News from July 2026:
Hydro(geo)logical study - Understanding water in the Arédien territory
Progress of work • Published on July 12, 2026
In 2023, the Compagnie des Mines Arédiennes hired studies on groundwater and surface water in the Arédien territory in order to have expertise based on several climatic cycles.
Currently, the Compagnie des Mines Arédiennes These studies on groundwater and surface water are continuing in order to establish a baseline of the water resource and monitor its evolution over two to three years. The extension of the Douillac PER (Plan d'Études et de Recherches - Research and Development Study) allows for a broader investigation area around the former mining sites.
The first phase of the study, conducted primarily on the sectors of Moulin de Cheni, Laurieras and La Fagassière This will allow us to characterize the variations in space and time in the quantity and quality of water. It will contribute to deepen the understanding of hydrology and hydrogeology at the scale of the river basin. It aims to validate, clarify and complete Ultimately, the conceptual model established from the study carried out from 2023 onwards, from historical archives resulting from more than 40 cumulative years of modern research and exploitation.
CMA commissioned this study to AqTerra Alliance, a consulting firm specializing in hydrogeological diagnostics and risk management for water resources.
Hydro(ge)logical study conducted by AqTerra Alliance
Definitions
Hydrology
Science of the water cycle at the Earth's surface who studies:
- The precipitations
- Runoff
- The flow rate of watercourses
- evaporation
- Surface flow
Applications :
- Water resources management
- Flood and inundation forecasting
- Dam and reservoir management
- Watershed management
Hydrogeology
Branch of geology on the circulation of groundwater in the soils and rocks that are being studied:
- Groundwater and aquifers
- Water infiltration into the soil
- The porosity and permeability of rocks
- Drilling and groundwater extraction
- Groundwater pollution
Applications :
- Groundwater management
- Protection against groundwater contamination
- Studies for drilling for drinking water or irrigation
- The rehabilitation of polluted sites
How is the current study progressing?
Two hydrogeologists from AqTerra Alliance conducted an initial sampling campaign in April 2026. high water periodThis intervention aimed to carry out the first measurements and samples in a hydrological context favorable to the location of sources and the identification of hydrological connections within the catchment area.
Their mission on the ground:
- Identification of springs, streams and bodies of water
- Identification and assessment of existing structures: wells, piezometers, recent or historical boreholes
- Measurement of the flow rate of springs and streams, and of groundwater levels
- Surface and groundwater withdrawals: a total of 77 withdrawals
Samples were taken and analyses were carried out in accordance with international standards quality control procedures included the use of field blanks, duplicates, and ionic balance verification. Samples intended for dissolved metal analysis were field-filtered to 0,45 µm and then preserved by acidification with ultrapure nitric acid. Analyses were performed by a COFRAC accredited laboratoryapplying quality assurance procedures based in particular on the use of laboratory blanks and internal standards in order to guarantee the reliability of the results.
Detailed location of samples
On the PER Douillac
On the PER Pierrepinet
On the PER Fayat
Characteristics of the samples
| Type of environment | Intervention |
|---|---|
| Wells and boreholes | Measurement of the structure's characteristics (depth, diameter), piezometric level measurement, pumping, physico-chemical measurements and water sampling |
| Springs, streams | Flow measurement (potting, FP111 current meter), physicochemical measurements and sampling |
Multiparameter probe for measuring physicochemical parameters (temperature, conductivity, pH, oxidation-reduction potential, dissolved oxygen)
Measuring pH in a watercourse
Sampling of a water sample for anion analysis
The water sample is bottled for dissolved metal analysis.
Characteristics of the analyses
The 77 water samples taken were analyzed to identify various hydrochemical parameters:
- Conductivity, pH, suspended solids
- Sulfates, carbonates, nitrates, nitrites
- Metals: 32 elements
The analyses were carried out by the Qualyse laboratory in Limoges.
| Measured parameter | Method of analysis |
|---|---|
| Physicochemical parameters: Temperature, pH, Conductivity, ORP, dissolved oxygen | Measured in the field using a WTW 3600 multi-parameter probe |
| Suspended solids (SS) | Filtration using fiberglass filters (NF EN 872) |
| Total Alkalinity (TAC) | Titration with sulfuric acid (H2SO4) |
| Anions: Sulfates (SO4), carbonate ions (H2CO3, HCO3, CO3), Nitrates (NO3), Nitrites (NO2) | Spectrophotometric and Turbidimetric Assay (NF EN ISO 15923-1) |
| Cations and trace elements: Ca, Mg, Na, K, Al, As, B, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Se, Zn, Ag, Be, Co, Sn, Li; Sr, Te, Th, Ti, U, V, Mo | Inductively coupled plasma mass spectrometry (NF EN ISO 17294-2) |
| Mercury (Hg) | Atomic fluorescence spectrometry (NF EN ISO 17852) |
| Hydrocarbon index (total hydrocarbons) | Gas chromatography (NF EN ISO-9377-2) |
| Cyanides (CN) | Photometric assay (NF EN ISO 14403-2) |
What next?
For 2026, a 2e the countryside sampling will be carried out low water period at the end of the summer in order to complete the exploratory phase in a context of lower dilution of the elements in solution in the water.
The results of the analyses are given to the owners or occupants of the plots where the samples were taken.
A summary and interpretation report of the results is being drafted and will serve as the first reference for subsequent environmental monitoring.