Beam Reach

Race Rocks tidal current power project

As multiple agents in Western Washington begin the process of harnessing the tidal currents of the Salish Sea for generating electricity, it’s worth a close examination of what’s been learned by a pioneering tidal turbine project associated with the Race Rocks Ecological Reserve/Marine Protected Area. Through a partnership between Pearson College of the Pacific (288 students from 28 countries study International Baccelaureate) and Clean Current Power Systems (Vancouver, Canada), a project was initiated to provide renewable energy to the marine station and lighthouse.

Today, a tidal and solar power system has replaced the twin 15kW diesel generators that provided electrical power (and noise, air pollution, environmental risks) during most of the 20th century and much of the history of the Race Rocks reserve (established in 1980). I assume wind was judged inappropriate because so many sea birds nest and rest on the Rocks.  I’m still just learning about the details, but wanted to share some notes and frame-grabs I took while watching a nice overview video of the Race Rocks tidal power project.

My overall impression is the turbine is big.  Approximately 4m in diameter, the ~65kW turbine is designed to be scaled up to 1MW (presumably for future commercialization by CCPS). The forces exerted on the support column during the maximum 3.35 m/s tidal flows must be tremendous.  A cool innovation I didn’t anticipate is that the blades are designed to turn in current from opposite directions.  This means that the whole turbine assembly doesn’t have to rotate on the support column (like wind turbines do).

It’s hard to find measurements or engineering data on the blade rotation rate.  Quoting from generic references about tidal turbines on the EIA page, “The blades themselves rotate quite slowly relative to hydroelectric and wind turbines, namely a few revolutions per minute depending on current speed, blade curvature and size but always to maintain a blade tip speed of less than 7m/s (when cavitation is likely to occur)” and typical rotation rates are “10-20 rpm.”  For a blade radius of 2m, the tip velocity would be ~4m/s at 20rpm and ~2m/s at 10rpm.  Given the arrangement of guided vanes I certainly wouldn’t want to swim through it at those rotation rates… but maybe a fish would do alright?

Funding for the project has come from Encana (natural gas and oil company’s Environmental Innovation Fund) and Sustainable Development Technology Canada (non-profit foundation created by Canadian government; Vicky Sharpe).

Chronology:

• Late 2005: preparatory (concrete) work on island for cable route and battery storage
• Jul 2006: Drilling complete (after 3 weeks), piling installation continues
• Sep 2006: Installation of turbine; hydraulic and electrical performance testing begins
• Dec 2006: Testing complete; cables connected to shore storage; Summary Report on Environmental Monitoring final draft submitted
• Apr 2007: Turbine raised to repair bearings
• Oct 2008: New turbine with stainless steel bearings, lubrication system, and reinforced augmenter duct.

Artists depiction of installed turbine

Technical details (these are surprisingly hard to find… values to be filled in are in italic):

1. located ~100m from Island, ~15m depth, ~20m of water
2. The top of the turbine is at a mean depth of 10m, or ~5m below MLLW; thus the whole assembly reaches about 10m off the seafloor.
3. post diameter?
4. turbine and funnel dimensions? (~3m diameter, but not sure if that’s augmenter or blades)
5. power and voltage (what function of current speed?)

Diver guiding generator unit onto post

The generator sans cowling

Clean Current Power Systems staff interviewed in video

• Russel Stothers
• Glen Darou
• Virgil Young (aerospace)
• Chris Gora

Pearson College staff interviewed in video

• Gary Fletcher
• Dave Skilling

Other projects to keep an eye on:

• 1.2 MW project in northern Ireland
• Tidal prospecting by Snohomish County
• Pilot project planning by Tacoma Power
• Monitoring by Biosonics of the Verdant Power turbines in the East River, NY

Midnight mantra: 40+ repetitions of S19

Happened to hear some of the clearest calls yet on the Port Towsend Marine Science Center hydrophone last night.  It was a treat to listen to the killer whales vocalize at night — and it reminded me of the night-time observations we did during the fall, 2005 program.  The calls I heard initially (as the noise from a passing ship subsided) were remarkably repetitive, so much so that at first I thought it was a new type of squeak from the overlying dock or nearby mooring buoys.

Listen to 5min clip of repeated calls off Port Townsend just after midnight

After a while, though, it became clear that these sounds were a very consistent killer whale call.  The calls were of the S19 call, favored by L pod, and many were spaced 2.6-2.7s apart.  Eventually, the mesmerizing repetitious call was replaced by a wide variety of calls, whistles, and buzzes.  What in the world was going on as they passed into Puget Sound.

