Determining Baseline case

I had the following question which I am sending to the GBCI as well but I wanted to consult with you guys to understand what you have seen based on experience: Establishing the baseline case- WEc1 Water Efficiency Based on what I have read on this forum, the baseline case is representative of conventional equipment and design practices. The area of the baseline and design cases are the same and they are based on the total landscaped area in the design case. If the building is a residential high-rise in NYC and were to have a green roof and apply for this credit - would the baseline case be the landscape design with typical irrigation, sprinklers and no irrigation controls and design case have more efficient irrigation and irrigation control ? OR Is the baseline case what is typical for a building in NYC which is no vegetation at all therefore effectively there are no potable water savings unless you are using cisterns or rain catchment? If you are using sedum green roof, what is the baseline case in that instance?