Karst Topography of Wisconsin

[AJE]

What is Karst and why its important here in Wisconsin?

Karst is a special type of geographical landscape that is formed by the dissolution of soluble rocks, including limestone and dolomite— these regions are susceptible to chemical erosion from naturally occurring carbonic acid as a result of water seepage. For the most part Karst topography is categorized under three divisions: Caribbean, Temperate, and Tropical. These regions contain aquifers that are capable of supplying large quantities of water known as our watersheds.

More than 25 percent of the world's population either lives on or obtains its water from karst aquifers. In the United States, 20 percent of the land surface is karst and 40 percent of the groundwater used for drinking comes from karst aquifers. Natural features of the landscape such as caves and springs are typical of karst regions. Karst landscapes are often spectacularly scenic areas. Examples include the sinkhole caves of central Kentucky ie: Mammoth Cave NP, the large crystal-clear springs of Florida ie: Blue Springs SP, and the complex, beautifully decorated caves of New Mexico ie: Carlsbad Caverns NP. I will only be discussing the temperate karst, which pertains to Wisconsin.

So where can this topography be found in Wisconsin?
Much of Wisconsin’s karst is masked by thick layers of glacial deposits, particularly in the southern-central and southeastern parts of the state. Bedrock areas in Wisconsin that have visible karst features include the Silurian dolomite in the eastern part of the state and the Sinnipee and Prairie De Chien dolomite located in the southern, eastern, and western parts of the state. The karst regions are very fragile ecosystems that are heavily influenced by how we use the land. Land subsidence, sinkhole collapse; groundwater contamination, and unpredictable water supply will become the results of both man and nature.
:arrow: Wisconsin counties that feature karst topographies include Brown, Buffalo, Crawford, Dane, Dodge, Door, Grant, Green, Iowa, Jefferson, Kewaunee, La Crosse, Lafayette, Monroe, Pepin, Pierce, Richland, Saint Croix, Sauk, Trempealeau, Vernon, and Waukesha

The Door is one of the many areas that we as residents need to be concerned about which is why I will be briefly discussing this particular county. Many of us have been up to the door, so I ask what do you remember? The thing that comes to my mind is the rock formations over looking the Green Bay and Lake Michigan. Now do a little experiment take a stick and push it into the ground until you hit bedrock. Due to a very thin soil layer overlying the highly fractured dolomite, much of Door County is highly susceptible to groundwater contamination. There are some 4,000 acres of cherry and apple orchards using pesticides, herbicides and manures to bear the fruits for our pleasures. Have you ever taken a moment to consider that the rainwater that fell maybe a mere hour ago is what you are drinking in your faucet? Karst features such as sinkholes, swallets (where a stream disappears into the bedrock) and collapse features are numerous throughout the area and are direct conduits for surface water to enter the aquifer with little or no filter from having the soils as a resource. So now I ask are you thirsty? :roll:

In conclusion, I hope you the folks of Wisconsin have a better understanding of not just the beauty that Karst regions provide for spectacular photographs but also the unfortunate fact that they are very fragile when it comes to our groundwater sheds. :P

[AJE]

Sinkhole warning signs
· Fresh exposures on fence posts, foundations and trees that result when the ground sinks
· Slumping, sagging or slanting fence posts, trees or other objects
· Doors and windows that fail to close properly
· Small ponds of rainfall forming where water has not collected before
· Wilting vegetation. This happens because the moisture that normally supports vegetation is draining into the sinkhole that is developing below the surface.
· Muddy water in nearby wells
· Cracks in walls, floors, pavement and in the ground

[AJE]

Geology or Geography Words of Interest and Definitions

KARST, also KARSTIC REGION—Limestone and dolomite areas with a topography peculiar to and dependent on underground solution and the diversion of surface waters to underground routes. Characteristic of an area of irregular limestone in which erosion has produced fissures, sinkholes, underground streams, and caverns. Also referred to as Karst Topography.

KARST HYDROLOGY—The branch of Hydrology that deals with the hydrology of geological formations having large underground passages or fractures which enable underground movement of large quantities of water.

:arrow: KARST TOPOGRAPHY—The structure of land surface resulting from limestone, dolomite, gypsum beds, and other rocks formed by dissolution and characterized by closed depressions, sinkholes, caves, and underground drainage. The result is a scenic landscape which is beautiful but fragile, and vulnerable to erosion and pollution.

