This Spring, East Bay Regional Park District (EBRPD) repaired some erosion on North Point Isabel (PI), the half of Point Isabel Regional Shoreline reached by the pedestrian bridge near Rydin Road. It is also installing a mesh fence along Hoffman Channel on that side to prevent erosion of the bank and keep people and dogs off dangerous boulders.
Both sides of the park are former dumps capped with several feet of clay. North PI is in a category of its own, however. Decades ago, it was a dumping ground for “lead-acid storage battery casings” and “other unspecified fill material,” according to a 1986 report by the California Water Quality Control Board. At least one park user still remembers clambering about back then on what appeared to be old car batteries along the edge of the mudflat.
Legend has it that North PI was a Superfund site, but that appears to be not true. However, the land owner, Santa Fe Land Improvement Company, was required to haul away tons of soil that was contaminated with trace metals, construct a thick clay cap, and do regular testing of the land, groundwater, and water off-shore.
Its troubled past has left North PI with unique constraints, because it’s vital that the clay cap stays intact. That’s why no trees can ever be planted on that side, and why the contractor who did the recent repairs was required to pound stakes into the ground rather than digging holes.
Never let your dog dig on either side of the park. People have stumbled and dogs have broken their legs in holes, and on North PI there could be a risk of exposure to lead and zinc. The other half of the park is not pristine, either. The mound of dirt that is fenced off between the bridge and PIDO’s bulletin board near Rydin Road was excavated a few years ago when EBRPD dug foundations for the restrooms. It tested positive for trace metals, is not considered safe for park visitors, and will stay permanently off-limits.