Part 2 Maureen Spencer Santa Barbara Flood Control
Part 2 Maureen Spencer Santa Barbara Flood Control
Part 2 Maureen Spencer Santa Barbara Flood Control
Dan Hoover USGS, Glen Shepard Ventura County Wathershed Protection District, Matt Roberts City of Carpinteria
The Coast and River Report
There is a constant flow of sand from the land into the ocean. Watershed run-off and bluff and hillside erosion bring sand to the beach. Sand grains travel southward down the coast, while finer particles of sediment are carried and deposited further out to sea.
Along the way, sand is washed ashore, temporarily resting on beaches, until it is re-suspended in the ocean by wave action or wind. The one-way journey down the coast ends when sand is blown inland forming sand dunes, or more commonly, when it flows into a submarine canyon. This deep underwater feature is essentially the dead end of a littoral cell, where sand is deposited for the long-term and, for practical purposes, lost.
A littoral cell is a distinct area of the coastline where sand enters the ocean, flows down the coast, and then is removed from the system. Permanent loss of sand occurs at the end of the littoral cell when it flows into a submarine canyon or, less frequently, when it accumulates on shore as part of a sand dune. The amount of sand available to…
Credit: Dave Hubbard and UCSB Sea Grant Team
Beach Erosion Authority for Clean Oceans and Nourishment
Sequence of Events
What Does Debris Flow Look Like?
Montecito Debris Flows Stats
Impact to Beaches
Fernald Point – April 2017
Fernald Point – January 2018
Fernald Point – February 2018
Loon Point – April 2017
Loon Point – January 2018
Loon Point – March 2018
Carpinteria Beach – April 2017
Carpinteria Beach – January 2018
Carpinteria Beach – March 2018
Goleta Beach – June 2017
Goleta Beach – January 2018
Goleta Beach – February 2018
Goleta Beach – March 2018
Predicted Shoreline Response
Unique Opportunity for Beach Nourishment
“Where is the mud and debris from Montecito going” by Oscar Flores
Source: KEYT online
Carpinteria Beach and other local beaches are the preferred locations for receiving excess sediment from the recent extreme flood event. Normally this sediment would have made its way to the coast in a controlled manner over the course of many years. But in the present case, heavy rainfall coupled with burned hillsides caused the sudden release of a large amount of sediment and debris leading to widespread flooding and damage.
When sediment arrives at the beach either by stream or by truck, natural wave action sends the finer material (clays and silts) offshore leaving the coarser material (sand, gravel and cobbles) nearshore. Further wave action mixes the gravel and cobble fractions downward into the beach face where they eventually form a hidden protective layer. The remaining sand fraction stays in the nearshore helping to nourish the beach profile.
Ash Avenue is an excellent receiver site for the excess storm sediments. Located at the end of a long rock revetment, it is the first to lose its sand during storm wave attack and the last to recover its sand during milder conditions. Placing excess storm sediment on the beach widens it providing added protection against storm wave attack and creates space in local debris to combat future flooding events.
Jim Bailard, Ph.D.
BEACON Technical Advisor
USGS Coastal Erosion Report May 19, 2017 by Dan Hoover, Lead Researcher.
Report given during BEACON Board of Directors Meeting, Carpinteria, CA.
Plans to tear down the long-defunct Matilija Dam jumped a hurdle earlier this year.
But officials said Thursday that bringing down the close to 200-foot concrete dam won’t be easy or quick.
“It’s like running a hurdle. You just have to keep jumping over these obstacles that keep presenting themselves,” said Sam Schuchat, executive officer of the California Coastal Conservancy.
“I think we’ll get there in the end. The question is how long it’s going to take.”
Local, state and federal officials toured the dam Thursday as Peter Sheydayi, interim director of the Ventura County Watershed Protection District, talked about recent steps forward and the work that still needs to happen.
For years, there has been widespread support to tear down the dam above Ojai. The problem is what to do with the about 8 million cubic yards of sediment that has built up behind it over the past six or so decades.
When the dam goes away, fine sediment could cause problems for those downstream, including the Casitas Municipal Water District.
The project to tear down the dam started in 1999, Sheydayi told the small crowd that included John Laird, secretary of the California Natural Resources Agency, county Supervisor Steve Bennett, U.S. Rep. Julia Brownley, D-Westlake Village, and Assemblyman Das Williams, D-Carpinteria.
A project OK’d by Congress in 2007 stalled a few years ago after costs climbed too high. But representatives from government agencies, nonprofit groups, property owners and others kept meeting to find a way to move forward.
In March, the group agreed on a new plan.
But it comes with a bit of a wrinkle. It’s different from the one Congress signed off on, and that means starting from scratch in a lot of ways.
