Most of California’s reservoirs are open to recreational activities like fishing and boating, but not Lake Mathews. The Riverside County reservoir was built nearly a century ago to hold water diverted from the Colorado River. In spite of numerous attempts over the years to open it to the public, Lake Mathews has remained gloriously isolated. And while Zocalo columnist Joe Mathews would like to claim some birthright privileges (there’s no relation), he agrees with the Metropolitan Water District’s decision to keep Lake Mathews fenced off. He says there are just too few mysterious places left in the state.