JOSHUA TREE NATIONAL PARK (CBS/AP) — Painstaking work by conservators has restored the appearance of Joshua Tree National Park’s historic Barker Dam, which became scarred with scratched graffiti as California’s drought caused water levels to fall.

The National Park Service says conservators from the University of New Mexico spent a year and a half developing a process to deal with the scratches and then worked last month to conceal the graffiti.

Pigments were added in a manner similar to the painting style known as pointillism to match surrounding colors, textures and patterns.

The dam, which is listed on the National Register of Historic Places, was originally constructed by a cattle company in 1902 and is an example of what it took for ranchers and homesteaders to survive in Southwest deserts. The dam can still catch rainfall but drought exposed its surface and people rapidly vandalized it.

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