News #12

Figure: Thermal imaging camera shots from rain gardens (photo K. Bobkowska).

DID YOU KNOW?

Nature-Based Solutions (NBSs) are emerging as effective tools for improving urban ecosystems by reducing runoff, preventing floods, protecting groundwater, enhancing biodiversity, and cooling cities. Gdańsk is one of the first Polish cities to widely implement rain gardens in parks, residential areas, the city center, and even historic districts — combining scientific research with practical application. Studies from Gdańsk University of Technology show that rain gardens significantly reduce flooding, achieving infiltration rates of 0.42–0.71 mm/day and capturing up to 30 mm of rainfall on-site. They also mitigate heat: thermal imaging reveals surfaces up to 7°C cooler on cloudy days and as much as 20°C cooler on sunny days. Biodiversity increases as well, with Shannon Evenness Index values of 0.84–0.96. By retaining water, rain gardens support natural water cycles, ease pressure on drainage systems, and strengthen long-term urban resilience. In one economic example, the 3 Maja St rain garden retained 98.2 m³ of stormwater, with an estimated benefit of about 14 196 zł.

Kasprzyk, M., Szpakowski, W., Poznańska, E., Boogaard, F., Bobkowska, K., & Gajewska, M. (2022). Technical solutions and benefits of introducing rain gardens – Gdańsk case study. SCIENCE OF THE TOTAL ENVIRONMENT, 835, 155487.
https://doi.org/10.1016/j.scitotenv.2022.155487