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Berlin Biotope Area Factor – Implementation of guidelines helping to control temperature and runoff

Berlin Biotope Area Factor – Implementation of guidelines helping to control temperature and runoff (2014)

In Berlin inner city, plans for the development of new buildings fall under a regulation requiring a proportion of the area to be left as green space: the Biotope Area Factor (BAF) or BFF (Biotop Flächenfaktor). All potential green areas, such as courtyards, roofs and walls are included in the BAF. The regulation is a part of a larger set of documents relating to landscape planning and design and species protection. It responds to the need to encourage more green space in densely built-up urban areas. Climate change is expected to increase and intensify heat waves and water-related extremes that are of particular relevance for cities. Thus, the BAF is an important mechanism to reduce local vulnerability as its measures help to lower the temperatures and improve the runoff management. The BAF started to be implemented in 1994 and is still on-going. A considerable number of new built areas in the inner centre have implemented this regulation, translating it into green areas.

Case Study Description

Challenges

Berlin climate is temperate, with a significant urban heat island effect which raises the temperature by up to 4ºC relative to surrounding areas. While there is much uncertainty about the precise impacts of climate change on the city, scenarios indicate that temperatures will be higher, extreme weather events like heat waves and intense rain and hailstorms will be more frequent, air pollution will increase, and there will be water shortage (the latter despite extensive sources of freshwater in the city, due to longer, drier periods without precipitation, increased water consumption, and the diversion of water further upstream). These modifications in climate are expected to have negative impacts on the population, especially considering that a high density of construction and great environmental impact characterize Berlin city centre. Land that experiences high use is often severely limited in its function by:

  • A high degree of soil sealing;
  • Inadequate replenishment of the groundwater, due to the rapid runoff of rainfall into the sewage system;
  • Lack of humidity and excess warming;
  • A constant decrease in biodiversity, due to inadequate green space.
Objectives

The BAF contributes to the following environmental quality goals:

  • Safeguarding and improving the microclimate and atmospheric hygiene, reducing the urban heat island effect and therefore reducing vulnerability to heat waves;
  • Safeguarding and developing soil function and water balance, reducing vulnerability to water-related extremes;
  • Creating and enhancing the quality of the plant and animal habitat as well as improving the ecosystem's functionality;
  • Improving the residential environment.

Thus, urban planning implemented to conform with the BAF can play an important role in minimising the consequences of climate change, as it affects phenomena like local heat island effects, flood magnitudes, water quality and availability.

Solutions

The Biotope Area Factor establishes that the development of new buildings requires a proportion of the area to be left as a green space. The BAF provides developers, architects and designers with clear but flexible guidelines on the portion of a plot of land that must be planted or provide other green space functions in terms of: improvement of the microclimate, urban cooling, sustainable drainage, improvement of natural habitats and enhancement of the quality of the residential environment. Specific solutions implemented in the BAF included: (i) greening of functional spaces (e.g. bike or bin sheds); (ii) planting trees and shrubs or, in smaller areas, climbing plants to create green walls; (iii) introducing green roofs; (iv) paving only on main routes and using permeable surfaces elsewhere.

These measures reduce radiation fluxes, provide shade, provide cooling effect inside buildings and outside, improve air and water quality, and improve storm-water run-off. The strength of the BAF concept is that it allows flexibility of the site design: the developer may decide what green space measures are applied, and where, as long as the required green space ratio is achieved.

The BAF formula calculates the proportion of an area that needs to be green space: BAF = Ecologically Effective Surface Areas/Total Land Area. BAF targets depend on the specific uses of an area. Residential and public areas need to achieve a BAF target of 0.6 while commercial, business and administrative areas are requested to achieve a lower target of 0.30. Different types of green spaces are weighted differently according to their “ecological value”, based on evapotranspiration capacity, permeability, possibility to store rain water, relationship to soil functioning and provision of habitat for plants and animals. For example, the weighting of surfaces with vegetation unconnected to soil below is 0.5; that of surfaces with vegetation connected to soil below is 1.0 and that of green roofs is 0.7. The developers can thus use a wide range of options combining different areas with different types of surfaces for achieving the required standard.

