Na New Belgrade, which still represents the largest spatial resource of the central area of the city, there is an extremely negative trend in the planning of massive underground square footage that threatens ecosystem role green areas.
New detailed regulation plans and urban projects such as the General Regulation Plan for the IMT area and new urban projects along Jurija Gagarina Street increase their square footage almost "imperceptibly" - and to the detriment of contact with the natural soil, Dr. Ivan Simić writes for the Klima 101 portal.
Namely, these plans and projects are promoted to the public as green oases, linear parks and corridors, but they include huge underground square footage, including underground garages, beneath their planned green elements.
The detailed regulation plan for the IMT II area in New Belgrade is a very illustrative example of how underground construction lines are used so extensively that they threaten the ecosystem role of green areas.
Namely, what is promoted by this plan and in the public as a "green line" is to a large extent (minimum 46%) located above the underground levels of planned buildings, or within plots for other public purposes. This means that there is very little space left for greenery in contact with the ground, in the form of relatively narrow corridors. In combination with other facilities that also belong to "free areas", greenery can be realized here mostly in the form of tree rows, but without space for a park that can support ecosystem services.
Why is this important?
The key property of greenery is soil
The "services" that greenery should provide are not only for the comfort and recreation needs of residents, but they are recognized as ecosystem services and are crucial for the adaptation and survival of not only people, but also the entire living community within an urban ecosystem.
In order for green spaces in the city to successfully respond to this call, it is no longer enough to consider them only in terms of quantity and availability. In order to enable ecosystem services, a key property of greenery is soil. Natural land cover and unchanged soil layers are necessary for the basic metabolic processes of an ecosystem, which are reflected in the circulation of matter and the flow of energy.
This has direct implications for urban planning, as traditional land use zoning is now linked to the soil substrate parameter, uniting the physical properties of land with dominant human activities (land use - land cover, LULC).
Let's take porosity as just one example: natural soil can absorb far greater amounts of water than planters, green roofs, facades and other solutions that are "green", but which are not characterized by contact with natural soil.
In fact, if we follow the "sponge city" concept, all these small elements play the role of fine receptors and receive atmospheric water, which further ends up in the natural soil through natural drainage paths and bioretention, thus rounding off its natural cycle. The sponge system thus consists of large and small absorbents that jointly contribute to the prevention of urban flooding when certain streets become torrential watercourses and settlements become temporary "lakes".
A scientific study by the Institute for the Environment of Leiden in the Netherlands, which covered the entire area of the highly urbanized Netherlands, indicated that 74,9% of native species, 83,9% of endangered species and 77,1% of rare species prefer landscapes with over 50% natural cover. Given the importance of the use of indigenous species in the strategies of adaptation of cities to climate change, it is clear how important the natural soil base is.
The system of green areas is organized hierarchically - not every green area is the same
Another illustrative example of endangering a key element of green infrastructure is the urban project for an underground garage under the park near the Bristol Hotel in Belgrade's Savamala.
Namely, this park is the only major element of green infrastructure in the conditions of high built-up Savamala, which is additionally burdened by the construction of "Belgrade on the Water". In such conditions, the complete preservation of the green area in direct contact with the ground is an absolute priority.
Instead of looking for solutions for parking in other, primarily private plots in the "Belgrade on the Water" area, a public park was sacrificed, which would have been ecologically devastated by the construction of underground garages.
While Belgrade and Serbia in general are still in the clutches of investor urbanism, many European and world cities are abandoning aggressive intervention on the ground, introducing regulations that limit the underground levels of buildings, and former industrial sites are treated as a valuable resource in the city center where green areas can be expanded and revitalized.
It is clear that in urban areas we cannot count only on surfaces that are in direct contact with the ground, but their presence must be defined in a plan and legally ensured in order for the "green system" to function.
Cities, especially in their central areas, are dominated by densely built-up areas with a high percentage of public and private lots occupied. In such conditions, every element of greenery is important, but the presence of natural ground cover is also necessary.
Therefore, it is necessary to introduce some kind of systematization of surfaces based on critical ecological parameters (such as the porosity of the land cover) in order to ensure the system functionality and connectivity of greenery.
The system of green areas is organized hierarchically and perhaps, for the sake of illustration, we could compare it to the human anatomy.
Fingers are necessary parts of the body without which a person would lose vital functionality, but they are not equally important and cannot replace the spinal column. It is the same with the "green anatomy" of the city: rows of trees, planters, green roofs and facades are necessary elements of the system, but they cannot be a substitute for city forests, parks and green-blue corridors.
Belgrade already has plans that could enable solving this problem
The planning basis for the implementation of the green area system in Belgrade is the General Regulation Plan of the Green Area System (PGRZP), which establishes greenery as a complete system of the "green infrastructure of the city" recognizing "green areas in direct contact with the ground" as the type of surface of greatest importance for ecologically functional spaces.
This document proposes a special methodology that would establish a hierarchy, that is, a gradation of green areas in relation to their ecological functionality: the ecological index.
It is about the methodology by which the so-called are added to different surfaces. weighting factors, values between 0 and 1, which are multiplied by the square. This index assigns the highest weighting factor (1.0) to greenery in direct contact with the ground. Next is the green area on the underground building (layer thickness greater than 80 cm) and green roof with 0.7, then green facades and semi-porous surfaces with 0.5, and so on.
In other words, according to this methodology, one square of greenery in contact with the ground is twice as valuable as e.g. green facades, and the index itself should be used with the measure of the minimum target ecological index, which depends on the urban form and type of construction, and which should be adopted for different forms of construction at the level of the entire city.
As we have already stated, full ecological functionality can only be provided by surfaces in direct contact with the ground, and that is why they form the backbone of green infrastructure, while other types of greenery are a necessary upgrade.
Our other strategies and plans, such as the recently adopted Green Infrastructure Strategy of Belgrade, recognize, define and provide clear standards and recommendations that are aligned with the modern concept of green infrastructure.
This very important strategic document prepared by a team of our experts headed by prof. Dr. Boris Radić from the Faculty of Forestry points to the great consequences of natural urbanization precisely by predicting the change of land cover in the territory of the city of Belgrade.
In the Strategy, this change was analyzed and simulated (modeled) using the CORINE input data set for the period 1990 - 2018, with predictions made for 2030 and 2040.
The results indicate that significant changes in the representation of land cover types in the territory of the city of Belgrade are expected from 2018 to 2040: a decrease in arable land and high vegetation, and a drastic increase in the total share of artificial surfaces - from 13,4% to almost 16% of the city's territory.
However, the main problem is that these documents, although adopted at the level of Belgrade, were adopted at the level of recommendation - and there is no obligation to implement the proposed measures. In fact, one of the priority goals of the Green Infrastructure Strategy of Belgrade is to ensure the legal implementation of these policies.
Just as construction parameters (built-up index and occupancy rate) are binding and strictly controlled, the same should be done with regard to environmental parameters, if we do not ensure the conditions for the development of green infrastructure as a key city resource for adapting to climate change.
Otherwise, Belgrade will continue to develop with "green corridors" that are only on paper, with greenery as a mere cover of gray construction, including the underground one.
