Foundation drains daylighting below 100 yr. BFE
Foundation drains daylighting below 100 yr. BFE
(OP)
Is it acceptable to daylight foundation drains below the 100yr BFE? or is it better to have the foundation drain system separated so backup does not occur during the 100 yr event. I have an existing building (100,000 sf.) that exists inside the 100 yr floodplain next to a river. Existing FF = 100.00 Proposed FF = 101.75 Existing BFE = 100.46. Approximate NWL = 96.71 Foundation drains (4") to be placed with invert at approx. 99.67 and existing walls backfilled to 108.00. Is this a bad design?





RE: Foundation drains daylighting below 100 yr. BFE
RE: Foundation drains daylighting below 100 yr. BFE
RE: Foundation drains daylighting below 100 yr. BFE
Moral of the story is this: "it depends on where you're at."
Question, though. Are you saying the 100 year is only 3.75 ft up from the normal water surface in the river? You sure about that? What's the 1 year, 5 year, and 10 year stage in the river?
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: Foundation drains daylighting below 100 yr. BFE
RE: Foundation drains daylighting below 100 yr. BFE
I would not want any foundation drain to exist at an elevation that could be covered by flood water. Instead I would use a closed system and a sump pump.
Mike Lambert
RE: Foundation drains daylighting below 100 yr. BFE