Hidrológiai Közlöny 1971 (51. évfolyam)

1. szám - Valló Sándor: Összefüggés a felszíni vizek minősége és a hidrológiai viszonyok között

Hidrológiai Közlöny 1971. 1. sz. 13 Relationship between the quality of surface water and hydrological conditions VALLÓ, SÁNDOR Department Head (Institute for Hydraulíc Plannfng, Budapest) I. The character, scope and trend of researeli It should be emphasised at the outset that in the eontext of the present subject, hydrology should be understood as the science dealing with every branch of the terrestrial part of the hydrological cycle, i.e., the internationally adopted wider interpretation of hydrology should be observed. Consequently, under this approach primary interest should be devoted not so much to the relationship between the quality of surface water and the conditions usually considered in engineering hydrology (e. g. hydroineteorology, stage, streamflow), but much rather to the investigation of any changes in the quality of surface waters and the regularities thereof, which potentially result from the interaction between water and the organisms living therein. This broader approach is essential when desiring to consider this subject according to its scope and importance in the field of watersupply. Increasing reliance is made all over the World on surface waters for obtaining water. The quality of these waters is influenced much more decisively —and alas adversely—by humán interference than by the factors resulting from meteorological factors. Humán interference, and especially the introduction of domestic and industrial wastes, tends to bring about fundamental changes in the biological life, chemical and phvsical properties of water. In scientific research this subject is commonly approached from two sides: 1. Methods are developed for the collection and evaluation of water-qualitv data, for the analytical computation of relationships between waterquality factors and streamflow (including the use of electronic computers), for predicting water quality, for estimating the permissible load which can be discharged into recipients based on more sophisticated investigations into oxvgen household. 2. Measures of operative character are considered, by which adverse biological, chemical and phvsical properties of a particular watercourse, laké, or reservoir can be influenced beneficially in the interest of watersupply. The great number of studies, experiments dealing with eutrophication, the effect of thermal stratification, oxygen supply and the attempts at the elimination of adverse conditions either in a preventive wav, or by operational measures (e. g. by the construction of new plants) are believed to belong to this latter group. A great volume of literature is available on the subject, mainly in the industrially highly developed countries. This is logical, since the watercourses are much more polluted, while at the same time increasing demands make supply inevitable from polluted watercourses, but alsó from natural lakes and artificial reservoirs exposed to the danger of eutrophication (treatment problems due to algae!). As reflected by the character and volume of domestic research, the use of surface waters for watersupply, and especially for drinking purposes, is rather limited still, but the danger of pollution increases in these waters. Accordinglv, research classified into the first group, i.e., of methodological character is seen to predominate in Hungary. This is in keeping with the recent stage of development, since these can be expected to yield information on the quality of wastes which can be discharged into a particular recipient, or on the quality of water to be expected. Similar data are of fundamental importance for both wastes treatment and water treatment technology and are therefore very valuable. In the future, however, it appears essential that scientific research should follow the example of industrially more advanced countries and focus attention increasinglv on operative methods of interference into the biology of waters. In this eontext hydrobiological research may well be regarded as of primary importance, since the lakes in Hungary are shallow, existing and potential reservoirs are — owing to topography—alsó of small to médium depth, while taste-, odour- and filtration problems due to eutrophication are sometimes too difficult to solve in the treatment of water. Under the same aspect research concerned with the artificial aeration and mixing of waters should alsó be promoted. These indirect methods of water treatment extend already into the field of water technology. Development of research abroad seems to be directed towards the measures of rather operative character, since extensive pollution is a fact which must be recognized and not even the most intensive methods of treatment can keep pace with the rate of pollution accompanying industrial development. Thus the main objective here is already the improvement of quality in existing watercourses by aeration, together with the ereation of artificial reservoirs and securing protection therefor. In compiling this report material contained in the following papers submitted to the Symposium has been used: 1. Fazekas, I. (Hungary): Investigations into the quality of surface waters and the interpretation ofresults. 2. Hock, B. (Hungary): Considerations 011 the permissible pollution load of watercourses. 3. Koenig, H. W„ Imhoff, K. R., Albrecht, 1). (FRD): Methods for improving the quality of surface waters. 4. Cooley, P. (Great- Britain): Wraysbury reservoir: prevention of thermal stratification. 5. Karliczky, K. (Hungary): Treatment problems associated witli reservoir storage in Hungary. 6. Sátorhelyi, T. (Hungary): Problems in the treatment to drinkingwater quality of water from shallow reservoirs.