Policies enforcing catchment-fit NBS

Effective implementation of nature-based solutions begins with clear political commitment and institutional mandates that translate strategic ambitions into actionable responsibilities across municipal departments. Most cities with structured approach to NBS, where NBS are embedded in policies, supported by dedicated organizational structures, and guided by coherent regulatory instruments, have reached there because serious flood events that have brought along significant damage.

It is however clear that institutionalization of NBS is not dependant from catastrophes and can be rolled out also by learning from peers and implementing pilot projects. This transition requires aligning political leadership with financing and resource mobilisation —ensuring that ambitions are backed by stable funding sources, defined responsibilities, and cross-sector coordination. As governance matures, municipalities move from relying on individual champions and external funding towards institutionalised frameworks, where NBS are systematically integrated into planning, budgeting, and infrastructure delivery processes.

Policy examples

  • Aarhus has developed strong policy support for catchment-fit nature-based solutions (NBS) through a combination of climate adaptation needs, water quality objectives, regulatory requirements, and a long-term vision for sustainable urban development. The city recognizes that climate change will bring both more frequent rainfall events and more intense cloudbursts, increasing flood risks across urban areas. As a result, climate adaptation has become a strategic priority embedded in municipal policies, plans, and investment programmes.

    Beyond flood risk, Aarhus faces significant challenges related to the ecological status of Aarhus Bay and the protection of groundwater resources that supply the growing city. According to assessments under the EU Water Framework Directive, several receiving water bodies have not achieved favourable ecological status. This creates a strong rationale for reducing stormwater pollution, restoring natural water cycles, and integrating stormwater management into broader water governance objectives.

    Municipal policymakers are well aware of these challenges and increasingly view catchment-fit NBS as a tool for simultaneously improving water quality, strengthening climate resilience, and enhancing urban environments.

    European and national legislation further reinforce this policy direction. EU environmental regulations require improvements in waterbody status and encourage integrated water management approaches, while Danish municipalities play a central role in implementing River Basin Management Plans. National climate adaptation, water management, and spatial planning legislation provide additional support for municipal action and create a favourable policy environment for integrated stormwater management.

    Public expectations have also contributed to political support. Residents increasingly value attractive, liveable, and environmentally sustainable urban environments, creating demand for multifunctional solutions that combine stormwater management with recreation, biodiversity enhancement, and placemaking. This has helped position NBS as an opportunity rather than merely a technical requirement.

    Over time, Aarhus has developed substantial institutional capacity to integrate climate adaptation and stormwater management into municipal planning procedures. Clear roles and responsibilities have been established between municipal departments and the utility company, creating a governance structure that supports coordinated implementation. Political commitment has enabled long-term planning and fostered collaboration across sectors involved in water management, urban development, and environmental protection.

    A key driver for the development of catchment-fit NBS has been the city’s ongoing effort to separate combined sewer systems and stormwater drainage networks. As urban growth, climate risks, and environmental pressures have increased, Aarhus has gradually shifted from a traditional drainage perspective towards a broader vision of optimizing the urban water system, reducing flood risks, and improving the ecological status of surrounding water bodies.

    This transition has strengthened the role of catchment-based planning as a framework for prioritizing interventions and coordinating investments. The city has adopted the theme plan “A Greener Aarhus with More Blue”, which integrates green and blue infrastructure planning, and has established a two-level catchment planning system that links city-wide objectives with local stormwater management plans.

    Catchment thinking is now embedded within:

  • Malmö has developed strong policy support for catchment-fit nature-based solutions (NBS) through a combination of climate adaptation needs, environmental objectives, and a long-standing commitment to sustainable urban development. As a low-lying coastal city with a flat terrain, Malmö faces increasing risks from climate change, including more frequent heavy rainfall events, urban flooding, rising sea levels, and periods of heat stress. These challenges have reinforced the need for integrated approaches that manage water while simultaneously improving urban resilience and quality of life.

    The city has been a pioneer in sustainable stormwater management since the 1990s, when several urban development projects demonstrated how open stormwater systems and blue-green infrastructure could provide effective alternatives to conventional drainage solutions. Early flagship developments, particularly the Western Harbour district and the Augustenborg regeneration project, showed that stormwater could be managed as a visible resource that contributes to attractive public spaces, biodiversity enhancement, and climate adaptation. These projects helped build political confidence and public acceptance of NBS as part of mainstream urban development.

