THE NBS PROJECT FOR THE ADAPTATION OF THE KYIV OSOKORKY DISTRICT TO CLIMATE CHANGES

Global climate changes have significant impact on cities around the world, although the exact threats can vary significantly depending on the geographic region. Kyiv is a capital city with large population and vast area, which faces different challenges imposed by changing climate. The analysis of climate models demonstrates vulnerability of Kyiv urban infrastructure to heat waves, urban heat island, increasing precipitations and negative weather phenomena. The research was conducted for the Osokorky district of Kyiv to determine its problem points and evaluate the resilience of infrastructure. The results of analysis show that in spite of novelty of the district it lacks sustainability components, has poorly developed green and blue infrastructure, as well as inefficient road network. All these factors combined with dense construction create favorable conditions for the thermal pressure at local population and other biotic components of the district. The suggested approach to the adaptation of Osokorky district to climate changes is through the implementation of nature-based solutions with the aim to expand green infrastructure and increase the volume of ecosystem services provided by urban plants. The green roofs design was developed for 15 sites around the district, based on their location and favorable technical conditions. The economic costs of the project were estimated and the payback period based on the value of ecosystem services provided was defined. In order to strengthen the resilience of the district a complex of additional organizational measures is necessary to support the progress towards safe urban environment.

also predict the extreme weather phenomena, in particular heat waves, to become more severe and frequent for Kyiv by 25% [11].
To approach the problem the city administration has conducted the assessment of Kyiv vulnerability to climate changed in the end of 2021 and the corresponding plan for adaptation has be announced later on (the relevant information is available a the official web-page of the Kyiv city council [12]). However, the final document hasn't been presented yet. The overview of the problem given by the National institute for strategic studies in 2016 included a range of recommendations on institutional and legislative initiatives necessary to enable municipalities to respond to climate change challenges. Unfortunately adaptation to climate changes is only mentioned as a potential field of actions [13].
Kyiv is also a signatory of the Covenant of Mayors initiative, which aims to engage and support cities and towns to commit to reaching the EU climate mitigation and adaptation targets. Signatory cities pledge action to support implementation of the EU 40% greenhouse gas-reduction target by 2030 and the adoption of a joint approach to tackling mitigation and adaptation to climate change [14]. 310 other cities of Ukraine have joined the Convention, however, only one city has taken commitment on adaptation and this is not Kyiv, even though it has the biggest resources available. The action plans are developed by 164 cities (53% of signatory cities), but most of these plans (115 cities) are on hold due to insufficient data provided or lack of real actions, instead of declarative formulation. Thus, the task of developing The city of Kyiv has diverse natural conditions and level of infrastructure development. As a result vulnerability to climate change effects is different depending on the part of city. The aim of the given paper is to evaluate the vulnerability of the sample district of Kyiv to climate changes and develop a project for its adaptation using nature based solution.
Analysis of current situation. Osokorky residential district is the youngest massif in Kyiv -its construction began in 1993 on drained wetlands around the village Osokorky. It is located in Darnytskyi district, between the Dnieper River and Lake Vyrlytsia. Until the 1990s, the Osokorki were mostly floodplain meadows with streams, swamps and lakes. For the construction of the metro and residential facilities the wetlands were drained and alluvium was extracted. This has led to dramatic changes in local landscapes. On the territory of the private sector there is a chain of residual natural lakes, the largest of which are Zaryvakha, Pidbirna, Yaremine.
The transport infrastructure of this area is well developed, it includes subway line and the system of roads. However, their planning is based on the rectangular principles, when all the traffic flows run into one central road and then major avenue of the urban district. This creates continuous traffic complications and contributes to the thermal pollution of the area [15], exacerbated by high-rise buildings into local heat island. It is mostly mitigated by the Dnieper River, but in some areas the canyon effect is very pronounced due to lack of vegetation. The quality of air according to the data from the online monitoring system (Kyiv eco city) usually fluctuates between satisfactory and poor. This is also the result of transport emissions concentrated along the roadways and inefficient aeration in the central part of the district.
The structure of residential estate is quite diverse. These are mostly densely located high-rise buildings, with lack green elements along them. The eastern part of the district is made of the buildings of the Soviet time, many of which are in unsatisfactory condition. The auxiliary infrastructure includes several shopping malls (Pyramid and Aladdin), two hypermarkets (Epicenter and Metro), several large supermarkets (such as Novus). They are characterized be low level of landscaping and vast areas of parking zones with solid cover, prone to overheating in warm season.
The pressure from local industrial facilities (furniture, textile and automotive services) is not high, as compared with the magnitude of technogenic impact of the Bortnytsia aeration station and the waste incineration plant "Energia" from the neighboring district. Continuous construction also contributes to poor air quality.
Power supply in the district is centralized and almost exclusively electric, while the old-fashion buildings are provided with gas supply. Even though most buildings were constructed in this century the application of sustainable technologies, green architecture principles and alternative sources of power supply is very limited. Thus, only one new building is equipped with solar panels.
The system of water supply and sewerage experience high levels of wearing, since it is based on the initial network, planned for lower-rise buildings of the soviet times. The level of storm waters management is considered unsatisfactory as well and under the threat of growing precipitation levels due to climate changes there is a risk of flooding in the area.
Municipal solid waste management system is still underdeveloped as in all other parts of the city of Kyiv. Waste collection is unsatisfactory and there is no holistic system of separate waste collection.
Despite the fact that newer buildings are provided with separate containers for waste sorting, their efficiency is limited by imperfect waste collection.
The land use planning in the district is mostly aimed at maximally dense construction of residential buildings. Such approach restricts the equal expansion of the green infrastructure in the district and further aggrevate existing environmental issues and upcoming challenges, posed by climate changes.
