home

archives

April 2016 home page

support us

Tunnel Vision
Jeff Barnouw | Amphitheatre Drive

The ongoing necessity for spinal surgery that adds more vertebrae to the cliffs supporting our bluff rail corridor was detailed at the February 25th meeting of the Sea-Level Rise Stakeholder-Technical Advisory Committee (STAC). To avoid further morbidity SANDAG plans tunneling to its prognosis.

Two guest speakers opened broad prospects for anticipating future developments, natural and technological. Bob Vitalio, the committee’s environmental hydrology consultant spoke about the US Geological Survey use of the CoSMoS 3 program, a physics-based computer model to predict sea level rise (SLR) in storm effects. The data it would provide the City of Del Mar would not take account of man-made structure such as sea-walls, so the projections would have to be adapted to local conditions. As important for the City, according to the very helpful Joseph Smith, Del Mar Senior Planner, is data on the impact of storm conditions on the San Dieguito River and Lagoon.

Bruce Smith of the San Diego Association of Governments (SANDAG) reported on an ongoing study for the North County Transit District (NCTD), owner of the right-of-way on the bluffs, which seeks to identify particular vulnerabilities and direct efforts at stabilizing the cliffs. Fifteen years ago it was projected that the single-track rails on the bluffs would last until 2020. That projection has now been extended to 2050.

Several Committee members and the City liaisons, Don Mosier and Dwight Worden, expressed skepticism about this time frame. Of course, the projection presupposes and is meant to guide the efforts to stabilize the bluffs. This means continuing the current practice of drilling vertical shafts from the top of the bluffs, mostly but not entirely west of the tracks, to create tie-back piles of steel-reinforced concrete, caissons four or five feet apart along the bluffs. You have seen the “architecturally enhanced concrete pile caps” while walking the cliffs. beyond stabilizing from within, these piles might provide the foundation for eventual sea-walls as they are exposed by erosion and receding of the bluffs. We could end up with prosthetic cliffs.

Committee discussion followed a natural transition to topics not strictly within their scope. Unlikely projections concerning the single-track connection through the great bottleneck in the LOSSAN Corridor (LA–SD) brought up the topic of the tunnel which has been underground for too long. The projected tunnel under Camino Del Mar is entailed by currently active plans to double-track up to the split in Jimmy Durante Blvd. For the main tunnel alignment and one possible alternative see the Coastal Rail LosSan website:

.

 

 

© 2007-2015 Del Mar Community Alliance, Inc.  All rights reserved.

 
 

 

ackli