Geothermal Hot Springs - McKenzie Bridge
In Oregon, United States
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HOT SPRINGS - a source of water flowing that emerges onto the surface of the earth from underground that has been heated by hot or molten rock while underground; often associated with areas of constant, rarely violent, volcanic activity
THE GEOTHERMAL RESOURCE
Under Earth's crust, there is a layer of hot and molten rock called magma. Heat is continually produced there, mostly from the decay of naturally radioactive materials such as uranium and potassium. The amount of heat within 10,000 meters (about 33,000 feet) of Earth’s surface contains 50,000 times more energy than all the oil and natural gas resources in the world.
The areas with the highest underground temperatures are in regions with active or geologically young volcanoes. These "hot spots" occur at plate boundaries or at places where the crust is thin enough to let the heat through. The Pacific Rim, often called the Ring of Fire for its many volcanoes, has many hot spots, including some in Alaska, California, and Oregon. Nevada has hundreds of hot spots, covering much of the northern part of the state.
These regions are also seismically active. Earthquakes and magma movement break up the rock covering, allowing water to circulate. As the water rises to the surface, natural hot springs occur, such as Belknap Hot Springs in the Cascades. The water in these systems can be more than 200°C (430°F).
Note that hot springs in volcanic areas are often at or near the boiling point. People have been seriously burned and even killed by accidentally or intentionally entering these springs. People should always use great care and respect all signs and warnings at hot spring sites. The hot springs in and around Belknap are quite safe for human use.
Hot springs range in flow rate from the tiniest "seeps" to veritable rivers of hot water. Sometimes there is enough pressure that the water shoots upward in a geyser, or fountain. The flow rate here at Belknap is approximately 60 GPM.
GEOLOGY OF BELKNAP
Belknap Hot Springs is located in the Willamette National Forest, in the heart of the Cascade Range here in Oregon. The Willamette National Forest is quite the diverse area. It ranges in elevation from 1500 ft. to 10500 ft. The hot springs is located closer to the lower elevation. But don't let this deceive you. Though lower in elevation it is still very much a part of the Cascade Range that experiences weather at all ends of the spectrum. This diverse weather nurtures a wealth and multitude of life. The forest area can receive 80 to 150" inches of precipitation a year. Most of this is in the form of snow in the higher elevations that melts throughout the warmer months and feeds into many creeks, streams and rivers. One of the most predominant features you'll find here are the trees, specifically Douglas Fir, though you will find many other varieties, such as, Pine, Cedar and Hemlock. Once you get beneath the canopy of the dense and lush forest of the Willamette, you begin to hear the sounds of life! That life is the snow melt coming down the mountains into rivers such as the Willamette, Santiam and the one of our focus the McKenzie! The McKenzie's headwaters rises up into the Three Sister's area in the East and comes cascading through the lava flows, in some areas forming majestic waterfalls, down through McKenzie Bridge, then later at Blue River where it meets up with the South Fork. Eventually down in the valley the McKenzie meets up the Willamette River. But we want to go back up to the McKenzie Bridge area. The life water helps support not only the growing life of the forests but some of Oregon's most prideful animal life. You may find the Spotted Owl, Bald Eagle, Chinook Salmon, Bull Trout, deer, elk and even a bear! Even though the forests are the obvious feature you'll see, water is pretty substantial as well. There are over 1500 miles of rivers and streams in the WNF as well as 375 lakes. The complete beauty of the area can lure people away from the mystique and true history to the area. These mountains are volcanic in nature and most of the surrounding area you will see was formed or created by volcanic activity. The Cascade Range is part of a chain of mountain ranges called the Ring of Fire. The Three Sister's are the most predominant of the nearby volcanoes. Though these three mountains and others nearby lie mostly dormant or asleep, they may be showing signs of life. In 2001, satellite photos showed an area just south of the sisters experiencing what they call an uplift. The magma that lies deep below the earths surface has been pushing towards the surface and causing swarms of earthquakes in the area. Recently the uplift has slowed but there is still thought that the area is slowly coming back to life or awakening. It's this magma deep below the earth's surface that is the culprit in bringing us this flow of hot water from inside the earth. Water seeps into the earth finds the gaps between rocks and flows into areas where volcanic or superheated rock and magma are. The water boils and under pressure from the heat is pushed back to the surface where it finds an opening in the earth's crust and we have a hot spring! The flow can be as little as trickle or as much as a gushing river out of the earth.
At Belknap Hot Springs there is a rocky outcropping out of the side of a hill along the McKenzie River. This is where, under pressure, water has forced it's way to the surface and continues to run out the side of the hill and into the McKenzie River. There are multiple places up and down the river where you will find these hot springs emerging from the earth. At this spot enterprising individuals have captured the hot springs for the enjoyment of many. In other areas you can come upon a spot where you will see the steam rising as hot water reaches the surface and mixes with the icy cold waters of the McKenzie. The water in this area when it reaches the surface is still very hot! It can cause bodily injury if not respected. So always treat hot springs in nature with the upmost respect! But certainly enjoy them as much as you possibly can too!
BELKNAP HISTORY - The first record of exploration and discovery of the springs occurred in 1854 by a group of men known as the "McBride Party". The group included George Millican, John T. Craig, James Storment, and Joseph Carter, all of whom settled in the McKenzie River Valley. It was 15 years later in 1869 when Rollin Simeon Belknap discovered the hot springs and took claim in 1870 with plans to make a health resort and mineral spa. Originally from Middlesex, Vermont, R. S. Belknap set off from Boston, Massachusetts to explore and look for gold in the Northwest Territory. He ended up in San Francisco in 1849 and later in Southern Oregon, where he fought in the Rogue River Indian War in 1855-1856. In the 1870's, R. S. Belknap brought his family to the hot springs and began development of a mineral spa resort.
THERAPEUTIC RESOURCE - Because heated water can hold more dissolved solids, warm and especially hot springs also often have a very high mineral content. Because of both the folklore and the claimed medical value some of these springs have, they are often popular tourist destinations, and locations for rehabilitation clinics for those with disabilities.
To get credit for the cache you must email me answers to the following questions:
1. What is the approximate temperature of the water at the source?
2. How do they bring the water from the source to the pools at the lodge? Especially with the river barrier, there appears to be nothing visible?
3. What is the temperature they try and maintain at the pool next to the lodge?
4. What process do they use to bring the water temp down for human use?
5. Name at least 2 minerals that can be found in the hot spring water.
6. Then you must take a picture of yourself and GPSr at the source to post with your log. (optional)
Any answers posted in your log will result in your log being deleted.
Though this area is open to the public, I have received permission by the owners to place earthcache here. Please be respectful of others when visiting location and leave no trace behind. They prefer that you visit between the hours of 8AM to 9PM. Answers to questions may require a little detective work and exploring of site.
(No hints available.)
Last Updated: on 9/11/2015 6:05:36 PM Pacific Daylight Time (1:05 AM GMT)
Coordinates are in the WGS84 datum