Jakarta faces a critical challenge of extensive land subsidence, ranking prominently globally. This research employs a combined technical and policy evaluation approach to analyze the issue, incorporating sustainability considerations to assess the efficacy of Governor Regulation of Jakarta Number 93 of 2021, focusing on how the groundwater-free zone relates to land subsidence in the city. We processed 81 ALOS-2 PALSAR-2 synthetic aperture radar (SAR) data using persistent scatterer interferometric synthetic aperture radar (PS-InSAR) with HH polarization from 2017 to 2022 and ground truthing with 255 global positioning system (GPS) real-time kinematic (RTK) validation points. Our findings reveal a significant misalignment in the designated groundwater-free zone in the central part of Jakarta. At the same time, severe land subsidence primarily affects northern and northwestern Jakarta, with an average land subsidence rate of 5–6 cm/year. We strongly advocate for a thorough evaluation to rectify and redefine the boundaries of groundwater-free zones, improve regulatory frameworks, and effectively address land subsidence mitigation in the study area. The impact of domestic water needs on land subsidence highlights the urgency of action. Based on a combination of land subsidence velocity rates and domestic water demand, we have classified the cities in Jakarta into three levels of recommendations for groundwater-free zones. The cities are ranked in order of priority from highest to lowest: (1) West Jakarta, (2) North Jakarta, (3) South Jakarta, (4) East Jakarta, and (5) Central Jakarta, which holds the lowest priority.

The North Java coastal area, known as the Pantura region, is experiencing significant land subsidence, with certain areas sinking up to 10 cm per year. Pekalongan is among the most affected, with subsidence rates between 10 and 19 cm annually, mainly due to groundwater extraction, sediment compaction, and coastal erosion. Other coastal cities, like Semarang and Demak, show rates averaging 4 to 10 cm per year. This rapid subsidence is due to favorable geological conditions and ongoing urban development. This study investigates land subsidence in Pekalongan using the PS-InSAR method and dynamic visualization of time-series land cover data. PS-InSAR was applied to 45 scenes from ALOS-2 PALSAR-2 to monitor subsidence from 2014 to 2022. The results were validated with in situ subsidence benchmarks. Urban development dynamics were analyzed through land cover and land use change (LULC) and population density over the same period, using the GLC_FCS30D dataset in the GEE to detect non-natural LULC. The PS-InSAR results indicated that over 60.9% of investigation points experienced subsidence, up to 100 cm between 2014 and 2022. Ground validation showed an 83% agreement with PS-InSAR results. A statistical analysis of LULC from 2014 to 2022 did not show significant built-up area development, but the extension of salt marshes and water bodies indicated subsidence expansion. The population density reached 6873 people per square km by 2022, causing extensive groundwater use for domestic and industrial purposes, further aggravating the subsidence.

This research aims to make a historical mapping of the development of road infrastructure and the impact on land use changes. A historical analysis was conducted based on the documents and reports of transportation development, road construction, and urban planning in Semarang City, the capital city of Central Java, Indonesia. From a historical perspective, the transportation development and the land use change of Semarang City were determined by economic activities from the early period of colonialism, especially when this city was devoted as a port city in Java with massive coastal inhabitants. Along with this economic activity, ports and roads were built, accelerating the city’s development until the mid of 20th century. Road construction generated urban problems such as rapid urbanization, and environmental problems. Meanwhile, the road construction also accelerated the city agglomeration, connecting Semarang City with other cities on the Java North Coast. However, in the 1990s the symptom of the use of private transportation occurred in Semarang which became the most critical issue in the later periods.

Kendal Regency as Special Economic Zone and Industrial Park is stimulating the rapid coastal urban growth. This condition initiates the high risk of disaster in the northern Central Java. The research aims to model the tidal run-up and spatial inundation distribution using numerical calculation of logical tool-less than equal and to identify the land uses that are affected by the tidal run-up and inundation in the Kendal coastal area. This research conducted by the digital elevation model in 7 m spatial resolution and the highest high-water level (HHWL) data in the one-year analysis. Furthermore, the data processing was run using Less than equal tools. The result showed that the HHWL condition in 2018 reached up to 0.35 m. Considering the HHWL data, the eastern coastal area of the Kendal Regency is massively being affected by the tidal run-up and inundation. The furthest distance of the tidal run-up and inundation reached up to 3.7 km. There are six land uses affected, i.e., built-up area (0.04%), garden (2.01%), dry land (4.89%), grassland (5.09%), a fish pond (41.95%), and paddy field (4.24%).