In Iowa, United States
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The beauty of the canyons and bluffs of Ledges very quickly became a major attraction to the growing local communities. Ledges was proposed as a state park as early as 1914. In 1924, the Ledges officially became one of Iowa's first state parks.
With its sandstone cliffs, native plant communities and deep wooded river valley, Ledges is a truly unique place. The winding road along Pea's Creek offers motorists breathtaking views of the "canyon" and the Des Moines River Valley.
The sandstone "Ledges" rise nearly 100 feet above the floor of the streambed. The sandstone was deposited 300 million years ago following the retreat of the shallow sea that covered much of the midwest. About 13,000 years ago, glacial meltwater began to cut down through the sandstone, forming the park's dramatic cliffs and valleys.
The Des Moines Lobe glacier advanced rapidly into Iowa about 15,000 years ago during a period of climatic warming. The initial advance of the glacier was followed by ice stagnation, then by at least three more rapid advances and longer stagnation phases. While the Des Moines Lobe was in Iowa, voluminous amounts of meltwater were released from on top of, within, and under the glacier into outwash streams that flowed from the ice margins. In many instances, large meltwater floods filled the valleys and had dramatic impacts on the landscape. Meltwater floods developed in three different ways: normal seasonal melting of glacial ice; episodes of extreme melting triggered by unusually warm or rainy periods; and sudden bursts of temporary glacial lakes. These events introduced pulses of meltwater that established the major valleys in the upper part of the present-day Des Moines, Boone, Iowa, Little Sioux, Big Sioux, Raccoon, Skunk, and Winnebago river basins. Outside the margin of the Des Moines Lobe where pre-existing valleys weren't covered by the glacier, meltwater floods eroded valley walls, deepened some valleys, and filled others with sand and gravel.
To satisfy this Earthcache you must do the following water volume calculations based on the old glacier water way and the new Pea’s Creek:
Old glacier water way
1) Proceed to the following coordinates:
a. N 41’ 59.602
b. W 093’ 53.249
c. There you will be in the middle of the scenic view of the Ledges to the north, south, east and west.
2) First measure the base of the old glacier water way.
a. Using long walking strides, walk from one side of the Ledge to the opposite side (this will take you across the road so watch for traffic)
b. One walking strides usually equals 3 feet
3) Take that measurement and multiple it by 100 feet (approximated distance to the top of the Ledges). Then multiple that number by 7.48 (gallons per cubic foot). This will give you the gallons of water needed to make a wall of water from the bottom to the top – side to side 1 foot think.
New Pea’s Creek
4) Now measure the new creek height and width
5) Multiple those numbers together, and then multiple that number by 7.48
6) This will give you the gallons of water needed to make that same wall for the new creek.
There are also three rock features to note:
1) A face in the wall (N 41’ 59.664 - W 093’ 53.245)
This face in the rock can be viewed only at certain angles and will appear in photos. Also, notice the birds nest at the top of the ledges.
2) Lovers rock (N 41’ 59.607 - W 093’ 53.293)
This rock has a smooth face and hallowed out sitting spot. Notice the steps carved into the rock. (Please do not damage the rock any further).
3) Table rock (N 41’ 59.607 - W 093’ 53.293)
This rock rises many feet about the valley floor and offers a great view of the parking area. Notice the many species of trees all around the area. (a steep hike is need to reach the top of Table Rock.
To get credit for this Earthcache you must email me the distances of the old and new creeks and your final water wall results, along with a photo of yourself (or team) at one of the three mentioned rock features.
Further information about the area can be found at the following web site (visit link)
(No hints available.)
Last Updated: on 9/15/2013 4:31:45 PM Pacific Daylight Time (11:31 PM GMT)
Coordinates are in the WGS84 datum