Tropical peatland restoration evaluation using time-series L-band InSAR analysis

Since 2016, tropical peatland restoration efforts in Kalimantan, Indonesia, have focused on rewetting through canal blocks installation-engineering barriers constructed across drainage canals. This structure is intended to raise the ground water table and re-saturate the peat, thereby reducing its flammability and preventing further degradation. Nonetheless, recurring fires triggered by climatic variability continue to raise a critical question, is canal block effective in controlling tropical peatland degradation? This study evaluates the impact of canal blocks by analyzing peatland displacement. We apply L-band Interferometric Synthetic Aperture Radar (InSAR), which provides wide-area, high-resolution measurements of surface movement derived from phase difference analysis of the SAR return signal, complementing spatially limited ground-based methods. A velocity map was generated to illustrate displacement distribution over time. Comparative analyses between pre- and post-restoration periods reveal a clear reduction in subsidence following canal block implementation. Histogram assessments of displacement further support a consistent subsidence decline. Notably, we observed greater stabilization during the stable phase of restoration, suggesting that time is a critical factor in achieving restoration outcomes. Overall, our findings demonstrate that canal blocks can effectively reduce peatland degradation when given sufficient time to take effect, reinforcing their role as a key strategy in tropical peatland recovery.