Big Spring sits in Southeast Dallas County Texas in the neighborhood of Pleasant Grove and the subsection of an area called Pemberton Hill, south of US 175 and west of Pemberton Hill Road Dallas, Texas 75217.
One of the only natural spring sites left in Dallas, Big Spring maintains a steady temperature and predictable flow year round with crystal clear and clean water. It discharges over twelve millions of clean water into the Trinity River watershed annually. With an average ph of 6.7, mineral rich and low dissolved oxygen content the water points to an aquifer not of modern origins. Carbon dating in 2013 resulted in a sample dating to 590 +/- 30 BP(1360 AD).
The outfall of Big Spring reaches a first-order stream named Bryan’s Slough (Oak Creek) which empties into White Rock Creek and eventually the Trinity River some one mile distant. At roughly 405 feet above sea level, the spring sits upon a slope that modern geology calls the Trinity Terrace. The Trinity Terrace is a series of orange and brown-yellow Pleistocene gravel deposits a top a layer of Austin Chalk, a cretaceous age limestone common to Dallas County. The Pleistocene is the geological epoch which lasted from about 2.5 million to 11,000 years ago, spanning the world’s recent period of repeated glaciations. Coupled with much wetter weather than today, the Trinity River was vastly larger, carrying large loads of sediment across a valley that extended from Fair Park on the north bank to the Dallas Zoo on the south.
It is believed that the porous Trinity Terrace gravels serve as the aquifer bearing strata from which Big Spring is supplied. This gravel also produces many fossils from the Pleistocene Megafauna with many museum quality specimens excavated on nearby properties.