Estuary News

March 2021

Nourishing Encinal Beach

Before the East Bay Regional Park District completed the Encinal Dune Restoration and Shoreline Stabilization Project in December 2020, this tucked-away beach frequented by locals and harbor seal enthusiasts needed some love. The ice plant that dominated the low-flung dune offered little sustenance to fauna; the beach required more sand; the washed-up creosote-treated timber was strewn about like a giant game of pick-up sticks; and the large, rusty barge that buttressed a short section of the San Francisco Bay Trail had become dangerous.

The nearly two-acre project site in the shape of an arrowhead includes Encinal Beach, the dune behind it, and a short section of the Bay Trail. Encinal Beach and its adjacent dune formed after the U.S. Navy installed a mile-long rock jetty in the 1940s off the southeastern shore of the Naval Air Station, now Alameda Point.

Restored site. Photo courtesy Carmen Erasmus.

To improve this locally loved site, East Bay Parks came up with a plan to “nourish” the beach and dune into a more natural condition and to improve recreational access. District landscape architect Carmen Erasmus and district fishery biologist Joe Sullivan identified a series of restoration steps and associated materials necessary to achieve these goals.

First the District trucked in medium-grain sand to elevate the beach and reduce the frequency of dune inundation during extreme high tides. At currently predicted estimates of sea-level rise, this measure should last for about 50 years. The nourished beach also improves non-motorized boat launching access to the San Francisco Bay Water Trail. Oakland’s Hanson Aggregates supplied the beach sand after extracting it from Point Knox Shoal in the San Francisco Bay.

In another important restoration step, the District weeded the ice plant matting the dune, brought in virgin marine sand from the Bay to raise it, and sculpted hillocks to enhance plant and wildlife habitat.

Next, workers seeded the dune hillocks with native plants and grasses such as pink sand verbena, beach evening primrose, and California poppies. As soon as they planted the seeds, rock pigeons swooped in for a feast. “Even with the pigeon feeding, we are hopeful the area will fill in as designed, given the current new growth,” says Erasmus.

Building the dunes at Encinal. Photo courtesy Carmen Erasmus.

Removing the creosote-treated logs required that East Bay Parks scoop them up and take them to a landfill licensed to handle creosote-contaminated waste. The old barge used for stabilization had become rusty and eroded with sharp edges. “The barge popped right out, and there weren’t any hazardous materials underneath it,” says Sullivan gratefully. After removing the barge, the next step was buttressing a short section of the Bay Trail with riprap that Dutra Materials supplied from a San Rafael rock quarry. It was tested and certified as being free of clay and other organic matter. “Replacing the rusty barge with rock provides better habitat for shellfish,” says Sullivan.

These improvements brought a total of 340 dump trucks full of sand and rock to the site, according to Erasmus. All the work near the waterline was done at low tide to protect water quality.

East Bay Parks’ finishing touches involved improving recreational access and enhancing habitat. Workers repaved a section of the Bay Trail, installed a split-rail fence to protect the dune, and planted coast live oak, toyon, and ceanothus behind the new bathrooms that, along with two new boat launching ramps for motorized vessels, were installed by the City of Alameda.

This project has been on the District’s wish list for at least ten years, but funds and permits were difficult to assemble until 2016. The San Francisco Bay Restoration Authority contributed $450,000 to the $1.1 million project, using local tax dollars from Measure AA, the San Francisco Bay Clean Water, Pollution Prevention, and Habitat Restoration measure passed by voters in 2016. East Bay Parks, which leases the land from the City of Alameda, matched that amount with funds from Measure WW, approved by voters in Alameda and Contra Costa counties in 2008. A grant from the National Fish and Wildlife Foundation also contributed $200,000 to the effort.

Mother and son stop on the Bay Trail to study the seals. Photo: Richard Bangert

To report this story, I visited Encinal Beach in February and found people enjoying the site on an unseasonably warm weekday. Kids played on the beach and in the water; kayakers launched from the beach and paddled around Seaplane Lagoon; and masked cyclists, runners, and recreational walkers made good use of the repaved trail.

To check out a rare treat in Seaplane Lagoon, I walked west on the Bay Trail for a short distance to view a harbor seal float anchored 300 feet from the shoreline. The float was installed in 2016 by the Water Emergency Transportation Authority to mitigate the loss of an old wharf used by seals that was being removed for new docks.

I learned from the Alameda Point Harbor Seal Monitors Facebook page that this is the only custom-built haul out designed for harbor seals in the world. The raft has a sloped end to make it easier for the seals to get out and warm their blubber, something they need to do for survival. Since 2016, volunteer monitors have counted and recorded the number of seals that use the raft daily. When people were social-distancing on December 14, 2020, a record number of 86 seals piled onto the 500-square-foot raft.

With more people using the shoreline during the pandemic, the City of Alameda started receiving complaints that some kayakers were paddling too close to the seals. City managers asked the monitors to help them develop signs to remind paddlers to keep a distance of at least 300 feet from the raft, especially during pupping season from March to July. Unlike the boisterous and seemingly entitled sea lions at San Francisco’s Fishermen’s Wharf, harbor seals spook easily, and if they continually feel threatened at their haul-out site, they won’t return. That loss would be significant, as it is the only spot in the East Bay between Yerba Buena Island and Newark where they haul out. It would also be a loss for people.

“There’s a whole universe of wildlife below the water surface, and here you can walk down a public trail and see the seals with your naked eye,” says volunteer monitor Richard Bangert. “It helps people connect to the marine ecosystem of the Bay.”

Now that the pandemic is sending so many more in search of open air and nature, voters’ investments in shoreline improvements are proving more valuable than ever.

Prior Estuary News Stories

Parks and Cities Seek Shore Resilience, June 2020

Hauling Out to Higher Ground, December 2018

Other links

Alameda Point Harbor Seals Monitor

Top Photo: Nursing pup off Alameda Point. Photo: Richard Bangert