IHA R Package: Indicators of Hydrologic Alteration Implementation

Open-source R package implementing the full Indicators of Hydrological Alteration (IHA) methodology for reproducible, scriptable analysis. Provides functions for calculating all 33 IHA parameters organised by group (group1 through group5), Environmental Flow Component (EFC) analysis, Range of Variability Approach (RVA) calculations, and publication-quality graphical output. Enables batch processing of multiple gauging stations, integration with other R hydrological packages (lfstat, hydrostats, fasstr), and custom statistical analysis beyond what the TNC desktop software provides. Input data format: daily discharge time series. Particularly valuable for researchers and practitioners needing reproducible workflows, version-controlled analysis, and the ability to process large datasets from DWS, GRDC, or other hydrological databases.