Aldarder, a burn in Knockando parish, Elginshire, running about 4 miles to the Spey. It became wildly riotous, and underwent a remarkable change in the great flood of 1829. It previously made a waterfall of 80 feet in leap: but, at the time of the flood it changed its course, rushed furiously against a small hill, undermined that hill, and swept part of it away, formed on the hill'ssite a chasm or ravine about 750 feet in length, and from 60 to 100 feet in depth, and underwent such alteration of its own bed as reduced its previous water-leap of about 80 feet to an inclined cascade of only about 7 feet.

(F.H. Groome, Ordnance Gazetteer of Scotland (1882-4); © 2004 Gazetteer for Scotland)