River Current
Current
Posted 9/25/2005 2:02 PM (#160645)
Subject: River Current


I read elsewhere that river current runs the same speed top of the river to the bottom. I remember from somewhere that it actually runs faster t at the top of the column than to bottom, is that true?
Dave Neuswanger
Posted 9/26/2005 9:31 PM (#160775 - in reply to #160645)
Subject: RE: River Current


Air and substrate both impose a "drag" on current velocity in a stream channel. In a channel with uniform depth and substrate, current velocity is always greatest at a depth 1/3 the distance from the surface to the bottom. I learned this while studying the limnology of backwaters on the Mississippi River as a graduate student. Thanks for cleaning out the cobwebs!

Dave Neuswanger
Fisheries Team Leader, Upper Chippewa Basin
Wisconsin DNR, Hayward
sworrall
Posted 9/26/2005 11:06 PM (#160788 - in reply to #160775)
Subject: RE: River Current





Posts: 32886


Location: Rhinelander, Wisconsin
I once heard it described as this:

Take 20 sheets of 1/2" plywood. Stack them with dowels underneath each sheet so all will roll freely. Give them a shove, evenly, and forward. Given that all have the same push forward which sheet of plywood will hit the ground first?