This paper presents a short overview about the discussion about the hydrogeological problems connected with oil shale exploration in NE Estonia. On the basis of the results of the solution to the hydrogeological model developed at Geological Survey of Estonia it was found that the proportion of unconfined groundwater in different open-cast mine fields accounts for 6-34% and precipitation water makes up 66-84% in the depleted area. Presently a unified groundwater model of Estonian-Russian border region comprising a 200×200-km area north from Lake Peipsi is being compiled under the initiative of French Geological Survey (BRGM).

Most cities in temperate climate zones, including Tallinn, face the threat of torrential rains and resultant floods, which cause extensive damage to city economies. The main causes of floods are climatic; however, unreasonable building activity and insufficiently developed and maintained drainage systems also contribute to this problem. The percentage of impervious pavement has increased with the consolidation of buildings and road networks. Rainwater drainage is an important issue in a number of different areas of human activity ranging from town planning and environmental protection to building, maintenance and operation of rainwater drainage systems. Hence, to deal with the rainwater drainage issue, it is necessary to develop an integrated and scientifically justified strategy. The present study represents a constituent part of the relevant strategy development process. The authors pay special attention to options for increasing rainwater percolation in different environmental conditions, including geological setting, topography and different soil filtration properties.