This study focuses on the role of VGI visualization in encouraging participation to environmental Citizen Science, taking as a case study the mobile application developed within SIMILE (Informative System for the Integrated Monitoring of Insubric Lakes and their Ecosystems) project activities. The main project goal is the protection of water quality for Lugano, Maggiore and Como lakes through a geoinformatics coordination of existing monitoring systems with new data collection methods (satellite images, high frequency sensors and citizen science). This tool enables the producers to perform a community-based monitoring side by side with local authorities and research bodies improving the efficiency of the current protocols.Referring to ontologies of geospatial data, the VGI samples are analysed under different aspects as their quality, quantity, variety, granularity, spatial and temporal distribution, highlighting their temporary, moving and changing nature. This analysis shows the presence of potential contradictions existing between the application use and the perceived lake water quality, to be mitigated mainly working on the user interface of the map view. So, a study of existing conventions, especially in terms of colours, is compared with the results coming from the application of consolidated survey methodologies to this specific context. Reflections on markers, symbols and attributes of features and maps are presented introducing geovisual analytical solutions for dynamic phenomena. The design solutions adopted are finally presented and validated with a combination of different usability evaluation methods like heuristics and field tests. [ABSTRACT FROM AUTHOR]