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Goose Falls: The Callahan Legacy EarthCache

Hidden : 06/13/2008
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Geocache Description:

Tides passing in and out over the shallow bottom ledge under the bridge into Goose Pond in the Cape Rosier community of Harborside, Maine, create a reversing waterfall effect that is very popular with whitewater boaters.

Goose Pond, a tidal estuary. Goose Pond is connected to Goose Cove to the north by a reversing falls known as Goose Falls. Goose Cove is located on the southern part of Penobscot Bay. As you drive by this tidal falls you will notice a small pond often filled with wildlife. This little tidal falls today is a place used by boater to play. The locals generally view this area as an extraordinary body of water that graces the shores of Penobscot Bay, well known for its local wildlife. While it is not the size of the stream or falls but a combination of the shape of the valley, bedrock geology and tides that work together to form this unique tidal phenomena.

The greatest influence on the reversing falls is the tremendous tides cause the periodic rise and fall of the ocean in this area. Tides are caused by the gravitational interaction between the Earth and the Moon. The moon’s gravitational attraction causes the oceans to bulge toward the moon with another bulge occurring on the opposite side. When this bulge is coupled with the shape of the Gulf of Maine the tides become extreme. Since the earth is rotating while this is happening, two large tide events happen each day.

The reversing salt-water falls occurs under the bridge on Goose Falls Road in a very narrow section of the river near Harborside. What makes this an ideal location for a bridge, good footing in an elevated very narrow section of the river also make the correct conditions to create this reversing falls. This set of falls is formed when the water rushes through a narrow gap between the ledges on both sides of the bridge. As the salt water passes over rocks under the bridge it causes the "waterfalls" effect. The reversing falls actually are rapids, which are caused by shallow bottom in a narrow passage of water. The boulders, ledges and other materials, in addition to the narrow passageway between the bridge cement structures form a bottleneck, causing a rise in the depth of water on the neap side of the falls. As the tidal current slows, the roar of the water gradually diminishes until at slack tide, for a short period of time, the water under the bridge is like a mirror. Gradually, the direction of the water changes and before you realize it ripples appear with the waves growing in size quickly.

Remember normally that the water flow to the ocean. At low tide, Goose Pond above the bridge empty into the bay under the bridge in a waterfall or rapid. As the tide rises above the falls, the seawater forces its way against the waters flow. The rapids slow to a stop for a short period of time giving the appearance that the falls have reversed. This process repeats itself twice a day. Because the water is constantly churning things up at the Reversing Falls it often attracts sea creatures due to the waters providing abundant food, which is an added bonus for this earthcache.

To log this Earthcache: You must visit the area and answer an earth science question. There is no container or logbook for you to sign just a beautiful and unique natural feature to observe. You must post a photo of yourself/your hand and your GPS with one of the water features in the background and then to log this cache you must record the time of your visit as it relates to the tides and what you observe, an example of a log might be, Arrived at 4:30 p.m. which was 1 hour after high tide, and the water was running upstream forming turbulence with wave up to two feet high. There were several seal fishing at the time of our visit. Over time as the logs accumulate visitors will realize if they want to have the best view of this tidal falls phenomenon the time that they should visit. Tidal charts are available at: (visit link) you will want to use Castine for reference.

Now for the story of the recent past as you look across the peaceful Goose Pond above the falls. The bridge was once the site of a dam at what was once part of the worlds only intertidal heavy metal mine. The copper/zinc mine was closed in 1972 and was flooded by opening a dam at Goose Falls. The mine is currently under water and is subject to daily tidal exchange in Goose Pond. The 150-acre Callahan Mine facility features include large waste piles (waste rock piles), a tailings pond, and mine operations buildings and structures. A clam digger discovered the zinc/copper sulfide deposit in 1880 at low tide. The first mine operated until 1887. Ore was mined from three shafts. Efforts were made to mine the ore sporadically through 1964. Callahan Mining Corporation geologists became interested in the potential of the property in 1964 and subsequently open pit-mining operations commenced in 1968. The open-pit mine was approximately 600 to 1,000 feet in diameter and 320 feet deep. Two major dams were constructed at the saltwater inlet and freshwater inlet of Goose Pond and the series of dams that had to be constructed as materials were added to the tailings pond. The final height of the dam is 82 feet. Fresh water that normally flowed into Goose Pond was diverted south to Wier Cove via a drainage ditch. Goose Pond was subsequently drained to allow for the excavation of the mine. Dyer Cove, currently a small part of the Goose Pond estuary, was a fully enclosed area used to temporarily store water pumped from the open pit mine. Particulates were allowed to settle out prior to pumping the water from this cove to Goose Cove. Mining operations ceased in June 1972 due to the depletion of the mineral reserve. Milling ceased in July 1972. On September 4, 2002 the Callahan Mine was added to the National Priorities List (NPL), commonly known as the Superfund. The Superfund is EPA's list of the country's hazardous waste sites that have been identified for possible long-term cleanup by the federal government. According to Robert W. Varney, EPA New England regional administrator the "Old mining sites pose significant environmental risks. For more than a century rainwater and snowmelt have been leaching metals from the tailings into Goose Pond, causing environmental damage to the fishery." So you see what today is a very beautiful and peaceful coastal location was at one time the site of a large open pit mine. If you look across Goose Pond image what it would look like without any water and a large open pit. As peaceful as it is today it once must have been a very active industrial setting.

If you enjoy this earthcache you may want to check the Maine Geological Survey located at (visit link)
They have developed a number of information sheets or field localities giving a great deal of information about geologic features. They also have a number of books and maps about Maine’s natural history/ geology that you might find interesting.

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