What is one method to reduce the quantity of stormwater runoff?

Installing permeable pavements is an effective method to reduce the quantity of stormwater runoff. This type of pavement allows water to infiltrate through its surface, which means that rainwater can penetrate into the ground rather than flowing over the surface and contributing to runoff. This infiltration process helps recharge groundwater supplies, reduces flooding, and minimizes the volume of water that enters storm drains and other runoff systems. Furthermore, permeable pavements can filter pollutants from the water as it seeps through, contributing to improved water quality in nearby rivers and streams.

The other methods listed would generally lead to an increase in stormwater runoff. Installing more parking spaces and constructing additional buildings typically involve adding impervious surfaces that prevent water from soaking into the soil, thereby increasing the volume and speed of runoff. Increasing impervious surfaces further exacerbates the problem, as it does not allow for natural water absorption and can lead to overwhelming stormwater management systems.