Jefferson County, Kentucky

 

 

KARST GEOLOGY

 

The term "karst" refers to a landscape characterized by sinkholes, springs, sinking streams (streams that disappear underground), and underground drainage through solution-enlarged conduits or caves. Karst landscapes form when slightly acidic water from rain and snow-melt seeps through soil cover into fractured and soluble bedrock (usually limestone, dolomite, or gypsum). Sinkholes are depressions on the land surface where water drains underground. Usually circular and often funnel-shaped, they range in size from a few feet to hundreds of feet in diameter. Springs occur when water emerges from underground to become surface water. Caves are solution-enlarged fractures or conduits

large enough for a person to enter.

 

 

 

 

In metropolitan areas where residential construction is common, care must be taken to ensure that septic systems are correctly installed to avoid polluting local streams and groundwater. In Jefferson County, this involves recognition of quaternary sediments near the river and karst geology in the eastern and central part of the county.

 

 

WATER QUALITY

 

 

The Floyd’s Fork Creek drainage basin contains a mapped wetland area in east-central Jefferson County. Water-quality issues in the rural parts of Jefferson County differ from those in the metro-Louisville area because fertilizers and pesticides applied to crops, and nitrates from cattle operations can affect groundwater from domestic (private) water wells.

 

 

SOURCE-WATER PROTECTION AREAS

 

Source-water protection areas are those in which activities are likely to affect the quality of the drinking-water source. For more information, see kgsweb.uky.edu/download/water/swapp/swapp.htm.

 

 

CONSTRUCTION MATERIALS

 

 

The Kosmos Cement Plant was founded in 1905, and the nearby community of Kosmosdale (formerly Riverview) was named after the plant.  About 720,000 tons of cement are produced by the plant annually. 

 

 

RIVER TRAFFIC

 

 

River traffic influences land use in Jefferson County. Canals and locks were first built in 1830 to bypass the shallows created by bedrock geology at Falls of the Ohio. In the 1960’s, older dams were replaced with the McAlpine Locks and Dam. More than 50 million tons of commerce annually transit the locks. Photograph by Bart Davidson, Kentucky Geological Survey.

 

FLOODING

 

 

A 29-mile long system of flood walls, gates, pumping stations, and levees allows for multiple land uses in the Louisville-metro area. The flood walls were constructed following the 1937 flood when the river crested at 85.4 feet. Ohio River flood stage at McAlpine Dam is 55 feet and the flood walls that protect the city are constructed for a river height of 88.5 feet.  This gate and berm in the left photo are located near Kosmosdale.  The photos below show the flood of 1997 in Louisville. Photographs by Bart Davidson and Steve Greb, Kentucky Geological Survey.

 

 

          

 

 

 

 

Growth of the metropolitan Louisville area has been accompanied by alteration of the existing landscape. In this example, retaining walls have been built along a drainage area for flood control adjacent to extensive development. In metropolitan areas, care must be taken to maintain water quality and control storm-water runoff from surrounding parking lots. Photograph by Bart Davidson, Kentucky Geological Survey.

 

 

SLOPE STABILITY

 

 

Drainpipes and limestone riprap are used along the shale slopes of the Muldraugh Escarpment to help prevent water infiltration and subsequent slope instability onto the Gene Snyder expressway. Photograph by Bart Davidson, Kentucky Geological Survey.

 

 

 

EROSION CONTROL

 

 

During construction, erosion-control fences such as these may be needed to prevent silt from entering local streams. Photo by Bart Davidson, Kentucky Geological Survey.

 

 

Riprap drainage control and erosion protection. Photo by Stephen Greb, Kentucky Geological Survey.

 

 

POWER PRODUCTION

 

 

Large cities such as Louisville require great amounts of electricity. Louisville Gas and Electric’s Mill Creek Power Station on the Ohio River is a 1600 MW coal-fired plant. The flue-gas desulphurization unit at the plant produces half a million tons of gypsum annually as a by-product that is shipped by barge to a wallboard plant. Photograph by Bart Davidson, Kentucky Geological Survey.

 

 

 

 

A sister power station to Mill Creek, the Cane Run Power Station burns 1.3 million tons of coal per year, all shipped by rail. The plant produces gypsum as a by-product that must be disposed of in environmentally safe landfills. Photograph by Steve Greb, Kentucky Geological Survey.

              

 

 

GROUNDWATER

 

The alluvium along the Ohio River is the best source of groundwater in the county. Many properly constructed drilled wells will produce over 1,000 gallons per minute from the alluvium; most wells in alluvium will produce enough for a domestic supply at depths of less than 100 feet. In the main sections of the larger creek valleys, and on broad ridges in the central part of the county, most drilled wells will produce enough water for a domestic supply at depths of less than 100 feet. Some wells located in the smaller creek valleys and in some broad ridges in southwestern and central Jefferson County will produce enough water for a domestic supply, except during dry weather. In the upland areas of eastern Jefferson County, most drilled wells will not produce enough water for a dependable domestic supply, although some wells along drainage lines may meet domestic needs, except during dry weather.

 

Water is hard or very hard but otherwise of good quality. Groundwater in upland areas may contain salt or hydrogen sulfide, especially at depths greater than 100 feet.

 

For more information on groundwater in the county, see Carey and Stickney (2001).

 

 

POND CONSTRUCTION

 

 

Successful pond construction must prevent water from seeping through structured soils into limestone solution channels below. A compacted clay liner, or artificial liner, may prevent pond failure. Getting the basin filled with water as soon as possible after construction prevents drying and cracking, and possible leakage, of the clayey soil liner. Ponds constructed in dry weather are more apt to leak than ponds constructed in wet weather. Illustration by Paul Howell, U.S. Department of Agriculture--Natural Resource Conservation Service.

 

 

A pond liner consisting of clayey soil is placed in loose, moist layers and compacted with a sheepsfoot roller. A geotechnical engineer or geologist should be consulted about the requirements of a specific site. Other leakage prevention measures include synthetic liners, bentonite, and asphaltic emulsions. The U.S. Department of Agriculture--Natural Resources Conservation Service can provide guidance on the application of these liners to new construction, and for treatment of existing leaking ponds. Photograph by Paul Howell, U.S. Department of Agriculture--Natural Resources Conservation Service.

 

Dams should be constructed of compacted clayey soils at slopes flatter than 3 units horizontal to 1 unit vertical. Ponds with dam heights exceeding 25 feet, or pond volumes exceeding 50 acre-feet, require permits. Contact the Kentucky Division of Water, 14 Reilly Rd., Frankfort, KY 40601, telephone: 502.564.3410.

 

 

 

CITY OF LOUISVILLE

 

 

Situated on the Ohio River, Louisville is the county seat of Jefferson County, and was founded by George Rogers Clark in 1778.  Lewis and Clark’s Corps of Discovery to the American West began their voyage here, at the nearby Falls of the Ohio (which Louisville was known as during it’s early history).   Louisville is the 16th largest city in the United States. Photograph by Bart Davidson, Kentucky Geological Survey.