Is anyone familiar with the basal flood irrigation system mentioned in this months State of the Art section in LAM (pg 88)? The article did not provide a lot of information about it.
Excerpt from June 2008 LAM
"...Miller uses basal rather than surface systems, which waste water and are hard to maintain. Basal systems embedded in course gravel in the drainage layer make water easily accessible for roots, and less water is lost to evaporation. They also can't be seen on the surface of the roof.
Basal systems work either through capillary action or a flood system, in which water is only delivered to plants when available water drops below a certain level. Floor irrigation, which is a good way to support turf on a green roof, is easily installed on flat roofs; a slightly more complicated variation can also be installed on a slope..."