Analysis of Rainwater and Runoff Water Quality on Vegetated and Unvegetated Green Roof

Green roof is a green technology innovation in the form of a roof planted with vegetation on a substrate that is an effective solution to replace the role of green open space (GOS) lost due to construction and development. As the main component of green roof, vegetation can significantly affect the quantity and quality of runoff water. This research aims to analyze the quality of rainwater and green roof runoff water on green roofs planted with Portulaca grandiflora (PG) and unvegetated green roof (UV) as a control. Runoff samples were analysed to determine the value of water quality parameters used, especially temperature, TDS, pH, BOD, COD, DO nitrite, ammonia. Water quality status is determine by applying the STORET (Storage and Retrieval) Method. Based on the quality standards of "Peraturan Pemerintah Republik Indonesia No 22 Tahun 2021", the STORET value in rainwater is categorized as moderately contaminated with a value of -20. While the STORET value in green roof runoff water planted with Portulaca grandiflora and unvegetated green roof, both are categorized as lightly contaminated with a value of -8 and -10 respectively. While based on the quality standards of "Peraturan Menteri kesehatan No 22 tahun 2023", the STORET value in rainwater is categorized as lightly contaminated with a value of -8. While the STORET value in green roof runoff water planted with Portulaca grandiflora and green roofs that are not planted, both are categorized as meet the quality standards.