The latest flap about “Malibu Lagoon,” which is actually the mouth of a stream channel that occasionally receives tidal water and for most of the year is blocked by sand bar, has to do with the breach of that bar. As one who started surfing Malibu in 1949, I know that the bar is breached nearly every year, and as one versed in ground water, I know why. Whenever an impounded level in the “lagoon” is above the tide elevation, lagoon water flows though the bar to the ocean.
During an especially low tide, spring flow from ground water in the bar develops. That flow erodes the bar and in the process creates a locally steepened slope. An especially low tide coupled with an especially high impounded level results in especially active erosion of the bar which works headward until a narrow breach opens. The breach then opens widely in response to flood erosion.
Breaching is a natural process. The only reason to mention it is the massive ignorance by our public officials who now are wondering who caused the breach and whether they had a permit to do it. With all the funding expended on studies of the “lagoon” and the Malibu Creek Watershed, and with all the technical personnel employed by the local public agencies, you’d think someone would have at least a rudimentary grasp of the physical principles of stream flow and ground water, but apparently not. In any event, one can hope that not too much time will be expended in attempting to cite God for breaching the bar without a permit.
Don Michael