A catchment that converts rain into a flood hydrograph. Horton infiltration soaks the soil, the rational method produces peak discharge, and a Kirpich time-of-concentration shapes the river's rise and recession — watch the level gauge and the streams respond in real time.
Horton infiltration: f(t) = f_c + (f₀ − f_c)·e^(−kt), f₀ = 5×f_c damped by antecedent soil moisture. Rainfall excess = P − f; routed by the rational method Q = C·i·A with C rising as soil saturates. Time of concentration from the Kirpich formula t_c = 0.0195·L^0.77·S^−0.385 min. Hydrograph = linear reservoir cascade: rise to peak near t_c, exponential recession R = Qp·e^(−t/k).