State of the Beach/State Reports/OR/Beach Erosion
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The report "State Coastal Program Effectiveness in Protecting Natural Beaches, Dunes, Bluffs, and Rock Shores" (T. Bernd-Cohen and M. Gordon) Coastal Management 27:187-217, 1999 suggests that the less than 13% of Oregon's shoreline is critically eroding.
OCMP staff estimate that 180 miles of beach (appoximately 50% of the coastline) is eroding. Approximately 120 miles of Oregon's Coast (33% of the shoreline) has no dry sand at high tide.
The U.S. Geological Survey is working with Oregon State University on a study analyzing shoreline changes in the nation’s coastal regions. The groups found that since the late 1800s, most beaches are either stable or adding a little bit of sand. However, 13 of 17 beach “littoral cells,” or beach stretches between rocky headlands and major inlets, have either eroded or built up less sand than in the past. The hardest hit littoral cells include the Neskowin, between Cascade Head and Pacific City, and the Beverly Beach littoral cell between Yaquina Head and Otter Rock. Shoreline change rates at Beverly Beach have averaged more than one meter of erosion a year since the 1960s. Read OSU press release.
Oregon’s coastal erosion is largely driven by major storm events that can produce waves 20 to 50 feet in height. The large waves coupled with high water levels from storm swash allow the waves to reach much higher elevations.
In Tillamook Bay, the construction of the north jetty in 1914 has controlled shoreline erosion and altered the shoreline forever. By 1920, the Bay Ocean Spit located to the south of the jetty experienced rapid erosion which lead to the destruction of Bay Ocean Park in 1940. The Bay Ocean Spit breached in 1952 and now has a dyke across it.
The Pilot Coastal Observatory for the Estuaries and Shores of Oregon and Washington Project (part of Northwest Association of Networked Ocean Observing Systems - NANOOS) gives an overview of shoreline erosion throughout much of the states. Beach profiles from several years are available here. Erosion data could be extracted from this data.
Erosion rates can vary greatly from site to site, so it's difficult to generalize for sections of the coast. Some of the highest erosion rates for bluff-backed shorelines are found along a segment within the Nesika Beach area of Curry County, with bluff toe retreats measured at 1.9 feet per year. Coastal dune areas are most vulnerable to erosion, as they respond very quickly to large storm events. Vegetated dunes have eroded back as much as 50 meters in just one or two winters in some areas. Unlike bluff-backed shorelines, dunes can accrete back during cycles of decreased storm activity, which may erase signs of long-term erosion rates, and mask the potential for catastrophic erosion events.
The Heinz Center's Evaluation of Erosion Hazards states that the average erosion rate in Lincoln, Oregon is less than 1 ft/year.
A report done in 1999 by the Federal Emergency Management Agency states that the average erosion rate in Lincoln, Oregon is less than 19 cm/year.
The 2001 Assessment, reporting the results of several recent reports and publications sponsored by the OOCMP, notes that storms experienced along the Oregon Coast during the El Niño winter of 1997-98 and the La Niña winter of 1998-99 were truly exceptional. Of the two major storms that occurred along the Oregon Coast during the El Niño winter, the highest waves occurred during the November 19-20, 1997, event. Deep-water significant wave heights reached 10 meters during this storm. This approximates the projected 100-year wave based on buoy data spanning the 15 years prior to the occurrence of the El Niño. During the La Niña winter the deep-water significant wave height reached or exceeded 10 meters on four occasions. During the March 2-4, 1999 storm, deep-water significant wave heights reached 14 meters. Recently completed analyses of buoy data that includes the recent El Nino and La Nina events suggests that the projected 100-year wave is now on the order of 14 to16 meters in elevation.
There is a great USGS website titled Coastal Erosion Along the U.S. West Coast During the 1997-98 El Niño: Expectations and Observations.
