Content

Potential for the Removal of Impervious Soil Coverage 2020

Methodology

The procedure was structured as a multistage concept, including a combination of survey and compilation of information of local and other experts, and an evaluation based on available geo-data of the State of Berlin.

In the context of the pilot phase of the project “Potential for the Removal of Impervious Coverage in Berlin”, the question as to the extent to which a purely automated area search based on the extensive geo-data of the State of Berlin could yield usable results by merging said data and applying filters was explored by way of example. Despite of great efforts, the generated results were unsuitable for further use. It was decided to continue with the survey process using local experts, and to refine the process.

Investigation of Areas

The survey was conducted during the years 2010 and 2019, in the borough offices of the 12 Berlin boroughs. Whenever possible, representatives of the borough offices responsible for urban planning, landscape planning and environment and conservation were included in the process. First, those boroughs with a high proportion of sites characteristic of the outskirts of the city were investigated. The survey confirmed the assumption that these boroughs would contain the greatest potential for the removal of impervious coverage.

Moreover, the survey was carried out at the four Berlin forestry agencies (Grunewald, Köpenick, Pankow, and Tegel). During this inquiry a total of 40 areas were recorded, which are located outside Berlin borders.

Also, public and private land owners of large properties which, from their portfolios, seemed to be likely to have suitable properties in their inventories, were contacted in writing.

The aim of the survey was to identify such areas which are permanently no longer required for construction use and for which the planned urban development does not prevent the permanent removal of impervious coverage in the foreseeable future. The requisite local, planning and other information could primarily be obtained from the interview partners in the urban and/or landscape planning authorities in the boroughs. A conclusive planning policy preparation of measures for the removal of impervious coverage, however, was not purpose of the investigation. The remaining needs for clarification or agreement were incorporated into the data compiled on the areas.

Ascertainment of Factual Data

For particular potential areas for the removal of impervious coverage, a variety of information was compiled which is to aid in the evaluation of the suitability of these potential areas, and for the further planning (cf. Tab. 1). This involves primarily information on:

  • the location of areas (borough, neighborhood, address/location description, coordinates),
  • the property situation, and contact data if appropriate,
  • existing (or former) use,
  • planned use or changes in use, and
  • type of impervious coverage, and extent of its possible removal.

Moreover, there is a space for comments, where unspecified information can be entered.

In order to permit a more precise assessment of the extent and cost of possible impervious coverage removal measures, about two thirds of the areas contained in the database have additionally been photographically documented to date. A selection of these photos is contained in the factual data on the respective areas, as a link.

Soil pollution of the ascertained areas is possible in general. With regard to further handling, a case-by-case decision is made by the responsible soil protection authority. For this purpose, data is compared with the soil pollution record. The removal of impervious coverage of parts of an area may potentially be possible.

Merger with Land Referenced Data

By merger with the extensive available digital land referenced data existing in the State of Berlin, information on current or concluded development planning and landscape planning procedures, the Land-Use Plan, as well as information from the maps, and the map “Planning Advice for Soil Protection” were linked to the potential areas for the removal of impervious coverage to make this information available at a glance (cf. Tab. 2).

Prioritization

Moreover, there are four criteria which are meant to guide the prioritization of potential areas for the removal of impervious coverage:

  • property rights,
  • expert assessment,
  • technical effort, and
  • time required for implementation.

This prioritization is to be carried out according to a three-point scale in each case. In cases in which an evaluation is not possible, a “n. a.” is entered; if appropriate, remarks can be entered into the comments associated with the evaluation (cf. Tab. 3).

In the evaluation of property rights/ area availability, areas, which are the property of the State of Berlin, or which can generally be considered available for other reasons (e.g. if an agreement with the private owner has already been reached) are classified as “high”. Areas which are predominantly the property of the Berlin Properties Fund (LSF), or, to the extent that is known, can be attributed to the Institute for Federal Real Estate (BIMA), or some other federal agency (e.g. the Federal Waterways) fall into the “medium” category. Areas with an unkown property situation, i.e. generally areas either in private ownership or federal assets, are classified as “low”.

With respect to expert assessment, areas where the impervious coverage can be completely removed, and where the resulting pervious surface will be connected with already existing or planned green and open-space are classified as “high”. Cases without large and connected potential areas for the removal of impervious coverage, but rather with comprehensive partial removal measures or scattered potential areas for the removal of impervious coverage fall into the “medium” category. Finally, areas which have a potential for small-scale isolated measures, or where only a very limited partial removal is possible, are classified as “low”. Additional information on expert assessment is provided by the so-called hydraulic removal of impervious coverage. This refers to areas mainly characterized by a change in coverage from areas with (fully) impervious coverage towards a type of coverage pervious to water and air, as these areas often still serve a development function (paths, courtyards, parking spaces, etc.). Essentially this is about increasing the infiltration of precipitation water. It is usually not possible to specify the removal of impervious coverage accurately in sq m.

The ascertainment of technical effort is oriented toward the type of impervious coverage, or the degree of construction on the area concerned. A high degree of building demolition or a high degree of multistory buildings possibly including basements accordingly implies a high level of effort, while a simple removal of impervious coverage, such as that of pathway or roadways, constitutes a low level of effort. Between the two lie demolition measures of a medium level of effort, involving the removal not only of the coverage itself, but also of small structures, such as cottages, garages or special structural facilities, such as greenhouses.

With regard to evaluating the time required for implementation, a rough assessment of the necessary planning effort/preliminary work was undertaken, and the implementability classed as short-term (1 to 2 years), medium term (up to approx. 5 years), and long-term (more than 5 years).

Implementation

After the process of the removal of impervious coverage has been completed, the areas are retained in the register, and marked on the map with a using a distinct type of hatching. The same process is applied to areas, where the impervious coverage has been partially removed. Moreover, information on the measures carried out, on the contact person, etc. are entered into the data table (cf. Tab. 4).

Tabular Overview of the Data

The following table lists each field in the data table with a brief description, distinguishing the following categories:

  • newly gathered data
  • data obtained by merger or manual comparison with geo-data existing in the State of Berlin
  • data fields containing evaluations of the areas, and
  • data fields containing information on the completed implementation of measures for removing impervious coverage.

The data on each field can be accessed via the map in the Geoportal/ FIS-Broker, or as a separate data table. Moreover, one can use particular data fields to filter the datasets in order to obtain an individualized selection of areas. In the following tables, data fields which support the filter function are marked by an “x” highlighted in green.

Tab. 1: Data on cases of impervious coverage removal - newly gathered data
Tab. 1: Data on cases of impervious coverage removal - newly gathered data
Image: Umweltatlas Berlin
Tab. 2: Data on cases of impervious coverage removal - using secondary data
Tab. 2: Data on cases of impervious coverage removal - using secondary data
Image: Umweltatlas Berlin
Tab. 3: Data on cases of impervious coverage removal – prioritizing potential areas for the removal of impervious coverage
Tab. 3: Data on cases of impervious coverage removal – prioritizing potential areas for the removal of impervious coverage
Image: Umweltatlas Berlin
Tab. 4: Data on cases of impervious coverage removal - implementing the impervious coverage removal
Tab. 4: Data on cases of impervious coverage removal - implementing the impervious coverage removal
Image: Umweltatlas Berlin