Background The development of any big city implies both groundwater resource exploitation and intensive use of the subsurface area: construction of subways, sewers, subterranean service lines, deep foundations, underground parking lots and storage. These have significant environmental implications, which can be exacerbated by local geological conditions. In the case of St. Petersburg, the swampland of the Neva delta was reclaimed to enable the construction of the city, and geological instability often held back urban development. Ongoing risks related to geological problems include damage to industrial facilities, oil tanks and reservoirs, which may cause groundwater pollution. Pollutants could be easily transported to surface watercourses and end up in the Gulf of Finland. At the same time, groundwater is becoming an increasingly important water source. It meets only 2% of the city's needs, being used as drinking water. However, due to intensive housing development in the city suburbs, it is becoming more important to protect groundwater resources. Many suburban houses have private wells, which are drilled and exploited without any control. This results in changes to the water level and threatens pollution of reservoirs. Objectives The GEOINFORM project aimed to improve environmental protection in the Baltic Sea Region through prevention of environmental risks caused by the human impact on the geology of St. Petersburg. The project worked to build administrative capacity in order to: Improve the management of mineral resources and subsurface space; Prevent the exceeding of critical loads to geological media while maintaining economic development of the area; Speed-up decision-making in case of environmental emergencies, especially in geologically unstable zones; Protect ground water from damage to water bearing layers and pollution; Improve provision of relevant geological information to other authorities, and thus improve environmental decision making; Train local officials in selecting and using geological information that they may need in their daily work; Work in multi-sector partnerships with the general public, NGOs and investors; Assist officials in avoiding planning decisions that pose a threat to the environment and may cause unacceptable pollution levels and environmental risks; Make environmental protection standards more clear to investors.The project also aimed to consolidate existing environmental information held by different public bodies, and to enable quicker and more efficient exchange of information by public bodies. Results The GEOINFORM project fulfilled its stated objectives, and the beneficiary had a valuable opportunity to work with partners that had extensive experience in the management of mineral resources and subsurface areas. The Project outcomes have long-term, environmental and economical benefits, because using geological information and tools for decision-making helps to avoid environmental risks and additional expenses for the city development projects. The project provided very efficient tools in support of decision-making. Preliminary assessment of the geological conditions of the areas under development will help to prevent the potential risks. Access to the geological information, geological risk mapping, using model simulations – all contribute to a better managerial capacity of the decision-makers. The tools for decision-making support will be used for preliminary assessment of the geological suitability of the areas for building and underground space exploitation. This shall prevent or decrease environmental risks in the Baltic Sea Region. Geological information contained in the Regional Geological Database, may help to avoid any additional expenses, because geological characteristics of the area would be taken into account in the planning and not construction phase. For example the project to construct a new subway tunnel was considerably revised after presenting geological data from the Regional Geological Database in 2009. Using ground water flow modelling (GWFM) tools will remarkably reduce costs of landfills or costs connected with the rehabilitation of highly polluted areas. This tool will help to model pollutant migration and develop effective measures for its prevention. It will also help to decrease environmental damage caused by oil products migrating to surface water bodies with polluted ground water. The beneficiary received some promising feedback from the experts of the Regional geo-ecological centre after the presentation of the GWFM tools at the Final Conference, as they now have several proposals to apply the tool for the city areas under development. Furthermore the project can be considered innovative for two reasons: for the technical solutions applied for geological data storage, processing and dissemination and for the new geological scientific approaches developed in order to reach the project goals. Specifically, the project: Analysed and reported on the needs of local stakeholders in terms of geological information, and the existing geological information held by St. Petersburg authorities; Developed and tested and put into operation a Ground Water Flow (GWF) model for St. Petersburg; training in GWF for Russian experts was organised; Established a Regional Geological Database and maps of single geological risks and integrated geological risks for St. Petersburg, accessible via multi-user tools; Developed a Regulation “On the Regional Geological Database of St. Petersburg”; and Carried out training sessions and seminars.The project had an impact because it was relevant to ongoing environmental policy making: the Environmental Policy of St. Petersburg 2008-2012, and the HELCOM Baltic Sea Action Plan.