Canal engineers and geologists have designed excavations to stabilize landslides and to straighten, widen, and deepen the Canal. These activities have affected most of the slopes in Gaillard Cut, many of them several times. The occurrence of the post-construction slides has been attributed to rainfall and time-delay factors. Notwithstanding the contribution of above mentioned factors, post-construction slides occurred as a consequence of the continuous improvement and maintenance of the Canal prism; and secondly, to a progressive deterioration of the surface and subsurface drainage conditions of the slope areas making them more susceptible, with time, to periods of high precipitation (rainfall).