Teen-Age Yosemite Visitor Drowns In Merced River Boy is caught in the swift current while swimming and pinned under a rock. by Michael Baker The Fresno Bee - August 5, 1999 YOSEMITE NATIONAL PARK - A 13-year-old boy drowned in the Merced River after getting swept away and pinned under a large rock. Sergeio Marcovich was visiting the park Tuesday with his family from Mexico City when he got caught in swift-moving water and drowned, rangers said Wednesday. Marcovich's drowning is the fourth accidental death, and the fifth overall, in Yosemite this year. Marcovich, known as "Sachi," was swimming with relatives about a half-mile below the Pohono Bridge at the western edge of Yosemite Valley when family members noticed he had been missing for several minutes, park ranger Scott Gediman said. After about 30 minutes of searching, the family called rangers for help about 1 p.m., Gediman said. About 50 National Park Service personnel - including park rangers, search and rescue staff members, fire crews and others - participated in the search.   Nearly four hours after efforts began, searchers found the body just below an area known as "Table Rock" in about 6 feet of swift-moving water. "The water flow there was so strong we couldn't even get down there to get him," park ranger Kendell Thompson said. Marcovich was swept through a narrow channel in the river and pinned under a rock just yards away from where he was last seen. The fact Marcovich was in a popular swimming area with 10 to 15 other children and the river level was low did not necessarily mean it was safe, Gediman said. "People normally swim there," Gediman said. "People should just always take precautions. Although the river is low, it is still dangerous." Thompson said: "The water can get channelized moving between large boulders and can get moving extremely swiftly." To recover the body, searchers built a temporary plywood dam to divert the rapidly moving water, Gediman said. Rangers pulled the body from the river around 6 p.m. Tuesday. It is the fourth accidental death in Yosemite National Park this year: Frank Peter Gambalie III, 28, of Olympic Valley died June 9 after jumping into the Merced River in an attempt to evade park rangers. Gambalie ran from rangers after he parachuted from El Capitan into Yosemite Valley. It's against the law to parachute in Yosemite National Park. His body was recovered almost a month later, about 300 yards from his entry point. June 13, experienced rock climber Peter Terbush, 22, of Colorado was scaling a cliff near Curry Village when nearly 550 tons of granite fell and killed him. July 10, Siddiq Parekh, 31, of Diamond Bar died when he slipped into the Merced River and went over 594-foot Nevada Falls on the John Muir Trail.