VEGETATIVE COVER AND STORMWATER TREES
STORMWATER MEDIANS
Vegetative cover and stormwater trees are complementary to each other measures. The area is enriched by 5,533 m2 of new pocket parks and gardens as well as 1,595 m2 of planters with stormwater trees.
Stormwater medians are applied for Lenina street by the deconstruction of the central lane. Currently, there are five lanes.The proposal implies 3 segments with width 3.6 m and length 151 m, 131 m, 131 m. The overall area is 1492 m2.
Stormwater trees with broad crown increase the efficiency of green areas regarding attenuation of the peak runoff. The tree canopies catch rainwater, the certain amount evaporates, while some volume is absorbed by the tree, the rest drops to the ground.
The stormwater median is presented by percolation trench in the middle in combination with the vegetated filter strip along both sides. The filter strips catch the sediment and provide pretreatment. The width is 1.05 m for each side. The slope 3% towards percolation trench directs the runoff. There is a 150 mm soil layer above the system which provides additional treatment and possibility to provide the vegetative cover. The underlying geocellular units with 95% retention capacity have a shape of a cuboid with 1.5 m width and 1.2 m height. One unit has the flowing parameters 1000 mm long, 500 mm wide, 400 mm high (Polypipe Civils Ltd, 2018). Thus, the overall retention volume is 706 m3.
GREEN ROOFS The rooftop of multi-story parking on Nemiga street with area 3,546 m2 is transformed into intensive garden roof. The thickness of the system is 260-470 mm and load is 320-680 kg/ m² (Optigreen Ltd, 2018). The rooftop functions currently as the parking lot, accordingly, the construction capacity is sufficient to withstand the garden. Rainwater is infiltrated and then directed to rainwater storage tank located in the technical floor. There are three segments with total volume 18m3 which is enough to hold 5mm rain event. Thus, water is collected and subsequently applied for the technical need. The system is connected with sewer in case of extreme rainfalls and necessity to discharge exceeded water.
Then, water is directed to the constructed wetland for further treatment and released to Svisloch.
CLOUDBURST ROADS The current profile of Revolyutsionnaya and Internatsionalnaya streets to its intersection with Komsomolskaya street is transformed into the V-shaped one. The width of these segments does not exceed 12 m. Thus, the cloudburst road for these streets is the measure to mitigate basement flooding. In this way, the capacity for the water redirection of Revolyutsionnaya street is 260 m3, and for Internatsionalnaya 221 m3.
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Table 5-06: Overall attenuation volume provided by WSUD measures for the sub-catchment area (Source: Author, 2018)
The implementation of the proposed scenario for the sub-catchment area allows to manage about 2,134 m3 at the place, Table 5-06.