Historical capacity and storage of managed water reservoirs in Spain (1988-2026): A standardized relational dataset

Aimar Rollán-González 

Long-term empirical baselines of water storage are critical for evaluating drought resilience, climate change impacts, and agricultural stress. However, historical hydrological records are frequently siloed in proprietary or high-friction formats. Here we present a continuous, harmonized, and relational Star Schema dataset of managed water reservoirs in Spain spanning nearly four decades (1988–2026). Derived from official administrative data published by the Spanish Ministry for the Ecological Transition (MITECO), the dataset liberates over 724,000 weekly volumetric records across 402 reservoirs and 16 river basins from a closed Microsoft Access (.mdb) binary container. To demonstrate extreme resource efficiency and hardware-agnostic reproducibility, the entire Data Rescue and ETL pipeline was executed on a consumer mobile ARM64 environment. The resulting FAIR-compliant database decouples geographical entities to minimize storage overhead, applies strict ISO 8601 temporal formatting, and achieves 100% volumetric reconciliation (0.0 hm³ deviation) with the primary source. By preserving explicit flood-routing anomalies and reporting omissions without statistical imputation, this dataset provides an immutable, machine-actionable foundation for large-scale hydroclimatic modeling and policy evaluation.