If you’re planning a visit to the beach near the lagoon this week, here’s a heads-up: the annual Los Peñasquitos Lagoon inlet maintenance is scheduled for May 8–12. The beach south of the inlet will be temporarily closed during this period to keep the public safe while heavy equipment and rock trucks are on site.
Here’s what you need to know.
Why is the beach closed?
Heavy machinery will be operating in the area, and equipment operators have limited visibility of people on the beach. The closure is purely a safety measure — and the good news is that the beach north of the lagoon mouth remains open throughout the maintenance window.
What’s actually happening out there?
The crew will be excavating sand that has built up and is blocking the lagoon inlet. This kind of maintenance is needed at least once a year — and sometimes more often — to restore tidal flow between the lagoon and the ocean.
Why does it matter? When sand bars close the lagoon mouth and cut it off from ocean tides for an extended period, the water inside becomes warmer, less salty, and lower in dissolved oxygen. Those conditions can suffocate fish, disrupt the food web, and create standing freshwater that breeds mosquitoes. Restoring the inlet allows tides to flow in again, delivering the oxygen and nutrients that birds, fish, and invertebrates depend on to feed, rest, and breed here.
Worth knowing: the inlet used to move around naturally, the way river mouths do. Today it’s fixed in place due to the road, bridges, and railroad infrastructure nearby — which is why this annual intervention is necessary.
What happens to all that sand?
The excavated sand is placed just south of the inlet along the tideline, where ocean currents typically wash it away within a day. It’s intentionally placed on the south side because the prevailing current along this stretch flows north to south.
We appreciate your patience during this brief closure and your understanding of why this work matters. The lagoon’s health depends on it — and so do the remarkable birds and wildlife that make this place so special.
Photograph by D Ramey Logan, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=34059145