The first [idea] concerns the social worker who arrives to tell James he has to go to school. I made her an authoritative Nigerian woman but because this was a story about magic I wanted to give her an unconventional background. That's when I decided that she was the spirit of a small river in Nigeria who had emigrated to the UK and having found the Thames abandoned by its native spirits had moved into that niche. The parallel to the many immigrant groups who moved into London and took over small businesses, corner shops and food outlets is obvious.See, this is an idea I've always wanted to see pursued in urban fantasy: immigrant groups bring their deities and nature spirits with them. I mean, if there are kelpies and whatevers in Ottawa because we have the descendants of Irish settlers in Ottawa (or at least North America) what did the Sikhs and Hindus bring to Calgary? (One suspects nothing that would be happy in that climate, but you know. I bet kelpies are miserable in Ottawa as well, not that de Lint ever says so that I recall. 'Cause I sure would be.) I know Nalo Hopkinson's done this, and Laurence Yep in his way, but I'm wondering who else?
All this with a view to having dragons take over the Humber and the Don, you understand. 'A river with no dragon in it? Ridiculous!' Which then raises the question of why the native spirit of the Humber and the Don left. The Thames we know-- "But since of late, Elizabeth, And later, James came in"-- or maybe just pollution. Would the same be true of a minor Canadian river?
(There's a certain resonance with Spirited Away-- dispossessed river spirits just move somewhere else. Though I suppose the whole point is that a Japanese river spirit wouldn't.)