S19 repeated about 40 times

Based on the great sequence of observations from the Orca Network today, it’s clear that some portions of L and J pod made a brief foray into Puget Sound.  Twelve hours after passing Port Townsend (presumably southbound as J, K, and L pod members were observed within ~5nm of Dungeness Spit ~8 hours earlier), members of J and L pod were documented heading back to the north from Bush Point (12:45) to Keystone (14:30).

Perhaps a school of chum they were persuing dispersed after getting into Puget Sound proper?

Orca "logging" for hours at Lime Kiln!

When killer whales remain at the surface for more than a few seconds, essentially floating with their dorsal fins consistently out of the water, the behavior is sometimes called “logging.”  I’ve seen orcas log when alone — often in tidal fronts — and once in a large group during a “ceremony.”  But never like this…

On September 20th, my father’s birthday, from 12:54-13:12 I photographed what appeared to be an orca “logging.”  It was completely motionless relative to the gentle ebb tide during this 16 minute period.  It passed Whale Watch Park at the typical distance of about ~200m offshore and I can only imagine the tourists at Lime Kiln lighthouse were overjoyed by the rare sight. We observed it for a couple hours and it never submerged, accelerated, or changed direction rapidly.

I became concerned when I later examined all of the photographs taken through a telephoto lens.  The pigmentation of the whale seemed off.  The dorsal fin was beyond raggedy…  I reached for the phone to contact the stranding network.  And then I realized I had been fooled by the Orcinus version of a wooden duck decoy.

On the Cat’s Cradle, we marveled and then chuckled.  Why not keep it for training Beam Reach students, or testing them on the first day of class when we traditionally visit Lime Kiln to formulate our initial research questions!?  Alas, the wind arose and we were forced to raise sails and celebrate by coasting away downwind…

Orcas in el Mar Vermejo

Do you feel cognitive dissonance when seeing killer whales with this desert backdrop?  As a Pacific Northwesterner used to emerald shorelines and snow-capped volcanoes, I sure do.

Some day Beam Reach will visit the Vermillion Sea and listen in on this playful pod that recently interacted with an ecotour in Baja .

Mother-calf communication in wild killer whales

On July 2, 2008, Val Veirs presented some of the most exciting research results yet gathered by Beam Reach students and staff.  In a talk entitled “Spatial confirmation of vocal communication between a killer whale calf and its natal family” (Powerpoint link), Val presented an analysis (by Val, Jason, and Scott) of a sequence of calls we heard while towing our hydrophone array in fall, 2007.  As these calls occurred, a juvenile whale (Oreo, J38) left its mother and brother, approached the array from the port side, turned underwater, surfaced off our bow, and then regrouped with its family.

With our ability to localize each of the calls, we learned that J38 was exchanging calls with its mother and/or brother.  (The latter two were too close together to determine who was making the calls that came from their area).   Val’s cool Flash animation of the localized orca call sequence marks an initial confirmation that orcas communicate by exchanging calls, rather than by having a leader issue all calls to the rest of the pod.  In fact, one interpretation of the call sequence is that juveniles not only communicate with their immediate elders, but also argue adamantly with their mothers as they rebelliously explore their environment!

Exciting dam removal video

One of the grandest gestures we humans in Western Washington can make for endangered orcas and salmon is to finally remove the Elwha dams.  The result would be a wonderful experiment in salmon restoration, as well as sediment dynamics.

I remember thinking that the removal was just a couple years away when I lived in Port Angeles for a couple months in 2002. For a LONG while we’ve all been thinking that the Elwha dam removal would be imminent.

I also imagined it would be more or less unprecedented.  Yet, today I learned that our neighbors in Oregon have set a remarkably good precedent by breaching the Marmot Dam on the Sandy River, a tributary of the lower Columbia near Portland.  This video of the river removing the dam in a single day should give us all hope in the current plan (sic) to let the Elwah sediment be transported naturally by the river.

How shall we help catalyze similar progress in Washington?

Thanks to the latest edition of Wild Salmon & Steelhead News for spreading the good news.

What did Lummi hear?

It was just announced that the oldest southern resident killer whale is believed to have died this year. Lummi (K-7) lived to be about 98 years old and was last seen by Brad Hansen of NOAA/NWFSC on December 23rd. As the Center for Whale Research has surveyed all of K pod multiple times this spring, they are now confident that K-7 died this winter or spring.

