On the 13th and 14th of July 2021 a cold pit caused extreme precipitation along with record discharges in tributaries of the Meuse. These discharges caused floods in Belgium, Germany and the Netherlands.

Extreme precipitation occurrence and its intensity are expected to increase in the area due to climate change, increasing flood risk. Flood risk is the product of hazard, exposure and vulnerability. Research indicates all three are equally important drivers.

Planning of adaptation measures has been done with Decision Making in Deep Uncertainty (DMDU) methods to account for deep uncertainty. These methods lack natural and institutional context. Literature suggests both the natural system and the system governing it are complex. Therefore there is a need for a method providing climate change adaptation strategies with regard for the context and the notion that these systems are complex.

To address the research gap, a Framework is developed that combines natural and institutional aspects of climate change adaptation. A systems approach is used to find leverage points for wider systemic change. This can be used to spark autonomous adaptation, thereby also targeting exposure and vulnerability. The Framework provides a solution space of possible adaptation combinations and maps of spatial cooperation difficulty. By combining these possible combinations and locations are proposed. Systemic leverage points determine preferential strategies and additional policies. The Framework is tested in a case study in the Geul, Methods used are expert judgment, literature review, social network analysis and using open-source information.

The adaptive capacity is roughly 20 millimeters equivalent (6,680,000 m3) upstream of Valkenburg and 23.6 millimeters equivalent (7,882,400 m3) in the city itself. Thousands of combinations are possible. Depending on preference, this number is severely reduced.

The network governing flood risk is dense and polycentric. Cooperation quality is likely not sufficient between many actors to implement very intrusive adaptation measures that would be needed according to the solution space. When a certain cooperation is required, Flanders and the Netherlands are central players in the network. Germany and France are isolated in the network, causing the national governments of those nations to hold brokerage positions. Cooperation is the hardest in transboundary subcatchments especially when multiple nations are involved.

Depending on the preferences in the network, several adaptation strategies are possible in the Geul. In terms of cooperation difficulty, downstream solutions located in the Netherlands are preferential. Natural solutions would be preferable to harness self-organizational capacities of nature. Strategies that would cause secondary effects by intervening deeper into the systems should be highly visible. In addition, adaptation strategies should be accompanied by policies aimed at restoring the flow of information to citizens, restore or create financial incentives for autonomous adaptation of inhabitants and alter the paradigm of manageability of nature. Delays in planned adaptation response could be shortened by network interventions such as creating a central operational role in the network, implementing binding adaptation goals using the common European legislation or improving regional cooperation.