Assessing reliability and rainfall reduction of a rainwater harvesting system in Metro Manila’s rail infrastructure

Rainwater harvesting is explored as a potential aid in supplementing both water supply and stormwater management in urban public spaces. LRT-1 Doroteo Jose Station in Manila, Philippines was selected as the study area given the presence of large roof catchment areas, high passenger demand, as well as medium to high flood risk and history. The storage component is designed by employing mass balance calculations using rainfall data, roof parameters, and water consumption data. YAS Algorithm was performed for four design cases corresponding to 1-, 5-, 10-, and 15-year design periods along with full station roof use. User-defined performance indicators are employed to evaluate tank performance, namely reliability and rainfall reduction. The optimal tank storage capacity was calculated at about 20 to 30 cubic meters when the entire station roof area of 2,887.26 square meters is used. Reliability is at 53% to 58%, rainfall reduction is at 74% to 75%, and overall performance is at 64% to 67% for the designed system.