Coach: Jan Hendrik Trapp (Difu)

The widespread introduction of blue-green infrastructure is changing and shifting the level of costs, cost categories and cost drivers within local authorities. For example, maintenance costs for technical infrastructure managed by the urban drainage department may fall, whilst, conversely, maintenance costs for municipal parks managed by the parks and green spaces department may rise.

As, for example, rainwater drains cannot simply be dismantled when blue-green infrastructure is introduced, overall costs may initially rise. At the same time, blue-green infrastructure improves quality of life and reduces the costs of infrastructure damage caused, for instance, by heavy rainfall – meaning it delivers benefits in the medium and long term.

Climate-resilient urban development therefore requires an integrated approach that takes into account not only ecological but also economic and social aspects, thereby laying the foundations for a sustainable and socially balanced transformation. The ‘Costs, Benefits and Financing’ module addresses this socio-economic dimension of introducing blue-green infrastructure for the cities participating in the coaching programme.

A fundamental distinction must be made between two categories of costs in connection with the introduction of blue-green infrastructure: on the one hand, the transaction costs – which are often higher than those of conventional centralised drainage systems – arising from the planning, consultation and coordination of stakeholders; on the other hand, the costs of replacing and supplementing existing urban drainage infrastructure with blue-green infrastructure.

It is also important to distinguish between a microeconomic and a macroeconomic perspective. From a microeconomic point of view, the focus is on costs (and benefits) at the level of individual plots of land or individual infrastructure components. The focus here is on owners, users and local stakeholders. Specific conflicts of interest regularly come to light in this context, requiring negotiation and cooperation between the parties involved.

From a macroeconomic perspective, blue-green infrastructure can, for example, influence the land and property values of surrounding plots, the quality of life in neighbourhoods and the public good as a whole. The macroeconomic effects – such as an improved quality of life, climate adaptation and increased resilience – justify public intervention whilst also presenting challenges regarding the equitable distribution of costs and benefits. To put it simply: who pays and who benefits?

To address these questions for cities, the BlueGreen City Coaching team offers two powerful tools that have proven their worth in practice:

• netWORKS fact sheets: Tool to support participatory planning processes
• Constellation analysis: Method for developing cooperation models in the implementation of blue-green-grey infrastructure; Schramm, Engelberg; Trapp, Jan Hendrig; Stein, Christian; Rauchecker, Markus (2023): Developing and maintaining blue-green-grey infrastructure for municipal climate adaptation. Case studies, constellations and cooperation management. Edited by the
• netWORKS Research Consortium. Berlin (netWORKS Papers, 39); Originally developed by: Schön, S., S. Kruse, M. Meister, B. Nölting, D. Ohlhorst (2007): Handbook of Constellation Analysis: An interdisciplinary bridging concept for sustainability, technology and innovation research. Oekom, Munich 2007

In addition, as part of the coaching programme, further tools are utilised and refined as required to address specific issues, including:

• The Rain Calculators from the Berlin Rainwater Agency (RWA)
• The guidance document ‘Indicative Cost Estimate for Soil Unsealing Measures’ from the Berlin RWA
• The urban green space assessment tool ‘GartenLeistungen’ from the Institute for Ecological Economic Research (IÖW)
  
  

The remaining modules: Law Politics and Administration Blue-Green Infrastructure Planning