Northern Mississippi River Delta, LA

Project Sheet

Location: Plaquemines Parish, Venice, LA, US

Year: 1996

Project Type(s): Marsh restoration

Project Description: The salt marsh that received dredged material is located near Venice, LA on the northern portion of the modern Mississippi River Delta. Marshes in this area experience high rates of sea level rise, subsidence, and anthropogenic disturbances including oil/gas exploration. The use of thin layer placement of dredged material was intended to restore elevations in shallow open water areas to a suitable elevation for emergent marsh and to assess the impact of the spray dredging technique on vegetated marsh. The salt marsh received thin sediment additions from a nearby canal in July 1996 utilizing the spray (rainbow) dredging technique. The thickness of sediment application was 23 ± 5 mm on the marsh and 116 ± 11 mm in the shallow open water areas. The addition of sediment increased the marsh elevation, which allowed emergent vegetation to colonize the once open water areas via rhizome growth from the edge of the marsh. Overall, the emergent marsh and shallow open water areas responded positively to thin layer placement.