Relevance

Case mainly developed and implemented because of other policy objectives, but with significant consideration of CCA aspects

Additional Details

Stakeholder Participation

The Biotope Area Factor was formulated for inner-city districts of Berlin by a large number of experts who agreed on the necessary proportion of green space areas for different development types, based on the layout of the buildings. Public consultation has always been considered highly important for landscape planning in Germany. The Landscape Programme was extensively consulted on with the public in 1986 in a targeted consultation exercise “Berlin hat Pläne (Berlin has plans)”. The second public consultation for the Programme was held after the fall of the Berlin Wall in 1993, with the Plan finally approved in 1994. The BAF was established in landscape plans as an ordinance. As part of the above procedures, public agencies and environmental agencies could participate in its development. In addition it was mandatory that the proceedings would be publicly displayed not only for residents of the particular area but Berlin-wide. Although there was a possibility for stakeholders to participate, they were not directly approached and therefore, stakeholder involvement was diverse depending on the case. Participating stakeholders included the local community, the public administration, and environmental NGOs.

Success and Limiting Factors

Use of regulations has proven to be an effective means of increasing green cover in Berlin city centre as every new development needs to comply with BAF targets. Flexibility of the approach provides significant advantages. Developers can choose between a number of different options for greening or creating permeable surfaces, and pick those that are the most beneficial and effective for themselves and the users of the development. Collaboration between the Berlin departments of landscape planning and land use planning ensured that the two planning instruments central to the implementation of the BAF are working in a coordinated way. Another factor that clearly contributes to its success is that the measures visibly proportionate the development of a better environment in the inner-city.

BAF is compulsory only in areas where legally binding Landscape Plans are present (16% of Berlin in 21 distinct areas). Outside these areas the BAF is voluntary and can be used as a guideline for encouraging environmental  measures to be incorporated when changes to the existing building structures are proposed. While this could significantly limit the applicability of BAF, due to its simplicity and the rising knowledge of environmental issues, architects, builders and property owners tend to use the BAF, which is a sign of its success.

Costs and Benefits

The costs of the measures selected on the basis of the BAF are diluted within construction costs. They may be calculated or not by each building owner who does not always inform administrative authorities. If building owners are confronted with inappropriate high expenses, they normally ask for an alleviation of the BAF which will be normally agreed to. An overall evaluation of costs has not been carried out due to a shortage of staff.

Benefits observed so far include an improved residential environment and quality of life and an increase of the effective area for biodiversity through restoring greened inner courtyards and front gardens. Other benefits such as reduced vulnerability to heat waves and to water-related extremes are expected but have not been quantified, yet.

Legal Aspects

In Berlin the BAF can be established primarily in landscape plans as an environmental planning parameter. BAF is applied to areas where legally binding Landscape Plans are present. The inherent legally-binding arrangements can be found in Berlin's "Handbuch der Berliner Landschaftspläne". Outside these areas the BAF is voluntary and can be used as a guideline for encouraging environmental measures to be incorporated when changes to the existing building structures are proposed.

Implementation Time

The BAF implementation begun in 1994 and is still on-going.

Life Time

> 50 years, depending on the specific actions and the management activities.

Reference Information

Contact

Sabine Kopetzki
Senatsverwaltung für Umwelt, Verkehr und Klimaschutz
Stadt- und Freiraumplanung
Am Köllnischen Park 3, 10179 Berlin, Germany
Tel.: +49 (0)30 9025 1341
E-mail: sabine.kopetzki@senuvk.berlin.de

Source
Green and Blue Space Adaptation for Urban Areas and Eco Towns (GRaBS)

Keywords

Air quality, biodiversity conservation, green roofs, green space measures, green walls, heat island effect, landscape design, landscape planning

Sectors

Biodiversity, Buildings, Health, Urban

Climate impacts

Extreme Temperatures, Flooding, Water Scarcity

Governance level

Local (e.g. city or municipal level)

Geographic characterization

Europe

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