UTILIZATION OF SUPER ABSORBENT POLYMERS (SAP) IN EXTENSIVE GREEN ROOF ASWATER RETENTION IN URBAN AREA

A green roof is formed by waterproof substrate covered with vegetation. It is capable of absorbing water and adding hydrogels may increase its water absorption. The objective of this study is to utilize hydrogel in extensive green roof as an aid in water retention in urban areas. There are four green roof models: Panel 1 has 0% of hydrogels, Panel 2 has 0.40% of hydrogels, Panel 3 has 0.50% of hydrogels and Panel 4 has 0.60% of hydrogels. Each green roof model undergo series of test through the rain simulator with rain gauge at the center of the panel to determine the rainfall intensity. Other than the percentage of hydrogel;; rainfall intensity, duration of rain event and moisture content of the substrate before testing are the factors that affect the water retention in the green roof. This study shows that the green roof with hydrogel has greater water retention than the green roof without hydrogel. It is determined that the hydrogels can absorb approximately 330 times more than its own weight in a day and 37.048 seconds shows the most probable value of water run--off that may occur in the rain event based from the data collected in this study. It was concluded that the maximum value of water that the soil can absorb is entirely dependent on the time the water system was used. The result of the data analysis shows that each of the independent variable has a positive correlation to the dependent variable which is the volume of the water retained in the substrate.