Association for Public Policy Analysis & Management

Due to climate change, coastal communities around the world are looking for ways to protect vulnerable infrastructure, people, and ecosystems in the event of sea level rise. In the coastal region between San Luis Obispo County and San Diego County in Southern California, sediment has long been considered a nuisance or a waste product, but it is now increasingly being recognized as a potential solution for protecting beaches and wetlands and combating coastal flooding. This change, however, will take a substantial shift in how sediment is regulated and managed by governments across the region. Focusing on two of the largest estuaries in Southern California, Newport Bay Estuary (NBE) and the Tijuana River Estuary (TRE) this paper details the experience of using participatory system dynamics to understand the coupled human-nature systems around sediment management in these two areas. Participatory system dynamics modeling engages stakeholders in co-developing a conceptual causal model of the system to understand the feedbacks, the points of discontent, the points of disagreement, and the points of intervention in the management of the coupled human-nature system. Co-development of models with stakeholders not only leads to researchers and managers gaining critical insights and nuanced understanding of the on-ground situation, but also building robust solutions to management issues of human-nature coupled systems. Co-development of models with stakeholders also leads to better policy and regulatory decisions, as well as stakeholder buy-in of the policies. Currently in the first stage of the four-year long project, around 30 stakeholders – from NBE, TRE and the state level – were interviewed individually to create a causal mental map of how the system works from their strategic position in the management chain and on ground experience. Overlapping these different causal maps allowed the researchers to get a bottom-up holistic understanding of the system and the decision-making processes. This paper details the process of this exercise, the lessons learnt about current sediment management in Southern California, and the preferred future policy and management interventions suggested by the stakeholders. The paper discusses the three causal models emerging from the interviews with the NBE, TRE and the state level stakeholders. While currently they are more conceptual and qualitative, these preliminary models will eventually be used as the base for creating an interactive communication, negotiation and decision-making tool in conjunction with other hydrological and ecological modeling conducted by the project team to assess future management practices and scenarios in the two case areas of NBE and TRE.