Encore - Big Spring, Missouri

June 04, 2016


Today, and every Saturday Earth Science Picture of the Day invites you to rediscover favorites from the past. Saturday posts feature an EPOD that was chosen by viewers like you in our monthly Viewers' Choice polls. Join us as we look back at these intriguing and captivating images.

Photographer: Tommy Hornbeck
Summary Author: Tommy Hornbeck

The photos above show the morning sunlight sneaking over the horizon and under the tree canopy to illuminate the autumn colors and surging waters of Big Spring, Missouri. Big Spring has an average daily flow of 286 million gallons of water and is not only the largest spring in Missouri but also one of the three largest in the U.S. and one of the ten largest in the world. Water flowing from this spring eventually joins the Current River. The volume of water from the spring varies with local rainfall but can reach as much as a billion gallons each day! The "big" in Big Spring is no exaggeration. Using dye to test its flow characteristics, it was found that water emanating from the spring travels through underground passages from as far away as 45 mi (72 km) and takes as long as 14 days to reach the spring's mouth. As water leaves the spring, it carries between 70 and 150 tons of dissolved limestone each day. The beautiful blue color of the spring's water is attributed to the dissolved limestone. Archeological evidence suggests that the spring has been a gathering place for people for at least 10,000 years. Big Spring is now part of the Ozark National Scenic Riverways, managed by the National Park Service. Photos taken On October 14, 2010.

Photo Details: Nikon D-80 camera; 1/3 second exposure;  f/16; lens at 16 mm; ISO 100.