KARSTIC RIVER—A river which originates from a karstic spring or flows in a Karstic Region.


1) Caribbean karst is found in relatively flat areas (e.g., Florida and Mexico's Yucatan Peninsula) and is characterized by sinkholes, sinkhole ponds, disappearing streams, crystal clear springs, and underground caverns that are often filled with water. In the Yucatan, where the the water table is relatively low, a large number of sinkhole ponds (known as cenotes in Mexico) with deep vertical cliffs and water at the bottom can be observed.

2) Temperate karst is found outside the tropics, especially in the mid-latitudes, in areas that generally receive less precipitation than Caribbean and tropical karst regions. Depending on relief, these areas may have similar topographic features as the other karst types, but often have underground features — especially elaborate networks of large and accessible caverns — that are more accentuated than their above ground features. Examples include Kentucky's Mammoth Caves and the karst region of Europe's Balkan Peninsula.

3) Tropical karst occurs in humid tropical regions with much topographic relief and is distinctly characterized by steep, rounded hills known as haystacks or mogotes (in parts of the Spanish-speaking Caribbean) and areas of "feral relief" (literally "relief gone wild") with steep, nearly vertical rock formations as seen in the Stone Forest of Yunnan, China. In addition to China, good examples of tropical karst can be seen in the Dominican Republic, Jamaica (especially well know for its "cockpit" country), and Puerto Rico.



Components of karst:

Springs: Natural resurgence, or discharge, of groundwater from rock or soil to the surface.

Caves: Natural cavities beneath the surface of the earth, created by groundwater dissolving rock.

Sinkholes: Rounded depressions in the landscape. Sinkholes are often collapsed caves and can be quite deep, or they can be shallow holes. Sinkholes collect surface water running off the surrounding land, and the runoff goes directly into the groundwater.

Losing Streams or swallets: Losing streams, or sinking streams, lose part or all of their flow to the groundwater system by suddenly disappearing underground. Bryant Creek is a losing stream, typical of the karst topography found in the Ozarks.

Natural bridges: Arches that are the remnants of collapsed caves, usually fairly short.

Seeps: Slow, small discharges of water from rock or soil to the surface.

[AJE]

Lake goes down the drain as sinkholes appear
Fish die, other wildlife scramble to survive in Fla.; one hole is 200 feet wide

LAKELAND, Fla. - Two giant sinkholes almost completely drained a lake, leaving dead fish rotting on oozing mud flats and alligators and snapping turtles fighting for their lives.

Scott Lake began draining last week, and the larger of the two sinkholes grew this week to at least 200 feet wide and 15 feet deep, claiming a dock, concrete walkway and chain-link fence.

“It’s heartbreaking,” said Linda Logan, a member of a local homeowners’ association.

The 291-acre natural lake is owned by the surrounding homeowners south of Lakeland, 30 miles east of Tampa. Residents formed a committee to figure out what to do.

The lake could be restored. If the sinkholes are filled in, rain and runoff would refill the lake, but that could take years, and experts say they would have to wait for the lake to finish draining first.

Sinkholes form when groundwater levels drop, leaving empty crevices and cavities in the limestone aquifer

[talleyJudy]

Thank You AJE for all that very interesting, informative information.

Being a resident of southern St. Croix County, I will now 'look' at our 580a. farm with new awareness.

Hubby and I often take 'scenic' drives' south along the Mississippi R. to just north of La Crosse, and then wend our way home on the back roads following ridge crests and valleys. We never tire of this scenery and always find something new. I will definately have him read this thread before our next "outing".

And yes, there are two places on our 120a. half of what we call "Yunkers Hill" that Hubby 'tiptoes' over because it's 'sinkey'. When planting corn he lifts the digger, waits for a hard freeze to combine and does that very early AM, and when baling hay does those spots first so the bail wagon is not heavey. On casual observation these 'spots' cannot be seen but he knows where they are and initially learned of them by 'the seat of his pants', litterally. :P

[talleyJudy]

Off Topic Post Script:

Did you know that on those scenic backroad drives at 15-35mph in a
2004 Chev Malibu you can get 35+ mpg!! 8) :wink: