Puddle alarm – Newspaper Kommersant No. 110 (7072) from 29.06.2021

by time news

Numerous flooding of the roadway and courtyards was caused by the tropical “super shower” that took place in the Moscow region, as forecasters called it. Within a few hours, up to 70% of the monthly precipitation rate fell in some areas of the city. The authorities eliminated the consequences of the disaster until late at night: the metro, outbound highways and district streets were damaged. Experts say that the Moscow storm sewer cannot cope with heavy rainfalls and has long been in need of “comprehensive modernization.” The State Unitary Enterprise “Mosvodostok” said that the system is working normally and in accordance with the “town planning norms”.

The heavy rain that hit the capital region was described as “super-intensive” in the Moscow city economy complex. In the center “Phobos” the element was called “super shower”. In an hour, a large number of flooding occurred on the streets: huge puddles formed on Leningradsky Prospekt near the Metropolis shopping center and in the Airport metro area, cars were forced to drive along the sidewalk. Some of the tunnels on Leningradka were flooded. On the street of the People’s Militia, eyewitnesses filmed a man swimming across the road. An emergency situation due to stagnation of water arose on Dmitrovskoe highway, the authorities were even forced to block traffic. Local flooding on smaller streets, according to Kommersant’s estimates, formed several dozen throughout the city – all of them provoked congestion (on Monday afternoon, traffic jams reached seven points atypical for Monday). A few hours after the end of the downpour, the water remained on the streets of Narodnogo Opolcheniya, Vavilov and Vilnius, Marshal Tukhachevsky, Profsoyuznaya, and a backup of Rublevskoye highway.

The Moscow mayor’s office said that 300 brigades and 290 units of equipment from the Mosvodostok State Unitary Enterprise took part in eliminating the flooding.

Large-scale flooding of streets is a regular occurrence in the capital after heavy rains: a similar situation was observed in the summer of 2018, 2019 and 2020. Each such case provokes controversy among experts about the state of the storm sewer and its ability to withstand the onslaught of the elements. In 2020, Deputy Mayor Pyotr Biryukov said that after heavy rains, Paris and Prague “really heat up” when they overflow the river banks, and this never happens in Moscow: “Our Moscow network is today one of the most progressive in the entire world practice “. It should be noted that Moscow has already encountered flooding of streets, intersections and underpasses this season – in particular, during heavy rain on May 29, when the city authorities reported that in some areas half of the monthly precipitation rate fell.

Residents regularly complain about flooding through gorod.mos.ru. In June 2021, 165 complaints about water in yards were registered (in May there were 60) and 149 complaints about flooding of the roadway (in May there were 39). Responsible for residents, as a rule, are the councils, the regional state budgetary institution “Zhilischnik” or “Highways”. Officials in their answers often use the same formulations: “the accumulation of water is temporary due to heavy precipitation”, pointing out that there are no disruptions in the work of the sewerage system. Some of the flooding, it follows from the answers, is related to repairs or construction works and is temporary.

In Moscow, storm sewers are not designed to handle large quantities of water in a short time, explains Irina Irbitskaya, an architect and consultant to the UN Development Program.

«Redoing the sewage system in Moscow is monstrously expensive, the city is unlikely to go for it, she explains. “It will not be possible to completely get rid of the consequences of the cataclysm in the form of local flooding in the near future.”

There are engineering solutions for the so-called soft sewerage, the expert says, which make it possible to compensate for the drawbacks of urban storm drains, for example, local reservoirs for receiving water along sidewalks. Also, she explains, it is possible to organize the flow of water from the roadway into lawns, squares and parks: “This is not an easy decision, not all vegetation will feel good with such volumes of water.” Note that on Monday, eyewitnesses published a video of the December Uprising Park in Presnya, which was closed for improvement – most of it is located above the carriageway, the fenced perimeter of the park was almost completely flooded, streams of water mixed with the ground flowed from there into the streets.

“The city needs a hydrological diagram that will show how precipitation is distributed, which the sewage system cannot handle,” says Irina Irbitskaya. “And on its basis, decisions can already be made.” In Moscow, unlike many cities, there is in principle a sewage system and it is maintained “not so badly,” says Svetlana Razorotneva, head of the Public Chamber’s commission on housing and communal services, construction and roads. “But there have been no large-scale modernization projects in recent years,” she says. “Often, storm drains are sealed during poor-quality landscaping due to the involvement of cheap contractors, especially in the yards. A lot of such problems have accumulated in the city ”. Indeed, in the past few years, it has been regularly reported about the occurrence of new flooding zones during heavy rains on the streets of the capital, which have already been improved, and about situations where road and construction work in the streets and in yards was carried out without taking into account the existing storm sewers, which ultimately was violated.

The press service of “Mosvodostok”, responding to a request from “Kommersant”, said that the drainage network of the capital “is designed according to the norms of urban planning regulation”, according to which the duration of “estimated rain for a given area” does not exceed 20 minutes, and the average intensity of such rain does not exceeds 75 mm for June.

“With such an intensity, the network will receive the entire surface runoff without water accumulation on the surface,” explained the State Unitary Enterprise. “Water accumulation is allowed due to the fact that water must reach the grate. The drainage network safely takes over the super-intensive volume in less than one hour. ” Such work, they explain in “Mosvodostok”, meets “common sense”, because “otherwise it would be necessary to pave the entire surface with storm gratings, and drainage pipelines would be of gigantic diameters,” which is “neither technically nor economically feasible.” The possibility of laying a large-diameter network in a megalopolis with a deficit of underground space is “practically excluded”, the state unitary enterprise emphasizes. “Most of the time, such collectors will not be filled with water, the speed of the water flow will be minimal, which will lead to siltation of the network,” the agency says.

Flooding as a result of intense rains, apparently, should be expected throughout the coming week: showers and thunderstorms are expected in the Hydrometeorological Center in the coming days. The forecast of the Ministry of Emergency Situations in Moscow for June 29 says that “dangerous meteorological phenomena are not predicted”, but emergencies are possible “not higher than the local and local level.”

Ivan Buranov

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