Mapping Groundwater Stress-Prone Zones in Dhaka District Using InSAR and Integrated Geodetic Observations

Dhaka District faces severe groundwater depletion driven by rapid urbanization, industrial demand, and over-abstraction that consistently outpaces natural recharge. Falling water tables have triggered measurable land subsidence, threatening infrastructure and long-term water security, yet integrated assessments combining direct and remote observations remain scarce. This study identifies groundwater stress-prone zones across Dhaka District by jointly analyzing GNSS, GRACE/GRACE-FO satellite gravimetry, GLDAS land surface model outputs, and Sentinel-1 InSAR measurements. GRACE/GRACE-FO mascon data are used to quantify terrestrial water storage anomalies, while GLDAS-2.2 CLSM outputs isolate the groundwater storage component by removing soil moisture, snow, and surface water contributions. Sentinel-1 DInSAR time-series processing maps cumulative ground deformation to detect subsidence linked to aquifer compaction. Continuous GNSS records provide independent, high-precision vertical displacement rates for calibrating and validating the InSAR-derived subsidence field. Groundwater level records from Bangladesh Water Development Board monitoring wells anchor the satellite observations to in-situ conditions. By overlaying storage decline, subsidence magnitude, and well-based depletion trends, the analysis delineates zones where multiple stress indicators converge. Results are expected to reveal that the most stressed areas concentrate in densely built urban cores and industrial belts where subsidence coincides with sustained storage loss. The integrated framework offers a transferable, multi-sensor approach for diagnosing groundwater stress in data-limited megacities, supporting evidence-based aquifer management, urban planning, and sustainable water governance in Dhaka and comparable rapidly urbanizing regions.