Water level gauge swept away by the River Loire in spate (Orléans, 2012). © BRGM - Benjamin Francois

Towards more effective communication of groundwater data

The EU-WFD, which sets out a framework for managing and protecting water resources by major hydrographic basins with a view to sustainable development, has brought a great deal of research on groundwater in its wake. In France, the BRGM is constantly innovating in this field, with tools such as QualiNet, developed to improve the communication of data from chemical and water level analyses.

Measuring the level of a water table

Measuring the level of a water table. © BRGM

In view of the growing strategic importance of water resources, whether for domestic or industrial uses, the EU Water Framework Directive (WFD) published in 2000 requires the Member States to take responsibility for protecting these resources. The question that arose was how to optimise the communication of groundwater data. This is the purpose of research now under way at the BRGM, where the aim is to develop better tools to manage information gathered by scientists.

Subsoils in mainland France currently hold an estimated 100 billion m3, on average, of water resources. About 30 billion m3 of water are abstracted each year for different needs. Groundwater accounts for more than 20% of the volumes abstracted (and about two thirds of all drinking water supplies).

Appropriate tools are essential to manage both the quantity and quality of these groundwater masses.

 an example for the Burgundy region

MétéEAU water level forecasts: an example for the Burgundy region (Tille river basin, piezometer 04398X0002/SONDAG). © BRGM

Publishing changes in water table levels in real time

The BRGM has been developing scientific tools for many years to improve knowledge on aquifers, measuring water table levels through an automated piezometric network, developing digital models to forecast changes in levels, etc. Our laboratory is also the national operator of the ADES databank and has developed data-processing software to characterise water quality or identify trends at different scales (nitrate and pesticide concentrations, for example). These tools are now readily available thanks to online data transmission. Producing and distributing raw data on a daily basis is now possible, which is particularly important during periods of drought.

As well as taking measurements in the field, the laboratory is now developing easily usable data products from its digital models. Ultimately, the aim is to publish water table trends in real time, and even to predict levels over several months.

A multi-criteria digital representation of water resources

QualiNet, funded by the Seine-Normandy Water Agency and the BRGM, is a step forward in this direction. This is a new tool to support WFD implementation by digitally analysing data to improve knowledge on groundwater, but with a difference - it applies a multicriteria approach to simultaneously process chemical data and ADES water level data.

In practice, QualiNet is a statistical computing application combined with an R-GIS mapping tool. Statistical processing output is delivered directly through the ArcGIS interface, a cartographic information system, but also in tabular, graph and map form.

The software developers were faced with a particular constraint : the characteristics of groundwater quality data are such that some statistical test results may be weak or even inapplicable. This is because the data are not regularly sampled, they are often self-correlating and do not have a normal distribution: the information is therefore frequently "silent" or below the quantification threshold The statistical methods used in tool to support were therefore selected in previous studies on the methods used to identify trends in groundwater time series (launched by the BRGM in 2010).

The result is a digital representation of water resources as easy-to-use maps, which also show their chemistry and an analysis of their chemical status, thus allowing continuous reassessments of groundwater status and the risks of falling short of the required standard.

In line with the BRGM's key role of providing support to public policy development, these data are used as an aid to decision-making in water agencies, for example.

QualiNet output to support regulatory calculations of the quality and chemical status of groundwater

QualiNet output to support regulatory calculations of the quality and chemical status of groundwater. © BRGM

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