The plan calls for boring two tunnels at the base of the dam and blasting open those holes during a big storm, allowing a lot of the fine sediment to wash through.
Once that happens — and if enough sediment washes away — the dam could be removed the next year.
As officials looked out at the dam, a giant pair of scissors and a dotted line still clearly showed on its face. Someone painted it there back in 2011, with the line running from the top of the dam down to the waterline.
When Schuchat first got involved about 15 years ago, those seeking the dam’s removal were still trying to get a project approved by the Army Corps of Engineers, he said.
In theory, they could do try to do it again. But going through the process likely would take up to 10 years of study with no guarantee that Congress would authorize the work in the end.
Then they would still need to get funding.
“From 2007 until very recently, we were still trying to get Congress to fund this project. We just sort of met with obstacle after obstacle,” Schuchat said. The Coastal Conservancy has funded much of the state’s share up to now in the process.
Instead, local officials want to look at whether they could fund the project without the Corps of Engineers. For now, that’s just something to explore.
The project likely will cost $60 to $80 million, but that’s only an estimate.
Along with getting the funding, officials will need to do some environmental review and get various regulatory agencies to sign off on the plan.
“The fact that we have to raise all the money, do most of the work, and then wait, is going to make this tricky,” Schuchat said. “It’s hard to — once you raised public money — to hold on to it over an undetermined period of time.”
And, of course, the weather is unpredictable.
To make it work, Lake Casitas needs to be 80 percent full, and “then we need a really big storm to hit upstream of the dam so we get a nice big flow,” he said.
After the tour, officials returned to the Watershed Protection District’s Saticoy office to talk about funding possibilities.
In the meantime, the next step is to take the concept that the groups agreed to and turn it into engineering drawings. Officials have applied for a grant from the California Department of Fish and Wildlife to pay for that next phase of work.
Permission to report from Ventura County Star
Click here for original story
Article Writen by Nicholas Korady
August 3, 2016
As global temperatures rise, the polar ice caps have begun to melt, bringing up sea levels around the world. Simultaneously, a veritable witch’s brew of meteoric, atmospheric, and oceanic forces are creating more intense and frequent storms. If you live in just about any coastal region, your home is likely at risk from crashing waves and rushing floods.
“Households will be particularly affected by climate change, which will include uncomfortable summer heat waves and more frequent and severe floods and periods of drought,” write ARUP in a report entitled “Your Home in a Changing Climate,” which focused on threats in the United Kingdom. But a report isn’t necessary to convey this point when the images of the devastation Hurricane Katrina unleashed on New Orleans (and the rest of Louisiana, as well as Mississippi, Florida, Cuba, and the Bahamas) remain burned in our retinas. Or Hurricane Sandy. Or recent floods in England or the Netherlands, in Pakistan or India or China or Myanmar.
According to a recent paper in National Geographic, “As many as 13.1 million people in the United States will be in the path of flooding by 2100.” That’s three times the current population currently at risk. As more and more people flock to cities, the fallout from major sea-level related disasters will increase. So what can be done about it? Well, that depends—on where you live, your finances, and how quickly sea levels rise.
Take the task of protecting a home in New Orleans, for example. As Hurricane Katrina made abundantly clear, the city’s not-so-old defenses weren’t as strong as many assumed—particularly in economically-depressed areas. Byron Moulton of the New Orleans-based practice Bild Design explained that, if you look at an 1880 map of the city, its borders pretty much correlate with the borders of the regions of the city that were spared the brutality of the storm. Before the levee system was in place, all buildings rested on high ground. “In short time, people forgot about the risk,” Moulton explains. Now, large populations reside on ground that’s below sea level. And, while post-Katrina defenses have been added to the levee system, such as water pumping systems and new legal regulations, “we’re still at a little risk,” says Moulton. So how do you protect New Orleans homes against inevitable flooding?
“There’s lots of ways to do it, frankly,” Moulton told me. If you’re trying to preserve an existing structure, which are common in the historic city, then your best move is to underpin the building—essentially, jacking it up in the air, putting in steel beams and a new foundation. With new construction, pyles are the predominant strategy, but since a house on stilts can look a bit funny, different techniques are taken. New Orleans has soft clay soil, so pylons are driven down to where the ground is harder, a concrete cap is poured, and then a better-looking foundation laid on top. There are other measures possible, but this is one of the most popular. “The city requires it,” Moulton explained of a minimum floor height for new residential construction. “And FEMA funding is available for homeowners to lift their houses out of the floodplain.”
But if you’ve ever been to New Orleans, you’ve probably noticed its street life. Towering houses aren’t exactly conducive to front-porch culture. “You can’t turn your back on the neighborhood,” Moulton states. So Bild has employed other strategies, such as lifting one unit of a two-unit home while keeping the other on the ground, heavily anchored. If flooding occurs, the residents can take refuge in the elevated unit, while the other unit takes on water—intentionally.
