Sloat Restoration through Managed Retreat

Sloat Restoration through Managed Retreat
This is our original vision for Sloat Restoration - graphic courtesy of PSA and Associates and the Ocean Beach Task Force

Our Vision of Beach Restoration and Preservation

The shorelines of Ocean Beach south of Sloat Blvd and Sharp Park in Pacifica are threatened by rip-rap seawallls and long-term erosion. This blog chronicles our campaign efforts to restore these beaches. Check out the web view of this site to see our proposed solutions and how to help- in the right hand column below. For all the latest about our efforts, see our monthly posts.

We advocate a managed retreat strategy to restore both Ocean Beach south of Sloat and Sharp Park.

At Sloat, our vision involves:

A long-term plan to relocate threatened infrastructure
(including the south of Sloat Great Highway, the two oceanside parking lots and the sewer lines underneath them).

The cleanup of all the rock and rubble littering the beach.

The use of sand dunes as the primary tool to slow erosion.

For Sharp Park, we advocate the decommissioning of the golf course, the removal of the rip-rap berm, and a full restoration of the wetland.

Saturday, October 2, 2010

Gearing up for SPUR Stakeholder Meetings

Greetings Surfriders and Friends,

San Francisco Planning and Urban Research (SPUR) is busy putting the final pieces together for the stakeholder process that will help bring a long term solution at Sloat. Dates are still TBA. In the meantime, DPW has provided technical reports on 2010 storm damage, and the options they are considering to complete the armoring project. http://www.sfdpw.org/index.aspx?page=724

The agency, while still acting under emergency powers, will have to get approval from the California Coastal Commission for whatever plans they select. What we can do: Please continue to send letters to the California Coastal Commission asking the agency to minimize any additional armoring at Sloat, as well as for rubble removal and clean-up as mitigation. http://www.coastal.ca.gov

In the meantime, below is a very informative article published back in June by George Wooding for the newsletter of San Francisco Tomorrow.

Winter storms and neglect devour The Great Highway at Ocean Beach

In January, Mayor Gavin Newsom declared a state of local emergency due to severe erosion which was causing parts of the Great Highway to slip into the ocean.
Yes, recent wind and rain storms eroded Ocean Beach, but this “emergency” was actually caused by years of City-deferred maintenance, inaction, and neglect. San
Francisco has long known that parts of the Great Highway — especially the 3,000-foot section between Sloat Boulevard and Fort Funston — face being permanently washed away. It’s embarrassing that City officials have once again been caught off guard by a known and often recurring problem. Isn’t this “déjà vu”?

San Francisco’s problems with Ocean Beach are manmade problems. San Francisco caused Ocean Beach’s beach-erosion problem by repeatedly increasing its size using landfill, and then building on the landfill. The current shoreline is a man-made extension. Between 1895 and the 1930’s the Ocean Beach shoreline was pushed at least two hundred feet seaward to promote urban development. Between the 1940’s and 1960’s, concrete debris, bricks, soil, and sand were used to increase the width of the beach and to form artificial bluffs. The City continued to increase the size of the beach through the 1980’s. The Pacific Ocean is now simply reclaiming the man-made beach and in-fill that has been extended into the Ocean.

The Real Problem

The City built the massive 16-year-old Lake Merced Sewage Pipe directly underneath (40 feet below) the Great Highway; it was completed in 1994 as part of the
San Francisco PUC’s $200 million Oceanside Water Pollution Control Plant. The Highway and parking lots were built on landfill the Ocean is now reclaiming. While
the 14-foot-diameter pipe was tunneled in harder native materials at elevations below the adjacent beach, it was located very close to the Ocean, below the southbound lanes of the highway. After ocean waves tore into the bluff that supports the Great Highway, the sewage pipe was just 10 yards — barely 30 feet! — from the ocean’s edge. Over 10 million gallons of Westside raw sewage and wastewater flow through this pipe following rainy conditions. The pipe takes sewage to the Oceanside
Treatment Plant where it is partially treated and then pumped through an underwater pipe for release four miles out into the sea. As the shoreline recedes, there is
a very good chance that the Lake Merced Sewage Pipe will either end up buried under the ocean floor, or exposed to the ocean. Now the southbound lanes are closed, but Department of Public Works (DPW) hopes to re-open them sometime this summer.
Any rupture of the sewage pipe could cause a huge ecological disaster, involving millions of gallons of treated and effluent (partially-treated sewage) and liquid
waste pouring into the ocean and onto the fragile coastline. Earthquake-induced liquefaction to the area would pose another distinct threat.
According to DPW, some sections of ocean bluffs south of Sloat Boulevard have eroded by up to 70 feet just within the last year. The rock crown of the Southwest Ocean Outfall Pipe — part of the plant that discharges partially-treated wastewater four miles off shore into the Pacific Ocean — is also threatened by erosion. A 2009
report filed by the Pacific Institute shows San Francisco’s sea level rose eight inches during the last 100 years, but is expected to rise an additional four-and a-
half feet — yes, feet — by 2100 due to increases in ocean temperatures and melting ice sheets. Report calculations project that Northern California’s sandy dunes could retreat an average of 558 feet (186 yards) and cliffs could recede an average of 217 feet by 2100.

