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The untold story of the Elwha nearshore, by A. Shaffer, Coastal Watershed Institute 13 March 2014

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The Elwha nearshore is one of the unique features of the Pacific Northwest The Strait of Juan de Fuca is 294 km long, 20-28 km wide, and up to 250 m deep. Over 80% of the water from Puget Sound and Strait of Georgia flows through the Strait (Mackas and Harrison 1997) So what is nearshore? ‘Nearshore’ is defined as  extending from the area of tidal influence in lower rivers, and  includes the riparian zone (along both river and marine shorelines), and reaches offshore to a depth of  30 meters

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mean low low water (MLLW).    Sediment is what makes our nearshore, and ‘drift cells’ define the sediment movement that creates our nearshore. Drift cells  have three main zones: Sediment source (river/bluff or both);  Transport zone, where wave energy moves sediment along shore, and the Deposition zone (spit) that is the terminus of a drift cell. Slide3

The Elwha nearshore in a nutshell is around 12 miles long and includes five main sections: 1. Lower river (north to south) 0.3miles 2. Estuary ( total area): 90  acres 3. Embayed shoreline (Freshwater Bay):4 miles 4. Feeder bluffs 4 miles 5. Ediz Hook (spit) 3 miles

 

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All provide critical habitat for the fish that are drivers for the dam removal project including Chinook, coho, chum, steelhead, bull trout, cutthroat, herring and eulachon (Shaffer et al 2008; Ward et al 2008). They simply can’t live without a functioning nearshore. Slide5

Two critically important species of forage fish, surf smelt, and sand lance depend on the nearshore with a fascinating life history. Most of their lives they are pelagic schooling fish but lay their eggs on high intertidal beaches. Each have very specific grain size requirements: surf smelt spawn on gravel sand mix; sand lance (in winter) on sand mix

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(Penttila 2007).  Sediment is a defining feature of Elwha nearshore-historically-prior to dam installation-260,000 m3/year total and over 85% of the sediment of the Elwha littoral system

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was recruited from bluffs. This sediment formed, and maintained, Ediz Hook, which in turn forms Port Angeles Harbor. (USCoE 1971)  Around dam installation, an industrial pipe line unwisely installed along approximately 2 miles of  Elwha feeder bluffs- and then armored. This made the shoreline hard and a hydrodynamic washing machine. It kicked off a series of

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horrible erosion-and more armoring events.  So sediment delivery to Elwha nearshore after dam constructions was severely limited- to less than 10% of historic rates (Parks et al. in prep). Synopsis? Primarily shoreline armoring-added with dams-has resulted in significant and persistent sediment starvation and disruption of hydrodynamics of the Elwha

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nearshore.  As a result, much of the Elwha nearshore is a hostile lunar landscape because of the sediment starved beach topography and wave energy-a far cry from what it should look

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like (Dungeness Bluffs)  What does this mean for the nearshore ecosystem? Nothing says it better than forage fish spawning distribution. The Elwha drift supports surf smelt spawning along less than 11% of it’s beaches compared to 47% along the comparative-and intact -Dungeness drift cell. And less than 3% of the Elwha drift cell supports  sand lance spawning, compared to 28 percent of the Dungeness drift cell beaches. Slide11

 

Sediment starvation and lower river alterations have also dramatically impacted Elwha estuary from once having two river mouths and stable complex lower river and estuary Slide12

To a channelized, coarsened and diked single river mouth that has a fraction of the complexity. But beginning in 2011, profound changes are underway. The river mouth has transitioned from this…

 

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To this:

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Approximately 16,000,000 cubic meters of sediment behind the dams-an asstounding volume- is predicted to reach the nearshore after dam removal. Sediment will leave the river mouth, and much will travel east to those sediment starved bluffs and spit. Only  2,500, 000 cubic meters-16%-  delivered to the nearshore as of Sept 2013 (Stevens et al 2013) so restoration opportunity just beginning.   As of September 2013 the river mouth has extended out 100 meters and depths have changed by 10 (Draut and Ritchie 2013; Stevens et al 2013) The area that historically was estuary is now freshwater, and new estuary is forming (Draut

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and Ritchie 2013) -literally before our eyes.  And what are the fish doing? Slide16   Freshwater species-including red sided shiner and prickley sculpin are using the new freshwater habitat (that was formerly estuary), and Chinook, chum, coho, juvenile surf smelt, and eulachon are using the new estuary (Shaffer et

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al unpublished data).  We’ll be providing details (and numbers) at the upcoming Salish Sea Conference in Seattle in May 2014.  The adage holds in the nearshore-if you build it they will come. None of us anticipated how quickly these changes and use would occur. Changes are starting to transform the other landforms of the Elwha nearshore-surf smelt are already spawning on previously inhospitable beaches along Freshwater Bay (Shaffer et al unpublished data). And we expect to see similar changes in forage fish spawning habitat along the Elwha feeder bluffs. But the sediment’s not there yet…. Slide18

But remember the restoration along the feeder bluffs and Ediz Hook due to dam removal sediment will only be temporary. Feeder bluff armoring structures will stay in place- with more installed every year. And the lower river will remain diked. This CAN be changed and true long term ecosystem restoration achieved along these shorelines-but we have alot to do to make it happen.

