When Shasta Reservoir levels drop 90 feet down from the top of the dam remnants of the “head tower,” a structure used during the dam’s construction in the early 1940s, becomes visible. To locals and water wonks alike, it’s a reminder that it’s going to be another dry year. … The lake’s historic lowest level was in the summer of 1977 when it was down 230 feet below the dam’s crest. Last year’s lake level was the second lowest on record, and yes, the head tower was exposed — along with roads, train tunnels, and car bridges.