The full article in the San Juan Journal got me wondering what Lummi heard in her lifetime. How much did the Puget Soundscape change since her birth in ~1910? The old matriarchs of the other pods, Granny (J-2, born ~1911) and Ocean Sun (L-25, born ~1928), also experienced the rise in anthropogenic noise in the oceans. Born at the end of the age of sail, they listened through two world wars, and persist during the crescendo of global shipping in the era of peak oil.  I wonder if they were hard of hearing in their old age!

Steam engines were becoming more prominent than sail power around 1850-1900.  The steam turbine was patented in 1897 and was initially used to power higher-speed ships.  The diesel engine was patented in 1892 and began being used in vessels, including the Danish freighter Selandia in 1903. The current wikipedia entry for ship says that “Transport of people and cargo on sailing ships continued until the 1920’s.” So, it was a time of transition for marine propulsion systems, and therefore for underwater noise.

Locally, it’s clear that many fishing vessels were becoming motorized about the time that Lummi and Granny were born. An article about the refurbishment of an old halibut schooner by the algal energy company Blue Marble, states that their vessel (the Lituya, re-named the Blue Marble) was “one of the 150 or so motorized halibut schooners built between 1910 and 1932 to work the northern waters off Alaska and Bristol Bay — resting during the off-season in the calm waters of Seattle’s Fisherman’s Terminal.” I assume the same was happening with shipping traffic that transited the Strait of Juan de Fuca…

A quick search isn’t turning up a synopsis of shipping traffic in the Salish Sea over the last century or so. I’ll have to resolve to look for publications that document number and types of ships in Puget Sound historically. It seems my best bet may be to visit the research library associated with the Museum of history and industry. Does the Coast Guard or the Ports keep track of how many of each vessel type have come/gone? What about on the Canadian side of the border? Can we separate traffic transiting south of Vancouver Island with ships transiting the north side?

Deck-mounted bicycle generators

I just read a story about a band that tours and amplifies under bicycle power alone. The technology they use could jump start an idea spawned during dinnertime discussions during past Beam Reach programs: mounting two bikes on the foredeck for power generation and exercise during the sea component. A nice twist would be having a couple nice, inspirational, bikes for Beam Reach students to use while on land. In homage to our bioacoustic spin, we could even outfit them with bike sound systems!

The fellow who designed Ginger Ninja’s system offers a variety of pedal power generator (PPD) products. Dante’s Do-It-Yourself predilections will resonate with some of Beam Reach’s core staff (Val Veirs, the tinkerer, specifically). It looks like a basic system can be purchased for about $1000. A crux for our application will be ensuring the system can endure the salt spray and precipitation of a catamaran’s foredeck. Another key issue will be whether the power is pushed into the house 12V battery or directly into the pedaller’s laptop…

No fish, no blackfish?

I’ve asked a lot of people why the southern resident killer whales spend so much of their time swimming up and down the west side of San Juan Island. Most folks suggest that they’re here because the fish are here. Ask long-time population surveyor Ken Balcomb of the Center for Whale Research what motivates the orcas to be resident and you’ll get the succinct synopsis he passes on from First Nations elders: “No fish; no blackfish.” Yet I’m amazed at how little is known about what fish are present at any particular time in this part of the San Juan Islands, not to mention the Salish Sea in general.

From April through October the three resident pods are most frequently found along this coastline, the eastern side of Haro Strait. Their most common dance is known as the “west side shuffle” in which the pod(s) travel back and forth from somewhere near Eagle Point in the south to Henry Island in the north, often pausing to forage, socialize, or mill, but rarely resting. I’ve yet to hear of the residents transiting the same body of water on the Canadian (west) side (though transients often do), and I doubt it’s because the Canadians don’t treat their sewage as much as we do.

The orcas often make intermittent excursions further afield. They loop out to visit Hein and Middle banks offshore. They zip west past Race Rocks for a listen along south Vancouver Island. Or they voyage northward to the Fraser River delta before circumnavigating the archipelago via Rosario Strait. But they always seem to return to the west side — the core of their summertime range.

There might be non-fishy reasons orcas might like the west side of San Juan Island. Perhaps they appreciate the great acoustics along the steep unsedimented submarine coastline. Maybe they have a rubbing “beach” like the Northern residents, but hidden deep off of False Bay. Or maybe the west side is just a cross-roads: a familiar pathway that you take whether you’re headed out to the Pacific and the Elwha, up to the Fraser or Nooksack, or down to the Skagit and Puget Sound.

