A good overview of Jasper Ridge Biological Preserve, looking northeast. The Preserve actually encompasses Upper Searsville Lake, just past the horse facility near the bottom center, this side of Portola Road. (The cleared strip at its left is for the SLAC power lines.) The prominent green at the center is Middle Searsville Lake, across Portola Road and in the main part of JRBP. The main body of Searsville Lake lies beyond, green growth rimming the upper end, Searsville Dam to the left. The Sun Field Station is this side of the dam. JRBP encompasses the riparian corridor upstream of the main Searsville Lake (to its right), and the chaparral-covered ridge beyond. The top of the ridge is bare. JRBP is bounded on the diagonal left (north) by the SLAC corridor. It extends past the bare ridgetop, and down the chapparal and forest, ending before the next bare hill. Mount Diablo, on the left horizon, reigns over the East Bay Hills beyond San Francisco Bay.

From the top:
Mount Diablo at the far left.
The Bay.
Palo Alto, Stanford, Menlo Park.
Highway 280.
SLAC.
Jasper Ridge — the tree-covered ridge, with serpentine grassland at the top. Oh, and there is Webb Ranch, the flat green area just past the ridge, right center. Ladera and Portola Valley’s Westridge are to the right of Jasper Ridge Biological Preserve. Felt Lake can just be seen at the far right.
Main Searsville Lake — bordered in green, the lake behind the dam, what we nowadays call “Searsville Lake”. The Corte Madera Creek channel goes to the right.
Middle Searsville Lake — bright green.
Portola Road.
Upper Searsville Lake, across Portola Road from the main part of Jasper Ridge Biological Preserve — dark brown. Bordered by a clear strip in the vegetation, for the SLAC power lines. On the other side is a horse facility.
Old La Honda Road comes toward us at the bottom of the photo.

These three “Searsville Lakes”, Main, Middle, and Upper, were once part of the original Searsville Lake formed by Searsville Dam in the 1880s, over the site of the original Searsville. As you see, much of this original lake has been filled in by sediment. Searsville Dam stops 90% of the sediment that comes down Corte Madera Creek. Searsville Lake will eventually fill up completely if nothing is done -- In decades or sooner.