Pillar Point (PPH) Boat Launch Ramp Maintenance Dredging (Harbor
UPDATE: ON JUNE 14TH, 2013, THE COASTAL COMMISSION APPROVED THE HARBOR DISTRICT'S APPLICATION TO DREDGE THE PILLAR POINT BOAT LAUNCH RAMP AND PLACE 3,500 CUBIC YARDS OF MATERIAL ON THE NEARBY PERCHED BEACH SITE, ITSELF COMPRISED OF DREDGED MATERIAL FROM PREVIOUS DREDGING EPISODES.
Background: The Harbor District's boat launch ramp at PPH, built
around 1992, periodically requires maintenance dredging to keep its three
ramps open for use. Emergency dredging was last done in 1999 and 2006
to remove siltation caused by severe storm activity leading to runoff from
Deer Creek in EI Granada. The dredged material was placed on the nearby
perched beach, a dredged material disposal site that was created in the
1980's by the original dredging to create Pillar Point Inner Harbor's boat
Once again, the ramp needs to be dredged. The District began the process
of applying for the necessary permits and approvals at the end of 201l.
The Army Corps permit, Regional Water Quality Control Board certification,
and the State Lands Commission lease have been received . The Coastal
Commission permit approval is expected in April. Regulatory requirements
for additional testing of the approximately 5,600 cu. yds. of material to be
dredged and conduct of an eelgrass study considerably lengthened permit
The perched beach disposal site will be used for this maintenance dredging
episode as in the past. The actual disposal location will not eliminate use of
the beach for commercial and private kayak use and other public water
access. Permit requirements call for the sediment to be contained within a
berm on the upland side of the beach. The actual amount to be dredged is
no more than in either ofthe two previous episodes in 1999 and 2006.
Urgency factor: Because over half of the launch ramp is now silted up, no
alternative disposal site to the perched beach site (which is very close to
the launch ramp and hence most cost-effective) is or will be available in
time to accommodate this dredging episode before the start of the salmon
fishing season in early April.
Surfers Beach Erosion Control and Beach Restoration Project (U. S. Army
Corps of Engineers). Background: The Pillar Point outer breakwater was
built and is maintained by the U. S. Army Corps of Engineers. After World
War 2, Coastside and other citizens petitioned Congress to provide a harbor
of refuge for the fishing fleet. In 1947, the Army Corps of Engineers
recommended constructing the breakwater. It was built between 1959 and
1961, with an addition to the west arm in 1966-67.
Erosion of Surfers Beach at an increasing rate has occurred since the east
arm of the federal breakwater was built (See Section 216 Initial Appraisal below). This is a longstanding
concern of beach users, surfers, local citizens, the Harbor District,
the County, and Caltrans, especially because of concerns regarding
protection of Highway 1. The District and harbor users have also been
concerned with the loss of vessel anchorage area within the outer harbor as
a result of sediment trapped behind the east arm of the outer breakwater. (see Bathymetry Study & Outer Harbor Channel Design following)
Pillar Point Harbor
Bathymetry Study & Outer Harbor Channel Design
Using these delta plots, we then identified 9 zones of scour and accretion for further examination (Work Product 3, see Figure 2). Zone boundaries were chosen to create areas having similar rates of scour or accretion and to also isolate the inner breakwater area from the outer areas of the harbor.
Results and Conclusions
As can be seen from Table 1 (Work Product 4), between 1994 and 2006 the entire harbor experienced 37,127 cubic yards (CY) of scour and 15 1,787 CY of accretion, resulting in a net accretion value of 114,660 CY. Each individual zone experienced scour and accretion, exemplifying the hydrological and sediment transport dynamics of the harbor.
Scour/Accretion Quantity Calculations
Since we are studying zones of differing sizes, it is helpful to examine the normalized rates of change in the last 2 columns of Table 1 (i.e., average depth of scourlaccretion over the 12-year period and on a per-year basis). This comparison uses net scour or accretion quantities coupled with the total area of a specific zone in order to give a relative assessment of scour and accretion rates. For instance, even though Zone 3 has a higher net accretion volume (33,874 CY) than Zone 2 (31,098 CY), Zone 2 covers a much smaller area. By taking the zones' areas into consideration, it can be noted that Zone 3 has less change in elevation (+0.32 feet) when compared to that of Zone 2 (+0.59 feet). Furthermore, the largest zone (Zone 5) has the lowest net elevation change (+0.02 feet). This example is striking when compared to Zone 4, which includes a much smaller area, but has experienced a net elevation change of +2.72 feet. click here to see zone map.
GSA Gahagan & Bryant Associates,
Inci Page 4
In 2007, the Harbor District asked the Army Corps of Engineers to
investigate the erosion along the approximately one mile of shoreline from
the foot of the breakwater to the vicinity of Medio Creek, in Miramar. At
this time the District had been approached by some local surfers who
expressed concerns about loss of beach. The Corps completed a Section
216 Initial Appraisal in July 2009 (see Section 216 Initial Appraisal below), which concluded that
there is a federal interest in addressing shoreline issues arising from the
SECTION 216 INITIAL APPRAISAL
The purpose of this Initial Appraisal is to review the existing United States Army Corps of Engineers (Corps) project Pillar Point Harbor (authorized in 1948 with initial breakwater construction from 1959 to 1961) to determine whether it is appropriate for the Corps to participate in the resolution of documented shoreline erosion and structural damage along the northern open-ocean shoreline of Half Moon Bay. The non-federal sponsor has stated that the negative shoreline impacts in that area can be attributed to the original Corps project.
