Blue Roof Water Retention

A blue roof may be used as a stand alone detention method or because they do little to improve the water quality of runoff as part of a treatment train that includes other low impact development and conventional best management practices bmps such as bioretention infiltration wetland systems or green roofs to enhance the function improve.

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. 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. 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. The rainwater is drained off at a delayed pace using a narrower lower situated opening.

The water only remains on the roof for a short period of time after 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. Problems with a blue roof system generally fall into two categories. This type of water roof is called a water roof for rainwater retention.

Retention means that a specific volume of water is retained on the roof for an indefinite period of time.