Why the Red River is red?! Sixty percent of Oklahoma is floored by red Permian-age bedrock. This bedrock is very poorly consolidated and, as a result, the landscape is very susceptible to erosion. Here is an example of Permian mudrock disintegrating when placed in water. This sample was taken from freshly exposed bedrock several feet below the surface using a miner's pick. Oklahoma's rivers run red because of this feature of the bedrock. During and after a vigorous rainfall event, the waters of the Red, Washita, Canadian, North Canadian, and Cimarron Rivers owe their color to this property of the bedrock.