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SINKHOLES IN ALABAMA

 

In Alabama, the most common causes of land subsidence are the development of sinkholes in areas underlain by soluble carbonate rocks or ground collapse above abandoned mines. Many areas of the state, particularly north Alabama, are underlain by carbonate rocks, such as limestone, that are susceptible to dissolution and the formation of caves and sinkholes.

 

Thumbnail and link to help on what to do if you have a sinkhole.

I have a sinkhole! What do I do?!

 

 

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Click the above map to see details.

Sinkhole Data and Maps

 

To explore sinkholes in your area, refer to the interactive map below.  The points on this map represent topographic depression features on historical 1:24,000-scale topographic maps. While most of the topographic depressions are related to sinkholes, some may also be related to mine subsidence.

 

Because the topographic maps were published in the 1930s-1980s, more sinkholes may have developed since then. Please note that this interactive map is for educational use only and is not meant for use for site-specific evaluations. Click here for sinkhole GIS data and metadata associated with the interactive map below.

 

Not all web browsers or connection speeds support the below interactive map. If you do not see the map below, click here.  

 

 



 

 

 

 

 

EXAMPLES OF KARST IN ALABAMA

 

Newsome Sinks as seen on a topographic map.

Newsome Sinks area of Morgan County on the Newsome Sinks 1:24,000 quadrangle map overlain with 2006 aerial imagery.

Largest Karst Topographic Area in Alabama

 

The topography of northern Alabama is dappled with sinkholes, springs, and cave openings – all features of what is referred to as karst topography. Of particular interest is the Newsome Sinks area in Morgan County. This topography is comprised of coalescing sinkholes and represents the longest karst topographic feature in the state – a little over 4 miles long! This area is underlain by the Mississippian age Bangor Limestone.

 

Newsome Sinks area of Morgan County on a 1:100,000 topographic map overlain with geology. Blue areas are Bangor Limestone.

 

 

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The Newsome Sinks area and much of northeastern Alabama is part of the Tennessee-Alabama-Georgia karst area that cavers call TAG. Click here to see some amazing TAG photos and read a National Geographic article featuring this karst area.

 

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Largest Sinkhole in Alabama

 

The largest sinkhole in Alabama developed near Calera in Shelby County in December 1972 and has been called the “Golly Hole.” A local resident heard what sounded like trees crashing during the night. The following day, hunters in the area discovered a large sinkhole - about 325 feet long, 300 feet wide (roughly a football field length across!), and 120 feet deep. This sinkhole occurred during a drought when the water table was much lower than normal.

 

This particular area of Shelby County has had a history of sinkhole development and is underlain by soft limestones.  Previous research indicates hundreds of historical collapse features within a 16- square-mile area (Warren and Wielchowsky, 1973). Most of these historical and recent sinkholes are within the Dry Valley which is underlain with deeply weathered Cambrian dolomites of the Knox Group.

 

Aerial image and topographic map of the Golly Hole sinkhole.

Photo of the Golly Hole sinkhole.

The “Golly Hole” in Shelby County as shown on aerial imagery (left), the 1:24,000 Alabaster topographic map (middle), and photo from the ground (photo by Tom Stone).

 

To read more on the Golly Hole and its related geology, see the below references:

 

LaMoreaux, P.E. and Warren, W.M., 1973, Sinkhole: Geotimes. v. 18, no. 3, p. 15.

 

Warren, W.M. and Wielchowsky, C.C., 1973, Aerial remote sensing of carbonate terranes in Shelby County, Alabama: Groundwater, v. 11, no. 6, p. 14-26.

 

To download geology shapefiles for the Alabaster Quadrangle geologic map, click here.

 

 

 

 

 

 

SINKHOLES NEAR YOU – WHAT YOU SHOULD DO

 

 

A ground depression (like a sinkhole) can be caused by a variety of geologic and non-geologic issues including drainage, abandoned water wells, buried construction material, septic tank collapse, water or sewer line leaks, as well as other area-specific issues.

 

What to do or who to call may depend on the cause of the depression. Below are some actions to consider when dealing with a depression on your property:

 

1. Put up a barrier (caution tape, rope, other) surrounding the hole for safety and liability purposes.

 

2. Contact your property or homeowner's insurance company.

 

3. Consider contacting a geologist, geotechnical or civil engineer, or foundation repair specialist to assess the situation further.

 

4. If the sinkhole is affecting public safety or public property (parks/sidewalks/etc.) or may be related to city/county water/sewer drainage, consider contacting the city or county engineer's office. Please note response capabilities vary from county to county.

 

5. If the sinkhole is affecting a public road, contact the Department of Transportation.

 

 

 

    Photo of damage from a sinkhole in the Birmingham area.

 

Home affected by developing sinkhole in the Birmingham area.

 

 

 

* Due to budgetary and staffing constraints, GSA does not perform site visits to evaluate sinkholes. GSA also does not mitigate or repair sinkholes.

 

 

LEGAL ASPECTS OF SINKHOLES IN ALABAMA

 

Did you know that sinkholes are protected in Alabama? Because sinkholes are a direct conduit to the groundwater, any contaminants dumped into a sinkhole may end up in the groundwater. About 40% of public water supplies in Alabama are from ground-water sources and 27 south Alabama counties receive all of their public water supplies from ground-water sources. Since much of Alabama gets their water from groundwater resources, it is important to protect the groundwater quality, and therefore sinkholes too. The below information lists some of the regulations related to karst, caves, and sinkholes in the state of Alabama.

 

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Specifically, the Alabama Cave Protection Law of 1988 states that “It shall be unlawful and constitute a misdemeanor for any person, organization, firm, corporation, including any officer, employee or agent of any town or municipality to risk the pollution of the underground water resources of the state by storing, dumping, disposing, or otherwise placing in caves, sinkholes or natural wells: chemicals, refuse, dead animals, garbage or other materials which are potentially injurious or hazardous to the quality of the aquifer, water and/or water table.” Alabama Cave Protection Law (1988), (Acts 1988, No. 88-582, p. 909, §4.), Section 9-19-4. Click here to go to the Alabama Legislative Information System Online to read the full text.

 

Additional regulations from the Alabama State Board of Health’s Division of Community Environmental Protection relate to onsite sewage treatment and disposal with respect to sinkholes and planning:

Administrative Code Chapter 420-3-1.

 

 

 

 

 

 

 

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