In 1797 the founding friars of the Mission noted the existence of a fresh water lake nearby the location of the Mission. At that time it was a spring fed sag pond on the San Andreas Fault, and probably often visited by the local native population. It was a source of water year round and a choice location when Colonel Hollister and then later, the Flints and Bixby’s chose to build on this site.
Margery Flint noted in her book, Life on the Escarpment, that those natural springs were closed off by the fore shocks to the great earthquake of 1906. Early photos of the lake show it receding after that time.
When Mme Hedges had the property, she was instrumental in having a diversion dam and collection canal build along the entire hillside west of the ranch house. All that run off was collected and brought into the lake. The lake stayed filled until the rains of 1995 hit. So much rain fell that El Nino year that the overflow from the lake eroded the canyon behind the Casita, causing concern about its safety, but also wiping out the cherry orchard on the neighboring property.
The retreat was forced to stop importing water to the property since it could not properly contain that amount of water safely. Ever since then the water level has decreased, exacerbated by the recent 3 year drought. Seasonal rains may bring some water into the lake bed, but we will not see the water level reach back up to the rock walls lining part of the lake bed.