Evaluation method of groundwater qualitative and quantitative fluctuations in the small river cathments of urbanized territories

Abstract

Preservation of groundwater resources and improvement of its quality are the main environmental problems of urbanized territories. The increasing levels of pollution reduce the number of surface water basins suitable for aesthetic and recreational purposes. Moreover, processes taking place in the small river basins deteriorate the groundwater quality. Meanwhile the groundwater and interstitial water of small river basins represent the main resources of drinking and technological water. Atmospheric water infiltration depends on the lithological composition of deposits. It is determined by analysis of geological and geomorphological maps and material from the boreholes in the studied areas. The data from boreholes also is informative about the groundwater table and chemical composition of infiltrated water. Water samples for quality assessment are taken from the topsoil (for determining the background), from the subsoil layer and from the aeration zone at 1 m intervals down till the depression zone. Also water sample is taken from the upper horizon of groundwater. A system of lysimeters and piezometers is necessary for observation of water quality fluctuations and vertical groundwater table fluctuations in the course of time. Also the system of lysimetric boreholes allows recording and mapping of spatial fluctuations of the mentioned parameters. The article introduces methods of drilling lysimetric boreholes of original construction and development and use of long-term water quality observation system.