    Environmental considerations provide an additional rationale for policy support. Stormwater management is increasingly recognized as an important factor influencing the ecological status of receiving waters and coastal ecosystems. Restoring natural water pathways, reducing pollutant loads, and improving urban ecosystem functions align with broader environmental objectives at municipal, national, and European levels. European environmental legislation, climate adaptation strategies, and water management requirements provide further support for integrating NBS into planning and infrastructure decisions.

    Public expectations have also played a significant role. Malmö residents increasingly value green, attractive, and climate-resilient urban environments. NBS are widely perceived as measures that improve neighbourhood quality, recreational opportunities, urban biodiversity, and overall liveability while simultaneously addressing stormwater challenges. This broad public acceptance has helped maintain political support across multiple planning cycles.

    The city has invested heavily in developing institutional capacity for integrating climate adaptation, urban planning, landscape architecture, and stormwater management. Over time, NBS have evolved from individual demonstration projects into a standard component of municipal planning and development processes. Cross-departmental collaboration and accumulated practical experience have enabled Malmö to move towards more systematic implementation of blue-green infrastructure.

    A key feature of Malmö’s approach is the integration of stormwater management with urban development and public space planning. Rather than treating stormwater as a purely technical issue, the city increasingly views water as a structuring element of urban design and neighbourhood development. This perspective naturally supports catchment-fit thinking, as stormwater flows, ecological networks, public spaces, and development patterns are considered together when planning interventions.

    Today, catchment-fit NBS are supported through:

  • Tampere’s support for catchment-fit nature-based solutions (NBS) is driven by the growing need to adapt the city to climate change and manage increasing stormwater risks. Climate projections indicate that precipitation intensity and frequency will increase in the future, leading to higher flood risks, particularly in the city’s dense urban areas.

    At the same time, urban growth and densification increase the vulnerability of built environments to heavy rainfall, while climate change creates additional challenges such as urban heat islands, droughts, and storm damage in different parts of the municipality.

    Flood risk assessments have provided a strong evidence base for policy development by identifying areas that are particularly vulnerable to stormwater flooding. These assessments have helped justify long-term investments in NBS as cost-effective measures for reducing runoff, mitigating flood risks, and improving the resilience of urban drainage systems. Rather than relying solely on conventional grey infrastructure, Tampere increasingly views NBS as an integral part of climate adaptation and urban development.

    Political acceptance of NBS has been further strengthened by public demand for attractive, green, and ecologically functional urban environments. Early demonstration projects, particularly in the Vuores district and the Housing Fair developments of the early 2010s, showcased the multiple benefits of NBS and helped build confidence among decision-makers, planners, and residents.

    National legislation requiring municipalities to prepare stormwater programmes has also played an important role by formalizing municipal responsibilities for stormwater management and creating a framework for integrating catchment-based approaches into local governance. Over time, Tampere has developed significant internal capacity for climate adaptation and stormwater management, enabling evidence-based policymaking and the systematic integration of NBS into municipal planning processes.

    The policy rationale for catchment-fit NBS is embedded across several strategic and operational documents, including the:

  • Tartu’s policy support for catchment-fit nature-based solutions (NBS) is primarily driven by the need to manage urban growth, improve the quality of the living environment, and address increasing stormwater challenges associated with climate change. As the city continues to develop and densify, stormwater management has become an increasingly important consideration for both infrastructure planning and urban resilience. More frequent heavy rainfall events, increasing impervious surfaces, and the need to protect receiving water bodies have strengthened the rationale for integrating stormwater considerations into spatial planning and urban development.

    The city’s Masterplan provides an important foundation for catchment-based thinking. The plan recognizes the importance of blue-green infrastructure, promotes the development of a high-quality green living environment, and identifies the city’s stormwater catchments as a basis for planning. By mapping catchment boundaries and acknowledging the role of natural systems in urban development, the Masterplan creates favourable conditions for implementing more integrated stormwater management approaches.

    Stormwater management approach is however still seen as advancement of traditional urban drainage infrastructure and the need to improve the performance of urban water systems. Therefore, Tartu’s policy framework remains largely focused on managing stormwater as a technical infrastructure challenge rather than as a broader catchment-based urban development opportunity.

    While catchments are formally recognized in planning documents, catchment-fit NBS are not yet systematically integrated into municipal policies, development procedures, investment programmes, or infrastructure planning processes. Green infrastructure, climate adaptation, biodiversity, and stormwater management objectives are often addressed separately rather than through a common catchment-based framework.