Monday, November 29, 2010

Surfers' Point Cobble Berm

The last post described the 'Managed Retreat' process at Surfers' Point. This is a description of the 'cobble berm' that is currently under construction.

During the design process, the cobble berm was seen as a means of providing assurance that future erosion would not damage the relocated bike path nor result in future impacts to the Fairgrounds. The final design was based upon the concept sketch below. The 'retreat zone' is the area of the parking lot, approximately 20 meters (64.5 ft) wide. (The current work (Phase 1) removes about half of the 1800 feet of parking lot.)

The plan is to remove approximately 3 feet of imported fill dirt that was placed beneath the parking lot in 1989, then further excavate down to the low tide level. The cobble berm is constructed by filling this area with an estimated 30,000 tons of river cobble between 6" and 18" in diameter. This 8 ft thick cobble berm will then be buried beneath constructed sand dunes. The idea is that when the beach erodes in future swells, this sand and cobble will provide natural shore protection for the bike path and fairgrounds parking lot.

The following photos show the sequence of events (so far), looking toward the rivermouth from the east end of the project area:

The cobble is being transported by truck from the Corps of Engineers project on Santa Paula Creek. ($4 million to clean out lower Santa Paula Creek to increase safe capacity prior to major storms) The Surfers' Point project calls for 30,000 cubic yards (about 3,000 truck loads) of cobble, and approximately 15,000 cubic yard of sand.

Once approximately 3 feet of cobble has been delivered and graded flat, sand is then placed on top and flushed with water hoses so it fills the spaces between the cobble. Additional layers of cobble and sand will gradually build up the berm to meet engineering specifications.

The scale of the berm is evident in this photo of the retreat zone - here the first 3 foot layer of cobble has been placed, and sand is being worked into the spaces.

This drawing shows an engineering 'plan view' of the buried cobble berm, illustrating its alignment along the backshore in relation to the new parking lot and bike path:


Friday, November 19, 2010

The Managed Retreat Process at Surfers Point

"Managed Retreat" is well underway at Surfers' Point, and things are happening fast. As the project title suggests, the goal is to remove all the man-made infrastructure seaward of the road, and reconstruct a protective beach in its place.

First the concrete barriers and landscaping trees and curbs were removed.

The next step was removal of the asphalt and concrete bike path, along with the riprap rock revetment on the beach. The parking lot started to look like this:

Next the underground utilities were removed, including a 3 ft concrete storm drain as well as electrical lines that ran the length of the parking lot.

At this point the stage is set for the restoration of a natural beach. This is what the erosion-damaged bike path looked like a decade ago:

The same area during the initial demolition:

This is the view from the levee looking back toward the project area. The hole in the beach is almost all that remains of the rip-rap revetment:

A couple of high tides, along with medium swells, quickly erased almost all traces of the rocks.

Next the graders went to work removing the dirt fill that had been placed underneath the parking lot.

Non-beach compatible soil was moved back into the fairgrounds parking lot, and the area beneath the parking lot was excavated down to around the elevation of low tide. Any excavated sand was set aside for future use.

This deep trench will be filled with a mix of cobble and sand, and then buried under reconstructed sand dunes. This 'cobble berm' was designed to provide protection from future erosion.

The next post will describe this more...

Tuesday, November 16, 2010

Santa Barbara Channel

Thursday, November 11, 2010

Educational presentations

November 5, 2010

Environmental Studies 119, Ecology and Management of California Wildlands, UC Santa Barbara (UCSB)

Watershed field trip: We visited a couple of sites in the lower river, and then went upstream of Matilija Dam. After looking at the extent of dam-accumulated sediment, we visited the dam site and discussed removal plans.

November 8, 2010

Class lecture for the Intro to Restoration Ecology class at CSU Channel Islands (CSUCI)

Topic: Ecosystem-based management and the Matilija Dam Ecosystem Restoration project.

November 18, 2010

Class lecture for the Coastal Processes and Management class at UC Santa Barbara (UCSB)

Topic: Ecosystem-based management and the Matilija Dam Ecosystem Restoration project.

Wednesday, November 10, 2010

San Antonio Creek Bridges

Two bridges are under construction on San Antonio Creek, a major tributary to the Ventura River. Both have received fisheries restoration grants for the potential benefits of barrier removal.

1) Old Creek Rd Bridge

This is the construction that is visible at the 'Arnaz Grade' on highway 33. Ventura County received $1M for steelhead enhancement to replace the low water crossing over San Antonio Creek on Old Creek Rd. The new $2.5M bridge on a dead-end road will serve approximately 35 residents, and moved forward despite numerous comments that cheaper alternatives existed. (A short emergency right-of-way could have provided access to nearby Sulphur Mountain Rd) "According to county specifications, the bridge will be a 210-foot-long, two-span, cast-in-place concrete box girder bridge designed to clear the 100-year floodplain."

