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Karst Terrain

There are no streams or creeks in Lewisburg. What happens to the stormwater after a heavy downpour? Can there be a flood in Lewisburg?

 

During the Carboniferous Period, a shallow sea covered much of what is now known as the Greenbrier Valley. 300 million years ago, Greenbrier limestone was formed from marine sediments in a layer up to 1000 feet thick. Because limestone is a carbonate rock, it can dissolve when groundwater becomes acidic due to dissolved carbon dioxide which forms a weak solution of carbonic acid. Cracks developed in the limestone and the acidic groundwater dissolved the limestone forming caverns and underground streams. Some of the caverns close to the surface collapsed and formed sinkholes along the underground streams. This type of terrain is known as Karst Topography. It is characterized by outcroppings of limestone rock, depressions and sinkholes, and springs. Throughout the Greenbrier Valley, there are many caves and caverns, sinkholes, and a number of underground streams coming to the surface as springs.

 

There are several springs and sinkholes in Lewisburg including those at Montwell Commons. The Andrew Lewis Spring is across the street from Hill and Holler and the Beirne Spring is on the hillside above the end of Lafayette Street. The water from these two springs flows down to the large sinkhole by the Meadows at Montwell Commons. Because of these springs and sinkhole, several industries were established there in the 19th century including a cannery, a creamery, and two tanneries. Information about these and additional businesses can be found under the “Industrial History” menu tab.

 

During heavy rainstorms, stormwater from several hundred acres of downtown Lewisburg and surrounding neighborhoods runs downhill and disappears into this sinkhole. Consequently, any pollutants such as oil from roads and parking lots are picked up by the stormwater and rapidly carried to the Greenbrier River. Aquifers in karst terrain are very susceptible to pollution because the limestone rock is relatively porous. Contaminants in the stormwater recharges the aquifer without being filtered by the soil, metabolized by bacteria, or taken up by vegetation

 

If there is too much stormwater for the sinkhole to carry away, flooding of the Meadow area occurs. There is an interesting account of such a flood in February 1890. Geologists have discovered that water flowing into this sinkhole runs underground for about 7 miles through caves and channels known as the Lewisburg Sink and emerges at the Davis Spring near Fort Spring along with five other underground streams. The spring is situated at the base of Muddy Creek Mountain next to Rt. 63 and flows a short distance to the Greenbrier River.

        Sinkhole Inlet

     Davis Spring