 Aside from sedimentation caused by normal earth-fill dam construction, much of the dam's clay core and soil overburden were washed away in a storm during construction in 1874, resulting in the formation of Arrowhead Marsh in San Leandro Bay, at the mouth of San Leandro Creek near the Oakland International Airport.Coastal surveys show the marsh appearing sometime between 1855 and 1895, though logging of the San Antonio Forest may have also played a role.Today, Arrowhead Marsh is one of the last remaining wetlands in the East Bay, and part of Martin Luther King Jr.