INTERA’s Dr. Abhishek Singh, PE, President, Water Resources and Supply and Principal Water Resources Engineer, and Tyler Hatch, Director of California Technical Services and Principal Engineer, are both supporting authors on two articles featured in the Groundwater Resources Association’s (GRA) HydroVisions, Winter 2024 issue (Volume 34). Dr. Singh is co-author on, “Part 10 – PFAS Source Areas and Groundwater Plume Persistence”, which focuses on the nature of vadose zone PFAS source areas and how those areas create and sustain groundwater plumes. Mr. Hatch is co-author on, “Subsidence Data: Techniques, Availability, and Interpretation”, which is the second installment of a five-part series on land subsidence (the lowering of land surface elevation) and provides an overview of methods to measure and monitor land subsidence. An overview of the physical mechanisms leading to subsidence due to groundwater pumping and sediment compaction can be found in “California’s Sinking Feeling: An Introduction to Subsidence” (published Summer 2023). To view the articles, visit: