Investigation of transboundary aquifers in Russia: modern state and main tasks

Abstract

ABSTRACT Transboundary problems of groundwater development are rather acute for Russia as it has land boundaries with 13 countries. The main research line concerning this problem is to develop principles and criteria of acceptable groundwater withdrawal by neighboring countries with compliance of environmental limitations. This includes groundwater protection from depletion and contamination, development of constant groundwater deposit models spread in border regions of neighboring countries in order to determine groundwater balance elements of certain hydrodynamic flows, their internal interaction and interaction with surface water. Estimation of potential groundwater shared use based on large scaled assessment and mapping of its sustained yield with regard to groundwater protection from contamination is of importance either. Determination of prospects for groundwater use and withdrawal management is always connected with the problems of exploitation restrictions in accordance with different criteria. The latter may be both of inside and outside types. Among inside criteria are limitations of hydrogeological and hydrodynamical operation conditions, such as groundwater recharge rate, tolerance dynamic level lowering throughout estimated period, risk of non-standard groundwater drawing up to a water intake, and others. The outside criteria that can restrict the groundwater use are related to possible impacts of a planned water extraction upon different environmental components including river runoff, suppression or death of vegetation due to excessive lowering of shallow groundwater level in the upper unconfined aquifer; activization of karst and suffusion processes; earth surface subsidence, etc. The main tasks of hydrogeological investigations are the following: • Determination of admissible limits of groundwater extraction in each of boundary countries in order to prevent water reserves depletion in neighboring countries. • Regional evaluation of natural groundwater resources of an exploited aquifer. • Assessment of a groundwater pollution hazard in trans-boundary aquifers and development of joint recommendations preventing such pollution. Specific examples of transboundary groundwater use perspective assessment in particular adjacent zone regions of Russia are presented