Green Roof Stormwater Performance in Puerto Rico: An Overview of the Effect in Greening The Old San Juan Area

Abstract

The lack of information about green roof stormwater discharge in subtropical scenarios make it difficult for engineer to use this technique for storm water mitigation in Puerto Rico. It has been proven by physical data collection and mathematical modeling that green roof can attenuate 75% of the roof peak discharge and can reduce 20% to 35% of the annual discharge volume. This paper also present the correct Curve Number values for green roof in Puerto Rico. In addition to presenting experimental values, an evaluation was carryout of the effect cause by greening 100% of the Old Town of San Juan. The total roof area for the analysis was around 70 acres an only 4” of growing media depth was considered. Result showed a stormwater discharge reduction of 25% and a average peak reduction of 8cfs of the Old Town Discharge. Key Terms — Curve Number, Green Roofs hydrology, Greening Old San Juan or Stormwater.