Area Braces for High Tide of 7 Feet : Coastline: The highest rise in 17 years is expected to hit Ventura and other state beaches Sunday. City workers are prepared to sandbag to protect residences.

By JOANNA M. MILLER

Dec. 1, 1990 12 AM PT

TIMES STAFF WRITER

Predicted record high tides this weekend have city workers on alert, prepared to sandbag residences if necessary.

The high and corresponding low tides, among the most extreme in the 19-year tide cycle, will hit Ventura and other state beaches Sunday, scientists at the Scripps Institution of Oceanography said. But the lack of any sign of a storm on the horizon means good news for residents and clam hunters, authorities said.

The highest tide in 17 years is expected to be produced by an unusual lineup of the Earth, moon and sun. Also, the moon’s orbit Sunday will place it 17,223 miles closer to Earth than it usually is.

“The moon has only been this close to the Earth 30 times in the past 300 years. It’s a very interesting natural phenomenon. As long as there is no wind,” said Fergus J. Wood, a geophysicist from San Diego County who has spent more than 30 years studying tides.

Meteorologist Rae Strange of Pacific Weather Analysis in Montecito agreed that the weather is the key to possible damage. “If there had been a storm with a 7.3-foot tide, it could have had a devastating effect on the entire coastline and its structures. But it’s as flat as it can be out there.”

The record high tide, at 7.3 feet, is due at 8:17 a.m. Sunday. That compares with tides of 4 to 6 feet during the rest of December. Low tide Sunday will be at 3:41 p.m.

Because the beach slopes upward toward residences, a 7-foot tide translates to sea water that is more than 200 feet closer to residences than it is at an average low tide, Strange said.

“Then the waves make it run up the beach even farther,” he said.

At high tide Friday, which was 6.7 feet, the water came up within about 150 feet from the nearest residence, said John Betonte, maintenance services supervisor for the city of Ventura.

Betonte and his assistants will also be out early today and Sunday monitoring the surges of the waves. “If we see anything that needs to be handled in the way of sandbagging, we’ll bring out the crews,” he said. “But unless there’s some high surf, there should be no problems.”

Stormy weather at sea washes sand away from the beaches, leaving residences more vulnerable. Storms also obliterate the clams’ sandy habitat.

The lack of substantial storms this season and a mild winter last year have left enough sand to support the unusually high number of Pismo clams now on area beaches, said Capt. Roger Reese, chief enforcement officer with the California Department of Fish and Game.

But a good clam population combined with record low tides brings out the indiscriminate clammer as well as those who abide by the law, Reese said.

“We’ll be patrolling the beaches in force,” Reese said. “People should not take the small clams so that they can continue to reproduce and exist.”

Clams must be larger than 4 1/2 inches when they are dug up from the sand to be considered a legal catch. Fish and Game also limits catches to 10 clams per person.

By Oct. 31, the department had arrested 91 people on suspicion of taking the small clams or exceeding limits. That was more than six times the number of arrests in a normal year, Reese said.

While Fish and Game searches for poachers, Ventura city workers will be prepared to help city beach residents sandbag their residences, City Manager John Baker said. “We’ll go through and knock on doors and tell people whether to leave their homes if necessary,” Baker said. The city provided a similar service in January, 1988, when a severe storm washed sea water through residences in Ventura’s Pierpont Bay area, Baker said.

The record tides stem from a series of astronomic events involving the relative positions of the Earth, moon and sun and their gravitational forces. Another 7.3-foot tide is expected Dec. 31.

With no storms in sight, however, the only possibility of damage to residences or other beach structures would be if strong winds were to develop in the Santa Barbara Channel, Strange said. High winds are not forecast, but they are less predictable than storms, he said.

“The winds could whip up some waves,” he said. “But that still shouldn’t be a major problem without the long swells in the ocean.”

And there is no evidence that the gravitational pull from the moon and sun will have any effect on seismic waves, scientists said, debunking a widely circulated prediction that the heavenly bodies will trigger a major earthquake Sunday or Monday in the Midwest.