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 The Elwha nearshore is an untold story and a once in a lifetime restoration event and opportunity

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Sediment from dam removals will be delivered to the nearshore within five years of dam removal- we’re two years into it. So if we’re going to optimize this once in a lifetime nearshore restoration opportunity…We’d better get busy. For more information on how you can join the team contact Anne Shaffer at anne.shaffer@coastalwatershedinstitute.org  

Citations

Draut, A. E., and A. C. Ritchie 2013.  Sedimentology of new fluvial deposits on the Elwha River, Washington, USA, formed during large-scale dam removal. River Research and Applications

Mackas, D. L., & Harrison, P. J. (1997). Nitrogenous nutrient sources and sinks in the Juan de Fuca Strait/Strait of Georgia/Puget Sound estuarine system: Assessing the potential for eutrophication. Estuarine, Coastal and Shelf Science, 44(1), 1-21.

Penttila, D. 2007. Marine Forage Fishes in Puget Sound. Puget Sound Nearshore Partnership Report No. 2007-03. Published by Seattle District, U.S. Army Corps of Engineers, Seattle, Washington.

Shaffer, J.A, P. Crain, B. Winter, M. McHenry, C. Lear and T. Randle. 2008. Nearshore Restoration of the Elwha River Through Removal of the Elwha and Glines Canyon Dams: An Overview. Northwest Science. 82:48-58.

Stevens, A., G.Gelfenbaum, J.Warrick,  2013.Morphological Monitoring on the Elwha River delta. USGS report., Menlow Park, California. U.S. Army Corps of Engineers (USCOE). 1971. Report on survey of Ediz Hook for beach erosion and related purposes. Part II. Seattle District Army Corps of Engineers, Seattle, WA.  

Ward, L., P. Crain, B. Freymond, M. McHenry, D. Morrill, G. R. Pess, R. Peters, J. A. Shaffer, B. Winter, B. Wunderlich. 2008. Elwha River Fish Restoration Plan, developed pursuant to the Elwha River Ecosystem and Fisheries Restoration Act, Public Law 102-495. U.S. Dept. of Commerce, NOAA Tech. Memo., NMFS-NWFSC-90, 168 p

The Northwest Nearshore.

Welcome to the Northwest Nearshore- the Coastal Watershed Institute (CWI) blog. We’ll post updates on our nearshore  observations, key events, and results here on a regular basis.  This post? A synopsis of how we got to the nearshore-and why it matters so much.

The nearshore extends from the area of tidal influence in lower rivers out to a depth of 30 meters (approximately 100 feet) mean low low water. It includes the vegetated shoreline. The nearshore is a place of high importance-all of our iconic species including salmon and forage fish depend on the nearshore for feeding, migration, and in some cases, spawning. There are countless references that provide details what exactly the nearshore is, exactly how it functions, and why it is so critical to protect.  CWI regularly provides workshops on the importance of the nearshore, and conducts research to define key elements to promote and protect.

But the nearshore is also a place of hardship. Because of it’s proximity to these resource and incredible beauty we insist on living ON the nearshore. According to WDFW, we are currently losing our nearshore to shoreline development at a ratio of 10:1. Surf smelt and sand lance spawning habitat is regularly lost thru armoring and fill. Jennifer MacIntyre (WSU/UW) has frankly demonstrated that run off from the impervious surfaces of development flat out kills juvenile salmon. Where is non-point runoff routed along our shorelines? The nearshore.

And of course, once we develop a shoreline we have to defend our infrastructure there.  Our active Strait of Juan de Fuca feeder bluffs, which we know thru multiple research efforts including DNR and DoE, erode  in feet-not inches- per year.

blufferosionratestable

‘Defending infrastructure’ is traditionally done thru bulkheading. This involves placing large rock and or sheet pile along the shoreline, which in turn ironically causes a swift and expensive increase in erosion, and rapid unbraiding of nearshore ecosytem function.  Revetments such as along the Port Angeles landfill shoreline are expensive and futile-maintenance costs for these armaments can average $2000 per feet per year (based on City of Port Angeles utility costs), and at best only slow erosion rates by half.

shorelinearmoringcostsynopsiscwi

There is no forage fish spawning here-and juvenile salmon are visibly stressed while migrating along this armored shoreline. We find dead Chinook along this stretch of the Elwha nearshore every year during surveys.

The bottom line: when we develop along our nearshore, shoreline erosion is accelerated, fish resources are lost, and those iconic northwest view scapes that we all cherish-and live here for-are literally washed away. The economics of ecosystem services that are lost when we lose the nearshore are just now being quantified-by Earth Economics. The numbers  are jaw dropping.

In contrast, protecting our nearshore  takes only common sense (otherwise known as ‘situational awareness’) and  costs-literally- nothing.  We are so fortunate to be in the position of having intact nearshore to protect here on the north Olympic Peninsula. We also have a world scale sediment restoration event that could turn back over 100 years

Comparision of unarmored Dungeness and armored Elwha feeder bluffs
Comparision of unarmored Dungeness and armored Elwha feeder bluffs

of sediment starvation and fully restore our nearshore Elwha-but we have to act now. Stay tuned for details on what CWI is discovering as we work to protect and restore our nearshore ecosystem-and how you can become part of the solution.