Initial conditions specify the model state at start time. They are similar to boundary conditions, which are applied along the spatial boundaries.
Initial water elevations in ADCIRC can be modified using nodal attributes like
initial_river_elevation. Boundary conditions also affect initial water elevations. If the water elevation is modified in more than one way, their effects are additive. Note that along elevation-specified boundary conditions (like a tidal elevation boundary),
sea_surface_height_above_geoid persists throughout the simulation, and so it can be both an initial and a boundary condition.