Today Mr kwong,who is my supervisor,ask me to assist him doing an experiment on "Green roof project".He told me that this project will be put in place on all HDB flats if it is prove to be as useful as it is stated in the documents.This experiment took about 3-4 days to completed and results obtained were reasonable good by calulate the water flow rate.The experiment involved from using many sizes of holes on the boxes,using a special layer "Geo-textile" , and putting real usage conditions like filling with earth in the boxes.