Participatory modelling in water resource management – involving diverse actors in what is traditionally a purely analytical process – is thought to broaden stakeholder engagement and improve outcomes. Further research and case studies are required to explore the practicalities of integrating meaningful participation within modelling processes in the water sector. Participatory modelling may be of particular interest within the context of urban informal areas, where the confluence of climate change, urbanisation and contested land requires new methods for engagement and planning. This paper develops new case-based knowledge to inform the application of participatory modelling and planning for informal urban areas. A flood-modelling project in the large informal neighbourhood of Kibera in central Nairobi, Kenya, is analysed using a newly established framework for the classification of participatory modelling approaches developed by Basco-Carrera et al. in 2017. Conclusions suggest that the further upstream more diverse stakeholders can be involved, the better the chance of co-producing new knowledge and of creating implementable plans and policies. At the same time, delivering ‘co-design’ of modelling processes in areas of limited co-operation requires a strong vision for participation, a tolerance for contention, a willingness to learn between actors and a budget to support additional time inputs.

Flood mitigation measures delivered at the London 2012 Olympic Park have reduced flood risk to more than 4000 residential and commercial properties, improving the quality of life for thousands of east London residents. Additional benefits include water quality, habitat creation, biodiversity, recreation, leisure and education. This was achieved by adopting a collaborative approach across a team that included contractors, planners and key stakeholders. The result is a true and lasting legacy for London and a model for sustainable flood risk management.