When I arrived for grad school in 1975, Lake Lagunita was an artificial lake that reappeared each rainy season. Water from San Francisquito Creek was diverted to the lakebed by opening a headgate off Alpine Road into a canal running along Alpine Road and Junipero Serra Boulevard. The maximum depth of the lake when filled was about three meters. The lake was enjoyed each spring by all manner of water enthusiasts, including canoers and small-craft sailors. County health regulations required that the lake be drained at the end of each spring to avoid putrification. A floating dock anchored to the lake-bed provided a fun place to swim, tan, and picnic. Each fall the dry lake bed became the site of another abandoned ritual, a huge bonfire prior to the Big Game with football rival U.C. Berkeley. At some point the surrounding earthenwork dam became so leaky (and perhaps dangerous to the campus below) that the artifical annual filling was abandoned. Signage at the lake cites environmental reasons as well. The "lake" now sits dry except for seasonal pools that provide essential breeding grounds for an endangered species of salamander and other creatures. After exceptional rains the lake fills with runoff from the adjacent hills.
This geocache overlooks the usually dry lake bed from a perch near the grilling area, and is easily accessible. While you are there you might enjoy the 1.4-kilometer trail running around the perimeter of the lakebed, which crosses the abandoned filling canal near the Stanford golf driving range.