PHOENIX (AP) – Construction crews rebuilding the damaged spillways at the United States’ tallest dam have switched to morning and graveyard shifts to avoid 115-degree temperatures in Northern California. Starting Monday, California switched the 425 contracted construction workers rebuilding spillways at the Oroville Dam to shifts starting at 5 a.m. and 8 p.m. Authorities say the idea is to avoid the worst of the afternoon sun in the heat wave withering the U.S. Southwest. Crew leaders also are providing water, fruit and shade for the workers, and counseling them to guard against overheating as they labor on the steep hillside below the dam. Both spillways at the 770-foot-tall Oroville Dam began washing away in last winter’s rainy season. Officials with Kiewit Corp., the Nebraska construction company doing the emergency $275 million repairs, said crews are using ice and chilled water to keep the concrete for the new spillways cool enough to work with.