BRIN Researcher: 65.8 Percent of Java's North Coast Line Experiencing Erosion
Jakarta (ANTARA) - Researcher from the Centre for Climate and Atmospheric Research at the National Research and Innovation Agency (BRIN), Tubagus Solihuddin, stated that 65.8 percent of the North Coast (Pantura) of Java area is experiencing erosion.
In a statement in Jakarta on Tuesday, Tubagus mentioned that the erosion is caused by the massive development of settlements and economic activity centres due to high demographic pressure, resulting in the extraction of marine and coastal resources.
“So, 84 percent of Java’s North Coast consists of fluvial deposits and delta deposits. Geologically, the deposits forming Java’s North Coast are still unconsolidated. They are not yet strongly compacted, making them very susceptible to erosion and compaction,” he said.
Tubagus explained an analysis of coastline changes using Sentinel satellite imagery over the period from 2000 to 2024, showing a worrying trend.
He detailed that coastline changes are dominated by an erosion rate of 65.8 percent, while the accretion rate (land addition) is only 34.2 percent.
He also highlighted an anomaly from the monitoring data, where massive erosion occurs in delta environments that are naturally areas of sedimentation.
“In terms of morphology, Java’s North Coast is dominated by low-relief beaches or lowland beaches with elevations below 10 metres. This accounts for 83 percent of the total length of Java’s North Coast,” Tubagus explained.
This condition is closely related to upstream modification activities, such as canalisation, river diversion, and dam construction, which ultimately disrupt sediment supply to coastal estuary areas.
The impacts of this anthropogenic modification are clearly recorded at various points. In Tanjung Pontang, Serang, an area of 1.72 square kilometres of land has disappeared due to erosion from the diversion of the Ciujung Baru River flow.
In the Pantai Bahagia area, Muara Gembong, Bekasi, seawater has intruded up to four kilometres inland, permanently submerging public infrastructure and flooding over 1,000 hectares of residents’ ponds.
Besides Bekasi, similar incidents are recorded in Legonkulon, Subang, where seawater intrusion up to two kilometres has submerged 700 hectares of ponds. Abrasion has also eroded village roads up to 500 metres to one kilometre in Krangkeng, Indramayu.
Specifically in the Demak region, Tubagus provided a historical note that the area was part of the Muria Strait waters in the 15th-16th centuries, which was later covered by sedimentation to become land. Now, seawater is returning inland up to five to six kilometres in Demak, swallowing rice fields and settlement areas.
This is worsened by sea level rise (SLR) and land subsidence.
Based on altimetry data modelling (1993-2025), the sea level rise trend on the North Coast averages 0.41 to 0.42 centimetres per year, resulting in an accumulated rise of up to 15.5 centimetres over 32 years.
“Java’s North Coast is facing a real crisis. As mentioned earlier, the challenges are not only erosion, abrasion, flooding, but also sea level rise and land subsidence. And this is not a local issue; it is a national issue. Considering that Java’s North Coast is the backbone of the national economy,” said Tubagus.
Facing the complexity of this crisis, Tubagus emphasised the importance of transitioning to a cross-sectoral and regional approach. He asserted that there is no single solution that can be applied across the entire North Coast area.
Looking ahead, he urged that coastal management policies must be grounded in scientific research, credible data, and prioritise ecosystem balance.