Climate Resilient City Tool (CRCTool)

Cities around the world are exposed to a variety of climate hazards. Planning climate adaptation interventions poses a complex challenge. Stakeholders with different roles, responsibilities, ambitions need to work together to find attractive, inclusive, fair and resilient solutions, both in the public and the private space.

Nature based remediation of the subsurface, Rotterdam

Nature based solutions

Increasingly, climate adaptation has been focused on incorporating or retrofitting Nature-Based Solutions that can effectively tackle climate hazards, while generating additional environmental and societal services and benefits. But how to identify the most appropriate applicable adaptation measures to address specific issues? And how to come up with an optimal set of measures that most stakeholders are content with? To address these challenges and bring together stakeholders, Deltares has developed the Adaptation Support Tool. This tool supports the collaborative planning of climate adaptation measures and strategy formulation for more resilient and attractive cities.

Interactive online tool

The Adaptation Support Tool (AST) is an interactive online tool and is easy to use by both experts and non-experts in the field of urban planning and adaptation. Versions of the AST that are customized to local conditions are commonly referred to as Climate Resilient City Toolbox.

Application of the AST

The AST supports integrated adaptation planning and the multi-disciplinary dialogue on adaptation options. The tool can be used in a workshop setting with multiple stakeholders as well as behind a desk to quickly explore and compare adaptation options for a project area. Results can then easily be shared with colleagues and other stakeholders working on the same project area. The AST focuses predominantly on the use of Nature Based Solutions to increase urban climate resilience; traditional grey measures are included to enable comparison. Many Nature Based Solutions have additional benefits, like enhancing health and social cohesions.

From risk analysis to adaptation planning

The adaptation planning process generally starts with an analysis of exposure and climate risk under current and future conditions based on e.g. hydrological simulation models like Delft3D FM and heat stress models. Such a climate stress test shows where problems are to be expected. Based on these results planning of adaptation interventions can begin, first conceptual and sketchy and later designed in more detailed. The AST is developed to support this first exploratory and conceptual phase.

The results of the AST can be used to inform urban designers and water managers on which adaptation measures are supported by the stakeholders and where they can be implemented.

Description of the AST

The AST tool contains a database of over 50 adaptation measures, descriptions, pictures of best practices and references for further reading. Based on the properties of the project area such as soil type, land use, scale and relevant climate hazards, the tool presents a selection of adaptation measures, ranked by their applicability and expected effectiveness in that area.

Use the AST in your own city

The AST can be applied in any place in the world. To apply the AST with reliable results the Tool is to be customized to the local conditions. The AST and underlying hydrological model have been developed open source, freely available for use via internet. Next to the freely available background documentation, training in the use of the tool as well as training on climate adaptation and Nature Based Solutions can be provided.


The AST has been used and applied in workshops in different cities around the world to plan and design for urban resilience incorporating primarily Nature Based Solutions for ecosystem-based adaptation. Examples of application of the AST by Deltares include:

  • Utrecht, the Netherlands – Co-creation of attractive, climate resilient alternatives for the reconstruction of the Beurskwartier Center area of Utrecht
  • Londen, UK – Design of sustainable urban drainage for Decoy Brook catchment, to support a cost-benefit analysis.
  • New Orleans, USA – Development of a bespoke AST version for New Orleans, and training of facilitators to support their outreach program
  • Berlin, Germany – Co-creation green and climate resilient alternatives for Moabit
    Amsterdam, the Netherlands – Design workshop as alternative approach to support climate resilient stormwater management.
  • Ålesund, Norway – Design workshop focusing on nature-based storm water management
    Quayaquil, Equador – Planning blue/green solutions for a climate resilient Urdesa district.
  • Antananarivo, Madagascar – Application of Nature Based Solutions for flood resilience
    Indonesia – Application of Nature Based Solutions for flood resilience in three cities
  • Xiangtan, China – Planning and training on Ecosystem-based Adaptation

Try the tool or learn more

A standard version of the AST can be found at: (freely accessible). This version has full functionality and is based on Dutch climate conditions. More in depth documentation on the AST can be found at:

The Adaptation Support Tool was developed in close cooperation with Alterra Wageningen UR and Bosch Slabbers Landscape Architects as part of the Climate KIC project Blue Green Dream.