After the St. Francis Dam failed on March 12, 1928 near Santa Clarita, California, the authorities in charge of the Mulholland Dam became worried. The Bureau of Water Works and Supply had built both dams along similar lines, and if the Mulholland Dam it were to fail too, the result would be catastrophic because it keeps the Hollywood Reservoir from flooding Hollywood. In 1933-34, part of their solution to shore up the structure was to dump 330,000 cubic yards on the dam’s downstream face, which had the added benefit of hiding the dam from view. Out of sight, out of mind!

Here is another view:

This is a satellite image of the dam from December 1, 2023. As we can see, that mountain of dirt is now covered with greenery.