Water cooled chillers for very dry areas

Dear forum, We have a very critical problem for a LEED C&S 2009 project located in the north of Mexico. The project will be a 13th story office building. Based on Appendix G the baseline HVAC system corresponds to system #8: VAV with PFP boxes, using a water-cooled chiller system. The main problem here is that for the location of the project the water resource is very limited, also the quality is very bad, so installing water-cooled chillers is not a viable option. Instead what is very common is to install air-cooled chillers. So when comparing the performance of the baseline model against the proposed design, of course we cannot achieve a better performance because the efficiencies of a water-cooled chiller are much higher than the ones of an air-cooled chiller. In conclusion, it will be very hard to comply with EAp2. Is there some kind of alternative compliance path based on the fact that for this particular location water is very limited and expensive? Hopefully there is, otherwise I doubt we will be able to achieve the certification.