What is a good drought-tolerant turf suitable for the Denver, CO area?
I would disagree with the Colorado State Extension. No Bluegrass cultivar is drought-resistant; each requires around 40" of water each year and Denver only receives about 16" annually. For a drought-tolerant turf grass in Denver I would recommend a Buffalograss or Blue Grama, or a mix of the two. They make a good mix because Blue Grama fills in quickly and Buffalograss becomes dense over time. These are native grasses which are adapted to our climate and require only about 20" of water annually.
I am not sure what you mean by SS 2.2; are you referring to LEED v2.2 Sustainable Sites?