The paper presents an approach to manage volunteered geographic information (VGI) to point out anomalous conditions of the environment to help administrators in charge of the governance and maintenance of the territory to plan mitigation and safeguard interventions. To this end they can formulate flexible queries on the VGI reports to analyze their contents. The novelty of the proposal is the search framework of VGI reports designed to support distinct needs, among which the assessment of VGI quality which is an important issue in such applications. Flexible queries are formulated and evaluated within a fuzzy database approach.