Question
I am trying to design a 7' x 11' area in front of a public library with
varied sizes of river rock set in concrete and suggesting a stream
flowing into a pond.  There will be many rock and a very small amount
of exposed concrete.  There will be 3-4 small circular areas with plants.  
How should the area be designed to avoid standing water?

Answer
I'm not exactly sure what you are looking for but the key is to make sure you don't have any areas that are either too flat or have depressions. Make sure surface slopes 1/4" per foot for best results. I supposed if you are putting down a lot of river rock there is always a chance for some small areas between stones to trap small amounts of water. Just make sure your slab is leveled with a 1/4' per foot fall before setting the stones.

Good Luck

Sean J Murphy, LA,ISA, LEED AP
Please check out my blogs and articles on landscape topics like this on my websites.
http://www.seanjmurphy.com
http://amenityarchitects.com