Vízügyi Közlemények, 1959 (41. évfolyam)

4. füzet - V. Kisebb közlemények-Ismertetések

(34) tical utilization of water is to establish the main characteristics of groundwater household under natural conditions. The information gained thus should be applied to determine the effects of technical interference, respectively, the correct technical solution by which groundwater household can be influenced in the most advantageous manner. The exact definition of groundwater is a rather difficult problem, inasmuch as its accurate discrimination from other subsoil waters in various layers and at different depths is usually not possible. According to Hungarian technical practice groundwater is understood as the subsoil water close to the surface, which fills the pores of loose sedimentary rocks continuously, is subject to the influence of gravity and hydrostatic pressure, and suffers frequent, directly observable changes in volume due to external factors. Groundwater is thus distinguished from so-called artesian waters to be found in permeable layers between impermeable ones at greater depths and from carstic waters, which occupy fissures, cavities in solid rock, and which have; properties similar to those of groundwater. Research into the characteristics of groundwater thus defined has been started in 1920, and after a few noteworthy preliminary results [3, 4, 24, 31, 55, 56], developed rapidly from 1950. Organized groundwater research is carried out at present at two institutes, the Research Institute for Water Resources and the National Geological Institute. Two branches of groundwater investigation have been developed within the frame work of geohydrological research, which complete each other mutually, and which are both essential to the study of groundwater household. The first in collecting information about groundwater conditions is to carry out the necessary surveying and muppiny work. Results obtained thereby should include: the groundwater table, the position of groundwater-bearing strata, the location of groundwater relative to geological and topographical conditions and data on the quality of groundwater. Similar information on static groundwater conditions alone is unsatisfactory for the development of an up-to-date water-conservation policy, the groundwater table being subject to continuous variation and significant changes in volume may occur. Therefore, the second branch of groundwater investigations is concerned with the determination of laws governing soil-moisture movements. The groundwater level at any time is the result of a water accumulation process influenced by phenomena taking place during a longer period preceding the observation. The depth of the groundwater table under any particular territory and the number, as well as pattern, of water-bearing strata may be the result of water accumulation and withdrawal over decades, centuries or even thousand years. A satisfactory explanation for this process is, at the present state of knowledge, impossible. On the other hand, changes occurring in the present, groundwater movements can actually be followed and the main characteristics of soil-waterhousehold, as well as possible methods of groundwater recharge, can be ascertained. Various opinions have been voiced in this respect [57, 61]. The approach will be correct, if the investigation is based on physical laws, and on those of hydraulics in particular, and, as a complementary measure, the result obtained is checked by methods of empirical hydrology and compared to results of the waterhousehold investigation. Recognized laws governing the groundwater regime and the waterhousehold of the soil are described in the first part of this paper, while the second part is devoted to summarily reviewing the application of these theoretical methods to various branches of water economy, as established in accordance with water conservancy practice established in Hungary, and with corresponding research. H. Groundwater regime and soil waterhousehold The basic feature of natural groundwater household is, that the long-term five rage of groundwater accumulation is zero. Accordingly, the groundwater level fluctuates around a constant stage defined by the long-term average (Fig. 1 ). Ter-