Groundwater quality and related data in Ono City, Fukui Prefecture, Japan

This dataset was compiled to evaluate long-term changes in groundwater quality in relation to the evolution of wastewater treatment systems in Ono City, Fukui Prefecture, Japan. It includes annual groundwater-quality monitoring data collected by the city, together with related location information, maps illustrating annual changes in the spatial distribution of groundwater quality, water-quality data from surrounding aquatic environments, and the Python analytical scripts and results. This dataset consists of four ZIP archives (Dataset 1: Geographic_data.zip, Dataset 2: WaterQuality_data.zip, Dataset 3: maps.zip, and Dataset 4: statistics.zip). 1. Dataset 1 (Geographic_data.zip) Dataset 1 consists of two Excel files (Table 1.xlsx and Table 2.xlsx). Table 1.xlsx contains groundwater monitoring well information, including well classification, location, and depth. Table 2.xlsx contains installation years and locations of combined-treatment johkasou units installed in Ono City. 2. Dataset 2 (WaterQuality_data.zip) Dataset 2 consists of two Excel files (Table 3.xlsx and Table 4.xlsx). Table 3.xlsx contains annual groundwater-quality data for 25 parameters measured from 1976 to 2023. Table 4.xlsx contains water-quality data for wastewater treatment plant effluent, river water, springs, and non-urban groundwater in the Ono Basin. 3. Dataset 3 (maps.zip) Dataset 3 consists of 11 image files: Ecol.png, HPC.png, NO3N.png, Cl.png, hardness.png, Fe.png, Cu.png, Zn.png, Pb.png, turbidity.png, and color.png. Ecol.png shows total coliforms and Escherichia coli together, while the other figures show heterotrophic bacteria, nitrate nitrogen, chloride ions, hardness, iron, copper, zinc, lead, turbidity, and color. 4. Dataset 4 (statistics.zip) Dataset 4 consists of a Python script (Ono_GW_all_stat.py) used to perform statistical analyses of relationships among groundwater-quality parameters, and four Excel output files (Table 5‑1.xlsx to Table 5‑4.xlsx) generated by applying this script (and a partially modified version of it) to the groundwater-quality data in Table 3.xlsx. Table 5‑1.xlsx contains analytical results obtained by applying Ono_GW_all_stat.py to the groundwater-quality dataset for the entire city. Because wastewater treatment systems and their historical development differ between urban and non-urban areas, groundwater-quality changes were classified into four stages (Stages I–IV) in this study. Table 5‑2.xlsx to Table 5‑4.xlsx contain analytical results for oxic groundwater used for drinking, classified into three spatial categories: the entire city, urban areas, and non‑urban areas. Each file summarizes pairwise statistical relationships among key groundwater‑quality parameters—including microbial indicators, trace metals, and physical properties—for all monitoring stages and for each individual stage.