Barker Dam was put off limits several years ago after vandals carved their names into the cement of the historic landmark, built by Old West ranchers for water storage.

Park officials said the graffiti started with just a few markings, but quickly spread.

To get rid of the blight, a team of conservators led by historic preservation expert Angelyn Bass painstakingly painted over the graffiti to restore the original look of the 19-foot-high dam.

"We had to use paints to simulate both the color and texture of the surrounding surface," she said. "With so much of the wall affected, it was challenging to achieve a natural appearance."

The Riverside Press-Enterprise reports (http://bit.ly/1DLyff7) the project cost $46,000, while conservators donated $33,000 in work hours to carry it out.

Jay Theuer, the park's chief of cultural resources, said officials plan to post signs and add volunteers to increase visitors' awareness of the growing graffiti problem.

"At least once or twice a week we get reports of graffiti in different areas," he said.