Annual Report 2004
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Water resources |
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Groundwater protection through stakeholder involvement
During the summer, GEUS and Københavns Energi (KE) completed an EU project, which examined how farmers, residents and other interested parties can be involved more effectively in the decisions necessary to protect Danish groundwater. The project tested whether graphical models can be applied in the management of water resources; the so-called Bayesian Belief Networks (BBNs).This decision-making tool makes it possible, with one tool, to illuminate the significance of various factors in a given protection measure, such as water cycle, groundwater quality, natural values, macroeconomics, and commercial aspects. By involving a stakeholder group of professionals and a citizens group, different measures were tested at St. Havelse Kildeplads north of Frederikssund, a recovery catchment area owned by KE. The project shows, for example, that voluntary cultivation agreements based on individual negotiations with each farmer are not readily applicable as a means of groundwater protection. Establishment of a cultivation agreement is not only dependent on farm economic consequences; it is also dependent on attitudes and basic values and opinions. The method has proven apt for mapping some of these fundamental factors.This is important knowledge to have when assessing how to ensure support for future implementation of planned measures. The project concludes e.g. that use of BBNs has made broader local acceptance of decisions possible, as well as improved the dialogue between water companies, local stakeholders and the authorities. |
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Groundwater monitoring 1998-2003
In 2004, the annual report on the state of groundwater in Denmark concentrated on the period 1998 to 2003, when the monitoring programme NOVA 2003 was underway. The report concludes that the Maximum Admissible Concentration (MAC) for nitrate was exceeded in around 16 per cent of all monitoring boreholes. However, there is a downward trend with regard to nitrate content in the youngest groundwater, although average concentrations here lie close to the MAC of 50 mg/l. A further reduction is therefore desirable, out of consideration for both nature and the quality of drinking water. The MAC was only exceeded in one per cent of the waterworks' abstraction wells, which is due to the fact that wells with a high content of nitrate are abandoned and the abstraction moved to deeper lying aquifers or to less affected areas. The frequency rate of pesticide findings in connection with groundwater monitoring has been constant in recent years, but there has been a slight increase in the number of incidents where MAC for drinking water have been exceeded. In contrast, there has been a drop in the frequency of incidents where MAC in the waterworks' abstraction wells have been exceeded.This is probably due to the fact that abstraction wells with high concentrations of pesticides are being discontinued. Finally, the report shows that the amount of water abstracted since 1998 has gone down.This has reduced the pressure on groundwater resources and the effect of water abstraction on water flow in water courses. |
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Possible to identify particularly pesticide-sensitive sandy soil
Due to lack of knowledge, the counties' task of identifying areas which are particularly sensitive to certain types of contamination has not previously included pesticides.A project, entitled KUPA (Concept for identification of Pesticide -Sensitive Areas) was therefore launched as part of Pesticide Plan II to investigate whether it is possible to identify areas which are sensitive to pesticide leaching. GEUS and the Danish Institute of Agricultural Sciences had been working on this since 2000, and in 2004 this work was completed with a report concluding that identification of sandy soils especially sensitive to pesticides is possible. The work shows e.g. that there are significant differences in the degree of sensitivity of sandy soils to leaching, and that for most of the known pesticides, the ability to bind depends on the same physical or chemical properties in the soil. Furthermore, it appears from the conclusion that the general sensitivity to leaching can be described by relatively few simple properties in the soil, and that it will be possible, with the help of known and relatively few new data, to carry out identification of particularly sensitive soils. The project also reviewed the development of methods for use on clayey soils. In a separate report, GEUS and the Danish Institute of Agricultural Sciences conclude that a similar basis for identification can be provided for clayey soils. This work has not yet been finished and will continue in the years to come with funding from the Government's Pesticide Plan 2004-2009. |
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Status and assessment of pesticide use
The Danish Crop Protection Association has asked GEUS to make a status of the incidence of banned and approved pesticides and their breakdown products in Danish groundwater, as well as an assessment of the probability that the use of the substances applied by agriculture today will create problems for groundwater in the future. In the report "Pesticidanvendelse i landbruget" (Pesticide use in agriculture) GEUS assesses that groundwater quality will be considerably improved in 20 to 30 years time, if the re-evaluation of approved substances is continued, e.g. on the basis of the results from the Danish Pesticide Leaching Assessment Programme. The majority of the substances being applied today are not likely to give rise to groundwater aquifer pollution exceeding the permitted limit value; however GEUS also assesses that there are substances in use today which may have to be regulated following testing under the Pesticides Leaching Assessment Programme. It is probable that some pesticides will leach due to local conditions or accidents, but this risk of contamination can be minimised if experience from research project KUPA is applied to sandy and clayey areas, and if guidelines are prepared for managing spraying equipment and pesticides. Finally, GEUS assess that Danish groundwater monitoring is better than in most other countries in Europe. |
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Studies of chloroform in groundwater
Groundwater containing more than one microgram of chloroform per litre must not be used as drinking water.A high content of chloroform can be due to human activities, however new research shows that naturally occurring chloroform may also be the cause. In 2004, GEUS commenced on a project to examine whether chloroform in groundwater is a problem for Danish drinking water supply and how much of the substance comes from natural sources. In collaboration with the Danish Hydraulic Institute (DHI), Rambøll, and Viborg Vand A/S, studies of current knowledge in the area were carried out during 2004, supplemented by new studies from a catchment area south of Viborg in Jutland. The results show with great certainty that natural production of chloroform is the cause of chloroform pollution in the Viborg area. Laboratory measurements of soil samples showed that chloroform production is greatest in the soil under coniferous forests. The work will continue in 2005 and will include a review of treatment principles, their financial aspects, and preparation of a practicable guideline for waterworks that have chloroform problems. The project is receiving financial support from the Danish EPA. Universities from Sweden and Switzerland are taking part in the project. |
