The Madrona Marsh or Madrona Marsh Preserve, located in Torrance, California, is the last vernal marsh remaining in the South Bay area of Los Angeles and one of few wetlands located within an urban landscape. Public access to Madrona Marsh was and remains controlled. Guided tours can be arranged through the "Friends of Madrona Marsh" or the City of Torrance Parks and Recreation Department.

Formed eons ago when the mountains of the Palos Verdes Peninsula rose to the south, Madrona Marsh is a shallow depression fed by wet season (Spring) storms as the name "vernal" indicates. After the rainy season, evaporation, percolation and transpiration reduce the water depth by about one-quarter of an inch (6 mm) per day. By the end of August, the wetland is dry and remains so until the following rainy season. Situated on land that was set aside for oil production in 1924, Madrona Marsh was never developed—unlike the surrounding city—and remains a valuable natural habitat for birds, reptiles, insects and even small mammals.

The Audubon Society has used Madrona Marsh for their annual bird census since 1967 and El Camino College uses it as an outdoor biology and botany lab.

External links

• City of Torrance Parks and Recreation, including tour and activity schedules
• Friends of Madrona Marsh website with additional history.