The 2001 Assessment reported that it has now been recognized that in addition to ENSO (El Niño-Southern Oscillation) events there are other inter-annual, inter-decadal, and even longer variations in storminess affecting flooding and erosion along the Oregon coast. The JOSAO/SMA Climate Impacts Group (1999) report "Impacts of Climate Variability and Change — Pacific Northwest," for example, describes the Pacific Decadal Oscillation. So-called PDO events are characterized by a shift between warm-dry and cool-wet climatic phases over a period of 20-30 years. It appears that the warm-dry phase favors El Niño conditions. Conversely, the cool-wet phase favors La Niña conditions. What is particularly important is the suggestion that a phase change from warm-dry to cool-wet conditions may have occurred in the mid-1990s. Because the cool-wet phase favors La Niña conditions and La Niña conditions are associated with an increase in the frequency and intensity of storms in the Pacific Northwest, the Oregon coast may be expected to experience an increase in flooding and erosion.
The 2001 Assessment also noted the results of recent analyses of spatial and temporal variation in the wave climate of the North Pacific by investigators at Oregon State University, which suggest that the height of storm waves may have progressively increased during the last three decades. Along the Oregon coast this annual average increase in winter significant wave height may be on the order of about 3 cm.
The towns of Neskowin and Rockaway on Oregon's north coast have experience severe coastal erosion beginning in the late 1990s. Today, virtually the entire length of Neskowin (which is about 20 feet above sea level) is protected by riprap. Rockaway, to the north, is in a similar predicament, having lost about 164 yards of beach in recent years.
In a study released in February 2017, U.S. Geological Survey scientists and their colleagues document how the 2015-16 winter featured one of the most powerful El Niño climate events of the last 145 years. Investigating 29 beaches along the U.S. West Coast from Washington to southern California, researchers found that winter beach erosion was 76 percent above normal, by far the highest ever recorded. If severe El Niño events such as this one become more common in the future as studies suggest, this coastal region will become increasingly vulnerable to coastal hazards, independently of projected sea level rise. The authors assessed seasonal changes on 29 beaches along approximately 2000 kilometers (1243 miles) of the U.S. West Coast. Surveying the beaches included making 3-D surface maps and cross-shore profiles using aerial LiDAR (light detection and ranging), GPS topographic surveys, and direct measurements of sand levels, combined with wave and water level data at each beach, collectively spanning 1997-2016. The full report, “Extreme oceanographic forcing and coastal response due to the 2015-16 El Niño,” was published in the journal “Nature Communications.” More.
In January 2010 a news release from Oregon State University stated:
A major increase in maximum ocean wave heights off the Pacific Northwest in recent decades has forced scientists to re-evaluate how high a “100-year event” might be, and the new findings raise special concerns for flooding, coastal erosion and structural damage. The new assessment concludes that the highest waves may be as much as 46 feet, up from estimates of only 33 feet that were made as recently as 1996, and a 40 percent increase. December and January are the months such waves are most likely to occur, although summer waves are also significantly higher.
In a study published online in the journal Coastal Engineering, scientists from Oregon State University and the Oregon Department of Geology and Mineral Industries reported that the cause of these dramatically higher waves is not completely certain, but “likely due to Earth’s changing climate.”
Using more sophisticated techniques that account for the “non-stationarity” in the wave height record, researchers say the 100-year wave height could actually exceed 55 feet, with impacts that would dwarf those expected from sea level rise in coming decades. Increased coastal erosion, flooding, damage to ocean or coastal structures and changing shorelines are all possible, scientists say.
“The rates of erosion and frequency of coastal flooding have increased over the last couple of decades and will almost certainly increase in the future,” said Peter Ruggiero, an assistant professor in the OSU Department of Geosciences. “The Pacific Northwest has one of the strongest wave climates in the world, and the data clearly show that it’s getting even bigger."
The study, "The impact of the 2009-10 El Niño Modoki on U.S. West Coast beaches", published in The American Geophysical Union's "Geophysical Research Letters" on July 9, 2011 was led by the USGS in collaboration with the Oregon Department of Geology and Mineral Industries, University of California-Santa Cruz, Washington Department of Ecology, Oregon State University and Scripps Institution of Oceanography. The authors took advantage of up to 13 years of seasonal beach survey data along 148 miles of coastline and tracked shoreline changes through a range of wave conditions. The following is from a USGS press release.
