Rewetting – putting the water back

Rewetting is the process of restoring peatland water conditions by slowing water loss and helping maintain a higher groundwater level. In degraded peatlands, this is important because peat that becomes too dry is more vulnerable to subsidence, degradation, and fire. Rewetting therefore focuses on restoring the hydrological condition of the peat before other restoration activities can be sustained.

At HLG Londerang, rewetting was the first step in the restoration process. Drainage canals can lower the peatland water table, causing the peat to dry out and become increasingly vulnerable to degradation and fire. To help restore and maintain water levels, 19 canal blocks were constructed in Dendang District, Tanjung Jabung Timur Regency, across the villages of Catur Rahayu, Jatimulyo, Rantau Indah, and Kota Kandis Dendang. Twenty locations had initially been planned, but the number was reduced following field surveys, community consultation, and a budget review.

The canal blocks were designed to suit both the peatland environment and the needs of surrounding communities:

• Local materials. The structures were built using gelam wood (Melaleuca leucadendron), a species commonly found in peatland environments, and were designed as semi-permanent structures with a service life of at least five years.
• Controlled water flow. Each canal block was fitted with a spillway, allowing excess water to pass over the structure during high-water conditions.
• Community involvement. The design process also considered local concerns, including the potential effects on farmland and boat access. In Rawasari, community consultation was conducted through a Free, Prior and Informed Consent process before construction proceeded.
• Continuous monitoring. Four observation wells were installed around each canal block, while 12 solar-powered water-level data loggers were placed across the project area. The system records water level, rainfall, soil moisture, and soil temperature, with the data transmitted to a web-based monitoring platform. 

Monitoring between March and June 2023 showed water being retained around the canal-block areas, with an average water level of 11.89 cm above the spillways. The recorded peat water table averaged −43.57 cm upstream and −46.64 cm downstream of the structures. Because these measurements were taken during wetter months, they were treated as an early indication of the rewetting effect rather than a final measure of performance.