Scenic photo of a rain garden beside a river

Quick answer：

A rain garden is a landscaped area designed to capture and filter stormwater runoff, reducing the amount of water that enters storm drains and nearby water bodies. These gardens are typically planted with native plants that are adapted to the local climate and soil conditions, and are effective in filtering out pollutants from the water. They serve as an aesthetic addition to riverbanks and contribute to the overall water quality of the environment.