Ledson Marsh

The marsh was formed by an earthen embankment dam about 300 feet (91 m) long, constructed in 1930 by a former landowner.

Over the years, the dam deteriorated, allowing water to seep through it and causing the marsh to dry out in the autumn and refill during the winter rains.

A catastrophic dam failure would destroy the marsh habitat and clog various Sonoma Creek tributaries with sediment.

The California Department of Parks and Recreation therefore repaired the dam in such a way as to preserve the marsh's seasonality.

[1] Because of its seasonality, the marsh was colonized by California red-legged frogs (Rana draytonii), a federal- and state-listed threatened species.