Green infrastructure of the district is of limited coverage and lacks well-planned structure. There are no large green areas in the study area, there is only vegetation along the main streets and near houses. However, there are some green belts of the embankment of Lake Teglya, Lake Silver Circle, Lake Vyrlytsia, Lake Nebrezh, Lake Lebedyne and Lake Poznyaki. To the west of the study area there is the private sector with denser vegetation. But we believe that this is not enough to significantly reduce local temperature extremes and heat island expressiveness.
Blue infrastructure of the district is made of waterbodies (natural and artificial) around the district: lakes, ponds and the Dnieper system. However, there are no water bodies within the area. Those water bodies at the borders of the districts are characterized by numerous environmental issues, in particular, insufficient maintenance and waste management; low biodiversity of aquatic species, which makes water ecosystems vulnerable to future climate changes; pollution with urban runoff and industrial discharges; illegal extraction of construction materials; construction in floodplains. These factors considerably reduce the role of blue infrastructure in the improvement of environment condition at the study are.
Results and discussions. Accounting the above presented strengths and weaknesses of the Osokorky municipal facilities, to mitigate the effects of climate changes and to adapt the studied district to growing temperature, a plan of green infrastructure development, using green roofs, is suggested.
Technical solutions. Green roofs are divided into two types: extensive and intensive. Extensive roofs are those covered with a relatively thin layer of substrate with hardy plants (sedums, grasses, cereals), which minimizes the necessary care and maintenance of them). Intensive roofs ("roof gardens") require a larger layer of substrate, and therefore are suitable for all plants -perennials, shrubs and trees,arranged playgrounds and recreation facilities. Consequently such roofs need much more intensive care and support.
There is a large number of low-rise buildings with flat roofs in the study area, suitable for alternative greening. We have selected 15 objects, including 5 schools, 2 parking spaces, 2 hypermarkets, 3 supermarkets, 2 shopping malls, and 1 ccommercial building (Fig. 1), offering specific solutions in terms of green roofs parameters for each site (Table 1).  Additionally we offer to install solar panels at some sites. The modern trends in the sustainability for cities include development of the decentralized power supply sources, including those based on alternative solutions. Since the construction of the district is an ongoing process, wider application of alternative decentralized power supply would provide a range of valuable benefits to the district, including higher energy independence and stability of supply, lower carbon footprint of utilities and additional reserves for local business development.
The pilot facility could be the roof of the Epicenter shopping mall due to its considerable area, availability of resources for in-time maintenance and well regulated power consumption. Growing plants under the solar panels is possible, if the shade tolerant plants are chosen (e.g. woodland bulbs (bluebells, aconites etc), woodland grasses, red or white dead nettle and primrose).
The climate conditions, accounting expected rise in precipitations, are favorable for green roofs, since they need minimal irrigation. The possible drawback is that some of the chosen sites are low buildings and are partially shaded by high rise apartment blocks.
Economic parameters of the project. The cost of a green roof includes: design and project permission acquisition; installation; materials; plants seedlings and seeds; transportation; of preparation of the object (repair, if the site needs it); additional materials to create a recreational area. Also, it is important to account running costs on the maintenance of green areas, which is also paid. The price also depends on the location, based on research data [16][17][18] and information from companies providing this type of works in Europe the average cost of roofs can be accepted as follows:  This project is designed for the long term perspective. Therefore, the payback will take about 15-20 years on average, depending on the object, but it will be very beneficial in terms of ecosystem resilience and human health. The project is not a platform for direct earnings, but a tool for improving the environment, which in turn will save money in the future. As such the "income" part of the payback period is based on oxygen production, carbon fixation and cooling effect, provided by green roofs in the form of ecosystem services. The period may be reduced, if the entrance to the green zone is charged.
Of course the cost of the projects is quite high and cannot be invested from the city budget, but the given calculations could be used as a reference point for similar projects, as the choice of materials will have a profound effect on the cost of their implementation.
Since the aim of the project is to reduce local temperature and mitigate the effects of climate change, the additional solutions could be recommended: -landscaping by the principle "15 minutes walk"; -installation of green fences where possible (for example, the fence of the gymnasium "Kyivska Rus"); -painting "dark" roofs and buildings in light color (almost all buildings in the area are dark, which increases the local temperature when heated. This is a low-cost, but very effective measure); -allocation of area for blue infrastructure, which will contribute to the reduction of thermal pressure and improve the quality of air; -distribution of information on the threats from climate change and need for adaptation efforts and investments.
The complex of the suggested solutions will enable adaptation to the adverse effects of climate change and increase district resilience.
Conclusions. The urgency of climate change is raising concerns in cities about their vulnerability and pressing the need for adaptation efforts. Densely build up areas of big cities are the hotspots of climate change effects in terms of urban heat island formation and amplified air pollution.
The Osokorky district is a prominent example of the outlined problem. Its area undergoes thermal pressure and properties of its urban structure reduce its resilience and impose additional threats for the population.
In order to adapt the district to climate changes it was offered to create a system of green roofs on 15 buildings with suitable roofs. The types of recommended green roofs are tailored to the properties of the chosen objects. The expected benefits from these roofs include reduction of thermal pollution and heat island, additional recreation opportunities and improvement of the overall air quality. The costs of the project by facilities range from almost 2 million to slightly above 20000. The probable payback period is estimated in the range from 15 to 20 years, depending on the type of roof created and changes for roof usage, if implemented. The recommended types of green roofs could be changed to a more cost efficient, but the general idea will be pursued if the district is to respond efficiently to the upcoming exacerbation of climate change effects on urban environment.