Mighty Miss EarthCache
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In order to count this Earthcache as a find, you must complete the following tasks and email the answers to me.
1. What is the elevation at ground zero?
2. At its origin in Lake Itasca, the Mississippi River has an elevation of 1475 feet. How many feet has the river dropped by the time it reaches St. Cloud?
3. Estimate the height of the dam.
4. Describe the amount of water flowing through the dam on a scale of 1-10, with one being very little and ten being a large amount.
5. Estimate the width of the river.
This Earthcache is located in Riverside Park close to the St. Cloud State University Campus. From here, you will have a great view of the dam that spans across the Mississippi River. A bike path runs directly through the park and a fishing pier can also be found in the area. Enjoy!
The Mississippi River is largely a product of glacial activity. About 20,000 years ago, what is now Minnesota lay under hundreds of feet of ice. As the glacier retreated, or melted, the world’s largest lake was created as much of the melt water pooled together. This lake was known as Lake Agassiz. A massive flooding of this lake caused a deep and wide river channel to be cut to help drain the area of water: Glacial River Warren. River Warren, along with its many tributaries and smaller glacial lakes, helped carve part of the Mississippi River bed. Other parts of the river valley were cut by the advancing glaciers.
Throughout its history, the Mississippi River has always been a major navigation route through the center of North America. Barges mainly use the Mississippi to transport goods from one city to another. In order to keep the river as navigable as possible, a series of dams were constructed on the river--despite its slow current and relative depth. These dams facilitate navigation for a stead stream of barge traffic carrying agricultural products from the fertile Mississippi Basin to the Gulf Coast. These dams also greatly reduce the flow of sediment in the river. This is good because this means fewer sediments deposited into the Gulf of Mexico in an area that is known as the Dead Zone.
From its origin at Lake Itasca to St. Louis, Missouri, the flow of the Mississippi River is moderated by forty-three dams. Fourteen of these dams are located above Minneapolis in the headwaters region and serve multiple purposes including power generation and recreation. One example of these dams can be found in St. Cloud.
This dam, also known as the Tenth Street Dam by locals, was originally built for flood control in 1970. Currently, the dam operates as a real life classroom for hydrology students at St. Cloud State University to demonstrate hydrodynamic properties and to show how power is converted into electricity. The dam also has two 4.5 megawatt turbines which generate electricity that is fed into the Xcel Energy power grid. The generators run in the run-of-river mode, which means that all water that flows into the dam each day has to pass over the dam or through the powerplant. There is no storage space for water behind the dam.
The dam has two other interesting features. First, it features lift-up gates that can control the water level by up to three feet. Second, the dam has grinders (also called dragon teeth) at the bottom of the falls to grind up debris and calm down the water. These grinders are a series of tooth-shaped concrete blocks that stick up about a foot and a half from the river bed. The dragon teeth are located under the section of white water at the base of the falls created by the dam.
NOT A LOGGING REQUIREMENT: Feel free to post pictures of your group at the area or the area itself - I love looking at the pictures.
Additional Hints
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