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

Industrial groundwater extraction is the main cause of land subsidence along the North Coast (Pantura) of Semarang, Central Java, according to Bosman Batubara, a researcher at the Asia Research Institute of the National University of Singapore. He stated that industries are major consumers of deep groundwater, and their extraction activities directly exacerbate the sinking of the land.

Batubara noted a linear relationship between industrial activity and land subsidence in the Semarang Pantura area. "The more industries that use deep groundwater, extract it, then logically, considering hydrology and rock formations, everything, the land subsidence will also worsen. That's what I mean by linear," he explained. This suggests that increased industrial demand for groundwater directly correlates with more severe land sinking.

Batubara and his team's previous research, documented in the 2020 book "Maleh Dadi Segoro (Malah Jadi Lautan)," examined the socio-ecological crisis in the Semarang-Demak coastal area, including land subsidence and tidal flooding. Their work also offered critiques of the Semarang-Demak Toll Road project, which includes the construction of a sea wall.

He further suggested that the actual rate of land subsidence in Semarang's Pantura region might be more severe than recorded by the Ground Surface Subsidence Observation Station (SPPPT), also known as Patok Pantau. Citing the book "Semarang Lemahe Ambles" by Bagas Yusuf Kausan and colleagues, Batubara mentioned that local experiences indicate subsidence rates of 20-30 centimeters per year in some places, significantly higher than the approximately 10 centimeters recorded by official stations. However, he cautioned that these figures are based on daily experiences and the methodology used.

Ultimately, addressing land subsidence in Semarang's Pantura region hinges on government policy, particularly concerning the management of industrial groundwater extraction. Batubara warned that poor governance, coupled with continued heavy extraction by industries, would lead to more empty spaces in the aquitard layer, worsening land subsidence. He also pointed out that industrial infrastructure itself adds weight to certain areas, further contributing to the sinking.