Wednesday, March 16, 2016

El Niño Accelerates Coastal Erosion!

Rip-rap Permeates Pacifica Bluffs
El Niño may have not lived up to some of the early hype but the accompanying high ocean swells have reigned havoc along the California Coast!

Pacifica is totally bordered by the ocean along it's entire western side. Most of the land hugging the coast is crumbling sandstone cliffs in a constant state of retreat.

A group of large apartments located on Esplanade Street in Pacifica has made national news this year and in the past due to erosion threatening the entire buildings. The apartment complex was constructed sometime before 1972 and the land in front of the buildings has been retreating steadily over the years. In 2010 2 Esplanade buildings were red-tagged and the tenants evacuated. Recently 3/16/16 a 3rd building was yellow-tagged and the tenants ordered out. At the same time the two buildings condemned in 2010 were demolished by the city of Pacifica. It's likely the 3rd and last apartment in this complex will be demolished shortly and this saga will end.

Monster Wave Beach Boulevard
Pacifica California

Esplanade Apartments 1972
The most visual and exciting place to see high surf in action is right down at the Pacifica Pier located on Beach Boulevard in Pacifica California!  The pier has been famous for years as many people flock to it during high surf conditions and it often makes the evening news with spectacular waves. This year has been one of the more spectacular for wave action and destruction. Beach Boulevard and the adjacent houses have been pounded and damaged this year and the future of Pacifica Pier is in question. North of the pier near the Esplanade Apartments are several homes also under attack and near total destruction. A little further south is the Rockaway Beach area, another pocket type beach with spectacular surf and potential for major damage and erosion.

The End of 310 Esplanade

Surfers Beach

Emergency Repair Surfers Beach
Figure 4. Surfers Beach at High Tide
Emergency Repair, Miramar 
High Surf Pounds Miramar
The Surfers Beach area may be the most interesting site for the future of highway 1 as this location is the most critical threat to the local highway infrastructure. From Pacifica to Ano Neuvo the ocean comes closest and most threateningly to the stretch of asphalt in the Surfers Beach area.  Currently emergency repairs are under way at this location due to erosion both from the wave action as well as the breakwater effects at Pillar Point Harbor.  In the past I've seen drift wood deposited onto the roadway at surfers Beach during storms. If all the elements for the perfect storm line up, high tide, high surf advisory, low barometric pressure,  high winds this could be an interesting scenario for sure. The vulnerability of this section reminds me of the situation after the March 11, 2011 Japan tsunami when a 3 foot wave from that tsunami made landfall of the US West Coast. The waves struck at fairly low tides and was only a curiosity to locals in this area, although over 100 boats were damaged in Santa Cruz as the result of this baby tsunami wave.  Looking at figure 4 and the 6.4  tide at that time makes me wonder what an additional 3 foot tsunami wave making the apparent tide over 9 feet would look like? We may not have to wait long to find out?
Mirada Road's Slow Trip to
Davy Jones' Locker

A short distance south of Surfers Beach is the community of Miramar with Mirada Road separating the community from the residents and businesses. Many years ago Mirada Road ran about 1 mile further north all the way to Surfers Beach, that portion of the road is totally gone and it may take a monumental effort to keep the remaining road from the joining it's northern section in Davy Jones' Locker! Most days involving a little high surf and higher tides one will witness the ocean splashing and clawing at Mirada Road. Recently the wave action started to erode the south end of Mirada near the pedestrian bridge threatening some businesses and residents and forcing the closure of the pedestrian bridge.

Gazos Creek Beach

I'm on a survey team sponsored by FMSA Farallones Marine Sanctuary Association funded by NOAA! I've been involved in this survey on a monthly basis for about 6 years. Beaches along the California coast are in a constant state of sand erosion and deposition depending on season and weather conditions. It's not unusual to see 10 feet of sand raked off the beach and redeposited later at another section.  The December storms have dramatically changed the landscape of Gazos to an extent I've never witnessed before. The total beach is about 2 miles long and during most surveys access is pretty easy and the entire beach can be walked on medium to hard sand. On the December 2016 survey after heavy rains and surf this beach had dramatically changed. We could only access about 20% of the entire beach, the north end was completely blocked off with waves running all the way to the bluffs.
Gazos Creek Normal Appearance 
Same Area as Above after December 2016 Storms

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