3 Post-tsunami assessment and restoration of soil and water

Previous | Download this chapter in PDF | Download citation | Next

Key points

  • The level of salinity in tsunami-affected soils in Aceh and the rate of salt leaching was influenced by:
    • the length of time that land was inundated by sea water
    • soil moisture levels at the time of the tsunami
    • soil type—salt leaches faster from sandy and peat soils than from clay soils
    • the depth and type of sediment deposited by the tsunami
    • drainage in fields and the local catchment
    • access to irrigation water to flush salt from fields
    • rainfall after the tsunami.
  • Salt can leach vertically through the soil profile and laterally across fields with surface waters.
  • Three years after the tsunami, high salinity readings were still measured in Aceh, mainly linked to poor drainage.
  • Construct in-field drainage to accelerate the salt leaching process.
  • Assess results from soil salinity surveys carefully to avoid misinterpretation.
  • Incorporate shallow sediments (<20 cm) that are not highly saline into the topsoil.
  • Remove deeper or highly saline sediments from fields.
Four men using an EM38 instrument to measure salinity on saturated, muddy land with no crop growth.

Photo: New South Wales Department of Primary Industries

Tsunamis can have a number of effects on coastal soils: increased soil salinity and sodicity, sediment deposition, and scouring and erosion of topsoil. The physical and chemical properties of tsunami-affected soils in Aceh are discussed in Agus et al. (2008), Hulugalle et al. (2009) and McLeod et al. (2010).

Particular requirements for the recovery of agriculture in Aceh included:

  • assessing and managing soil salinity and other soil issues
  • managing the sediments deposited by the tsunami
  • assessing and managing water quality
  • repairing drainage and irrigation structures.

This section includes:

  • methods of salinity assessment
  • soil salinity impacts
  • soil and crop rehabilitation related to the commonly experienced post-tsunami problems
  • observations of the physical and chemical impacts of the tsunami.

Previous | Download this chapter in PDF | Download citation | Back to top | Next