Industrial Groundwater Extraction Worsens Land Subsidence Along Semarang's North Coast

A researcher at the Asia Research Institute of the National University of Singapore, Bosman Batubara, has revealed that one of the main causes of land subsidence in the North Coast (Pantura) area of Semarang, Central Java, is groundwater extraction by industry. According to him, this subsidence could be more severe than that recorded by the Land Subsidence Monitoring Stations (SPPPT). “Industry is one of the largest users of deep groundwater in Pantura Semarang. Meanwhile, one of the biggest causes of land subsidence is deep groundwater extraction,” Bosman said in an interview on Wednesday (3/6/2026). He stated that industrial activity and land subsidence in the Pantura Semarang area have a linear relationship. “So, the more industries that use and extract deep groundwater, then logically, considering hydrology and rock mechanics, everything, the land subsidence will also get worse. That’s what I mean by linear,” he said. Bosman and his team previously published a book titled ‘Maleh Dadi Segoro’ (It Became the Sea Instead) in 2020. The book examines the socio-ecological crisis in the coastal areas of Semarang-Demak, including land subsidence and tidal flooding. The book also critiques the Semarang-Demak Toll Road project, which includes the construction of a sea wall. According to Bosman, land subsidence in the Pantura Semarang area could be more severe than that recorded by the SPPPT, more commonly known as Patok Pantau. He said this was documented in the book ‘Semarang Lemahe Ambles’ written by Bagas Yusuf Kausan et al. “If we read the book by Bagas and colleagues, which detects land subsidence by exploring people’s daily experiences, it actually shows that subsidence in some places is worse than what the measurement stations record. Because it can be 20-30 centimetres per year, but those stations [record] maybe around 10 centimetres,” he said. However, Bosman cautioned that these land subsidence figures are derived from the daily experiences of residents in Pantura Semarang. “That means it also depends on the method,” he said. According to Bosman, addressing land subsidence in Pantura Semarang depends on government policy, including managing groundwater extraction by industries in coastal areas. “The worse the governance is, and at the same time more industries extract groundwater, the more voids the aquitard will have, and land subsidence will worsen,” he said. “On top of that, of course, the industries themselves are infrastructures that create a load in certain areas, which is an equally important factor in causing this land subsidence,” Bosman added.