Nestled between the City of San Bruno to the north and Woodside to the south, Crystal Springs is a county park comprised of two main trails, Sawyer Camp Trail in the southern end and San Andreas trail in the northern section, which run along the eastern shore of San Andreas Lake in San Mateo County.
Settled thousands of years ago by the Shalshone Indians, the Crystal Springs reservoir, also known as San Andreas Lake, is currently part of the City of San Francisco's Hetch Hetchy water system.
Crystal Springs is currently a popular area for non-motorized recreation, including bicycling, running, walking and hiking. The trails are known for their spectacular views, abundant wild- and plantlife.
Note that the San Andreas Fault runs right through this reservoir (and is actually the cause of the rift's formation). However, the Crystal Springs Dam survived both the 1906 earthquake and the 1989 Loma Prieta quake with no damage whatsoever (according to the US Geological Survey).
US Geological Survey: Crystal Springs 3D photo tour (http://3dparks.wr.usgs.gov/3Dbayarea/html/CrystalSprings.htm)
San Francisco Public Utilities Commission: Crystal Springs history (http://sfwater.org/detail.cfm/MSC_ID/37/MTO_ID/NULL/MC_ID/5/C_ID/796/holdSession/1)
The "Spring of 10,000 Fish" is constantly replenished by millions of gallons of crystal-clear water and is a refuge for manatees that have been injured, orphaned or born in captivity.
The park is much more than just a safe haven for manateesit provides educational programs, wildlife displays, boat tours and nature trails that meander throughout this lush, hydric hammock environment.
One of the parks main attractions is the 168-ton underwater observatory where you can see the manatees and a wide variety of freshwater and saltwater fish.