Nature as an ally: scaling up Nature‑based Solutions in the NL2120 programme

Nature‑based Solutions (NbS) are an important ally in addressing complex societal challenges, such as the nitrogen crisis, climate change adaptation and improving water quality. NbS build on the natural functioning of water, soil and ecosystems, while enhancing biodiversity and water and soil quality. In addition, they contribute to the sequestration of nitrogen and CO₂.

To deploy NbS on a large scale, more knowledge is needed – but also more integrated and specific knowledge. For example, we do not always fully understand how Nature‑based Solutions perform in the long term, what they cost and what they deliver. Business models that are more strongly based on natural systems are still under development, and the biodiversity benefits of NbS are not always unambiguous. This is where NL2120 aims to make a difference: by embedding Nature‑based Solutions in the way we design and manage our country, and by applying this knowledge internationally.

An unique collaboration

In 2023, the consortium received an allocation of €110 million from the Dutch National Growth Fund, submitted by the Ministries of Infrastructure and Water Management and of Agriculture, Fisheries, Food Security and Nature, to be invested over a ten‑year period. The fact that this cooperation between science, industry, public authorities, nature organisations and education is both unique and far from self‑evident led to NL2120 being awarded the Grote Maaskant Prize in the previous year.

Deltares in NL2120

To better integrate Nature-based Solutions into the approach to major societal challenges, Deltares contributed to the National Growth Fund proposal for NL2120. For Deltares, NbS are crucial to achieving the mission of ‘Enabling Delta Life’.

Deltares boasts many years of experience in developing knowledge regarding the application of NbS for climate adaptation and future-proof infrastructure. For instance, Deltares experts have contributed to projects such as Room for the River, the MarkerWadden, Water as leverage, FloodAdapt, SpongeScapes and NBracer. We also develop knowledge on green-blue solutions for cities and natural coastal protection, both nationally and internationally, for example in Building with Nature with Ecoshape.

According to Deltares, analysis and understanding of the natural system are essential to harnessing the full potential of natural solutions. The right conditions are also important for NbS to function optimally. In a country like the Netherlands, where the water system has been heavily adapted to human use, the application of NbS presents many challenges. For instance, healthy natural systems require space and dynamism, whilst space is usually already allocated and dynamism is often difficult to achieve in our regulated system.

That is why Deltares is contributing to a vision of the potential of NbS in various landscapes within the NL2120 initiative. The benefits of working with NbS are also being highlighted, along with an initial overview of the actions required to adapt water and soil management. In addition, Deltares is taking the lead in translating knowledge into policy that integrates NbS and in defining transition pathways to scale up its application. Deltares plays a leading role in the physical-ecological research within NL2120, focusing on technical feasibility as well as incorporating a broader portfolio of (technological) solutions.

To date, Deltares has worked within NL2120 on the inventory and analysis of existing NbS, an overview of barriers and obstacles to their upscaling, knowledge sharing and future development, and the drafting of monitoring plans for the pilot areas.

Perspectives & priorities

Partners in NL2120 focus on opportunities and barriers for applying Nature‑based Solutions through three perspectives:

• Physical‑ecological: How effective are Nature‑based Solutions, and how can they be applied under changing climatic conditions?

• Socio‑economic: What are the costs and benefits of large‑scale Nature‑based Solutions for society and overall wellbeing?

• Institutional: How can cooperation between sectors be improved, and how can Nature‑based Solutions be embedded in legislation and policy?

NL2120 develops knowledge for five types of landscapes: peatlands, coastal areas, rivers, cities and higher sandy soils. Within these landscapes, the consortium focuses on 13 promising Nature‑based Solutions, selected based on their contribution to societal challenges (such as climate adaptation, nature restoration and broad prosperity), their scaling potential and their prospects for use in policy and implementation. These are solutions that show great promise but still require further development to become widely applicable. This prioritisation enables targeted research, faster progress towards implementable solutions and stronger collaboration with partners in practice.

