A. The interior grade of a crawlspace must not be below the BASE FLOOD ELEVATION and must not be more than two (2) feet below the exterior lowest adjacent grade (LAG).
B. The height of the below-grade crawlspace, measured from the interior grade of the crawlspace to the top of the crawlspace foundation wall, must not exceed four (4) feet at any point.
C. There must be an adequate drainage system that removes floodwaters from the interior area of the crawlspace. The enclosed area should be drained within a reasonable time after a flood event.
D. The velocity of floodwaters at the site should not exceed five (5) feet per second for any crawlspace.
NOTE: See Technical Bulletin 11 for further information.
CAUTION: Buildings that have below-grade crawlspaces will have higher flood insurance premiums than buildings that have the preferred crawlspace construction, with the interior elevation of the crawlspace soil at or above the BASE FLOOD ELEVATION. (Ord. 254, 7-12-2021)