Potomac

Please explain how a 1-mile stretch of river can have average gradient of 100 FPM and maximum gradient of 500 FPM. Maximum gradient figures cited 'up top' should always be computed across a full mile, otherwise they are meaningless. If you wish to convey that some shorter portion has steeper gradient, you may express that within the text of the description (as 'the river drops 50 feet in a quarter mile, for an effective gradient of 200 FPM') but that should NOT be in the 'Maximum Gradient' area.