This represents a combination of two of seven strategies outlined by Laura Tam of the San Francisco Bay Area-based group SPUR in an article entitled “Strategies for Managing Sea Level Rise”: floodable development and elevated development. Unfortunately, such strategies aren’t necessarily adaptable to San Francisco and its environs. “Some types of housing are never going to be able to withstand flooding,” Tam told me over the phone. And elevated development isn’t appropriate in earthquake-riddled California.
“A lot depends on a situational assessment,” Tam explains. Each particular area is different and what may work in one place may not work in another, even in the same city. “What the right strategy is for any one place depends on so much,” she elaborates. “What land use is like; what development looks like, now and in the future; what land values look like; whether uses are residential or commercial in nature; whether there’s a lot of elevation and topography or not; whether or not the shoreline can effectively host a large wall, which isn’t a viable thing to do in some places.”
And, in general, any conversation about mitigating the risks of sea-level rise for a private home necessarily involve planning and design at the regional level. “I think in a lot of places and, in particular, places that are settled densely, you have to look at more of a neighborhood or a district scale strategy. You can’t take a building-by-building assessment and flood-proofing approach.”
One such regional plan is “Living with the Bay,” developed by Brooklyn-based Interboro Partners for their winning Rebuild By Design submission. “The damage from Sandy was caused primarily by storm surge. But unfortunately storm surge is not Long Island’s only water-related threat,” they write. “Long Island faces serious threats from sea level rise, stormwater, and wastewater. The latter two threats are a major source of pollution: unfiltered stormwater runoff entering the bay by way of the region’s rivers and creeks threatens the bay’s ecology.”
Their comprehensive resiliency plan for Long Island, where 35,725 residents were displaced by Hurricane Sandy, takes a multi-pronged approach towards these multi-faceted, and co-constitutive, risks. The plan includes five strategies: “a protective infrastructure that doubles as a landscape amenity” for the very vulnerable barrier islands; new marshlands that help prevent erosion and can absorb water surges; “slow streams” to mitigate run-off; a green corridor built in part to encourage relocation further upland; and recovering and strengthening sediment displaced by Sandy.
But even such a comprehensive plan runs into other issues, such as legal and policy impediments. “Coordinated, regional decision-making is essential to the resiliency-building process. This is easy enough to say, but it is of course harder to achieve,” Interboro added over email.
“Because New York is a ‘home rule’ state, municipalities have the power to effectively chart their own course, which creates a barrier to the kind of regional decision-making that is required to adequately address regional issues like housing, transportation, or sustainability.
“Home rule can lead to redundancy (the State of New Jersey has 585 school districts), but it can also distract us from the simple truth that our fates are shared—that decisions made by and for one municipality have consequences for other municipalities in the same region. Disasters don’t stop at municipal lines; why should our responses?”
To help facilitate regional cooperation, Interboro has developed a strategy they call “grassroots regionalism”. In part, this involves figuring out ways that regional responses can also improve daily life on a local level, such as new recreation areas and more greenery. Interboro actively solicits community input in their design processes. Their “grassroots regionalism” also involves appropriating existing forms of regionalism, which they note are already happening all around us, such as sending-receiving relationships among schools or watershed management areas.
While disasters produced by the (larger) disaster of global warming and sea level rise threaten the solidity we associate with being at home, mitigating and preparing for them doesn’t have to diminish the quality of everyday life. In fact, disaster preparedness can improve neighborhoods and help foster a sense of community.
“Architecture that protects us from the occasional disaster (for example, a terrorist attack or a flood) too often requires us to sacrifice things we enjoy about everyday, non-disaster moments,” states Interboro. “It’s important that each and every investment in flood protection in one way or another improves everyday life. If we’re going to build protective structures, there is simply no reason not to add value to them so that they do more than merely protect.”
Global sea level rose during the 20th century, and projections suggest it will rise further and at a higher rate during the 21st century.
The West Antarctic Ice Sheet, which holds enough water to raise global seas by several feet, is thinning. Scientists have been warning of its collapse, but with few firm predictions or timelines. A study published May 16, 2014 in Science details how University of Washington researchers used topography maps and computer modeling to show the collapse of the West Antarctic Ice Sheet may have already begun. Eric Rignot, a glaciologist at the University of California, Irvine, and NASA’s Jet Propulsion Laboratory in Pasadena, California has said, “A large sector of the West Antarctic Ice Sheet has passed the point of no return” in terms of its retreat. Researchers say that the fast-moving Thwaites Glacier will likely disappear in a matter of centuries, raising sea level by nearly 2 feet. That glacier also acts as a linchpin on the rest of the ice sheet, which contains enough ice to cause another 10 to 13 feet of global sea level rise.
