The rainwater is drained off at a delayed pace using a narrower lower situated opening.
Blue roof water retention.
A blue roof is a roof of a building that is designed explicitly to provide initial temporary water storage and then gradual release of stored water typically rainfall.
Blue roofs are constructed on flat or low sloped roofs in urban communities where flooding is a risk due to a lack of permeable surfaces for water to infiltrate or seep back into the ground.
A blue roof is designed to slow or store stormwater runoff easing the burden on the stormwater systems.
The water needs to be drained off to create sufficient storage capacity in time for the next rainfall.
1 the system drains too slowly resulting in buildup of excess water on the roof for extended periods of time bypasses of the controlled flow roof drains or bypasses overflows during small rainfall events.
Problems with a blue roof system generally fall into two categories.
The water only remains on the roof for a short period of time after rainfall.
So at maximum water detention the blue roof solution would add up to 18 2 pounds per square foot of load to the weight of the.
This type of water roof is called a water roof for rainwater retention.