As Inland Becomes Coastal: Shifting Equity and Flood Risk in the Amite River Basin (USA)

Coastal Louisiana is experiencing the most rapid relative sea-level rise in the US due to a combination of a subsiding delta and rising coastal waters. Consequently, the influences of extreme coastal weather are reaching farther inland and impacting urban areas where traditional environmental policy, organised at the parish (county) level, is unable to address this changing flood risks. This situation is most prominent in the metro Baton Rouge region with the largest city situated upstream from two small, but rapidly growing, parishes. Following a massive flood in 2016, the upstream parishes have undertaken policy adjustments to facilitate the expulsion of water toward downstream neighbors and foster redevelopment in the floodplain. The lower parish has expressed concerns about the anticipated increases in discharge to be sent its way. Although the state is concerned with rising sea levels, it has not merged coastal and inland flood policy considerations. Downstream residents have little voice in upstream policy making and the absence of basin-wide management strategy perpetuates emergent risks and environmental injustices. As climate change drives coastal conditions inland, the misalignment between locally based governance and regional environmental realities will become more pronounced and exacerbate social injustices.

Hydrologic Restoration of the Lac des Allemands Swamp, Barataria, Louisiana

Most of the forested wetlands of coastal Louisiana are in decline, primarily due to impoundment and increased flood duration. The Lac des Allemands swamp of Barataria Basin was a prime example of prolonged inundation prior to hydrologic restoration completed in February of 2018; the swamp had been impounded for over 60 years. To characterize restoration benefits, eight paired 625 m2 permanent sites were established close to and halfway between eight 30 m × 122 m gaps cut into the spoil bank of Bayou Chevreuil. During 2018, canopy closure increased by 20%. In addition, aboveground production of wood and leaves increased over 2017 from 2018–2020. Furthermore, natural regeneration has occurred annually and many of the seedlings are now approximately 1 m tall. In conclusion, hydrologic restoration of impounded wetlands in coastal Louisiana is an extremely cost-effective landscape restoration method.

A Review of How Uncertainties in Management Decisions Are Addressed in Coastal Louisiana Restoration

Louisiana has lost over 4800 km2 of coastal land since 1932, and a large-scale effort to restore coastal Louisiana is underway, guided by Louisiana’s Comprehensive Master Plan for a Sustainable Coast. This paper reviews science-based planning processes to address uncertainties in management decisions, and determine the most effective combination of restoration and flood risk reduction projects to reduce land loss, maintain and restore coastal environments, and sustain communities. The large-scale effort to restore coastal Louisiana is made more challenging by uncertainties in sediment in the Mississippi River, rising sea levels, subsidence, storms, oil and gas activities, flood-control levees, and navigation infrastructure. To inform decision making, CPRA uses structured approaches to incorporate science at all stages of restoration project planning and implementation to: (1) identify alternative management actions, (2) select the management action based on the best available science, and (3) assess performance of the implemented management decisions. Applied science and synthesis initiatives are critical for solving scientific and technical uncertainties in the successive stages of program and project management, from planning, implementation, operations, to monitoring and assessment. The processes developed and lessons learned from planning and implementing restoration in coastal Louisiana are relevant to other vulnerable coastal regions around the globe.

Solastalgic Landscapes: Prospects of Relocation in Coastal Louisiana

Globally, rapid and slow-onset socio-environmental coastal disasters are prompting people to consider migrating inland. Climate change is exacerbating these disasters and the multi-faceted causal contributing factors, including land loss, livelihood shifts, and disintegration of social networks. Familiar with ongoing disruptive displacements, coastal Louisiana residents are now increasingly compelled to consider permanent relocation as a form of climate adaptation. This paper elicits and analyzes coastal Louisiana residents perceptions of socio-environmental changes as they pertain to relocation as adaptation and the precariousness of place, both biophysically and culturally. It investigates how these external mechanisms affect relocation decisions, and empirically expand on how these decision-making processes are affecting residents internally as well. Research methods include semi-structured interviews with coastal Louisiana residents, participant observation, and document analysis. The paper integrates literature on environmental migration, including climate-driven; regional studies on Louisiana, and disasters, with empirical, interview-based research. It is guided by theoretical insights from the construct “solastalgia,” the feeling of distress associated with environmental change close to one’s home. The findings suggest that residents’ migration decisions are always context-dependent and location-specific, contributing to a broader understanding of coastal residents’ experiences of staying or going.

The “Problem” of New Orleans and Diminishing Sustainability of Mississippi River Management—Future Options

Climate change forcings are having significant impacts in coastal Louisiana today and increasingly affect the future of New Orleans, a deltaic city mostly below sea level, which depends on levee and pumps to protect from a host of water-related threats. Precipitation has increased in the Mississippi River basin generally, increasing runoff, so that in recent years the Mississippi River has been above flood stage for longer periods of time both earlier and later in the year, increasing the likelihood that hurricane surge, traditionally confined to summer and fall, may compound effects of prolonged high water on river levees. The Bonnet Carré Spillway, just upstream of New Orleans has been operated more often and for longer periods of time in recent years than ever before in its nearly 100-year history. Because all rain that falls within the city must be pumped out, residents have been exposed to interior flooding more frequently as high-intensity precipitation events can occur in any season. A sustainable path for New Orleans should involve elevating people and sensitive infrastructure above flood levels, raising some land levels, and creating water storage areas within the city. Management of the lower Mississippi River in the future must include consideration that the river will exceed its design capacity on a regular basis. The river must also be used to restore coastal wetlands through the use of diversions, which will also relieve pressure on levees.