VARIABILITY OF KARST SPRING SEDIMENTS WITHIN AND BETWEEN STORM WATERS

Storm sediments from a karst spring were analyzed to determine whether sediment morphology varied within a storm and among storms from different seasons. Storm data was collected from the Bushkill Spring in southeastern Pennsylvania by an automatic sampler that was triggered by the level of the storm water. Samples were collected from storms in March, May, October, and November. Storm water was filtered to remove all sediments larger than 5 micrometers and these sediments were then analyzed using a 40X magnification microscope. The sediments from these four storms were analyzed for their size, angularity, mineralogy, and plant/organic material.

Sediments during an individual storm changed very little morphologically. Changes observed within a storm included minor increases of plant/organic material, grains coarsened or fined, and roundness or angularity increases or decreases. The analysis of sediments between storms showed that storm sediments vary from season to season. The March and November storms had plant material while the May and October storms had sediment only. The May sediment was more uniform in its morphology throughout that storm, while the October storm was more variable with a mix of round and angular grains and darker mineral composition. Mineralogy of the samples will be analyzed to determine any further variability of storm sediments. The variability of sediments within storms is much less than that of sediment variability between storms.