Linda Velazquez visited the headquarters and test facility station of Optigr?n in the summer of 2001. Optigr?n has established a long-range and scientific based work on stormwater management, including their computer simulation program which was conducted over three years.

The Optigr?n test facility has a weather station to measure rainfall amounts, temperatures, and wind speed. They measure water retention and runoff rates in varying greenroof systems, growth media depths, substrate mixes, and plant types with flat panels and panels with slopes from 0? to 15?. Optigr?n maintains several control panels, i.e., gravel, tile and concrete. Optigr?n developed its RWS Computer Simulation Program after extensive monitoring at this site for over a three year period. For example, based on rainfall from 1990 through 1992, the average three year water retention amount on a 4.72″ (12 cm) greenroof is 73.5%, or about 31,000 cubic yards (26,600 m?).