Long-Term Groundwater Level Decline Analysis for the Hungarian Great Plain - Analysis Scripts

Analysis scripts for investigating multi-decadal groundwater level trends in the Hajdusagi (HAHO) region of the Hungarian Great Plain. Covers 40 TIKEVIR wells (1966--2022) and 208 SQL database wells (1935--2025), with 69 quality-filtered wells forming the primary cohort. Methods include Sen's slope estimation, Hamed-Rao autocorrelation-corrected Mann-Kendall trend test, Benjamini-Hochberg FDR correction, Pettitt change-point detection, SPI-12 precipitation coupling from FORESEE gridded data, and composite groundwater z-score analysis. Includes network overlap analysis, survivorship bias diagnostics, and representativeness testing. Catchment delineation was performed in ArcGIS Pro 3.6 using the ArcHydro toolset.