In general, the water shallowed abruptly from the channel entrances to the extent that approximately one half the channel lengths were to a depth of ten feet or less of water. The depth of water at the heads of cargo or combination cargo personnel piers was required to be eight to ten feet minimm at low tide; for the smaller personnel piers, three feet was the minimm. Coral head obstructions were blasted and leveled off. 5-302