High Quality Content by WIKIPEDIA articles! Laguna Creek (Spanish for: Lake Creek) is a perennial stream that flows northwesterly for 2.6-mile (4.2 km) along the San Andreas Fault from Woodside in San Mateo County, California and, after crossing the Phleger Estate and Filoli, enters Upper Crystal Springs Reservoir, where it is a historic tributary to San Mateo Creek. San Mateo Creek then carries its waters over Crystal Springs Dam northeast to San Francisco Bay.