Charakterystyka hydrogeologiczna źródeł Gór Stołowych

Abstract

Przedstawiono wyniki badań hydrogeologicznych źródeł polskiej części Gór Stołowych. Przy podziale źródeł zastosowano następujące zespoły kryteriów: siła motoryczna źródeł, środowisko cyrkulacji wody podziemnej oraz kryterium morfologiczno-strukturalne. Reżim hydrogeologiczny źródeł postawiono w drugiej kolejności jako rezultat kryteriów poprzednich.

HYDROGEOLOGICAL CHARACTERISTICS OF SPRINGS IN THE GÓRY STOŁOWE MTS

The paper presents the results of hydrogeological studies on springs in Polish part of the Góry Stołowe Mts. The studies were based on results of field works covering about 184 springs in the area of about 144 km² in the years 1973 – 1976.

Taking into account the mode of groundwater outflow at terrain surface, the springs were classified as single, clustered and seepage springs. Clustered springs, grouped in the form of spring zones, markedly predominate here.

Groundwater circulation was found to be related to a network of water migration routes of the joint type. Depending on distribution of fissures in permeable rocks, the springs were assigned to fissure- intraformational or fissure-contact type.

Taking into account structural criteria, it may be noted that the springs are distributed along marginal parts of beds with horizontal fissures dipping at the angle of about a dozen degrees towards the center of the structure which, in turn, is inclined south-eastwards.

The major group of springs here comprises descensional ones, with motional force, related to short-distance flow of groundwater from the supply area in top parts of the structure to local drainage base. The contribution of vertical fissures is markedly high in the case of supply of aquifers and that of horizontal fissures in the case of outflow from drainage in the form of springs.

The group of ascensional springs, concentrating groundwater due to its rise in discontinuity zones, is smaller.

The distribution and hydrogeological regime of springs are influenced by intensity (850 mm per year at the average) and favourable distribution of atmospheric precipitation. The precipitation is markedly more intense at windward side of the mountain range, comprising the major part of the studied area. Because of marked differentiation in hypsometry of the Góry Stołowe Mts (from 360 to 919 m a.s.l.) and erosion affecting slopes of that structure, erosional-slope springs predominate here.

With reference to the output, springs belonging to the VIth class in the O. Meinzer's subdivision (0.06–0.6 l/sec) predominate here. In accordance with classification of changes in the output, almost all the springs fall within the interval of weakly changeable ones (R = 2 – 10) whereas regression coefficients are concentrated in two intervals, from 0.0078 to 0.01 and 0.01 to 0.072, respectively.

Spring waters, except for those from the zone of mineral waters of the hydrocarbonate-calcium type, are characterized by low content of dry residuum: 50–400 mg/dm³. Groundwaters of the Góry Śtołowe Mts are characterized by stable temperature in a given spring throughout the time of studies. In turn, differences in water temperature between individual springs are of the order of a few degrees. Physico-chemical properties of spring waters appear to be closely related to lithological environment of the Góry Stołowe Mts.