Higher sea levels, coupled with high tides and fierce storms, will cause storm waves to make increasingly deeper inroads into the receding shoreline. The City has responded to the latest Ocean Beach emergency by placing a 425-foot-long rock wall —
approximately 12,000 tons of rock — south of Sloat Boulevard below the San Francisco Zoo. This rock wall or revetment starts at the base of the eroded beach area and extends up the cliff’s face. Ideally, sand will be added on top of the rock to increase the width of the Bluff. The Army Corps of Engineers — the same folks involved with the New Orleans levees — is continuing to dump sand near the revetment changing the ocean’s littoral (sand transport) current, hoping to create a beach, but the “beach nourishment” approach is limited at this location because the Ocean’s littoral current is taking sand away from this section of shore. As the surrounding edge recedes, this divergent zone is aimed directly at the Great Highway and the Lake Merced Sewage Pipe. The effect is the same as aiming water from a hose directly onto pavement, 24/7.

This emergency Ocean Beach coastal armoring is a short-term, Band-Aid approach that will gradually fail. Coastal armoring can only be engineered to accommodate a certain storm size or rise in sea level, and at Ocean Beach would require regular monitoring and constant, expensive maintenance. Besides, armoring the edge is not as effective as a natural shoreline at dissipating the energy from waves and tides. As a result, armored shorelines are more vulnerable and cause increased erosion of adjacent beaches. In July 1999, the unanimous Board of Supervisors passed Resolution 698-99, prohibiting the expenditure of funds on the use of hard rock structures (such as rock revetment or seawalls) to stabilize conditions at Ocean Beach. The City’s emergency action this winter circumvented this Resolution and began expending funds on coastal armoring of Ocean Beach. The 1999 Board Resolution also called for a long-term plan to address erosion at Ocean Beach.

In 2002, Mayor Willie Brown’s Ocean Beach Task Force issued a Resolution supporting long-term solutions “through the planning partnership process.” The Mayor
took three years before establishing, in 2005, the Ocean Beach Vision Council charged with developing a 30- to 50-year plan for Ocean Beach. The Vision Council must be wearing very dark sunglasses, since it hasn’t even issued a draft report in the five years since being created. DPW and the Recreation and Park Department
(RPD) are currently working on a plan with the Army Corps of Engineers. No one knows how much of the RPD budget is funding the coastal armoring to protect City recreation and park land.

On April 19, 2010, Supervisor Ross Mirkarimi, with the support of Supervisor Sean Elsbernd, drafted a new Board Resolution requesting a “comprehensive planning
process be re-established to develop long-term solutions to the erosion problems at Ocean Beach.” All these attempts at long-term plans are either not drafted, completed, followed or implemented. Nothing changes except the eroding shoreline’s increased risk to the 14- foot-diameter Lake Merced Sewage Pipe and the Great
Highway above it, and risks to the Southwest Ocean Outfall Pipe.

Coastal experts are recommending a gradual surrender of the coastline to the Ocean. They believe that: 1)Infrastructure such as the Great Highway and the Lake Merced Sewage Pipe may have to be moved away from coastal erosion hazard zones; 2) Coastal armoring and structural measures should be minimized, with all armoring and rubble to be removed as soon as practical; 3) A sand management plan needs to be developed
where sand is placed to maintain the beach and dunes; 4) The natural ecology of Ocean Beach’s flora and fauna needs to be re-established; and 5) There should be
extensive Ocean Beach monitoring and adaptive management. This should become the template for the City’s long overdue Ocean Beach management plan.

As the sea rises, San Franciscans will be forced to decide: Should we adapt to the changing environment, or should we try to make it adapt to us? No matter what
we do, there will be consequences down the line. It’s time to decide the fate of Ocean Beach and San Francisco’s endangered infrastructure. San Francisco needs to immediately develop a realistic, long-term Ocean Beach management plan, before the 14-foot diameter sewage pipe and the Great Highway only 40 feet above it collapse under the weight of inaction. But by the time the City actually develops a long-term plan for Ocean Beach, we may all be up to our knees in sea water filled with effluvium (odorous waste matter).

Thanks to George Wooding, President of the West of Twin Peaks Central Council

1 comment:

  1. Bill, I think both the W. Twin Peaks and W. Sunset Democratic clubs have monthly meetings. Thanks for the info. I also wonder about these things at OB:

    -occasional black tarry sand

    -dolphins/whale carcasses showing up. Beach
    patrol said the Aquarium carves these up to study samples but don't know where to get study results

    -general human dumping of plastic, cigaret butts, feces

    -suds-like bubbles on the sand beyond the edge of the water

    -people who let pit bulls run free, and need to call them up as you jog past their area of the beach

    ReplyDelete