Sign up with Facebook / Twitter / Google / OpenID. Profiles of members of the community would have contributed data, projects, narration ...
There should be a notion of 'organisation' these people can belong to/associate with. It could be "Environmental manager" at "City of Darebin". You should be able to list/filter people by organisation. Not sure yet how to link people to buildings though ... (what is the logical / appropriate port of call?) Disclosing affiliation = transparency especially to avoid conflict of interests
There should be a notion of Q&A which is the mean by which people would acquire points/reputation/visibility. Top 10 questions / questions by keyword or topic / sticky topics => do we just need a forum or something lighter, cleaner, more reputation oriented?