Colorado Plateau
About 90% of the area is drained by the Colorado River and its main tributaries: the Green , San Juan , and Little Colorado . 
<triplet> Colorado River <subj> Green <obj> tributary <subj> San Juan <obj> tributary <subj> Little Colorado <obj> tributary <triplet> Green <subj> Colorado River <obj> mouth of the watercourse <triplet> San Juan <subj> Colorado River <obj> mouth of the watercourse <triplet> Little Colorado <subj> Colorado River <obj> mouth of the watercourse