Impact Of Ground Subsidence On Groundwater Quality: A Case Study In Los Angeles, California

The main aim of this paper is to measure land displacements, as a result of fluid overextraction, and evaluate the impact of measured deformation on the groundwater quality in the Inglewood region, Los Angeles. Therefore, persistent scatterer interferometry (PSInSAR) technique was applied on a set of Sentinel-1 radar images to monitor the subsidence rate in the interested area between June 2017 and May 2018. Then, groundwater data were used to assess the variations in water parameters affecting its quality. Changes in the concentration of the studied parameters including total dissolved solids (TDS), biochemical oxygen demand (BOD), arsenic, and lead were investigated. The PSInSAR outputs demonstrated a high-rate of subsidence in the Inglewood field (30 mm/year). The results showed that uplift as a result of water injection lead to significant increase in TDS, arsenic, and lead, diminishing the water quality and exceeding quality limits and standards. Water injection does not enhance water quality, only preventing the subsidence in this area.