Determining beaches vs banks

Discussion created by phill214 on Oct 12, 2010
Latest reply on Oct 1, 2011 by cderolph
Hi All,

I'm trying to model landforms around a reservoir.  The only datasets I've got are a Lidar-based DEM and the water elevation.  I've also been given some guidelines for what slopes to use to define beaches (low slope against the waters' edge) and banks (high slope break between water/beach and inland).  The trick becomes when the slope of the beach is gentle enough that there is no clean break from the landscape surrounding it.  A simple slope < x% ends up catching both the beach and the area away from the water.  Doing a "Distance from water" in conjunction with the slope sometimes catches too much or too little for the beach.  I've thought about using the banks as breaklines to separate the beach from the upland, but this doesn't work where the slope never reaches the "bank" threshold.  The only thing I could think of was a aerial photo classification, but I don't have the right software.  Any suggestions using the various results of a DEM?