Grundvandsovervågning 2010 - Geus

English summary
Groundwater monitoring in Denmark has now taken place for fully 20 years, with systematic
sampling and reporting since 1989. The monitoring programme is presented in chapter 2.
Compared with last year this report presents new data from 2009.
Data
The report encompasses chemical analysis of groundwater, measurements of groundwater
table and information on the amount of water abstraction from groundwater and surface water.
Data from ”Det Nationale Vand og Natur overvågningsprogram (NOVANA)”, includes chemical
analysis from the groundwater monitoring programme (GRUMO) and the groundwater activities
of the agricultural catchment monitoring (LOOP) plus monitoring of groundwater table from
the national groundwater table monitoring programme and all monitoring wells samples in
GRUMO. Nearly all data have been correct and timely uploaded to the JUPITER database.
Only a minor part of the samples from LOOP 3 (Horndrup Bæk) are not available for this reporting
due to technical data mistakes.
In the past year a significant improvement in the amount of monitoring data from the sounding
programme have been uploaded to JUPITER has taken place. Still some work is remaining
before all monitoring data are available, especially from the continuous data logging. In addition
to this, many corrections of the existing data in the database, have to be done.
All relevant data on groundwater and drinking water have to be available in the public JUPI-
TER database, which is common for all public administrative units in Denmark. Most municipalities
are now uploading data, but a considerable backlog still remains in many municipalities
on the amount of abstracted water from groundwater and surface water from waterworks, irrigation
and other abstractors. Also significant mistakes in the uploaded data are found, especially
on the use of surface water, which tends to be overestimated for the fish farms. It is not
possible to find out to what extent the reporting is completed.
Nitrate
In order to judge the change of nitrate concentration in groundwater due to the implementation
of the Water Action Plan in 1987 and the following legislation and action plans, one has to look
at the youngest oxic groundwater. It appears that the nitrate concentration in the youngest
groundwater is going in the desired direction, and that the effects of the action plans now can
be seen in the groundwater.
Statistical trend analyses were conducted in last years report on each monitoring point with
oxic groundwater in the groundwater monitoring programme (GRUMO) and in the monitoring
of agricultural catchments (LOOP). These results are still expected to be valid, since the development
in the groundwater quality are slow and only can be identified with sufficient confidence
after several years of careful monitoring.
It can be concluded, that the development of the nitrate content in groundwater is going in the
right direction, but that upward trends of nitrate to some extent occur even in young groundwater
formed after the action plans implemented. Further investigations are needed to clear the
picture.
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