution and erosion effects from storm water runoff.

This function is crucial not only for flood prevention but also for maintaining water quality in the environment by reducing the peak flow of runoff and providing time for natural filtration processes to occur before the water reaches downstream areas. Other answers, such as collecting hazardous waste, filtering pollutants, or serving non-water management purposes like parking lots, do not adequately represent the primary and most beneficial purpose of retention basins in storm water management practices.