"The stormy conditions of the 2009-10 El Niño winter eroded the beaches to often unprecedented levels at sites throughout California and vulnerable sites in the Pacific Northwest," said Patrick Barnard, USGS coastal geologist. In the Pacific Northwest, the regional impacts were moderate, but the southerly shift in storm tracks, typical of El Niño winters, resulted in severe local wave impacts to the north-of-harbor mouths and tidal inlets. For example, north of the entrance to Willapa Bay along the Washington coast, 345 ft. of shoreline erosion during the winter of 2009-10 destroyed a road.
Here is a nice summary article regarding Oregon's coastal erosion, with a focus in Neskowin.
Statewide and site-specific erosion data are collected as part of beach and dune erosion hazard studies, and ongoing beach monitoring studies using GPS and LIDAR data. Both of these types of studies are being undertaken by Oregon Department of Geology and Mineral Services (DOGAMI) with funding from OCMP. Data on coastal and beach erosion in Oregon is collected and stored by OCMP in the Department of Land Conservation and Development and DOGAMI. The data are published in Local Comprehensive Plans, DOGAMI publications, and OCMP files. The data are accessible on-line at:
- Oregon Beach and Shoreline Mapping and Analysis Program
- DOGAMI Catalog of Publications
- Oregon Coastal Atlas (maps and general erosion information).
DOGAMI regularly updates the data. Coastal hazard studies for entire counties or littoral cells are updated as requested by Counties and when funding is available. Currently, Lincoln County is being completed. Specific beach monitoring projects are constantly being updated, through on-going field analysis by DOGAMI. A five year strategy is in place to continue monitoring and analyzing beach processes, and use this information to assist regulatory agencies in preparing and adopting enhanced shoreline management regulations. Erosion "hot spots" are identified based on the impact or potential impact to developed areas and are graphically depicted relative to erosion rates at other sites. (Interpretation required) These tend to be areas of dune backed shoreline. Discussions of erosion hotspots may be included in specific DOGAMI reports.
NOAA's Digital Coast site features applications of topographic Light Detection and Ranging (LIDAR) in coastal regions around the country. One of the early applications is the Dune Hazard Assessment Tool. The OOCMP created a decision support tool based on an existing foredune erosion model and traditional ground survey beach elevation data. The NOAA Coastal Services Center modified this tool and added LIDAR data, to combine a science-based decision support tool with cutting-edge remote sensing technology. This union resulted in a product, the Dune Hazard Assessment Tool, which can help coastal managers identify the relative risk to properties from coastal erosion. A more recent application of LIDAR in Oregon is Using Lidar to Plan for Sea Level Rise.
Additional information on beach erosion is available on the DOGAMI website. Scientists with DOGAMI have proposed that the state do a "state of the beach" study of the coast to establish a baseline of conditions and study sand supply and transport systems.
The northernmost portion of the Oregon Coast, the Clatsop Plains, was covered as part of the Southwest Washington Coastal Erosion Study.
The Oregon Parks and Recreation Department (OPRD) had regulatory agency responsibility for erosion response activities and projects initiated by private property owners. OPRD, Oregon Department of Transportation, and the Department of Land Conservation and Development have regulatory agency responsibility for erosion response activities and projects on state lands. The Oregon Coastal Management Program monitors erosion response activities for compliance with beach and shorelands goal compliance.
Funding for erosion response projects comes from the state general fund, DOT funds, and NOAA funds.
An excellent source of information about beach erosion and coastal processes in the Pacific Northwest is the book The Pacific Northwest Coast: Living with the Shores of Oregon and Washington, by Paul D. Komar. This well-written and informative book is targeted towards the general public.
