This Earthcache takes you to Soap Lake, both the town and the lake, located nearly in the middle of Washington State 1,075 feet above sea level. The community of Soap Lake is around 1,200. There’s no McDonald’s, Safeway or Best Western; just peace and quiet and an abundance of sunshine in the summer months and a highly mineralized lake overflowing with history and therapeutic promise.
Geology
The chain of lakes down the center of the Lower Grand Coulee ends with Soap Lake. These lakes originally fed one another in mostly underground streams. The mineral content of the water in the lakes increased with each lake ending in Soap Lake. Banks Lake Reservoir seen in the upper right of this view is about 17 miles north of Soap Lake and 900 feet above Soap Lake in elevation.
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Soap Lake's story really begins about sixty million years ago. At that time, molten rock from the earth's mantle pushed toward the surface. A few thousand feet before it reached the surface, the molten rock cooled and solidified into great slabs of granite. Over the next several million years, erosion, minor earthquakes, and weather changed the landscape into a series of hills and valleys. At that point, another eruption from beneath the earth brought forth another flood of molten lava that filled the low spots and diverted the Columbia River. These basaltic lava flows occurred intermittently throughout the next several million years.
The big change came about 13,000 years ago during the last ice age. Glaciers blocked the flow of the Columbia River, forcing it into a lake for a time. Eventually the water found a new channel through which to flow--that of the Grand Coulee. While flowing through this area the water deposited large amounts of silt and gravel along its path. Nearby hills caused swift currents to churn away at the underlying lava, digging holes. The holes were eventually partly filled again and waterfalls began forming. Over time this "wave action" cut the lava cliff back toward the direction the water was flowing. At some point during this period, the ice dam suddenly went away, and the river reverted to its former channel. The water stopped flowing down the coulee, and left behind a series of small lakes geologically known as plunge pools. Dry Falls is at the upper end of the coulee, the point where the water stopped churning out holes. Soap Lake is at the low end of the coulee.
Over the next several thousand years, seepage from the subterranean lava flows began to fill these plunge pools with minerals. Being at the low end of the coulee, Soap Lake received more than its share of minerals seeping through cracks in the lava.
Mineral Content
There are up to 23 different minerals in Soap Lake water. The most abundantly occurring are calcium, magnesium, potassium, silicon, and sodium. At various times over the last 90 years, water quality assays have been conducted to test the mineral content of Soap Lake water. Records show that the mineral content of the lake has declined. Compared to the ocean, and other known naturally occurring mineral resources in the world, Soap Lake still has the highest diverse mineral content than any other body of water on the planet. Soap Lake water also contains ichthyols, an oil like substance sold over the counter in Europe to treat infections and abrasions. The icthyol in Soap Lake water most likely come from decomposition of tiny brine like red shrimp that flourish in the water from late spring to mid-summer. Like the Dead Sea, the high mineral content of the lake makes the water very buoyant.
As of 2000:
| Mineral |
Milligrams/Liter |
| Sodium |
5760 |
| Bicarbonate |
2480 |
| Sulfate |
2540 |
| Carbonate |
3840 |
| Chloride |
2290 |
| Potassium |
504 |
| Organic nitrogen |
0.9 |
| Fluoride |
7.2 |
| Ortho-phosphate |
6.3 |
| Nitrate |
0.7 |
| Calcium |
2.5 |
| Magnesium |
2.9 |
Less than 0.01 mg/l of aluminum, iron, copper, rubidium, lithium, strontium, barium, chromium, lead, manganese, titanium, vanadium, and boron.
A Meromictic Lake
Soap Lake is one of only 11 known meromictic lakes in the United States. The water in meromictic lakes separates into layers of differing mineral concentrations and these layers of the lake water remain unmixed for years, decades, or centuries. In other words, the lake never 'turns over'. The upper layer of Soap Lake is a little less than half the saltiness of the ocean, but more than 100-times saltier than river water. The bottom layer is more than twice as salty as the ocean and more than 700-times saltier than river water. These two layers are thought to have remained unmixed in any significant way for the past 2,000 to 10,000 years. The conditions of Soap Lake are considered so extraordinary the National Science Foundation designated it a "microbial observatory." However, Scientist Brent Peyton has noted the lake's saltiness is being diluted, likely because of a major irrigation project built (Grand Coulee Dam Reclamation Project) in the 1950s. It is already 60 percent less salty than 50 years ago. In another 50 years, Soap Lake as we know it - and the unique life it harbors - may not exist.
