Jul. 3—The lake is almost full. The roads are mostly open. And the Kern River Valley is buzzing with business.

Thousands of visitors and valley residents lined the shores of Isabella Lake on Saturday to watch a fireworks display over the water paid for by donations from KRV residents and business owners who refused to let the annual tradition die.

Several motels and inns in the valley flashed "no vacancy" signs, and restaurants and convenience store gas stations were crammed as tourists streamed into the mountain valley from all over, especially Southern California and the San Joaquin Valley.

Cheryl Borthick, owner of Cheryl's Diner in Kernville, said the restaurant had to keep the doors open later than normal just to accommodate all the hungry customers.

"We're slammed today, again," she said Monday.

With Independence Day on Tuesday this year, the weekend was like a warmup, and lots of visitors are staying through the holiday — if not all week, said Borthick, a longtime member and past president of the Kernville Chamber of Commerce.

Allison Clark, manager of the Fastrip store in Wofford Heights, multi-tasked on the phone with a news reporter as she rang up customers and described the situation from the point of view of an employee.

"It's exhausting having a store full of customers," she said. "It's nonstop."

Clark has been watching the shorelines of Isabella Lake move steadily closer and higher for months. It's a sight no one in the valley has seen for nearly two decades.

The U.S. Army Corps of Engineers' Isabella Dam Safety Modification Project, a multiyear monster project designed to repair and strengthen the earthen dam, changed the face of Isabella Dam, raising it 16 feet and adding a huge emergency spillway the Corps hopes it never has to use.

In 2006, the 70-year-old dam was found to have serious flaws. The dam's safety features have since been completed, but during those years, the water level in the lake was restricted to about one-third less than the lake's normal capacity.

That restriction is expected to be washed away.

Over the weekend, Isabella exceeded 500,000 acre-feet of water for the first time since the restrictions went into effect. The lake will reach "gross pool" when and if it reaches 568,000 acre-feet.

For thousands of people who use the lake for boating, fishing and windsurfing, the return of cold, clear water to the lake means fun and recreation and the simple pleasures of life.

And those visitors bring dollars, the life-blood of any tourist economy.