Where \(H_{1}\) represents the water level increase at \(t_{1}\),\(H_{2}\) the water level at \(t_{2}\) and \(A\) is the lake area. This equation assumes the lake area as constant: the lake is assumed to have a cylinder-type shape, in which the area is not a function of the water level.
There are various equations that can be used to compute the outflow discharge. In this study the rectangular weir equation was used. This choice was driven by the simplicity of the equation, which requires only the weir width to be derived from remotely sensed data.