This year, a state of emergency was introduced six times in Sochi, three of them were in the summer. All misfortunes were associated with torrential downpours. The resort city was hardest hit by flooding in June and July, ninety percent of the monthly rainfall was recorded in the city. As a result, fourteen rural settlements, sixty streets, about a hundred residential buildings, more than three hundred cars and sixteen beaches were flooded. Today, 655 people need financial support, 455 of whom have completely lost their property. The compensation to victims of the weather disaster in Sochi for the year exceeded 77 mn roubles. Once again, nature pointed out the mistakes made by humans. Olga Shebzukhova, the resort city planner and Director General of the “New Horizons” Centre for the Development of Recreational Territories, speaks about why the floods in Sochi turn into natural disasters and how to deal with them.
- How often are floods in Sochi?
The floods in Sochi are quite logical and such bad weather in the city is rather regular. Floods have occurred almost every year since 1968. There were several largest floods, for example, in 1968, a huge downpour came down to Sochi; then, in July 2022, Donskaya Street was flooded. In many ways, such huge flooding of this particular street is due to the fact that it is a paved riverbed. There are watersheds in Sochi that border on Vinogradnaya and Pasechnaya streets, where the river used to flow. it was equipped with large sewers, but, nevertheless, did not always cope with heavy rainfalls. The worst flood disaster was on August 1, 1991 and was not associated with the rain, but with a tornado that broke up into fragments in the Matsesta River valley. The building of the health resort served as a man-made dam in the way of a powerful stream. But the main reason is the way the Matsesta riverbeds were fortified in the 1950s and in the 1970s when the mouth of the river was narrower than the rest part of the river. In June 2011, the Imereti Lowland was flooded. In many ways, this tragedy was associated with the recklessness of people who built their houses right on the bank of the Khorota River. In 2015, the airport was also flooded. By the way, over 150 mm of rain fell at that time, slightly more than in July 2022. In August 2018, a very tragic disaster happened, two heavy rains led to the death of three children. One boy fell into the manhole, and the other two were swept out to sea by a storm.
- It turns out that floods in Sochi are a fairly common phenomenon ...
- In many ways, the Sochi floods are explained by nature itself. Sochi is located in the northern subtropics. On the one hand, there are warm winters, good conditions for growing exotic plants like palms, cypresses, and magnolias. On the other hand, there are heavy rainfalls. But for the most part, floods are due to the errors made by humans. For example, the lack of storm sewers in the city. Today, only a quarter of one thousand kilometres of stormwater networks are maintained by the “Vodostok” Municipal Unitary Enterprise. The rest are not maintained, some of them have been partially dismantled, which resulted in the disrupted network of storm drains. However, there are also less obvious factors.
In the Soviet times, the city development was as a complex one. Before starting the construction activities in any area, all its engineering infrastructure was built, including storm sewers and landslide protection structures. A lot of engineering solutions were applied. For example, in the Soviet times, concrete fences were banned in Sochi. The fences were either green hedges or chain-link fences. Everything was taken into account and the water quickly drained into the ground. And concrete fences in the streets have recently led to the formation of artificial channels like the one, for example, on Rachmaninov Street. Cars that were carried this year by turbulent water streams in July were in the way of the water elements, which, in principle, was caused by humans. It is no coincidence that a large number of trees were planted in the city earlier, there was a certain standard. They did so because the speed of the water draining down the crown was much lower than just along the sidewalk, and this allowed to avoid the load on the storm sewers’ network.
- So, it is not recommended to build and acquire real estate in Sochi?