Qualities
Soap Lake's mineral-rich waters have long been thought to have medicinal value. In fact, it is said that rival Indian tribes would call a truce when they came to Soap Lake to relax and heal themselves and their animals. This is verified by recorded history and the number of Indian artifacts found in the area over the years. Washington State tourist guides in the 1920s referred to Soap Lake as the "world's greatest mineral sea" people afflicted with Buerger's disease[1] found that bathing in the lake would cure their illnesses. Early white explorers called it Soap Lake because its natural minerals and oils give the water a soft soapy feel and create a suds-like foam on windy days. The only other place on earth with similar water is said to be Baden Baden, Germany.
The Mud
Soap Lake mud can be found in various locations on both the north and south end of the lake. There are different “grades” of Soap Lake mud, the best being the creamiest, almost gel-like in your hand, jet black variety that has a strong sulfur odor. There are several locations on the East Beach as well as the cove - behind the library where it can be obtained by diving in shallow water. The best way to find out is to ask a local resident, or to inquire at the Healing Water Spa on Main Street or the Visitor Center on the west side of the highway right past the town.
TO CLAIM THIS EARTHCACHE:
ÜPart One: Choose one of the field work options listed below and follow the directions.
ÜPart Two: Email (please do not post) the answers to the questions listed below. The answers can be found by reading the above text.
FIELD WORK
- Take a bucket, cup, or any small container and visit one of the several locations mentioned above under 'The Mud'. At your chosen location wade into Soap Lake and retrieve a sample of Soap Lake Mud. Note the color, texture, smell, and viscosity of the mud and email your findings to Three Bottles.
- In addition to playing with the mud, please take a photograph of yourself with the mud in hand (or on your body for extra credit!) while holding your GPS and then post it on the cache page.
QUESTIONS/ANSWERS
- Soap Lake is one of only 11 known meromictic lakes in the United States. What makes a meromictic lake unique?
- How many minerals can be found in Soap Lake?
- How many bodies of water on Earth have a higher diverse mineral content than Soap Lake?
- What causes the suds-like foam to appear on Soap Lake?
FUN FACTS:
The alkalinity of the lake is similar to that found on the moons of Jupiter. Because of this, in 2002 the National Science Foundation awarded a grant to researchers from Central Washington University to study the lake to learn about the possibility of life on Mars.
The name Soap Lake came from the word Smokiam, an Indian term which translates to “Healing Waters.”
It shines 310 days a year over Soap Lake, and only rains eight inches annually.
Buerger's Disease: When the word spread in the late 1920’s that Soap Lake water was a cure for Buerger’s disease (thromboangiitis Obliterans), the flood gates opened. Buerger’s disease is a circulatory disorder that affected hundreds of World War I Veterans. Victims of the disease would experience excruciating pain as their skin rotted away exposing nerves around gangrenous lesions. Amputation was the only relief.
Victims of Buerger's disease, who agreed to quit smoking and take at least one hot Soap Lake bath a day for several weeks found that progress of the disease was arrested, with no further amputations required. Other folks flocked to the lake to "take the cure" for such ailments as psoriasis and arthritis, and in fact many people still do (and with great success) today.
SOURCES:
Decker, S (November 2002). "Taking the Waters" at Soap Lake, a personal experience, taken from http://www.flakehq.com/soaplake.htm
Ellig, T. (2002). Ecosystem of vanishing lake yields valuable bacterium. Physorg.com, 149. October 16, 2006, from http://www.physorg.com/news80241737.html
Kiefer, K. (2004). Soap lake: A mineral lake in the heart of washington state. Retrieved from www.soaplakewa.com
Meromictic. (2008, May 19). In Wikipedia, The Free Encyclopedia. Retrieved 21:03, June 30, 2008, from http://en.wikipedia.org/w/index.php?title=Meromictic&oldid=213454977
Pitcher, D. (2002). Excerpted from Moon Handbooks, Avalon Travel Publishing http://www.nwsource.com/travel/scr/tf_detail.cfm?dt=4217&cid=2&pageid=WA&cityid=50
Soap Lake. (2008, February 3). In Wikipedia, The Free Encyclopedia. Retrieved 21:03, June 30, 2008, from http://en.wikipedia.org/w/index.php?title=Soap_Lake&oldid=188699920
Soap lake. Retrieved from http://www.spokaneoutdoors.com/soaplake.htm