This paper presents a case study of the Rajang Delta in Sarawak, Malaysia where peatland subsidence will cause flooding, rendering more than half of the Rajang Delta unsuitable for any agriculture cultivation due to severe floods in 50 years. The land area which will be inundated is 3 times the size of Singapore!! What a great loss!
Case study summary:
The case study reveals that about 87% of the Rajang Delta in Sarawak may be flooded within 100 years if current peatland management is continued. Presently substantial areas are already experiencing drainage problems. This will eventually take a toll on the local communities, the economy and biodiversity. Over time problems will escalate unless management and policies are changed.
Wetlands International therefore recommends that for long-term sustainable use of these peatlands, measures such as planting of alternative crops that do not require drainage of peatlands and rewetting of peatlands should be undertaken. We also call for conservation and sustainable management of peatlands in Malaysia.
A study commissioned by Wetlands International and executed by Deltares suggests that extensive drainage of peatlands for oil palm cultivation in the Rajang river delta results in massive land subsidence that will lead to extensive and devastating flooding incidents in the coming decades.
From the study done, it was projected that under a conservative peat soil subsidence rate of 3.5 cm yr-1 approximately 57% of peatlands in Rajang Delta will likely be subjected to severe flooding in year 2034 and 69% in year 2059 (see Figure 1).
Such extensive flooding is due to massive conversion of peat swamp forests to agriculture, mainly oil palm plantations. These valuable crops require drainage in order to be profitable. Currently only 16% of Sarawak’s natural peat forests remain.