Monitoring of Changes in Water Content in Soil Pores of Earth-Fill Dams

Abstract

The Czech Republic (CR) lies on the watershed divide of three seas—The North, Baltic and Black Seas. The watershed of these seas divides the territory of the CR into three international catchment areas (Labe, Odra and Danube). In conjunction with the fulfilment of obligations arising from the Convention of the European Economic Commission of the United Nations Organisation on the protection and use of transboundary watercourses and international lakes, an “International Commission” was founded in 1990–1998 for each international catchment area. The CR is a member of the International Commissions for the protection of these catchment areas. The purpose of the activity of these institutions is to support cooperation in water management at the level of international catchment areas. It is obvious that practically all significant watercourses in the CR drain water beyond its boundary on the territories of the neighbouring states, resulting in the fact that water sources in the CR are practically dependent on the amount and distribution of atmospheric precipitation. In the context of discussing changing climatic conditions, atmospheric precipitation of very different intensities increases the likelihood of the occurrence of extreme floods and dry episodes. The theme of protection from the consequences of floods and drought is part of joint debates of all three international commissions. The approach to the solution of the issues above, however, can be different because it is based on the current conditions of the given international catchment area. Many fields and areas give attention to the theme of threats posed by natural disasters created by flood situations and drought not only from the view of science. It is not possible to prevent floods or drought by the present scientific knowledge and technical options. In case of floods, it is possible to reduce their impact on the lives and property of inhabitants by constructing efficient flood control works. However, it is necessary to have in mind that even the best flood control measure will only be as reliable, efficient and safe as its weakest element will be reliable, efficient and safe. In many cases, this element is earth-fill dams. Therefore, it is necessary to have continuous and long-term information on their condition. When addressing the issue of drought in the CR, it is necessary to realise that the absolute majority of water sources depends on the retention and accumulation of water in the territory of the CR. At present, the impacts of drought and lack of water in the conditions of the CR are significantly mitigated by the existing water management infrastructure. However, it can be expected for the future that the existing water sources will not be sufficient. Not only the aspect of the potentially diminishing available amount of surface water and subsurface water in the CR will be problematic, but also the aspect of the unsuitable quality of water. Also from this aspect, it is possible to see the earth-fill dam as an element that helps retain and accumulate water in the landscape. The reality is that every inhabitant of the CR is a significant user of its water sources, and it is necessary to bear the responsibility for them. Unfortunately, people usually realise neither the significance nor the value of the discussed irreplaceable nature wealth for everyday life, nor the scope of activities and financial costs that are associated with this “matter of course”. In this chapter, the team of the authors provides a view of international cooperation and its achievements when dealing with a project of applied research in the EUREKA programme, which was focused on the development and construction of monitoring technology enabling changes in water content to be monitored in a porous medium. The selected results are documented in a link to remedial measures applied to earth-fill dams of water reservoirs in the conditions of the CR, emphasising the use of the method of electrical impedance spectrometry. The authors are aware of the fact that it is only a fragment of the solution of the complex of the outlined issue. However, it is obvious that without the safe operation of water management works, the irreplaceable part of which is their monitoring, it is impossible neither to ensure water sources nor to manage them.