Watson Lake was created in the early 1900s, one or two man made reservoirs at the Granite Dells (about four miles from Prescott). The Granite Dells is a 1.4 billion year old geologic feature of intriguing rounded boulders, rock layers shedding off over time like the layers of an onion. There is a 4.8 mile trail that goes around the entire lake, but you don’t need to do it all for beautiful highlights. Starting at Watson Lake Park, you can follow the white dots as far as you please. We walked to the dam and back. The last time we were here the lake water was deep blue and crystal clear. Regardless of the water quality, these beautiful granite formations make for a surreal location to hike. And, unlike hiking anywhere in San Diego county, we had the place virtually to ourselves.