Redirecting sediment and rearranging social justice

Abstract

Efforts to manage the Mississippi River have produced hydrologic, geomorphic, and social change. Sediments have been the focus of contentious litigation; and engineers in the mid-nineteenth century argued for returning sediment to the city to raise land. Levees, built of sediment, protected the city and also guarded the powerful planter class. By forcing the sediment-bearing discharges into the Gulf of Mexico, the levee system denied sediment to most of the floodplain which allowed the delta to subside at a pace that was faster than land building caused by crevasses, and also permitted the intrusion of salt water into the valuable fisheries in the adjacent bays and estuaries. Further manipulations in the form of massive spillways followed the 1927 flood. This hydrologic re-plumbing disrupted the ecology and economy of floodplain and coastal areas. Current plans to restore the disappearing delta using sediment diversions will further disrupt the re-established economies. Upstream, reservoirs now capture much of the river-borne sediment which limits the viability of restoration efforts. The redirection of sediment has produced both geomorphic and social change in the lower delta and efforts to restore coastal wetlands, as previous alterations, will impose disruptions on the state’s marginalized residents.