According to Ventura County documents the total cost of this project is over $3.5M. From Board of Supervisors meeting this week, a change order for an additional $40k was approved for biological consulting after the endangered red-legged frog was found at the construction site.

In the news: Old Creek Road getting safety makeover with $2.5M bridge


2) Lion Creek Bridge

Lion Creek is a tributary to San Antonio Creek, and is ephemeral in the lower reach in some years, with perennial water in the upper reaches of the canyon.

According to CDFG documents, "this project improves fish access for adult and juvenile steelhead to 9.5 miles of upstream habitat in Lion Creek, which is a tributary to San Antonio Creek in Ventura County. The project is collaboration between private, non-profit, local, state, and federal agencies. It includes demolition of an existing low water crossing, which was replaced with an 85 ft long X 13.75 ft wide Railspan steel flatcar bridge. Steelhead are now able to access medium to high quality habitat in the upper reaches of Lion Creek, thereby facilitating migration for spawning adults and over-summering juveniles.

More information and photos are here:

Project managed by South Coast Habitat Restoration

View Ventura River in a larger map

Wednesday, November 3, 2010

Coastal Erosion studies

Two studies on coastal erosion will have implications for Ventura County beaches:

(1) California Beach Erosion Assessment Survey

This week the Coastal Sediment Management Workgroup (CSMW) released the California Beach Erosion Assessment Survey 2010 (CBEAS), which reports on the erosion of California coastal beaches and provides a list of sites, called “Beach Erosion Concern Areas (BECAs),” where beach erosion has been identified as a concern to state, federal, and/or local/regional agencies. The report can be downloaded from the Department of Boating and Waterways website.

A news article highlights the Ventura County sections of the report, including mention of Matilija Dam and Surfers' Point. Brian Brennan is quoted as saying “We can’t keep shoring up the beach and armoring the coast. There is a point in time when you have to fix these things naturally.”

Paul Jenkin, environmental director of the Ventura chapter of the Surfrider Foundation, said people are used to seeing crumbing sidewalks and massive rock walls along the beach — they have forgotten what a natural shoreline looks like.

He said that the report is good if it leads to more natural restoration projects like the one at Surfers Point. But he worries that ultimately the fix for the erosion issue will only be more seawalls and attempts to keep the ocean at bay — and that will just further the problem.

(2) BEACON’S Coastal Regional Sediment Management Plan (CRSMP)

EACON website.

The project comprises onshore and offshore developme
nts and consists of sand management, dredging, sand deposition and grading, and the placement of offshore sand retention structures. The individual projects are identified below. A more detailed description of the project components is provided in the Draft PEIR.
1) Oxnard Shores Sand Management.
2) Regional Sediment Management Stockpile and Processing Center.

3) Sand Retention Pilot Projects at: Arroyo Burro County Beach, Butterfly Beach,
Summerland Beach, Santa Claus Beach, La Conchita Beach, North Rincon Parkway, and South Rincon Parkway.
4) West Hueneme Beach Re-nourishment Longevity Improvement.

5) North and South Rincon Parkway Shoreline Restoration.

6) Sand Capture at Mugu Submarine Canyon

Surfrider has concerns that this plan is primarily a coastal engineering plan, rather than a strategic 'Coastal
Regional Sediment Management Plan.' The basic premise that we need 'wider beaches' is flawed – many of the beaches in the region are naturally narrow, bluff-backed, beaches. “Beach erosion” is a result of poor land use planning, and in areas where coastal development has encroached into the coastal zone, damage to property and infrastructure are a predictable inevitability.

The proposed CRSMP capital projects mainly consist of expensive structural engineering and beach nourishment projects. To date, BEACON has not been able to attract the huge federal appropriations that it would take to implement the large-scale beach replenishment and sand retention projects described. 'Recycling' sand before it goes into Mugu Canyon, while in theory may make sense, is cost prohibitive and likely has environmental consequences to ocean ecosystems that may not be immediately evident.The EIR includes a description of the proposed artificial reef pilot project at Oil Piers, although it is not one of the projects in this plan. Surfrider feels that until this project is implemented and monitored, it is impossible to adequately assess the potential impacts of large-scale deployment of similar structures. Recent experience on both the West Coast (i.e. Pratts Reef) and elsewhere around the world has demonstrated the difficulty associated with placing artificial reefs in the surf zone, and expenses associated with removal if they fail to perform or otherwise become a problem.

Our letter is here: EIR SurfriderComments 11-1-10.pdf