Rain gardens are efficient nature-based solutions (NBSs) for the sustainable management of surface run-off in urban areas. The functionality of a rain garden in an urban environment depends on the resistance of plant and soil components to anthropogenic stressors. In temperate climates, the negative effects of de-icing chemicals applied in wintertime are one of the major anthropogenic stressors for the rain gardens’ ecosystem. The research aimed to study the effect of a NaCl-based de-icer in the mesocosm experiment, where materials of soil mixtures (seven parts by volume of quartz or carbonate sand and three parts by volume of loam or peat), plants (Hemerocallis hybrida), de-icer dose (529 mg L⁻¹ for Cl⁻ and 472 mg L⁻¹ for Na⁺ concentrations), and irrigation period simulated typical conditions for the Moscow city—the largest world megapolis with permanent snow cover during the wintertime. For all soil mixtures, a short-term negative impact of salinization on soil health included a decrease in microbial biomass (4–7-times) and basal respiration (2–3.6-times). After six months, soil health indicators recovered by 80–90% in the peat and carbonate sand mixture, whereas the negative effects on the quartz sand and loam mixtures remained irreversible (1.3 and 3 times lower than the control, respectively). The chlorophyll content of the plants on all soil mixtures was reduced compared to the control plants (37.1 ± 4.1 vs. 39.9 ± 1.2 SPAD units). The worst plat condition was observed for soil mixtures based on quartz sand. In this variant, the negative effect of salinization coincided with low nutrient content. In our results, the ash content was up to three times less compared to the initial state, as well as to the other materials. Plants grown in mixtures based on loam were more resistant to salinization due to higher nutrient content than peat. Overall, based on soil Na uptake, plant biomass, and recovery of soil microbiota, soil mixtures based on peat, loam, and carbonate sand will be the most resistant to NaCl-based de-icers and could be recommended for the creation of rain gardens in cities with permanent snow cover in winter.

Its proved, that phytofilters are environmental friendly solution of problem of purification of surface plate from urbanized territories. Phytofilters answer the nowadays purposes to systems of purification of land drainage. The main problem of it is restrictions, connecter with its use in the conditions of cold temperature. Manufactured a technology and mechanism, which provide a whole-year purification of surface plate and its storage. Experimentally stated optimal makeup of filtering load: peat, zeolite and sand in per cent of volume, which provides defined hydraulic characteristics. Stated sorbate and ion-selective volume of complex filtering load of ordered composition in dynamic conditions. Estimated dependences of exit concentrations of oil products and heavy metals on temperature by filtering through complex filtering load of ordered composition. Defined effectiveness of purification at phytofiltering installation. Fixed an influence of embryophytes on process of phytogeneration and capacity of filtering load. Recommended swamp iris, mace reed and reed grass. Manufactured phytofilter calculation methodology. Calculated economic effect from use of phytofiltration technology in comparison with traditional block-modular installations.

A technical solution for the use of rain gardens for treatment of surface runoff in a moderate climate is proposed. The experience of implementing a pilot rain garden for the treatment of surface runoff from the parking of the tenement building is described. Study results of the efficiency of surface runoff purification from suspended substances, petroleum products and some heavy metals in a pilot rain garden are presented. Recommendations for improving the quality of treated surface runoff are given. The directions of further research of rain gardens are outlined.

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.