Thanks, guys. Learning the bottom does seem important. Our reservoirs, built over the stream that was dammed for that purpose, conceal lots of texture. Also, I think that fishing over the former creek bed might be productive as they probably have a natural pull to that habitat. I frequently cast to the rise ripples, being a fly fisherman. I might get a little more use out of my sinking line and appropriate wet flies.
Here's a lake that I particularly want to examine the underwater parts. http://www.denverwater.org/Recreation/GrossReservoir/
As can be seen from the photo there are lots of exposed rocks that at one time were cliffs over the creek. The shoreline is steep and deep in many places. There are some big fish hiding down there.
YakCatcher Rod Holder
Free Standing Boat Racks