Environmental problems are multidimensional and usually complex. Collaborative integration of multiple forms of knowledge is one approach used to develop meaningful solutions to complex problems. In this regard, spatial data and knowledge about the environment have been managed extensively with Web geographic information systems (Web GIS). However, past Web GIS research has focused mostly on using spatial tools to manage explicit (codified) knowledge. This has reduced the complementary contribution that tacit (experiential) knowledge can provide to environmental solutiodragns. In this study, Web GIS and knowledge management technologies are used to integrate multiple forms of spatial knowledge in support of collaborative community planning. The system design included a customized end-user interface for data entry, georeferencing tools for asynchronous collection of local data, and protocols for knowledge management dealing with species location, ecological habitats, and environmentally sensitive areas among others. The system enabled access, query, sharing, and updating of environmental knowledge using visual map-based tools. The utility of the integrated system design is discussed.