A specific feature of the period of transition in Bulgaria in the field of urban planning is that a large part of the newly developed urbanized territories was transformed from their previous purpose (mainly agricultural lands) via detailed urban plans that were very fragmented. When changing the purpose of the land in this way, the procedure is significantly easier than with an Urban master plan, but this leads to many negatives. Thus, the territory becomes significantly fragmented when it comes to the purpose of the properties. This leads to environmental consequences that are overlooked by the officials in charge. One such example is the basis of our present study - the attempt to destroy the Boyana Marsh so that the land can be used for building a residential complex. In this study we examine the application and integration of various types of geospatial technologies for the purpose of land use change detection and monitoring of endangered territories that should be protected.  We examine the processes of collecting primary historical spatial data and their combination with two UAV field surveys carried out specifically for this purpose. Based on the collected data, specific analyzes of the affected territories were made. The data and all results are presented in a web application that aims to promote the case study and help garner wider public support for the initiative “Save the Boyana Marsh”.