2.5.1. Characteristics of Groundwater
In France one can distinguish between three types of groundwater regions. Due to estimations of experts 30 % of these regions are situated in porous media; <10 % in karst media and about 60% in other media. In 1981 an estimation on potential water resources showed that about 440,000 mio m³/year come from precipitation; 2,000-3,000 mio. m³/year are inflows from neighbouring countries. The rate of evapo-transpiration is about 270,000 mio. m³/year.
Most of the water is consumed for cooling power plants, it takes about 20,000-22,000 mio. m³/year. This amount is followed by water consumption of households with 5,500-6,000 mio. m³/year, then industry with 4,400-5,500 mio. m³/year and finally agriculture with 4,000-5,000 mio. m³/year. Thereupon groundwater resources provide the following percentages of the whole water consumption: porous and karst aquifers together 37-40% (cooling excluded); springs 16-16.5% (cooling included).
2.5.2. Structure of the Administrative Organisations Concerning Groundwater Quality
The French groundwater monitoring programme, the Observatoire National de la Qualité des Eaux souterraines -ONQES" is a composition of many different regional, local or basin networks. More details can be found in the Catalogue des Sources de Données de lEnvironnement" released 1994 by IFEN (Institut Français de lEnvironnement)/Lavoiser. There is no single administrative structure dealing with groundwater quality monitoring but for a brief overview: the Ministry of Environment/Water Department co-ordinates the programmes for groundwater monitoring activities. The Ministry is supported by the B.R.G.M (Bureau de Recherche Geologique et Minière) an organisation which manages the national database, and the Ministry of Social Affairs and Integration, which is responsible for sampling and analysing procedures.
In fact, the only national network which collects data related to groundwater quality has as legal basis the application of Decree 89-3 (as result on Drinking Water Directive). Natural Water used for drinking water supply is regularly monitored and the results are incorporated in the ONQES database. Other responsible network systems are: the Alsace aquifer network, the Basin Seine Normandie networks (including the AQUAREL special network, devoted to aquifers used by small collectives, unable to afford the analytical obligations of the aforesaid decree), the Basin Loire-Bretagne Triazine/Simazine network (including some surface waters), the specialised network held by Basin Rhone-Méditerranée-Corse. In the North of France, the Basin Artois-Picardie also manages a patrimonial network, in an area, where most resources are obtained from underground waters. The IFEN is not concerned with the quality of data this is the responsibility of the network owners.
The main purposes for monitoring are to collect information, to survey the water quality, to identify water quality trend and process a system which aims at
facilitating the reinforcement of water policy
ensuring the best action from water agencies and
detecting variations of water characteristics.
The monitoring is undertaken due to legal order.
2.5.3. Monitoring of Groundwater Quality
The French groundwater network covers the whole country. The sampling sites are concentrated around drinking water wells in every kind of groundwater aquifer. The sampling frequency for basic monitoring programmes vary between 0.5-4 times a year. The parameters observed are listed in an ordinance of the French Health Ministry that lays down the detection limit, analytical reference methods and the percentage of precision. More than 200 institutions are involved in sampling and analysing the groundwater quality data. These activities are not standardised and there is also a lack of national quality control and assurance procedures. But of course there are internal obligations for the laboratories to use comparable standardised methods within the whole network as well as ones obliging them to follow standardised regulation for precision and accuracy.
The network has been in operation since 1902. It has an average length of 8 years. The data management is done by the B.R.G.M which loads data on to an ORACLE database using VAX as hardware. Language, software, query, reporting tools are SQL+, ARC/INFO for servers and MS/Windows, MS/ACCESS, MAP/INFO or ARCHVIEW for the clients. The data are evaluated and can be requested due to clients interrogation, or are published e.g. as maps or structured tables with possibilities for statistical computations. The Comité de Coordination de ONQES" has the authorisation for the data release. No fee has not to be paid for data. Public organisations may provide reports made by the B.R.G.M of groundwater quality information due to authorisation.
2.5.4. Structure of the Administrative Organisations Concerning Groundwater Quantity
With exceptions, groundwater quantity monitoring is not held at national level. But the installation of a basic national network has recently been planned. The Ministry of Environment charged the DIREN (Direction Régionale de lEnvironnement) Alsace to make a nation wide inventory of all significant networks. As an result there is to be a selection of about 1,500 piezometers which will constitute a national basic network in the future. At present the number of piezometers in function is diminishing each year, mainly because of the cost of data collection after recording at the site. For this reason many efforts have been undertaken to solve this problem. There were attempts to automate data collections but they turned out to be not as successful as expected.
Most of the networks are held by the DIREN. They form 22 regional headquarters for environment which are the regional representatives of the Ministry of Environment). Their involvement in groundwater monitoring vary according to the importance of this task in the former organisations of the Ministry of Agriculture, that have been merged into the new DIREN structure. From case to case the DIREN is partly subsided by local authorities in managing the networks.
Due to the strategic importance of the Rhine Aquifer a special network has been established in the Alsace region. The measurement structure has a high degree of political implication. This is also the case in some special areas (such as the Gironde/Bec dAmbrès system, involved in the Bordeaux city water supply, the aquifers being under the threat of saline, poorly reversible, intrusion).
2.5.5. Monitoring of Groundwater Quantity
The information provided at this stage was taken from the Catalogue des Sources de Données de lEnvironnement", released 1994 by IFEN. Fourteen names of regional organisations have been listed. These organisations co-ordinate the regional network programmes, co-operate partly with other regional agencies together for reporting and are responsible for the database management. All monitor the groundwater level for basic data collection and for a quick indication of changes of the water level. Most of them co-ordinate the water supply. The IFEN pointed out that these data were without warranty. The information given will be updated in future. That is why the majority of the groundwater quantity questionnaires remained unfilled.
For references, please go to http://www.eea.europa.eu/publications/92-9167-032-4/page007.html or scan the QR code.
PDF generated on 23 Mar 2017, 03:15 AM