Which of the following measures can effectively reduce urban stormwater runoff?

Implementing green infrastructure like rain gardens is a highly effective measure for reducing urban stormwater runoff. Rain gardens are designed to capture and infiltrate rainwater from impervious surfaces, such as driveways and roads, allowing it to percolate through soil and vegetation rather than flowing directly into storm drains. This process not only minimizes the volume of stormwater entering drainage systems but also helps filter pollutants, thus improving overall water quality.

Rain gardens utilize native plants that thrive in local conditions, enhancing biodiversity and providing additional ecological benefits. By promoting infiltration, reduces the risk of flooding and erosion, ultimately contributing to more sustainable urban water management practices.

Other options like installing more drainage pipes and increasing impermeable surfaces can exacerbate stormwater runoff problems, while large retention ponds may be a solution but often require significant space and maintenance. Therefore, the implementation of green infrastructure represents a holistic approach to managing urban stormwater effectively.