Tuesday, August 26, 2014

California Adaptation Forum

August 19, 2014:  Surfers' Point at the California Adaptation Forum in Sacramento.
This conference attracted over 800 participants from around the state including "elected officials, public- and private-sector leaders, nonprofits and researchers addressing public health, energy, water, emergency management, agriculture, biodiversity conservation and coastal management issues associated with climate change and adaptation."

Surfers' Point serves as a case study for "Managed Shoreline Retreat, a viable response to coastal erosion and sea level rise, and a strategy for climate adaptation.

This presentation was given in a session titled "From Watershed to Coast," which profiled “No regrets” adaptation projects which increase climate change resilience and enhance existing conditions. What makes these projects truly adaptive and not just a repackaging of existing programs? This session looks at four no-regrets projects to address this question: (1) Water L.A. uses “urban acupuncture” to capture rainfall and infiltrate it into the aquifer. The project promotes retrofitting residential properties through education and permit streamlining. (2) Surfer‘s Point Managed Retreat (Ventura) relocated roads and parking lots threatened with wave erosion. Moving from a highly engineered solution to managed retreat was transformative. (3) The Marin Carbon Project utilizes a simple rangeland management protocol to increase carbon sequestration and drought resilience. The protocol, now under review for inclusion in carbon markets, consists of a single addition of composted organic matter to rangeland, yielding benefits over decades. (4) The Coastal Streamflow Stewardship Project (Statewide) utilizes changes in water rights to promote a shift from year-round stream withdrawals to winter withdrawal and storage, reducing impacts to salmonids and increasing drought resilience.

It was clear in this forum that local actions are where positive change is happening.  Ironies abound with government and industry responses.  Case in point: a state sponsored energy conservation PR campaign is using the grizzly bear as mascot...

Monday, August 25, 2014

C-Street, Ventura - more cobble berms

October 18, 2013: C-Street panorama before cobble berm
May 16, 2014: C-Street panorama with cobble berm

In February 2014, the City of Ventura constructed a "cobble berm" to protect the public amenities along the promenade and bike path in Ventura.  The panorama above illustrates the exposed riprap and concrete debris that, while providing some level of erosion protection, also presents a hazard to beachgoers and surfers.  According to the City staff report:

C-St before cobble nourishment - debris marked for removal
Feb 19, 2014: C-St cobble nourishment in progress

Over the last several years, severe erosion has become visible along the state beach at Surfers' Point and the Promenade.  The loss of sand and beach is threatening the palm trees, the bike path and other City public improvements along an 800-foot stretch of beach.  To restore and protect this shoreline and to prevent further erosion from occurring, it is recommended that the successful shore protection that was installed with the Surfers' Point Managed Retreat Project (2010) be extended easterly.  The complete nourishment of this stretch of beach requires the placement of an estimated 4,800 cubic years of small stone/cobble and 1,000 cubic yards of sand topping.  In addition, existing concrete and other debris that is encountered by this work would be removed.  The improvements would effectively widen the beach along the bike path in this area by 10-feet and would protect the bike path and other infrastructure from costly damage. 

March 26, 2014: C-St cobble berm
The placement of cobble and sand is not a permanent fix to control erosion.  It is anticipated that this project will arrest erosion along this stretch of beach for 
approximately 10 years and perhaps longer.  Periodic cobble beach nourishment is an economically viable option that is necessary for ongoing stability of the beach as well as 
protection of existing public improvements.

At the regular City Council meeting on September 16, 2013, Council authorized the use of $450,000 of line of Credit Repayment Funds to be use to fund this beach nourishment work.  Approximately 1/2 to 1/3 of this 800 foot shoreline will be addressed with available funding …  The apparent low bidder… submitted a bid in the amount of $319,970…

These aerial photos help illustrate the evolution of the shoreline following the construction of the cobble berm.

October 18, 2013: C-Street before cobble berm

February 25, 2014: C-Street shortly after construction of cobble berm

The image above taken shortly following the construction clearly shows the downcoast extent of the constructed cobble berm and the concrete debris directly downcoast.

May 16, 2014: C-Street 3 months after construction of cobble berm

Although the site did not experience many large winter swells in 2014, the beach quickly adjusted to the new cobble berm.  The image above clearly illustrates that by May much of the cobble had migrated downcoast, filling in on top of the concrete debris.

May 16, 2014: C-Street view looking toward the cove further downcoast of project site 

 The image above shows how the cobble has migrated around the Figueroa St drain and into the cove.  The cobble is evident in the photo below looking back upcoast from the drain on March 26, 2014 - note the relatively homogenous rocks filling in between the larger riprap from the constructed berm in the far background of the image.

March 26, 2014: View from Figueroa storm drain looking upcoast toward cobble berm. Cobbles are migrating through the riprap toward the viewer.
Aug 29, 2014: View from Figueroa storm drain looking upcoast toward C-St cobble berm. Note riprap now completely buried by cobble migrating downcoast 

We shall continue to monitor Ventura's cobble shoreline management, as there is a lot to learn. This cobble berm placed within the active littoral zone is a contrast to the Managed Shoreline Retreat project just up the point.  Questions remain as to how long this cobble remains in place, how fast it moves along the shoreline, and how rising tides and future large swells will affect this stretch of coast.  Stay tuned…