The Effect of Shallow Water:-
The tide raising forces set up oscillations of small amplitude in the deep oceans and these oscillations travel as waves towards the coast, into estuaries & up rivers. As the water becomes shallower the amplitude of the wave increases & further amplification occurs when the tidal wave travels up an estuary which, typically, gradually narrows from a wide entrance.
The effect of a tidal wave entering shallow waters is, besides increasing the amplitude of the wave, to distort it in the same way that an ordinary wave on the beach may be observed to become progressively distorted as it approaches the shore; it tends to aquire a steep front, that is to say that the period of rise becomes shorter than the period of fall. These shallow water effects are present to a greater or lesser degree in the tides of all coastal waters and they make the prediction of such tides more complex than for simple oceanic tides.
As discussed the response of water is modified by topographical conditions which can retard or advance the time at which the tidal wave arrives and can increase or decrease the amplitude of the wave