The area of concern (proposed project area) starts at the root of the East Breakwater and extends southward a distance of approximately one mile to Arroyo de en Medio, which is near the southern end of Miramar Beach. Because of its relative stability since breakwater construction, the Half Moon Bay shoreline between Arroyo de en Medio and Miramontes Point is not included in this Initial Appraisal.
Federal interest will be based on two factors:
The extent of the post-construction shoreline change beyond the natural change that would have been expected without the Pillar Point Harbor project
The economic viability of a potential project to mitigate for such physical changes.
TABLE 2: Construction at Pillar Point Harbor and Shoreline Condition
Prior to 1959
Minimal erosion with broad sandy beach
1959 to 1965
Two Outer Breakwaters Built
Increase in erosion with a loss of approximately 75,000 yd3 per year (USACE, 1971)
Prior to 1971
500 ft revetment built starting at root of East Breakwater
Stopped local cliff retreat (USACE, 1971)
Two Inner Breakwaters Built
No impact on erosion south of the East Breakwater
1959 to present
Various remedial actions induding rubble-mound revetments
Erosion rates increased from 0.25 ft per year to as much as 7 ft per year (Griggs et a!., 2005) where the bluff is exposed.
Inside the harbor, sediment has accumulated adjacent to the East Breakwater creating dunes and a beach. Between that beach and the inner breakwater, sufficient sand has accumulated to elicit concern from the Harbor District about restricted small-boat access to the inner harbor via the east entrance. That sand probably comes from erosion of the Princeton shoreline and material coming down Denniston Creek and Deer Creek. It is also possible that some of the sand in the delta comes from the south or through the harbor entrance during large storms. Pre-breakwater, that sand would have moved alongshore to the south.
The District and the Corps signed a Feasibility Cost Share Agreement (FCSA)
in September 2010 for a project under Continuing Authorities Program
(CAP) Section 111 Mitigation of Damages Caused by a Federal Navigation
Project. The Corps is the Lead Agency for the project; the District is the
Local Sponsor. This FCSA provides for a 50:50 cost share between the
Corps and District for the pre-design phase of the project.
The project's two-to-three year feasibility phase, now in progress, is
focused on identifying the feasibility of a possible project that would
demonstrate solution(s) to the beach erosion problem that will have no or
minimal environmental impacts on marine sanctuary and other natural
resources. This could potentially include transferring sediment trapped
behind the breakwater onto Surfers Beach according to a permitted project
To facilitate public and technical input to the Corps during this phase, the
Harbor District organized a Working Group consisting of concerned federal
and state agencies, representatives from elected Representatives' offices,
technical resource persons, and community residents. The Group has been
convened and will continue to function during the Corps project.
The Corps has convened public meetings, with the District's assistance and
coordination. The District notices these meetings on its website and at the
The Army Corps has finished its analysis of existing site conditions and is
now examining potential project benefits, including economic and
environmental considerations, going forward from the start of this project.
Meanwhile, District staff has met with County Parks Division staff regarding
their public safety and beach access improvement project at EI Granada
above Surfer's Beach. An inter-agency meeting was recently held involving
the Army Corps, County Parks and Public Works, Coastal Commission,
Caltrans, the Gulf of the Farallones National Marine Sanctuary, the Harbor
District, and staff from elected Representatives' offices to exchange
information, establish coordination links, and identify next steps for action.
Key Issues: Some community members have expressed concern at the
apparent slow pace of the Corps' project. Questions also have been raised
as to why the Harbor District cannot apply for a permit and deposit
sediment on Surfers Beach from its launch ramp dredging or from the buildup
inside the breakwater. Regarding the first - timing, the Corps' project
development process calls for a Feasibility Planning Phase of 2-3 years
duration. (The Corps/District Agreement was executed in September
2010.) Some may be unfamiliar with what seems a lengthy period needed
Regarding the second, any agency seeking permission to dredge and
dispose of the material needs permits, certifications, and approvals from
several federal and state agencies. Additionally, for Surfers Beach, the
Monterey Bay National Marine Sanctuary and the Gulf of the Farallones
National Marine Sanctuary (which administers sanctuary waters for
Monterey Bay in the Half Moon Bay [and Surfers Beach] area) follow a
national sanctuary policy that prohibits artificial placement of any material
in sanctuary waters. An agency, be it the Army Corps or the Harbor District,
could seek sanctuary approval to deposit sediment on Surfers Beach, but
they would have to demonstrate that such action would have no negative
impact on sanctuary resources, species and habitats. And then, the
sanctuaries would have to find a way to grant an exception to the national
policy prohibiting artificial placement. Moreover, the applicant agency
would still need all the other permits and approvals.
An essential part of the Army Corps' Surfers Beach project, for which the
District is the local sponsor, is precisely to develop the information
necessary for the sanctuaries, and other permit agencies, to reach a
positive conclusion about the project's impacts.
Regional sediment management planning is beginning for the Santa Cruz
Littoral Cell, which goes from the northern end of Monterey Bay north to
Pedro Point in Pacifica, and which includes the Half Moon Bay area. This
effort may provide valuable information regarding possible project
alternatives for beneficial use of sand at Surfers Beach that could be
favorably viewed by the marine sanctuaries.