West Fork Island EarthCache
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This geocache is placed with permission of Great Parks of Hamilton County Permit 140319-07 .
Participants must stay on designated trails until they get close to the designated area and follow all park rules.
West Fork Island:
An island is defined as a tract of land completely surrounded by water, and not large enough to be called a continent. The island near the listed coordinates is no different than Australia or Greenland – it’s just much, much smaller. Approximately 2/3 of the earth surface is covered with water and in a manner of speaking all the dry land that protrudes above it are “islands”. Natural islands are formed from uplifts of the earth crust due to plate tectonics or by volcano. What you see before you is sometimes called and artificial island. It is “artificial” in that the lake surrounding it is man made. If not for the dam on this creek this little knob of earth would not be surrounded by water, but would really be a large hill in the middle of the valley. This valley has been dammed to form West Fork Lake and this island is above the water level normally maintained on the lake.
Gorge Geology
Approximately 325 to 350 million years ago, Ohio was under the waters of a vast, shallow, inland ocean. Silt and clay were deposited and compressed to form layers of Ordovician limestone. Great forces in the earth caused the rock to be uplifted, forming the Appalachian Mountains. The uplifted land was eroded over time by four great, continental glaciers, the last of which was the Wisconsin glacier 12,000 years ago. These glaciers had a major effect on the topography of the Winton Woods area. The resulting erosion and sedimentation created the subsoil that forms the hill tops in Winton Woods. The Mill Creek and this gorge were formed by the run off the Wisconsin glacier as it retreated.
West Fork Lake:
As the metropolitan area of Cincinnati expanded in the 1900’s local flooding became an issue and the flow of this creek system was controlled. West Fork Lake (also known as Mill Creek) was authorized under the Flood Control Act of 1946. The Louisville District of the U.S. Army Corps of Engineers designed, built, and operates the project to reduce flood damages downstream from the dam. The dam is 6.5 miles above the confluence with Mill Creek.
Should heavy rains occur, surface water runoff is stored in the lake until the swollen streams and rivers below the dam have receded and can handle the release of the stored water without damage to lives or property.
The dam is a rolled earth fill 1,100 feet long. The height of the dam is ???? (see below – you are to estimate it.) The drainage area above the dam is 29.6 square miles. When the lake is at normal levels it occupies 183 acres, but at flood stage it is 557 acres.
The Army Corps of Engineers estimate the flood prevention provided by the lake impoundment is about $52 million and in 2005 it generated nearly $16 million in visitor expenditures. The dam not only produces the island, but great economic benefits. The Corps works with the Hamilton County Park district to develop the park around the lake. Within the park are baseball diamonds, picnic areas, a golf course, campground, riding stables, concession stands, frisbee golf, playgrounds, and miles of hiking and bridle trails.
The Island:
You’ll need to paddle to the island to make some observations there to fulfill the requirements of this earth cache. Below I give some details on how to go about doing that. You do not need to leave the boat to perform the logging requirements.
Logging requirements:
A photo with the boat and the island in the frame – no telephoto lens! Another photo of yourself in the boat – no swimming allowed!
Estimate the maximum height of the island above the water.
Estimate the height of the top of the earthen dam above the water (hint: the length is 1000’)
Using observations of the island has it been underwater recently (last few years)?
Like any isolated plot of land, the island plants and animals do not mirror that of the land surrounding the lake. Include any observations of differences.
Getting to the island:
You can use your own vessel or one can be rented at Winton Woods Lake during the warmer months (March-October). I have added a waypoint for the only publicly available boat put in at the lake.
Additional Hints
(No hints available.)
Treasures
You'll collect a digital Treasure from one of these collections when you find and log this geocache:
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