How could we demonstrate that prey availability is the factor that focuses the southern residents attention on the west side of San Juan Island? What kind of fish are they eating? Why and when are which fish available; and implicitly, how do the killer whales navigate the complex distribution of salmon in the Salish Sea? More practically, which (endangered?) fish population segments should we be saving for our endangered whales?

Our primary approach to answering such questions is to discern what the southern residents eat and then observe the behavior of those prey items along the west side. Secondarily we gather basic information about distributions of potential prey in case the prey sampling studies have biases that lead us to overlook important food sources.

The growing body of information about what orcas eat is the best evidence we have of what prey they are after. The current scientific consensus — from analysis of scraps, underwater video, the rare stranded whale’s stomach contents, and poop — is that southern resident killer whales really like Chinook salmon. In the best synopses I’ve seen (of data predominantly from May-October) Ford et al (1998) and Ford and Ellis (2006) suggest that Chinook are preferred at all times except perhaps in the late fall when chum salmon return to many local rivers (and the residents, especially J pod, begin making southward forays into Puget Sound). There also hints that bottom fish such as halibut, lingcod, and dover sole are taken occasionally.

A big problem is that not many people are doing a good job of monitoring what fish are present in the Salish Sea (as opposed to Northwest rivers) generally, and in Haro Strait specifically. A major goal of the spring 2008 Beam Reach program was to test new acoustic tools that could help us fill the observational gap. I’ll post separate articles with detailed results this summer, but for now here is a synopsis of the two new tools we tested:

First, through a new partnership with Seattle-based Biosonics, we used a 200 kHz scientific echosounder to measure fish densities in Haro Strait.  Mounted on a pole and pointed straight downward, the echosounder projected sound in a 6-degree-wide beam and received the echoes from fish, plankton, and the sea floor. With real-time display and data logging, we were able to survey fish distributions in Haro Strait (and map bathymetry and bottom type) both in the presence of orcas and when they weren’t around. Thanks to the generous donation of equipment and software, we were able to observe remarkably complex distributions of fish along the west side and to quantify fish densities in a preliminary suite of foraging locations.

Another active acoustic technology we tested was an acoustic tag that can transmit a depth measurement from inside a fish. We purchased two tags from Vemco and guided by instructor Eric Eisenhardt, implanted them surgically in lingcod near Lime Kiln State Park. With the mobile tracking unit that Vemco kindly provided for free, we were able to monitor the two young fish for about a month and learned they make only occasional depth excursions while remaining in the area where they were caught and released. The fish stayed near 18 and 40 meters depth throughout our study, suggesting that when killer whales make deep dives (>100 meters) to the local bottom (Baird, 2003) are probably not related to foraging for young lingcod on the west side of San Juan Island in the spring.

References:

Baird, Robin W., M. Bradley Hanson, Erin E. Ashe, Michael R. Heithaus, and Gregory J. Marshall (1993) STUDIES OF FORAGING IN “SOUTHERN RESIDENT” KILLER WHALES DURING JULY 2002: DIVE DEPTHS, BURSTS IN SPEED, AND THE USE OF A “CRITTERCAM” SYSTEM FOR EXAMINING SUB-SURFACE BEHAVIOR. Report to the National Marine Fisheries Service, National Marine Mammal Laboratory, 7600 Sand Point Way N.E., Building 4, Seattle, WA, 98250 USA.

Ford, John K. B., Graeme M. Ellis, Lance G. Barrett-Lennard, Alexandra B. Morton, Rod S. Palm, and Kenneth C. Balcomb III (1998) Dietary specialization in two sympatric populations of killer whales (Orcinus orca) in coastal British Columbia and adjacent waters. Can. J. Zool. 76(8): 1456–1471 | doi:10.1139/cjz-76-8-1456.

Ford, John K. B., Graeme M. Ellis (2006) Selective foraging by fish-eating killer whales Orcinus orca in British Columbia. Marine Ecological Progress Series, 316:185-199.

Whale power!

Thanks to Lindsay Delp (081) who just sent me a Discovery Channel article about the fluid mechanical efficiency of cetacean fins and flukes. It turns out (ha!) that wind turbines can be made more efficient by roughening the leading edge of the blades. The idea was inspired by studying the bumpy fins of humpback whales.

Seems like a nice next step (alluded to in the article) would be for the Beam Reach boats to substitute robotic flukes for the propellers! I’ll bet the resultant propulsion would be not only more efficient, but also more quiet underwater. Perhaps some day the whole whale watching fleet will be using different flukes, optimized for making Zodiacs porpoise and deep-keeled boats thrust silently along at 5 knots?