Many times (more than 1500) I crossed this stream in my youth, and each time I was drawn to its beauty and wondered about its colour. There is no other stream around here with blue water. In limestone areas creeks are blue, in glaciated areas glacial rock-flour makes the streams and lakes very blue, but this is neither a karst are nor a glacial area.
Now I have worked it out. I have found some white clays in the upper catchment and these produce very white particles (colloids) that are suspended in the water giving it its milky blue appearance, especially where the water is pooled.
Blue Creek flows from the northern slopes of Mt Grainger to Kandanga Creek. Most of its valley is referred to as Melawondi locality, named after a railway siding on the Mary Valley Branch railway that crosses this valley.
Some of its catchment is now included in a newly gazetted area of national park, some of its catchment was used for pineapple growing in the past, most is now used for cattle grazing, and there is a moderate sized sawmill or timber reprocessing plant using hoop pine from forest plantations around Imbil.