Metodyczne zasady interpretacji wahań zwierciadła wód podziemnych niecki lubelsko-radomskiej

Abstract

Przedstawiono metodę opracowania wyników stacjonarnych obserwacji zwierciadła wód podziemnych prowadzonych na obszarze niecki lubelsko-radomskiej przez dziesięć lat. Zaproponowano wyznaczanie średniej z wielolecia oraz przedziału ufności, który określa granicę możliwych zmian zwierciadła przy prawdopodobieństwie 95%. Uśredniona krzywa stanów zwierciadła pozwala wyznaczać okresy wezbrań, czyli stany maksymalne i czas ich trwania oraz depresje spowodowane regresją. Zaproponowano też sposób wyznaczania współczynnika zasilania i regresji zwierciadła, który pozwala prognozować stany krótkoterminowe na okres 2-3 miesięcy dla wzniosów i regresji.THE METODICAL RULES OF INTERPRETATION OF THE FLUCTUATIONS OF GROUNDWATER TABLE IN TlIE LUBLlN-RADOM BASIN In the present paper the metodical rules of working-out of the data concerning the fluctuations of ground water table in the area of Lublin-Radom Basin were presented. It is the first trial of the working-out the data taken during the observations in ten-year period. It was found, that different types of fluctuations existed. In the shallow wells the fluctuations are frequent with small amplitudes, which shows the immediate influence of the atmospheric precipitates. In the deeper wells (30-50 m) the fluctuations are greater, even to 6 m, but not very frequent. The water level in these wells is characterized by slow rises and long regressions. The water level in deep wells (80-100 m) is characterized by very small fluctuations, amounting to about 20-30 cm, without distinct rises and regressions. In this analysis the measurements made in the years 1979-1989 were taken into account. The water level in each well was measured four times in every month, on Mondays, which makes 52 measurements yearly and 520 measurements in the period analysed. Each observation opening was analysed separatedly. The openings in which the fluctuations were less than 0.5 m were not taken into consideration. The gathered data were analysed using the statistical methods. From among many possible methods the determination of the arithmetic mean and the confidence interval! with the lower and upper limit. The arithmetic mean determined and its confidence interval! with the: probability 95% indicates, that in the further observation cycle the position of middle the water level will change in these limits. The probability or exceeding the limits of the confidence intervall is only 5%. The results of such computation are shown as an example for the observation opening No 331. The distribution of fluctuation is shown at Figs 1-3. The index of rise, called the index of intake, and the index of regression of the water level were determined. Using these indices, on the assumption that they are the permanent features during the intake and regression of the aquifer, it is possible to compute the foreseen time of the supposed regresion or rise of the water table. In this way it is possible to draw the synoptic maps of the high and low levels, for the short period of time, using the formulas given in the text. The influence of various geological, geographical, hydrogeological and hydrographical factors on the water levels has not been analysed because the suitable data have not been gathered during present investigations. The existence of some dependance on the depth (Fig. 7) was found; it was however not confirmed for all wells.