Study

Restoring marsh elevation in a rapidly subsiding salt marsh by thin-layer deposition of dredged material

  • Published source details Ford M.A., Cahoon D.R. & Lynch J.C. (1999) Restoring marsh elevation in a rapidly subsiding salt marsh by thin-layer deposition of dredged material. Ecological Engineering, 12, 189-205

Actions

This study is summarised as evidence for the following.

Action Category

Add sediment: brackish/salt marshes

Action Link
Marsh and Swamp Conservation
  1. Add sediment: brackish/salt marshes

    A before-and-after, site comparison study in 1996–1997 of two coastal marshes in Louisiana, USA (Ford et al. 1999) reported that one year after spraying dredged sediment onto a marsh, cover of three of four plant species was greater than before spraying. Statistical significance was not assessed. One year after spraying, the marsh had 66% cover of smooth cordgrass Spartina alterniflora (before: 19%), 35% cover of hairy cowpea Vigna luteloa (before: 1%), 16% cover of three-square bulrush Scirpus americanus (before: 7%) and 0% cover of saltmeadow cordgrass Spartina patens (before: 11%). Meanwhile, cover of the first three species was stable over time in a nearby unsprayed marsh (smooth cordgrass: 54–55%; cowpea: 8–12%; bulrush: 7–9%) whilst cover of saltmeadow cordgrass declined (from 6% to 0%). Methods: In July 1996, dredged canal sediment was sprayed in a high-pressure jet onto an area of subsided marsh in the Mississippi Delta. This increased the marsh surface elevation by approximately 2 cm. Cover of each plant species was surveyed in the sprayed marsh and a nearby reference marsh (not subsided, not sprayed), five weeks before spraying (June 1996) and for up to one year after (July 1997).

    (Summarised by: Nigel Taylor)

Output references

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