The uniqueness of this innovation lies in the collaboration among various stakeholders involved in the use of water buffers where different interests come into play—ensuring sufficient available irrigation water for the horticultural companies, while minimizing the risks of flooding for the surrounding areas. By integrating technical, legal, social, organizational aspects and involving all relevant stakeholders in the chain, this approach fostered substantial mutual trust and built joint ownership, which is one of the reasons why all participating parties speak proudly of this collaboration.

Rainlevelr has significantly grown from 25 companies at the beginning of 2020 to 75 companies by the end of 2023, reaching a total area of 400 hectares, which represents 10% of the horticultural area in Delfland. Rainlevelr is designed in a way that allows for easy adoption outside Delfland by other organizations.

While Rainlevelr is fully operational, there are several innovative steps on the horizon, including:
- Rapid expansion of the number of participants;
- Automation of water discharge (realizing storage capacity), partly facilitated by the established mutual trust;
- Adjustment of the system to buffer rainfall of up to 50 mm;
- Utilization of smart technologies to enhance prediction reliability and manage interaction with the water system;
- Storing valuable irrigation water underground instead of discharging it for later utilization – currently undergoing the ‘Waterbank Westland’ pilot project.

Rainlevelr is a collaboration between the municipality, the horticulture sector, Glastuinbouw Nederland, and Delfland. The project was made possible in part by a subsidy from Sponge2020 (Interreg 2 Seas). The relevant partners in this regard are not limited to: horticultural companies, horticulture advisory firms, water basin installation companies, suppliers of horticultural automation, and various departments within Delfland.

Rainlevelr prevents damage as a result of flooding. It not only avoids material damage for horticultural companies losing crops but also for residents whose gardens, basements, or homes get flooded. An additional advantage for horticultural companies is that there's no/less need to allocate horticulture area for constructing natural water buffers. This gives regional governments more control and insight into the discharge of excess rainwater from horticultural companies into the water system.

The results are diverse:
- 40,000 – 80,000 m3 of additional storage capacity spread over a densely built area, consequently reducing the risk of flooding;
- Preservation of the current production area for horticultural companies;
- Strong collaboration and mutual trust;
- The potential to multiply storage capacity in the short term;
- A very successful example of peak management within conflicting interests that can also be applied in other circumstances.

The greatest challenge lies in the unpredictability of the weather. Particularly, summer thunderstorms are difficult to forecast. If a storm doesn't occur or is less severe than anticipated, resulting in the water basin not being filled, a horticultural company loses valuable irrigation water. That risk needs to be minimized. Additionally, if a storm occurs and Rainlevelr isn't deployed, this affects Rainlevelr's reputation. This risk also needs to be mitigated. If the participants release more water, the correlation with the water system and its management becomes more critical. If everyone discharges water simultaneously without coordination, there's a risk that this discharge may cause flooding if it cannot be pumped away adequately.

Conditions for success include:
- Collaboration and trust among all parties;
- Thinking from the perspective of horticultural entrepreneurs and considering each other's interests in managing the irrigation water supply;
- Established based on individual responsibility to avoid complex structures with risks of damage claims;
- Sector awareness of the existing risk of flooding and its consequences;
- Continuous improvement driven by feedback and tips from the participants;
- Sharing successes, partly through ambassadors (participants) from within the horticultural sector;
- Continuity of the people involved;
- Excellent communication within Delfland, between Delfland and participants, and between Rainlevelr and the surroundings.

Currently, Rainlevelr is limited to the management area of Delfland. However, the system is designed in such a way (including digitally) that upscaling or replicating it to other (horticultural) areas (within the Netherlands or globally) is easily achievable. The principle can also be applied to other climate-adaptive measures in densely populated areas, such as distribution centers, parking lots, and businesses where rainwater is stored and utilized.

- Value suggestions from the sector and allow companies the space to contribute to solving societal issues. Then, thank them for their contribution and assist them in promoting it within their surroundings.
- Foster commitment by requesting involvement and a contribution (in kind) from the counterpart.
- Continuously consider the next steps and anticipate what needs to be addressed now to avoid stumbling over your own success later.
- Empathize with the interests of the collaboration partner, be clear about your own interests, and structure the system in a way that accommodates all interests.
- Be open to (ideas for) improving your system.