aqua-terrarium suggestions

Hello,  I am currently constructing an aqua-terrarium out of a 75g tank.  
I will be dividing the tank into two sections (75% soil, 25% water) by a 
5.5 inch high piece of glass.  My calculations show that my water section 
(18x18x5.5) will hold about 7.7g of water.  I am looking for grass-like 
plants that will thrive in 5.5 inches of water.  There is plenty of light 
and the temperature is low 60-70F. The terrarium is going to be housing 
2-5 amphibians, but they will not eat the plants, but may occasionaly 
trample the plants.  Also the water will be filtered.  If anyone out 
there has a similar setup or any sugestions I would appreciate any 
help.  Thanks in advance.

Phillip A Sheppard
University of Delaware
80934 at udel_edu