I drive past Folsom dam (1952) every day and have watched the incremental maintenance as well as a few large scale projects progress first hand. One of the most amazing things to witness was the construction of the spillway they have been building around the outer perimeter. They essentially are creating a second dam around the main dam to release water from a lower point due to a scare many years ago. Months of sorting dirt and rock at some kind of large facility nearby and a good year of constant trucks moving the dirt down the road. Even the asphalt on the road began to sink from the constant pressure of the heavy loads.<p>A few of the old spillway gate failures over the years are outlined here:<p><a href="https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Folsom_Dam" rel="nofollow">https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Folsom_Dam</a>