Vízrajzi Évkönyv 91., 1986 (Budapest, 1987)

Tartalomjegyzék

2. Notes on the various chapters

A. THE DATA COLLECTION NETWORK

1. The chapter on the data collection network contains the list of the stations constituting the network. The list of gages presents the main data on the gages both comprised in, and outside of, the standard network, on which water levels are observed regularly. The data on gages not read regularly, such as e.g. flood gages, are not included in the list. The gages within the standard network, except those on lake Balaton have been operated since January 1, 1981 by the district water authorities, where the waterlevel data are also processed. The code number of the gages within the standard network is a five-digit number consisting of Arabic figures, while the gages not comprised in the standard network bear code numbers consisting of Roman and Arabic figures. In the chapter the gages of the standard network are shown on a schematic map.

Responsibility for the operation of the observation wells on groundwaters at small depth

was transferred in 1981 to the district water authorities. The list of wells comprises the

data on the wells which were transferred for operation from the Hydrographic Institute to the district water authorities, as well as on those in which the waterlevel readings had earlier also been taken by the district water authorities. The wells, just as the river gages, are designated by names coinciding with that of the village in whose area they are situated. Where the name of the village changed after the well drilled, the designation of

the well remained the same, but the name of the village to whicht the well belonged in the year of report has also been entered in brackets along the wells. In the list of groundwater

observation wells, just as in the list of river gages, data have beend entered on the

wells alone, in which water level readings were taken regularly during the year.

In the list of deep wells tfyose drilled for observing artesian water and water in karsti- fied rocks have been grouped separately. The list of springs contains the main data of the springs, where the yield has been measured regularly by the district water authorities during the year of report. The water levels in the deep wells were also read in 1985 by personnel of the district water authorities.

The major part of the meteorological stations belongs to the National Meteorological Serj vice, the rest being operated by the district water authorities. The lists of river gages, wells and meteorological stations contain all the observation sites, where regular readings were taken over the entire year, or over a part of the year, viz.the data of sites abandoned or newly established during the year of report.

2. The relevant data of the hydrographic network have been presented in a separate chapter, grouped according to river gages, artesian and karstic wells a.nd springs.

3. The modificated filing data of the stream gages and shallow wells are given in Chapter A. 3.

4. In publishing the observation data for the year of report, the groundwater wells and

the meteorological stations have been grouped according to catchment areas, the boundaries

of which are shown in a schematical map.

B. HYDROLOGICAL CHARACTERISTICS

1. The water regime of the streams, the variations in the level of subsurface waters,

the ice conditions on the streams, the depth over the fords on the Danube are described

on the basis of the measurement and observation data. These serve also as the basis for the comprehensive figures on inundations by undrained runoff, as well as on the operation of drainage pumps. The hydrometeorological factors, such as precipitation, air temperature, evaporation, which have a substantial influence on runoff conditions are also analysed.

2. In the chapter entitled: "The characteristics of surface waters" the river gages are presented by streams in downstream succession, adopting a system in which the river gages on the main streams /the Danube and the Tisza rivers/are followed by those on the secondary tributaries, again in a succession proceeding downstream along the river.

The tabulation of daily stages contains the water levels observed in the morning. The

morning stage readings are taken at 07.00 hours in the period between the 1st April and

the 30th September, while at 08.00 hours over the rest of the year. During "Summer time"pe- riods the times of reading are shifted accordingly.

The stages read while the water surface was partly, or entirely covered with ice or with open water in the gaging cross-section but with the water level influenced by a more distant ice jam are distinguished.

In order to characterize the water regime of the stream, the typical monthly and annual stages for a decade with normal water regime, and for a recent period, further the extreme stages on record are also indicated at each gage for the sake of comparison. However, when

examining the stages over an extended period of time, any occasional change in bed geometry

over the particular river section must also be taken into account.

The elevation of the zero pont had to be changed on some gages over the time. For the details thereof reference is made to the volumes of the Hydrographic Yearbook. The past

stages entered in the Yearbook for the sake of comparison are related invariably to the

Current gage zero elevations.-22 -