Water on Pedro Point comes from rain and fog.
Rain produces seasonal streams like Arroyo Creek while fog regularly nourishes the entire headlands.
The constant force of the Pacific Ocean eroding the headlands has had a major role in shaping, and is constantly reshaping this land.
California's winter-wet, summer-dry climate makes water vital to the ecology of Pedro Point Headland. Precipitation falls during the winter months, typically during storms. These storms nourish the vegetation and wildlife of the headland, while shaping the Pedro Point through slope erosion and runoff. Heavy surf carves away at headland cliffs below, leading to landslides and cliff retreat. Sediment laden waters erode open gaps in the vegetation, as seen on former off-road vehicle tracks, and this runoff finds its way down to San Pedro Creek where it impacts habitat for Steelhead and California red-legged frogs.
During the long dry season, storms are rare. Even without heavy rain Pedro Point Headland is still bathed in moisture; Pacific marine layer fog. Coastal fog keeps the headland cool and moist during the summer making the vegetation on Pedro Point so rich. Lichens and mosses drape the trees and shrubs that dominate the headland illustrating the importance of this fog.
Pedro Point Headland has a seasonal yin and yang of water, through the power of winter rain and pounding surf to mold and transform the shape of its rocks, slopes, and soil. The gentle caress of fog in the summer brings cool moisture to drought challenged vegetation that cloaks its headland contours.