Sea-Level Rise (SLR) (and often subsidence) are realities in coastal settings. Planning adaptive designs for this reality is prudent, safe, and cost effective.
Three levels of construction are outlined: (1) Needed now, (2) Deeper and wider foundation, (3) Vertical extension added when higher sea level occurs. Option (1) would require demolition at a later date.
Cost estimates are made to construct to current sea-level. Then additional costs are proposed to enable adaptation to SLR/subsidence. In our Texas flood-control projects, the extra $3,000/ft is now included in order to avoid costly future adaptation requiring demolition of the seawall.