The influence of the specific gravity of groundwater on the conditions of its equilibrium and movement

Abstract

The issue of the influence of the specific gravity of groundwater on the conditions of its occurrence and movement is rather poorly covered in the literature. When studying fresh and slightly mineralized waters, their specific gravity is usually taken to be equal to 1, neglecting its minor changes depending on temperature, pressure and concentration of dissolved substances. However, when studying waters of increased mineralization (approximately starting with a total mineralization of 5-10 g / l) and especially brines, the increased specific gravity of water so strongly modifies the hydrodynamic conditions and affects the water level in wells (data used to determine the direction and speed of movement of groundwater), that conventional methods of calculations and constructions lead to gross errors and even complete distortion of reality. It is known that the presence of water of increased specific gravity in boreholes (caused by high mineralization or the content of suspended particles) leads to a decrease in the water levels in them, and to calculate the level corresponding to fresh clean water ("reduced level"), the following are introduced simple corrections. However, these corrections are still insufficient for calculating the movement of groundwater, which requires a significant modification of the usual filtration equations. The most difficult issue is determining the conditions of equilibrium, as well as the direction and speed of movement of groundwater with their variable specific gravity, especially when the specific gravity changes in the vertical and horizontal directions, which is usually observed in nature.