This picture was taken in Conrwall where I am natively from. This river i believe was once used by the China Clay Industry to carry away their waste. The panorama shows two rivers meeting one which has carried clay debris along with it and one which has carried oxidized iron (rust). As both of these rivers meet the two distinct colours show clearly where their current is strongest. The river has been like this for some time as you can see from a dam of rubbish that has been stained an orangery red colour.
The image is a 36 stitched image panorama. Processed in Photoshop with parts being hand stitched.