In my talk, I present a sequence of research works, integrated into my Ph.D thesis, on dynamics of macroscopic tunneling in systems governed by the Gross-Pitaevskii equation. Such systems are weakly interacting
trapped Bose-Einstein condensates, and propagating light pulses in Kerr media. Adopting the hydrodynamic representation of the many body Schrӧdinger equation, and the assumption of two distinct time scales of the problem, a unique formalism was developed, that led to the short and long time scale behaviors of the system. These were solved for both the interior and the exterior regions of the trap, and for two common trap configurations: point-like and elongated trap. Several fundamental and conceptual derivations were implemented in a suggested mechanism of a pulsed atomic laser. Through all this, the short and long time dynamical evolution of nonlinear manifestations, namely, solitons, dissipative and dispersive shock waves, were thoroughly investigated.