Why is so much room on the Valhalla site taken up with ponds?
A. In 2005, King County adopted new requirements for managing stormwater that are even more stringent than anything seen before. All the water that runs off of parking lots, play areas and other impervious surfaces must be managed on site; nothing can leave the site except in very controlled quantities and qualities, as though the whole site were a native forest. If the new design had more parking, or a one story design, the ponds would be even larger! Even with the size of “detention” that we have, putting tanks and pipes of the same volume, underground would be cost prohibitive. Valhalla is actually designed with both water detention ponds (which are fenced for safety) and with rain gardens – an area that is not expected to retain water, but provides for the natural filter to meet the “native” forest requirements.
