Adaptive Flood Barrier (2D)

Flood Water Level

Water level 0.00 m

Gate Design

Buoyant chamber mass 300 kg/m

Water level at zero — gate resting on the sill.

Live Readout (Archimedes' Principle)

Barrier (gate top) height

0.00 m

Draft (submerged depth)

0.60 m

Hydrostatic pressure (base)

0 kPa

Force on gate / m width

0 kN/m

How it works

This is a self-closing flood barrier: a sealed, hollow buoyant gate that sits at the bottom of a guide-rail channel across a doorway or culvert. It needs no pumps, sensors or electricity — it is lifted purely by Archimedes' principle, the same physics that floats a boat: buoyant force = ρ_water × g × V_submerged.

Resting on the sill, the gate floats free only once the water covers enough of it to displace a volume of water weighing as much as the gate itself. That balance defines its draft: d = m / (ρ × A), where m is the gate's mass per metre of width and A is its cross-sectional footprint. Below this water level the gate stays grounded; once the level reaches the draft, it lifts off and — like any floating body — its waterline tracks the rising flood exactly, rising 1:1 with the water while its draft stays fixed.

The gate keeps rising until its top edge meets a fixed sealing frame at the design flood height. From that point on, continued buoyancy just presses the gate firmly into its watertight seal — it is held shut, not floating free. Meanwhile the water pushing on the sealed face grows fast: hydrostatic pressure is P = ρ × g × h, increasing linearly with depth, so the total force the seal and guide rails must resist is the area under that line — F = ½ × ρ × g × h² per metre of width. A barrier only twice as deep must resist four times the force.

Buoyant gate Flood water Seal frame (design height)

Water level Barrier height