Big Spring, Missouri --This spring produces an average flow of 276 million gallons of water per day and has had measured peak flows of 800 million gallons of water per day. It has been calculated that a daily average of 175 tons of calcium carbonate (CaCO3) is removed from underground in solution from Big Spring.* As a result, in one year the total volume of cave openings increases by 949,000 cubic feet. Dye trace studies show recharge areas for Big Spring may be tens of miles away and cross under existing surface drainages. Water from Big Spring flows into the Current River.

Part of the outflow of Alley Spring, Missouri (left). -- Scenic Alley Spring contributes an average of 81 million gallons per day of water to Jack's Fork in the Ozark National Scenic Riverways.**

Blue Spring, east of Eminence, Missouri (above). -- The outflow of Blue Spring is another major contributor of water to the Current River. The Indians called this "the spring of the summer sky". It is the deepest explored spring in Missouri. Divers have descended to a depth of 256 feet, virtually straight down. An average flow of 90 million gallons of water per day discharges from beneath a bluff of Eminence Dolomite.

Greer Spring, largest spring on U.S. Forest Service land, averages 187,000,000 gallons per day

** In the 1920's Josiah Bridge, a geologist mapping in the area, reported that Alley Spring ceased flowage and the water level dropped to 5 feet below the surface for 12 hours before a muddied flow resumed. This coincided with the collapse of a large sinkhole about 15 miles to the northwest. Presumably the collapse dammed the underground passageway feeding the spring.

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