Eildon Quaw in the Borders and Castle Quaw near Cartland Crags in Lanarkshire both incorporate the term qwaw, which indicates a piece of very soft ground or quagmire. S. R. Crockett provides the following description in his novel, The Raiders (1894):
Green, deceitful, 'quakkin-qua's, covered with a scum that looked like tender young grass, but in which, at the first step, one might sink to the neck.