An interesting pattern of increased beach erosion occurred during the winter of 2007-2008. Although winter storms were somewhat fierce, the winter did not compare to the series of storms that struck the coast in 1998-1999. What appears to be happening is that the natural beach replenishment that typically occurs every summer has been substantially muted. As a result, the winter erosion of each of the last few years has been additive. There’s “significant” erosion at Cape Lookout State Park, such that one of the sewage drain fields built in the foredune was completely destroyed and another is approaching the same fate. And at least a dozen homes on the north coast are threatened by erosion. On the south coast, tectonic forces are actually pushing the North American plate upward, so rising sea levels aren’t so much an issue there. The erosion has also uncovered long-buried ships and other artifacts, including:
- The wooden-hulled George L. Olson at Coos Bay's North Spit
- Cannons at - you guessed it - Cannon Beach
- The ship Bella, south of the Siuslaw River in Florence
- Possibly another shipwreck near Bandon's Cut Creek
In 2008 the Oregon Department of State Lands initiated a seafloor mapping program within Oregon’s Territorial Sea. After more than two years of intense field work and digital cartography, researchers unveiled new maps of the seafloor off Oregon that cover more than half of the state’s territorial waters. The mapping project was a collaborative effort of the National Oceanic and Atmospheric Administration, OSU’s College of Earth, Ocean, and Atmospheric Sciences, David Evans and Associations, and Fugro. It was funded by NOAA and the Oregon Department of State Lands. The researchers have created numerous different habitat maps covering 55 percent of Oregon's Territorial Sea, which show distinction between fine, medium and coarse sands; display rocky outcrops; and have topographic contour lines. More info on this project.
General Erosion Data References
The Heinz Center's Evaluation of Erosion Hazards, conducted for the Federal Emergency Management Agency (FEMA), studied the causes of coastal erosion hazards and proposed a variety of national and regional responses. The study, published in April 2000, concentrates on the economic impacts of erosion response policies as well as the cost of erosion itself to homeowners, businesses, and governmental entities.
A NOAA website that has graphs of sea level data for many coastal locations around the country over the last 40 to 50 years and projections into the future is Sea Levels Online.
NOAA Shoreline Website is a comprehensive guide to national shoreline data and terms and is the first site to allow vector shoreline data from NOAA and other federal agencies to be conveniently accessed and compared in one place. Supporting context is also included via frequently asked questions, common uses of shoreline data, shoreline terms, and references. Many NOAA branches and offices have a stake in developing shoreline data, but this is the first-ever NOAA Website to provide access to all NOAA shorelines, plus data from other federal agencies. The site is a culmination of efforts of NOAA and several offices within NOS (including NOAA’s Coastal Services Center, National Geodetic Survey, Office of Coast Survey, Special Projects Office, and Office of Ocean and Coastal Resource Management) and other federal agencies to provide coastal resource managers with accurate and useful shoreline data.
A related site launched in 2008 is NOAA Coastal Services Center's Digital Coast, which can be used to address timely coastal issues, including land use, coastal conservation, hazards, marine spatial planning, and climate change. One of the goals behind the creation of the Digital Coast was to unify groups that might not otherwise work together. This partnership network is building not only a website, but also a strong collaboration of coastal professionals intent on addressing coastal resource management needs. Website content is provided by numerous organizations, but all must meet the site’s quality and applicability standards. More recently, NOAA Coastal Services Center has developed a Sea Level Rise and Coastal Flooding Impacts Viewer as part of its Digital Coast website. Being able to visualize potential impacts from sea level rise is a powerful teaching and planning tool, and the Sea Level Rise Viewer brings this capability to coastal communities. A slider bar is used to show how various levels of sea level rise will impact coastal communities. Completed areas include Mississippi, Alabama, Texas, Florida, and Georgia, with additional coastal counties to be added in the near future. Visuals and the accompanying data and information cover sea level rise inundation, uncertainty, flood frequency, marsh impacts, and socioeconomics.
Erosion Contact Info
Coastal Geomorphologist & Coastal Section Leader
Oregon Department of Geology and Mineral Industries
P.O. Box 1033
Newport, OR 97365-3800
Phone: (541) 574-6658
Fax: (541) 265-2541
- Paul Klarin, OOCMP. Surfrider State of the Beach Survey response. November 2003.
- Paul Klarin, OOCMP. Surfrider State of the Beach Survey response. November 26, 2002.
- Beachhead Defense: Oregon Takes a New look at How It Governs Its Public Sands. The Register-Guard. November 17, 2002.
- Paul Klarin, OOCMP. Surfrider State of the Beach Survey response. November 26, 2002.
|State of the Beach Report: Oregon