Erosion

Ocean Beach erosion plan being reviewed by SF Planning Commission

by Thomas K. Pendergast

 

Efforts to deal with the severe erosion of Ocean Beach south of Sloat Boulevard might

move forward on June 8, should the SF Planning Commission adopt proposed

amendments to the Western Shoreline Area Plan.

 

The plan now in effect addresses things like public access

and recreation, transportation and land use but it does not consider

the erosion that has been taking place over the last decade,

nor the possibility of rising seas.

 

The proposed amendments would add policies to deal with

erosion, coastal flooding and sea rise.

 

OceanBeachMeeting

Anna Roche of the SFPUC (left) assists a woman with questions
about Ocean Beach changes. Photo by Thomas K. Pendergast.

 

“The Ocean Beach Master Plan, because of erosion at south

Ocean Beach, identified the need for some retreat so that the beach

can persist there, also protection of the wastewater infrastructure

there,” said Maggie Wenger, of the SF Planning Department,

during a community meeting in May.

 

“A policy draft was published in November and a revised version

was initiated at the Planning Commission in March, which just means the official

public period, although we had it out for review before that,” Wenger

said. “If it’s adopted on June 8, which we hope it will be, then it

goes to the SF Board of Supervisors for approval. They have 90 days, and then it goes to

the California Coastal Commission.”

 

One of the most important changes under consideration is the eventual removal of the

Great Highway, between Sloat and Skyline boulevards, by rerouting northbound and

southbound traffic around the eastern edge of the city’s Zoo and

wastewater-sewage treatment plant.

 

They are not proposing to create a seawall to save that section of highway; instead they

want to adopt a policy of “strategic retreat” in an effort to save what’s left of the beach.

 

The consensus among city planners is that building a giant sea wall to save that stretch of

roadway would mean losing the beach entirely because it would all eventually

erode away. While that might be OK with commuters, it would not be fine with the

California Coastal Commission, National Park Service, surfers and environmental

groups, including the Sierra Club.

 

However, a small seawall, buried beneath the sand dunes is being proposed to

protect the Lake Merced sewage tunnel and the sewage treatment plant.

In addition to that, another option under consideration is a “dynamic cobble base” of

round stones, laid out around the tunnel area, which would provide a base for sand

dunes that could then shift around according to the weather and seasons, and

which will, hopefully, maintain the beach while protecting the sewage infrastructure.

 

“We’re experiencing chronic erosion along this coastline and we are looking at different

options for protecting our infrastructure but at the same time recognizing that we have a

recreational area,” said Anna Roche, a climate change and special projects manager with

the San Francisco Public Utilities Commission (SFPUC), which is responsible for the

sewage plant and tunnel. “We need access to the beach. We have habitat, and

(we are) trying to find a balance between addressing all of those needs: protecting our

infrastructure, making sure we maintain a sandy beach, a safe place for people to go and

any habitat for birds or whatever else that exists out there.”

 

Roche said they replenished some of the sand at the beach erosion site back in

November as a temporary fix.

 

“We moved 70,000 cubic yards of sand into two locations: just south of the parking lot

where the bathroom is and then at the southern-most end (west and a little bit

north of the wastewater treatment plant).

 

“These measures are meant to protect this area,” Roche said.

“We’re doing an alternatives analysis report, which means

we’re doing an engineering analysis of the different options that

we can look at to protect the area. Once we complete that, then we would have a project

and we move into conceptual engineering, environmental reviews and then into the

design for the project; we’re expecting to be ready to go into

construction by 2021.”

 

Another issue that needs to be dealt with is the intersection of Sloat and Skyline

boulevards, which sits at the eastern end of the SF Zoo. The Great Highway

currently allows commuters to bypass the intersection, but the

new plan would route all traffic on Sloat directly through it,

which could significantly increase traffic congestion.

 

Three options are under consideration by the San Francisco Municipal Transportation

Agency (Muni), the department now dealing with the issue: a “low cost, near-term”

approach, roundabout or a “T” intersection with a traffic signal light.

 

Anna Harkman, a Muni transportation planner, said the agency

will evaluate all three options and then make some proposals.

 

“The low-cost, near-term would be things that we can do primarily with paint and

signage, without necessarily having to tear up the intersection,” Harkman said.

“There’s existing infrastructure there … We want to find the best alternative for the

intersection. We’re going to look at doing a less intensive treatment

versus doing something that would require really reconfiguring

the intersection.”

 

The roundabout and the T-intersection alternatives would

likely require a reconfiguration and construction at the intersection.

 

In 2016, however, Oscar Gee, project manager for the SF Department of Public Works at

the time, expressed doubt that the roundabout option would work out.

 

“It just didn’t seem like it was going to work from a layout perspective,”

Gee said. “It’s pretty tight at the intersection. The geometry didn’t seem like it could

really work.”

 

Harkman said Muni will be asking a professional consulting firm to look at the feasibility

of the different options, but the study probably will not start until early in the fall.

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