Big Spring, dye tracing, Galena Dolomite, groundwater tracing, karst, sinkholes
A large naturally flowing spring emitting from the Galena Dolomite Formation in the valley wall of the Turkey River, 8 km northwest of Elkader, is the source of water supply for Big Spring Trout Hatchery. Precipitation in northern Clayton County infiltrating the bedrock and moving laterally along crevices and cavities in the dolomite rock is the principal recharge source for the spring. Numerous sinkholes as far as 13.9 km to the north and northeast capture surface runoff and funnel water to the spring. Chemical dyes and plastic spheres were used to trace the groundwater movement from the sinkholes to the trout hatchery. The dye tracers also helped to establish a general groundwater basin boundary for Big Spring. The travel time of the dye tracers varied from 24 to 144 hours and was related to the quantity of water entering the sinks immediately before and after introduction of the dye. All sinkholes were mapped to aid in any future plans to control the amount of soil and other contaminants entering the aquifer.
Proceedings of the Iowa Academy of Science
© Copyright 1980 by the Iowa Academy of Science, Inc.
"Water Source of Big Spring Trout Hatchery, Clayton County, Iowa,"
Proceedings of the Iowa Academy of Science: Vol. 87:
, Article 10.
Available at: http://scholarworks.uni.edu/pias/vol87/iss4/10