Traces of the 1995 Mega Rice Project in Kalimantan’s Forest and Land Fires: A Civil Engineering Perspective on Recovery.
Gambar 1. Kanal di lahan gambut bekas proyek era Soeharto. Sumber: money.kompas.com (2023).
Each dry season, smoke from Kalimantan’s burning peatlands settles over Southeast Asia, yet the fires owe as much to infrastructure as to ignition. Central to this story is the Mega Rice Project (Proyek Lahan Gambut Sejuta Hektare, or PLG), a scheme whose canals continue to shape fire behaviour decades after its abandonment. This article traces the causal chain from design decisions of the 1990s to present-day fire risk, and argues that civil engineering is indispensable to breaking it.
A Landscape Engineered to Burn
The PLG converted a fire-resistant ecosystem into a combustible one through its drainage design. Presidential Decree No. 82/1995 authorised the conversion of up to one million hectares of peat swamp forest in Central Kalimantan into rice fields (Keppres No. 82/1995). To achieve this, contractors excavated a canal network in the order of 4,500 kilometres, intended to drain the peat and to carry water and transport. The scheme was halted in 1999 after the soils proved unsuitable for rice, yet the canals were left open and unmanaged (Keppres No. 80/1999). The failure was therefore not only agronomic but hydrological: intact peat swamp holds up to roughly 90 per cent water by volume and resists fire precisely because it is saturated (Wösten et al., 2008), so draining it removes the very property that protected it. Consequently, the PLG should be read as a design error whose consequences were physically embedded in the landscape, which explains why the damage outlived the project itself.
Why the Canals Keep Working Against the Peat
The canals continue to drive fire risk because drainage is a continuous process rather than a one-off event. Open channels lower the groundwater table across the surrounding peat dome and keep it low, particularly in the dry season (Wösten et al., 2008). Once peat is exposed to air it oxidises and compacts, and drained tropical peat has been measured subsiding by roughly 5 centimetres per year in the first five years after drainage and by about 2.5 centimetres per year in the long term (Hooijer et al., 2012). Dried peat also becomes hydrophobic and cannot easily reabsorb water, which makes the damage largely irreversible without active intervention (Agus & Subiksa, 2008). Indonesian regulation uses a concrete threshold for this condition, since a peat ecosystem is considered damaged when its water table lies deeper than 0.4 metres below the surface (PP No. 57/2016). Beyond fire, such drained peat is a major carbon source, with emissions from drained peatlands in Southeast Asia estimated at about 632 million tonnes of CO₂ per year in 2006 (Hooijer et al., 2010). Hence, every month that a canal stays open extends the period in which the peat is both dry enough to burn and actively losing carbon.
The Fire Record Written Along the Canals
The fire history of southern Central Kalimantan confirms that drainage, not drought alone, converted ignition into catastrophe. During the 1997 El Niño, roughly one-third of a 2.5-million-hectare study area in Central Kalimantan burned, and Indonesia’s peat and forest fires that year released an estimated 0.81 to 2.57 gigatonnes of carbon (Page et al., 2002). Repeated burning then degraded the former forest into fern and shrub vegetation, which is itself easy to ignite and thus perpetuates the cycle (Hoscilo et al., 2011). The same pattern returned in 2015, when about 2.6 million hectares burned nationwide at an estimated cost of US$16.1 billion (World Bank, 2016), and when the resulting haze was linked to around 100,000 premature deaths across Indonesia, Malaysia and Singapore (Koplitz et al., 2016). People still light most fires and El Niño still sets the severity, but drained peat decides whether a small fire stays small or smoulders underground for weeks. This logic points to the remedy: if the fuel condition is engineered, then it can in principle be re-engineered.
Restoring Hydrology: The Core Civil Engineering Task
The primary engineering response must be to raise and hold the water table, which in practice means blocking and managing the canals. Indonesian technical guidance recognises canal blocking, together with backfilling and wells, as a standard instrument of peat restoration (Permen LHK No. P.16/2017), and the Peatland Restoration Agency was mandated in 2016 to restore approximately two million hectares within five years (Perpres No. 1/2016). Field experience in Central Kalimantan shows that blocks function best as coordinated cascades rather than isolated dams, with spacing set by canal gradient so that the water retained behind each block backs up toward the next one upstream (Ritzema et al., 2014). International reviews similarly emphasise matching the structure type, whether compacted peat dams, timber or sheet-pile weirs, to canal width, flow and local materials (Dohong et al., 2018). The hydraulic reasoning is simple: a closely spaced cascade keeps the head difference across each block small, which reduces seepage and erosion, the usual causes of failure in peat. Small or redundant canals are better backfilled completely, while navigable channels need adjustable gates so that communities retain access without sacrificing water-level control. Accordingly, restoration design should begin with accurate elevation data and hydrological modelling of the whole dome, because blocking a single canal in isolation cannot rewet peat that other channels continue to drain.
Building on Peat Without Re-Creating the Problem
Geotechnical design determines whether new infrastructure in the former PLG area will repair or repeat the original damage. Peat is characterised by very high water content, low shear strength and large, prolonged settlement under load, which makes conventional embankments on peat prone to differential settlement and failure (Edil, 2003). Heavy earthworks also squeeze water out of the peat and encourage the subsidence that engineers are trying to prevent. For this reason, roads and structures should use lightweight fill, load distribution and pile-supported foundations, and Indonesian ground-improvement practice has long relied on timber pile mattresses and similar techniques for soft organic soils (Mochtar, 2000). Roads and embankments also act as barriers to lateral groundwater flow, so adequately spaced cross-drainage and culverts are necessary to avoid waterlogging on one side and drying on the other. Thus, good geotechnical design serves a hydrological purpose as well as a structural one, since it prevents new construction from becoming a fresh drainage or subsidence source.
Monitoring, Water Supply and the Limits of Engineering
Engineering works only deliver results if they are verified, maintained and embedded in governance. Because the regulatory benchmark is a water table within 0.4 metres of the surface (PP No. 57/2016), restoration requires continuous measurement, and the Peatland Restoration Agency introduced a real-time monitoring system for peat water levels to track compliance (BRG, 2020). Monitoring from canal-blocking projects indicates that the rewetting effect is strongest close to the blocks and weakens with distance and during prolonged drought (Ritzema et al., 2014), which is why block networks must be dense and well maintained. Boreholes and retention ponds can supplement this by supplying water for suppression when ignition occurs despite rewetting. Nevertheless, even excellent structures will be bypassed or damaged if residents have no viable income beyond drainage-based agriculture, which is why drivers of peatland degradation include socio-economic as well as physical factors (Dohong et al., 2017). In conclusion, the legacy of the PLG is best addressed by pairing hydrological and geotechnical engineering with livelihood alternatives such as paludiculture, so that a landscape drained by design can be restored, also by design, to a condition in which fire cannot easily take hold.
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