Peatlands

In peat areas, the focus is on rewetting to limit subsidence and greenhouse gas emissions, combined with future‑proof forms of land use:

• Wet crops (e.g. cattail, reed, forest), including applications in biobased construction chains
• Extensive livestock farming under high groundwater levels (with a focus on dairy farming)
• Permanent peat marshes for nature, recreation and water storage

Coastal areas

Along the coast, solutions focus on ensuring future water safety while preserving unique delta nature such as tidal flats and salt marshes. These areas can help keep our coast resilient and safe in the long term by growing with sea‑level rise. NL2120 aims to maximise these natural growth processes for nature and water safety, as well as for recreation, landscape quality and fisheries. The programme focuses on:

• Dynamic sandy coastal protection (such as notches in dunes and the Sand Motor)
• Adaptive landscapes (e.g. exchange polders and double dikes)
• Forelands and shores (salt marshes, mud motors and vegetated foreshores)

Rivers

In river areas, restoring natural dynamics and system functioning is central, with a focus on:

• Flood defences with vegetated foreshores (low vegetation and floodplain forests)
• An integrated multi‑channel river concept (side channels, floodplains and river widening)

Sandy soils

On higher sandy soils, the emphasis is on increasing the landscape’s sponge capacity through:

• Stream valley restoration with natural floodplains
• Nature‑inclusive, climate‑resilient agriculture (soil improvement and reduced drainage)
• Water retention areas with nature functions (forest development and hydrological restoration)

Urban areas

In cities, green and water are used to support climate adaptation and improve liveability:

• Green‑blue networks and urban parks and waterways (including applications such as tidal parks in coastal cities)

International

Internationally, the focus is on applying and scaling up NbS that are globally relevant and build on Dutch knowledge and experience:

• Muddy coastal solutions (such as mangrove restoration)
• Sandy coastal solutions
• Integrated river basin management
• Green‑blue urban solutions

In the coming years, NL2120 will further develop these Nature‑based Solutions to make them implementable and scalable in practice. This includes deepening insight into their functioning, costs and benefits, barriers to scaling up, and integration into policy and implementation. This work is carried out in collaboration with public authorities, market parties and knowledge institutions, and in close connection with ongoing programmes and practical projects. Step by step, this results in solutions that are not only ecologically effective, but also economically viable and institutionally feasible.

System knowledge

Knowledge of water, subsurface and nature is essential in all landscapes for properly assessing the applicability of Nature‑based Solutions. Deltares is involved across all components of NL2120, with more intensive involvement in certain areas. For peatland landscapes, for example, Deltares contributes knowledge for developing future visions and coordinates the monitoring programme, with a focus on greenhouse gas emissions under different land‑use types.

In coastal landscapes, Deltares plays a crucial role through its system knowledge of flows, sediment dynamics and ecological functioning of estuaries, including estimating sand and silt volumes and predicting system responses to changing conditions such as sea‑level rise. These boundary conditions are essential for effective NbS in coastal zones.

Deltares’ expertise in river discharges and morphological system behaviour supports assessments of opportunities for alternative, more nature‑oriented design options, such as integrated multi‑channel systems. For sandy soils, Deltares contributes water balance knowledge relevant across landscapes. Finally, Deltares supports economic valuation of NbS and the development of institutional arrangements to facilitate their future application.

Practice

The knowledge developed is applied and tested at scale in pilot areas. In the Frisian peat meadow area De Hegewarren, for example, the consortium experiments with rewetting to reduce peat degradation and associated greenhouse gas emissions. Together with land users, the programme explores future‑proof and economically viable land‑use options, while also assessing the effects of rewetting on biodiversity, water quality and groundwater levels.

Consortium partners

In addition to Deltares and Wageningen University & Research, the NL2120 consortium includes Stiftung Ecoshape, the Province of Fryslân, the municipalities of Dordrecht and Rotterdam, Staatsbosbeheer, Delft University of Technology, the University of Twente, Utrecht University, the educational institutions COE Groen, Deltaplatform and Yuverta/Aeres, and a broad range of nature organisations, including ARK Rewilding NL, De Noordzee, IUCN NL, IVN, Natuur & Milieu, the Provincial Nature and Environmental Federations, Natuurmonumenten, SoortenNL, Vogelbescherming and WWF‑Netherlands.

Together with our partners in NL2120, Deltares seeks answers to questions like How can we unlock the full potential of natural water and soil systems to make deltas worldwide future‑proof?

Bregje van Wesenbeeck, scientific director at Deltares and initiator of NL2120