I wonder, if uinen is connected to rivers by being the "coast-maia", how closely would very inland river spirits be connected to her? I'd think the river has as many or more ties with its source and the land around as it has with the sea. I could see river spirits in general being related/allied with Uinen though, but Goldberry is much more local right? This discussion was on ELotR too but I'm forgetting the details.