Assessment of the effect of atmospheric pressure on the level and ground waters flow

Abstract

The problem of understanding the interaction of river and ground water waters is intimately bound to questions of formation and unloading of ground waters in river network. The analysis of the previous researches showed that change of atmospheric pressure affects on the water level in observation wells and water discharge of springs. However, the mechanisms of this influence still weren't completely opened. For the solution of this task the complex laboratory, field and theoretical researches including overseeing by a drain, ground water level, atmospheric pressure and air pressure in an unsaturated (vadose) zone were conducted. On the basis of the conducted researches regularities the connecting size of change of ground water level and a drain of ground water waters with atmospheric pressure were received. As a result of generalization field and laboratory researches it was shown that the crucial role in formation of these regularities is played by the area located over a mirror of ground waters with the isolated interstitial air.With an increase in atmospheric pressure, the volume of interstitial air decreases, and at pressure drop volume increases. It, in turn, leads to change in the level and a flow of ground waters. The settlement formula for numerical assessment of variability of level ground depending on atmospheric pressure (barometric efficiency) and degree of air isolation was received from it in an unsaturated zone. As an indicator of isolation, a characteristic is used such as the volume of interstitial air involved in the inflow (outflow) of water into a measuring well or watercourse and not having direct contact with the atmosphere. Research results showed that, in addition to gravitational force in the movement of ground water and the formation of ground water inflow of rivers and lakes, another force plays a certain role - the pressure difference between atmospheric air and air in the unsaturated zone above the aquifer.