James River EarthCache
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This location is along a gravel road. A safe area to park along the side of the road is 100 feet south of the posted coordinates.
The James River has been declared by some as the longest un-navigable river in the United States. It begins in North Dakota and slowly winds south-southeastward for 710 miles before emptying into the Missouri River about five miles east of Yankton SD. Water in the James River comes mostly from surface waters. Ground water contributes very little if at all to the flow of the James River.
The James River floodplain varies in width from a quarter to a half mile. Flooding of the James River valley is most often caused by heavy snowmelt. Because the James River gradient is extremely low, it can take months for the flood waters to fully recede back into the river banks.
The river gradient north of Huron, SD is 0.2 foot per mile average. Because of this extremely low gradient, occasionally a tributary with high flow will cause the James River to “back up” or flow backward for a few miles from where the tributary meets the James River. At this location, where the Mud River meets the James River, is one of these locations. South of Huron, SD the river gradient increases to 0.4 foot per mile. Reverse flow of the James River south of Huron has occurred, but it is not common.
The James River Basin (also called the James River Valley) is relatively level land stretching between fifty to seventy-five miles wide and 250 miles long. It was formed by glacial ice that entered South Dakota from the northeast. Glacial ice was once approximately 1600 feet high above the ground in the northern James River Basin. Since a cubic foot of ice weighs about 57 pounds, a glacier 1600 feet thick would exert 45 tons of pressure on every square foot of ground it covered. Movement of the glacier acted like a bulldozer, moving inches each day, scraping and pushing debris along the edges of the glacier. When the glacier receded, the materials picked up along its movement were left behind forming glacial moraines.
Send your answers to the cache owner to claim this find:
1) What is the elevation at the posted coordinates?
2) How many people are in your group?
3) At this location, several forms of man-made materials have been placed to reduce erosion, if these materials were not present, which direction do you think the river junction would move and why?
4) Post a photo of yourself at the junction of the Mud and James Rivers.
Additional Hints
(No hints available.)