This article was written by Peter Blanken, and was first published in the Winter 2009 issue of The GLLKA BEACON.
The Great Lakes affect several aspects of our daily lives,
including weather and climate, transportation, agriculture, the economy, health, recreation, etc. Although it can be quite hard to imagine landscape
with the Lakes appearing much different than they do today, the Lakes are
geologically very young, and are dynamic.
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| A chart of northern Lake Huron showing the location of Spectacle Reef light station |
Changes in water temperature, chemistry, ice cover, lake
ecology and lake levels do occur at various time scales and for various
reasons. Superimposed on natural ecological and geological changes are
additional factors such as population growth, and of recent concern is how lake
water levels are affected by current and projected climate change.
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| Cake & Ice Cream crew took turns manning the vessel as she lied at anchor off the light |
The Lake’s water levels are affected by numerous factors
across various time scales. Large-scale, relative slow processes include the
continued uplift of the Great Lake Basin after removal of the Laurentide Ice
Sheet beginning 14,000 and ending 4,000 years ago; smaller-scale, relatively
fast processes include the Lakes’ annual water budget. Each of the Great Lakes
has a topographically-defined drainage basin that defines the catchment area
where any precipitation that falls drains into the lake through rivers and
streams. Other than the shear volume of melt water from the Laurentide Ice
Sheet that created the Lakes, precipitation is the only contemporary source of
water to the Lakes. Outputs, or losses of water from the Lakes are increasingly
numerous, and include runoff from one lake to another (ultimately leaving the
Basin through the St. Lawrence River & Chicago River), withdrawals for
residential, agricultural, and industrial use, and evaporation; with the
balance of inputs versus outputs determining the lakes’ water levels.
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| After landing on the crib, entry into the lighthouse tower itself is made up this double flight of stairs in the fog signal building |
The purpose of our trip to the Spectacle Reef Lighthouse was
to directly measure one component of Lake Huron’s water balance, evaporation,
and to determine the physical processes regulating evaporation to help
understand how the lake’s water levels may change with predicted climate change
scenarios. Understandably, other than several ice-free season buoy and
ship-based observations, there are few meteorological observations made
directly on the Lakes, and no direct measurements of evaporation. Our
measurements of evaporation are based on high-frequency wind and water vapor
density measurements, and require a high, stable platform that is free from the
splash of waves and especially the winter ice. A tall, stable structure located
far from shore, the Spectacle Reef Lighthouse is an ideal measurement location.
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| Chris Spence pulls equipment up from the dinghy, which made numerous trips back and forth between the light and the boat |
The instruments required for this research are delicate and
complex, with each having demanding calibration and power requirements. In
total, we are measuring nearly 200 variables, some at a rate of 10 times per
second. Making sure the instruments work properly, and planning for how to
install the instruments on a 135 year-old structure that you’ve never been to
before is a huge challenge. Added to the challenge is the limited amount of
time you have at the site, no AC power, no knowledge of the condition or type
of structures on which to mount the instruments, and the requirement that
everything must be removable without any structural damage to the lighthouse
(no drilling holes) and the navigation aspects must not be interfered with.
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| Newell Hedstom works on the lantern roof, while Peter Blanken and Pakorn Petchprayoon seek ways to route the wiring |
After securing funds for this project from the International
Joint Commission, the instruments were tested in my laboratory. Then, with the
approval of the State of Michigan’s Historic Preservation Office and the US
Coast Guard, Kevin Robinson (US Coast Guard) suggested I contact Terry Pepper.
Terry was instrumental in arranging local logistical support and travel to and
from Spectacle Reef on the boat Cake & Ice Cream captained by Dick
Moehl. The history and old drawings and
photographs of Spectacle Reef provided by Terry and Dick, helped my planning
for several scenarios for mounting the instruments and solar panels. Every
possible size of u-bolt and hose clamp, along with several crates of
instruments were shipped from the Department of Geography and the University of
Colorado, Boulder, to the GLLKA office in Mackinaw City. Along with my graduate
student Pakorn Petchprayoon from Thailand, and Chris Spence and Newell Hedstrom
from Environment Canada, Saskatoon, we all boarded planes and arrived in
Cheboygan, MI on September 21, 2009 to install the instruments.
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| While paint is peeling badly, the lighthouse appears to be in good condition after being untended for almost 25 years |
Although we planned for one long day at the lighthouse, I
scheduled one full week for the installation, to allow for weather or other
unforeseen delays (the forecast was for rain and wind for the entire week). The
four of us spent our first day visiting every hardware store in town buying
more u-bolts, hose clamps, plywood, pipe, batteries, tools, etc. We had a
half-dozen contingency plans for ways to secure instruments and solar panels 85
feet above the water to endure the harsh conditions far offshore on Lake Huron.
We met with Terry and Dick at the Cheboygan Marina, and
began loading the boat with supplies. The weather was cooperating, and the next
day looked promising for the trip. After meeting for an early breakfast, and a
final check on the forecast, Dick decided that today was the day (Tuesday September
22, 2009), so along with crewmembers Terry Pepper, Mark Siegman and John
Wagner, we boarded the boat and left the Cheboygan Marina at 7 am.
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| Peter Blanken (left) Mark Siegman (center) and Pakorn Petchprayoon (right) insert the mast into its flange on a custom cut plywood base on the narrow lantern gallery |
Some light fog and clouds and calm seas greeted us as we
sailed past the historic Cheboygan River Front Range, Fourteen Foot Shoal and
Poe Reef Lighthouses. After 2 hours, Spectacle Reef was in-sight, under
clearing skies and increasing winds. The shallow water and 2-3 foot waves
required us to use a Zodiac to reach the Lighthouse. Chris and I made the first
trip to unlock the door and assess the condition of the lighthouse while the
others began shuttling our instruments and equipment from the boat via the
Zodiac to the lighthouse. Although suffering from thick peeling paint, the
lighthouse was in remarkably good, clean shape. This made the long transfer of
instruments, tools, and equipment from Cake & Ice Cream to the Zodiac, 20-ft to the top of the crib deck, pulled by
rope, and then up 8 flights of tight, narrowing spiral staircases to the top of
the lighthouse.
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| The room immediately below the service room contains some incredibly beautiful hand-cut stone molding |
Newell quickly scrambled across the top of the lighthouse to
determine the best way to secure the instruments, and after some discussion, we
had a plan: two sections of threaded galvanized pipe resting on the upper deck
(bolted to plywood), secured with u-bolts, metal strapping, and aircraft cable
for guys, would get the instruments clear of the top of the ventilation ball.
Newell and I went to work on this, while Pakorn and Chris mounted the solar
panels to an existing panel support, and Terry and John Wagner photographed and
documented each and every crevice of the lighthouse.
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| Peter makes some final programming adjustments to the monitoring equipment |
After a very pleasant lunch provided by Terry, everyone
continued working non-stop, and soon the sun was beginning to set. Thanks to
all the planning efforts and solid, hard work from everyone, we finished the
final wiring and programming of the data logger at around 6 pm.
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| One last look up at the monitoring equipment before we return to CAKE & ICE CREAM and head for the Cheboygan River |
We cleaned-up, and started transferring crates back to the
Cake & Ice Cream as Spectacle Reef’s red light began to flash, likely one
of the few times in recent years when people were on the site when that
happens. Having been engrossed in our work all day, it suddenly became clear to
us just how high the waves had become through the day.
