Association for Public Policy Analysis & Management

Riverine flooding poses a substantial risk to human life and property. Already the most frequent and costly natural hazard, the risks of riverine flooding are expected to increase due to changes in the timing and intensity of precipitation arising from anthropogenic climate change; in land uses and land cover; and in exposure of human populations and assets. Reducing these risks can be achieved through a variety of mechanisms ranging from ‘flood defense,’ which utilizes infrastructure and engineering approaches to control or block flows, to ‘making space for rivers’ through nonstructural or natural measures such as restoration of floodplains, removal of embankments, riparian buffers, and restrictions on encroachments.

Due to its jurisdiction over land use and its responsibility for local public infrastructure, local government is often tasked with the decision of which of these approaches to implement. This research examines flood mitigation decision-making across 50 municipalities in Massachusetts and Vermont in order to identify how flood mitigation strategies are decided upon and implemented. Through semi-structured and structured interviews and secondary data analysis, we investigate how and when municipal officials make decisions, what drives the decision-making process, and how state and federal mandates, whether the provision of knowledge via risk maps and geomorphic assessments influence outcomes. Beyond the standard finding of capacity and resource constraints of local government, we find municipal government structure to be particularly prominent in encouraging structural flood mitigation measures and we find uncertainty or a lack of quantification of risk mitigation benefits to inhibit the uptake of non-structural measures.

Our in-depth depiction of flood mitigation processes by rural municipalities has both theoretical and practical implications for flood risk planning and management. We contribute contextualized understandings of how institutional structures; data, knowledge and knowledge gaps; and the policy environment combine to influence local government’s choice of flood mitigation measures. These understandings add nuance to the primarily quantitative-correlative body of research on local-level government engagement with flood mitigation, by delineating process and how process subsequently influences outcome. Better understanding of municipal decision making is important for enhancing policies that aim to influence municipal decision-making, for informing analyses of flood impacts, for developing decision support tools.