The public has heard mostly about climate change driven sea level rise impacts on economies and infrastructure, and to a lesser extent on habitat, but not much on recreational resources. Surfing is ideally suited as a key recreational resource to consider as one potentially significantly impacted by sea level rise. Of course, many surfers actually live in the coastal zonenand have to worry about issues more serious than the surf quality, like the potential inundation of their home, roadways, schools and businesses. Broader climate change impacts stand to affect surfing in a myriad of ways. To pick one example, changes in rainfall patterns will affect transport of pollutants to the line-up in urban areas and also affect the delivery of sediment to the coast which will subsequently affect the health of beaches and sandbars. Of these broader impacts, surfers seem to have been mostly focused on how climate change will impact wave climates, or the average condition of waves at a particular place, over a period of years. Climate change will result in changes in average wave heights, periods, and directions. But what will the beaches at which those waves will be arriving look like? Sea level rise alone stands to be the most significant impact to surfers, combined with the other broader climate change impacts affecting surfers.
Surfers are going to be on the front line of climate change driven sea level rise impacts, both via recreational impacts realized directly and wider impacts experienced as users of coastal infrastructure. In many cases those that live near the beach, impacts experienced as coastal dwellers. Surfers’ access and entry pathways to the surf will be affected: the beach, parking lots, access roads, staircases, etc., not to mention our homes, schools and places of business. Regional examples help illustrate. The Pacific Institute report The Impacts of Sea-Level Rise on the California Coast concludes that sea-level rise will inevitably “change the character of the California coast.” The Pacific Institute has a web based tool that shows populations and critical infrastructure at risk under various sea level rise scenarios. The available maps show coastal flood and erosion hazard zones under sea level rise scenarios.
Under the 2100 sea level rise scenario, my home near the beach in Oxnard, California will be threatened by inundation, as well as a lot of important infrastructure around my house. Of course, this won’t happen instantaneously, but rather on a continuing and increasing basis, with irregular spikes in impacts and inundation along the timeline. Correspondingly, the impacts are likely to be felt much sooner than the scenario offered by this image eight decades into the future.
Needless to say, adding one to three feet of water over our coastal ocean and surf spots in the next couple of decades to three quarters of a century is going to affect the surf quality. To illustrate in simplistic terms, take the example of a reef where the surf is highly tide dependent. A spot that currently breaks properly only on a high tide will in the future break on what is now the low tide once sea level rise is superimposed on its current condition. More critically, a surf spot that currently breaks only on a low tide will cease to break. Of course, beach breaks will be affected in potentially numerous ways, too. Coastal erosion will likely accelerate surf zones will become narrower and, as in the reef example, surf-tide relationships will change. All of our surf spots will be affected by the phenomena of coastal squeeze.
Coastal squeeze occurs as follows. As sea levels rise, coastal habitats like salt marshes, if in an entirely natural situation, would respond by migrating landward or “rolling back” to adjust their position to the best ecological fit for the new sea level. Rising land, development, or fixed man-made structures such as seawalls prevent or severely limit this landward movement, restricting the ability for beaches to adapt to rising sea levels. The coastal habitats, if present, are therefore squeezed between rising sea levels and fixed defense lines or higher land, therefore there is a risk the beach and adjacent coastal habitat may be lost altogether.
A significantly worrisome specter will occur along our urban beaches where people surf most: an unknown but foreseeable human response will unfold as sea level rises. Along these urban coastlines where significant infrastructure exists, communities will take action in response to sea level rise as valuable infrastructure is threatened; seawalls, probably the most likely short term human response and the one that stands to cause the most damage to coastal access, beaches, and surf quality, will proliferate. The human response to sea level rise also has large uncertainty associated with it in relation to timing, location, extent, and feedback loops. Sea level rise therefore presents both a direct and an indirect threat to our beaches, our surf, and our ability to access the surf.
What can you do as a surfer? Firstly, educate yourself on climate change and sea level rise and take actions that address the big problem: climate change. Reduce your environmental footprint through conservation, recycling and changing consumption patterns. Focus on your ability and approach to changing laws; for example, campaign for low carbon public transport and organize to elect officials who protect the environment. Secondly, be aware of the potential local impacts. In your coastal communities, educate decision makers and citizens and be a voice for decisions that have a long term view, account for sea level rise, preserve beaches and allow for shoreward migration of coastal habitat, decisions such as managed retreat of threatened infrastructure rather than placing seawalls to protect poorly located infrastructure.
“In the U.S., you have the best data set on what’s happening in the world, and yet it’s not used in public policy,” observed Robert Nicholls, professor of coastal engineering, University of Southampton, England. It’s a paradigm we surely need to reverse.
Reproduced with permission from Shawn Kelly.
Link to original article on The Inertia