Fig. 2.

Diagram representing the gauge transformations: based on steady-state numerical modelling of water surface elevations (w.s.el.) for characteristic discharges Q, the unknown water levels h for specific points in time t_i at arbitrary locations within the computational domain can be derived from known water surface elevations at the gauge h_g; maximum (I_max) and minimum gradients (I_min) for every location are applied for water levels above the highest or below the lowest modelled discharge, respectively.