Year one of the peat rewetting trial
We blocked drainage canals on 120 hectares of drained peatland to raise the water table. After a year the peat is wetter, and the fire risk has dropped sharply.
Drained tropical peat is both a slow carbon release and a fire hazard. Once the water table drops, the peat dries, oxidises and gives up carbon it has held for thousands of years, and in a bad dry season it catches and burns underground where no one can put it out.
The fix is unglamorous. You block the old drainage canals so the water stops running off and stays in the ground. On this 120-hectare block we built 38 small dams in the canals, working with the Long Pasai community who know where every channel runs.
The dams are mostly wood, clay and sandbags, built by hand. Nothing about them is clever. The skill is in placing them so they hold the level without flooding land that drains naturally, and that took several rounds of building, watching and adjusting.
We have been logging the water level since the first dam went in. After a year the water table sits within 40cm of the surface across most of the block, up from more than a metre down when we started. That is the difference between peat that smoulders and peat that does not.
Wet peat does not burn, and that alone justifies the year's work. The block sat through the dry season with no fire while drained land nearby went up, and the community fire crews had far less to worry about along this boundary than before.
Rewetting is the first half of the job. Now the ground holds water again, we start planting the swamp forest trees that belong here, the species that can take wet feet and that we could never have established in dried-out peat.
