The science — equations & assumptions
A single idealised lunar semidiurnal harmonic varies the model water level. The foreshore estimate counts sample cells between tide elevation and 1.5 m terrain height; it is not a survey.
η(t) = A sin(2πt / T)
A = 0.80 m; T = 12.42 h
p = ρ g d
ρ = 1025 kg/m³; g = 9.81 m/s²
No actual astronomical prediction, atmospheric surge, wave setup, currents, sediment transport, or conservation-based hydrodynamics. Terrain areas use an 8 m sampling grid. Tide range is 1.60 m peak-to-trough. Toggle the cyan contour to see the moving flood boundary.
In the browser console: window.__selfTest() runs three independent closed-form checks.