- You can buy or build it, but you need to use the right engineering solutions. In fact, not only Sochi faces such severe floods. For example, in Bolivia, a special system of technological lakes has been created to fight against the floods; and in Japan, underground tunnels have been laid to eliminate water that tornadoes ‘soak up’. Another recommendation for fighting the floods is cleaning the riverbeds from thickets, which used to be part of the integrated protection of the area from flooding. Pebbles collect naturally in the rivers. Over time, water carries pebbles to the mouth of the rivers, they accumulate, and serve as an obstacle during the rise in water level due to rains, tornadoes and melting snow. The accumulation of pebbles is called ‘bars’. And these ‘bars’ serve as an obstacle to the water coming out from the riverbed into the sea. In addition, the pebbles accumulated in the river are covered with a fertile soil layer, silt up, and plants begin to grow. The riverbed level rises, which naturally prevents the water flow. Therefore, if the riverbed is deepened in certain places and pebbles are transferred to sea beaches, it is possible, on the one hand, to avoid flooding, and on the other hand, to strengthen the coast-protection by increasing the width of the sea beach. Naturally, the bank protection of riverbeds, the strengthening of the embankment should be carried out in a complex manner, taking into account the calculations and modelling. It is impossible to build only one part of the river embankment, everything must be done taking into account the influence of one bank on the other.
- What ways of solving this problem do urban planners see?
- Firstly, as for Sochi, it is necessary to make changes to the legislation to introduce more stringent requirements for construction. Unfortunately, there are no requirements now to carry out geological surveys during the implementation of large-scale construction projects - it is enough for a separate site. At the same time, urban planners assure that for Sochi - taking into account its terrain and features - it is necessary to conduct comprehensive studies on the areas of two hundred to three hundred hectares. But according to the law, even designing is not necessary to build a private house - it is enough to draw it on paper. Urban planners are convinced that it is possible to build anywhere, but it is necessary to take proper engineering measures. One of the main strategic solutions to the flooding problems of Sochi may be the revival of the relevant designing institutes. In the Soviet times, there were several State designing institutes in Sochi with over 1,000 workers engaged in designing the city of Sochi and the Black Sea coast area. The engineers made serious monitoring of the area and landslide processes and created special maps. Unfortunately, many archives were lost when the institutes were liquidated. Today, these mistakes need to be corrected. Naturally, it is necessary that these institutes would employ the professionals who are familiar with the peculiarities of the Sochi’s climate and geology. There are few such experts left, but they still are in the city. One of the first steps to ensure the urban safety of Sochi is the creation of an engineering council that can bring together professionals and act as an expert group.
- The revival of designing institutes takes time. But what should be done now?
- The Ministry of Construction of Russia is implementing now a programme for the integrated development of Sochi that includes a number of projects for bank protection, system of drainage pipes and protection against landslides. Also, a master plan is under development in the city and potentially hazardous areas for construction will be specified. It is clear that all this is not a fast process. Therefore, now, if you need a helping hand, you will find one at the end of your arm. The tips may seem simple, but they actually help. Are you going to build a house in Sochi? When choosing a construction site, consult not only a real estate company, but also some engineers and geologists. They will help to create a full-fledged right project and plan the right utilities supply lines. Also, July of 2022 taught a lesson to everyone that they should not park cars on the slopes along the streets.
Veniamin Kondratyev, Head of the Krasnodar Territory (Kuban), has instructed to develop a draft storm sewer scheme in Sochi by the end of 2022. It is planned to build and reconstruct 22 complexes of surface water run-offs treatment plants, 19 deepwater outlets, as well as almost 750 km of storm sewerage lines in the resort city. This will help equalize the load of treatment facilities during torrential rain, as well as improve the quality of storm water treatment.
A mechanism for cleaning riverbeds was also found. Due to the imperfect legislation, there has not been a large-scale programme to do this in the city since the Soviet times. Meanwhile, 64 large rivers flow within Sochi and 26 settlements are under the threat of flooding. The Ministry of Natural Resources of Russia supported the initiative of the Kuban authorities and gave the regions the authority to do cleaning. Today, work is already underway on the Sochi River, the main one in the city. During the July rains in 2022, the water level in the river rose to dangerous levels. The contractor’s specialists work on the most problematic five-kilometre section of the river. About 600 cubic metres of soil will be removed that prevent a free water flow along the river. Work is also in progress on 34 km of other rivers that pose a threat of flooding. By the end of 2025, it is planned to clean up about 80 km of rivers in Sochi under various programmes. Sections of the riverbeds of the Ashe, Psezuapse, Shakhe, Chukhukta, Chemitokvadzhe, Tsuskhvadzha, Western and Eastern Dagomys, Khosta, Matsesta, Buu, Sochi, Kudepsta, Mzymta rivers as well as of the Belyi Stream will be cleaned.