The effects of implementation of nature-based solutions in stormwater management for the case of a former industrial zone in Moscow

Abstract

The development of blue-green infrastructure is a new, but dynamic trend in urban ecology and city planning, especially relevant in the global climate change context, that in addition to increasing temperatures leads to intensification of storm precipitation unusual for the middle zone. The situation with surface flooding is significantly worsened not only by the high percentage of impermeable surfaces in the city, but also by small slopes, which lead to the difficulties of surface runoff. This factor is typical for old city districts or former industrial areas. The increasing storm rainfall leads to additional load on engineering communications and forces to think about alternative solutions, such as rain gardens. The paper evaluated the efficiency of flood risk reduction due to the application of rain gardens on the territory of the projected residential complex in the Moscow megalopolis. The results of modeling the surface slopes of the territory showed that ⅓ of the territory excluding highways has an unfavorable slope (less than 0.5%) for the formation of surface runoff in green areas. At the same time, the most unfavorable areas with slope below 0.003 (0.3 %) account for 13.7% of the territory. It was also determined that the predominant type of catchment surfaces of the territory are catchments of depressional landforms, the most suitable solution for surface runoff drainage for which are rain gardens. At the same time, an increase in the area of rain gardens from 1.5 to 5% of the catchment area of various functional zones showed a decrease in the calculated surface runoff rates from 0 to 78%. The greatest reduction was observed when increasing the area of rain gardens up to 3%, and further increase gave insignificant effect. At the same time, for recreational areas, replacing lawn to rain gardens by more than 2% is excessive, so when the proportion of rain gardens in parks in the study area is increased, the value of overflow tends to zero. Thus, the most effective area of rain gardens for the case study (area - 95 ha) is 2.5 ha, while in recreational zones it is recommended to use only 0.5 ha for rain gardens.

Keywords

• rain garden
• blue-green infrastructure
• landscape planning
• surface runoff
• storm water drainage